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Journal articles on the topic 'Fishes Fish stock assessment'
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1
Saul, Steven, Elizabeth N. Brooks, and David Die. "How fisher behavior can bias stock assessment: insights from an agent-based modeling approach." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 11 (November 2020): 1794–809. http://dx.doi.org/10.1139/cjfas-2019-0025.
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During stock assessment, fishery-dependent observations are often used to develop indices of abundance or biomass from catch per unit of effort (CPUE) and contribute catch at size or age information. However, fisher behavior, rather than scientific sampling protocols, determines the spatial and temporal locations of fishery-dependent observations. As a result, trends from fishery-dependent data may be a function of fishing activity rather than fish population changes. This study evaluates whether data collected from commercial fishing fleets in the Gulf of Mexico are representative of trends in fish population size. A coupled bioeconomic agent-based model was developed to generate simulated fishery data, which were used to populate an age-structured stock assessment. Comparison of stock assessment results with simulated fish population dynamics showed that management advice from assessment models based on fishery-dependent data could be biased. Assessment of fish with small home ranges harvested by fishing fleets that frequent the same fishing grounds could cause overestimation of fishing mortality. Not accounting for the spatial structure of the fishers or fish can cause biased estimates of population status.
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Alós, Josep, Andrea Campos-Candela, and Robert Arlinghaus. "A modelling approach to evaluate the impact of fish spatial behavioural types on fisheries stock assessment." ICES Journal of Marine Science 76, no. 2 (November 27, 2018): 489–500. http://dx.doi.org/10.1093/icesjms/fsy172.
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Abstract Spatial behavioural types (SBTs) arise from between-individual differences in behavioural traits that foster spatial behavioural patterns that are consistent over time and ecological contexts. Fish stocks are regularly assessed using catch per unit effort (CPUE) as input data that may non-linearly co-vary with the underlying abundance (N) of the exploited stock when SBT affect catchability. We hypothesized that SBT promote characteristic changes in catchability within harvesting seasons that affect catch rates and in turn catch-based fish stock assessments. To test this hypothesis, we developed a spatially explicit agent-based simulation where we measured encounters between fish and fishers and estimated the shape of the CPUE–N relationship. We ran the simulation in a prototypical fish–fisher encounter-leads-to-catch-type fishery and systematically studied outcomes in the presence or absence of SBTs. It was revealed that the existence of SBTs leads to CPUE inevitably declining faster than N (a process known as hyperdepletion) when compared with a simulation lacking SBTs. This finding was consistent in a wide range of fishing effort scenarios. The emergent hyperdepletion of catch rates was caused by fast and behavioural-selective exploitation of vulnerable SBT that encompassed the mobile component of the fish stock. The theoretical predictions received support from field data from a coastal recreational fishery. Our work suggests that the consideration of SBT when interpreting trends in CPUE data may notably improve stock assessments by providing a more reliable CPUE–N relationship.
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Chavez, Rosa A., Isabel M. Valdivia, and Marcelo E. Oliva. "Local variability in metazoan parasites of the pelagic fish species, Engraulis ringens: implications for fish stock assessment using parasites as biological tags." Journal of Helminthology 81, no. 2 (June 2007): 113–16. http://dx.doi.org/10.1017/s0022149x07726573.
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AbstractParasites have been used successfully as biological tags in population studies, mainly in marine fishes, but also in marine mammals, crustaceans and molluscs. Almost all published information dealing with parasites as biological tags evaluates differences between localities. However, local variability in the component community has not been assessed. In this work, we examined whether local variation of the metazoan parasite fauna of Engraulis ringens, extracted from five independent samples from two nearby localities in northern Chile, can be a factor causing bias in stock identification. Our results show that local variability, as estimated by a single sample, may suffice to represent component community variability with no need for replicated data.
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Schweder, Tore. "Integrative fish stock assessment by frequentist methods: confidence distributions and likelihoods for bowhead whales." Scientia Marina 67, S1 (April 30, 2003): 89–97. http://dx.doi.org/10.3989/scimar.2003.67s189.
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Kuznetsov, Mikhail Yu, and Yury A. Kuznetsov. "Hydroacoustic methods and tools for fish stock assessment and fishery maintenance Part 2. Methods and tools of fishery biohydroacoustics." Izvestiya TINRO 184, no. 1 (March 30, 2016): 264–94. http://dx.doi.org/10.26428/1606-9919-2016-184-264-294.
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Studies on influence of hydroacoustic fields on behaviour of commercial species and using of hydroacoustic tools for management of fish and squids behavior to increase the fishing efficiency are overviewed. The methods and means of fisheries biohydroacoustics are considered critically and the reasons of their unsatisfactory using in fishery are analyzed. Sounds with a certain spectrum and level are still applied for influence on fish behaviour without sufficient scientific and technical substantiation, so a complex approach to development of effective hydroacoustic tools for remote control of fish movement is necessary. Results of studies on acoustic reception and acoustic activity for schooling physostomous fishes are presented. Spectral-power and temporal parameters of the sounds and their frequency differentiation by fish size are determined. Sound-generating mechanisms of fish are considered and signal significances of the sounds radiated by fish are recognized. Stereotypes of acoustic behaviour are revealed for toothed whales during their hunting upon fish: these predatory cetaceans have special acoustic manipulators able to generate signals for concentration and holding the fish, adapted for hearing system of the prey. Results of hydrobionic modelling of organs and mechanisms for sound generation of marine animals and their technical realization in hydroacoustic devices are presented. The developed devices allow to generate underwater pulse sound signals simulating biological signals of certain physostomous fish species and predatory cetaceans (dolphins and killer whales). Efficiency of these simulating signals influence on behaviour of fish is proved by behavioral experiments and fishing tests. Applications of these devices for various fisheries are discussed.
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McGilliard, Carey R., André E. Punt, Richard D. Methot, and Ray Hilborn. "Accounting for marine reserves using spatial stock assessments." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 2 (February 2015): 262–80. http://dx.doi.org/10.1139/cjfas-2013-0364.
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Some fish stock assessments are conducted in regions that contain no-take marine reserves (NTMRs). NTMRs are expected to lead to spatial heterogeneity in fish biomass by allowing a buildup of biomass inside their borders while fishing pressure occurs outside. Stock assessments do not typically account for spatial heterogeneity caused by NTMRs, which may lead to biased estimates of biomass. Simulation modeling is used to analyze the ability of several stock assessment configurations to estimate current biomass after the implementation of a single, large NTMR. Age-structured spatial operating models with three patterns of ontogenetic movement are used to represent the “true” population dynamics. Results show that assessing populations as a single stock with use of fishery catch-rate data and without accounting for the NTMR results in severe underestimation of biomass for two of the movement patterns. Omitting fishery catch-rate data or allowing time-varying dome-shaped selectivity after NTMR implementation leads to improved estimates of current biomass, but severe bias in estimated trends in biomass over time. Performing separate assessments for fished areas and NTMRs leads to improved estimation performance in the absence of movement among assessment areas, but can severely overestimate biomass otherwise. Performing a spatial assessment with estimation of movement parameters among areas was found to be the best way to assess a species, even when movement patterns were unknown. However, future work should explore the performance of spatial assessments when catchability varies among areas.
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Al-Mamun, Md Abdullah, Qun Liu, Sayedur Rahman Chowdhury, Md Sharif Uddin, K. M. Shahriar Nazrul, and Rokeya Sultana. "Stock Assessment for Seven Fish Species Using the LBB Method from the Northeastern Tip of the Bay of Bengal, Bangladesh." Sustainability 13, no. 3 (February 2, 2021): 1561. http://dx.doi.org/10.3390/su13031561.
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Assessment of fish stock status is generally required for fisheries management, which is difficult when the data are limited. The length-based Bayesian Biomass (LBB) approach is a powerful and new method, where only the length-frequency data are used for estimating the status of fisheries resources. Here, we applied the LBB method to assess the status of seven commercially valuable marine fishes from the northern tip of the Bay of Bengal (BoB), Bangladesh. These species were Lepturacanthus savala, Pampus argenteus, Nemipterus japonicas, Nemipterus randalli, Ilisha filigera, Saurida tumbil, and Upeneus sulphurous. The current relative biomass (B/B0) ratios were smaller than the BMSY/B0 in five stocks, except for N. japonicas and N. randalli, and this indicates that, of the seven populations assessed, two are grossly overfished, three are overfished, and two are healthy stocks. Moreover, the length at first capture (Lc) was lower than the optimal length at first capture (Lc_opt) in all seven populations, which indicates growth overfishing, suggesting that increasing the mesh sizes would be beneficial. The present findings confirm that Bangladesh’s coastal water fishery resources are declining. More specific targeted management measures should be taken to recover the country’s marine fishery resources.
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Simpfendorfer, Colin, and Kevin Donohue. "Keeping the fish in ‘fish and chips’: research and management of the Western Australian shark fishery." Marine and Freshwater Research 49, no. 7 (1998): 593. http://dx.doi.org/10.1071/mf97043.
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The shark fishery in the southern half of Western Australia fishery began in 1941 and developed slowly until the mid 1970s when the fishery began to expand rapidly. A management plan incorporating limited entry, gear specifications and effort controls was introduced in 1988 in response to concerns about the status of the stocks. Research has focused on the assessment of stocks, and has involved the collection of catch-and-effort data since 1975, and tactical research projects to gather data on biology; this has allowed the implementation of stock assessment, modelling and forecasting techniques. The fishing industry is involved in the development of the research projects and in the decision-making process of management. This, together with regular reporting of research results, assists in maintaining industry support and acceptance of results. A potential disadvantage of the involvement of industry is the delay in implementation that may be caused by the complexity of the system of consultation or by the conflict between regulation of the fishery and the present livelihood of fishers. However, this is minimized by the creation of clear quantitative targets for management.
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Pinto, Cecilia, Morgane Travers-Trolet, Jed I. Macdonald, Etienne Rivot, and Youen Vermard. "Combining multiple data sets to unravel the spatiotemporal dynamics of a data-limited fish stock." Canadian Journal of Fisheries and Aquatic Sciences 76, no. 8 (August 2019): 1338–49. http://dx.doi.org/10.1139/cjfas-2018-0149.
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The biological status of many commercially exploited fishes remains unknown, mostly due to a lack of data necessary for their assessment. Investigating the spatiotemporal dynamics of such species can lead to new insights into population processes and foster a path towards improved spatial management decisions. Here, we focused on striped red mullet (Mullus surmuletus), a widespread yet data-limited species of high commercial importance. Aiming to quantify range dynamics in this data-poor scenario, we combined fishery-dependent and -independent data sets through a series of Bayesian mixed-effects models designed to capture monthly and seasonal occurrence patterns near the species’ northern range limit across 20 years. Combining multiple data sets allowed us to cover the entire distribution of the northern population of M. surmuletus, exploring dynamics at different spatiotemporal scales and identifying key environmental drivers (i.e., sea surface temperature, salinity) that shape occurrence patterns. Our results demonstrate that even when process and (or) observation uncertainty is high, or when data are sparse, if we combine multiple data sets within a hierarchical modelling framework, accurate and useful spatial predictions can still be made.
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Demer, David A., Juan P. Zwolinski, George R. Cutter, Kyle A. Byers, Beverly J. Macewicz, and Kevin T. Hill. "Sampling selectivity in acoustic-trawl surveys of Pacific sardine (Sardinops sagax) biomass and length distribution†." ICES Journal of Marine Science 70, no. 7 (August 19, 2013): 1369–77. http://dx.doi.org/10.1093/icesjms/fst116.
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Abstract Demer, D. A., Zwolinski, J. P., Cutter, G. R. Jr, Byers, K. A., Macewicz, B. J., and Hill, K. T. Sampling selectivity in acoustic-trawl surveys of Pacific sardine (Sardinops sagax) biomass and length distribution. – ICES Journal of Marine Science, 70: . To annually assess the northern stock of Pacific sardine (Sardinops sagax) in the California Current and set harvest quotas for the US fishery, managers have used an age-structured stock synthesis model fitted with results from acoustic-trawl (ATM), daily-egg-production, and aerial-photogrammetric survey methods, fishery landing and individual-length data, and many assumed or empirically derived parameters. In these assessments, sardine landed at ports spanning from Ensenada, México to Vancouver Island, Canada were assumed to be solely from the northern stock. It was also assumed that the ATM estimates of sardine biomass were negligibly biased for the sizes of fish sampled by the survey trawls (i.e., catchability q = 1 for sardine standard length (SL) values greater than ∼17 cm). Due to these catchability and length-selectivity assumptions, the ATM- and assessment-estimated abundances are mostly similar for larger sardine. However, the assessment estimates include large abundances of small sardine (SL values less than ∼15 cm) that are not represented in either the ATM-survey results or the fishery landings, and generally did not recruit to the migrating northern stock sampled by the ATM surveys. We considered four explanations for this disparity: (i) the ATM length-selectivity assumption is correct; (ii) the non-recruiting small fish may comprise a smaller portion of the stock than indicated by the assessments; (iii) during years of low recruitment success, those size classes may be virtually completely fished by the Ensenada and San Pedro fisheries; or (iv) they may belong to the southern sardine stock. This investigation emphasizes the previously identified importance of differentiating samples from the northern and southern stocks and surveying their entire domains.
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Thorson, James T., Olaf P. Jensen, and Ray Hilborn. "Probability of stochastic depletion: an easily interpreted diagnostic for stock assessment modelling and fisheries management." ICES Journal of Marine Science 72, no. 2 (July 24, 2014): 428–35. http://dx.doi.org/10.1093/icesjms/fsu127.
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Abstract Marine fish populations have high variation in cohort strength, and the production of juveniles (recruitment) may have persistent positive or negative residuals (autocorrelation) after accounting for spawning biomass. Autocorrelated recruitment will occur whenever average recruitment levels change between oceanographic regimes or due to predator release, but may also indicate persistent environmental and biological effects on shorter time-scales. Here, we use estimates of recruitment variability and autocorrelation to simulate the stationary distribution of spawning biomass for 100 real-world stocks when unfished, fished at FMSY, or fished following a harvest control rule where fishing mortality decreases as a function of spawning biomass. Results show that unfished stocks have spawning biomass (SB) below its deterministic equilibrium value (SB0) 58% of the time, and below 0.5SB0 5% of the time on average across all stocks. Similarly, stocks fished at the level producing deterministic maximum sustainable yield (FMSY) are below its deterministic prediction of spawning biomass (SBMSY) 60% of the time and below 0.5SBMSY 8% of the time. These probabilities are greater for stocks with high recruitment variability, positive autocorrelation, and high natural mortality—traits that are particularly associated with clupeids and scombrids. An elevated probability of stochastic depletion, i.e. biomass below the deterministic equilibrium expectation, implies that management actions required when biomass drops below a threshold may be triggered more frequently than expected. Therefore, we conclude by suggesting that fisheries scientists routinely calculate these probabilities during stock assessments as a decision support tool for fisheries managers.
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Fischer, Jesse R., and Michael C. Quist. "Gear and Seasonal Bias Associated with Abundance and Size Structure Estimates for Lentic Freshwater Fishes." Journal of Fish and Wildlife Management 5, no. 2 (July 1, 2014): 394–412. http://dx.doi.org/10.3996/082013-jfwm-054.
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Abstract All freshwater fish sampling methods are biased toward particular species, sizes, and sexes and are further influenced by season, habitat, and fish behavior changes over time. However, little is known about gear-specific biases for many common fish species because few multiple-gear comparison studies exist that have incorporated seasonal dynamics. We sampled six lakes and impoundments representing a diversity of trophic and physical conditions in Iowa, USA, using multiple gear types (i.e., standard modified fyke net, mini-modified fyke net, sinking experimental gill net, bag seine, benthic trawl, boat-mounted electrofisher used diurnally and nocturnally) to determine the influence of sampling methodology and season on fisheries assessments. Specifically, we describe the influence of season on catch per unit effort, proportional size distribution, and the number of samples required to obtain 125 stock-length individuals for 12 species of recreational and ecological importance. Mean catch per unit effort generally peaked in the spring and fall as a result of increased sampling effectiveness in shallow areas and seasonal changes in habitat use (e.g., movement offshore during summer). Mean proportional size distribution decreased from spring to fall for white bass Morone chrysops, largemouth bass Micropterus salmoides, bluegill Lepomis macrochirus, and black crappie Pomoxis nigromaculatus, suggesting selectivity for large and presumably sexually mature individuals in the spring and summer. Overall, the mean number of samples required to sample 125 stock-length individuals was minimized in the fall with sinking experimental gill nets, a boat-mounted electrofisher used at night, and standard modified nets for 11 of the 12 species evaluated. Our results provide fisheries scientists with relative comparisons between several recommended standard sampling methods and illustrate the effects of seasonal variation on estimates of population indices that will be critical to the future development of standardized sampling methods for freshwater fish in lentic ecosystems.
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Human, Brett A., and Haithem Al-Busaidi. "Length and Weight Relationships for 31 Species of Fishes Caught by Trawl Off the Arabian Sea Coast of Oman." Journal of Agricultural and Marine Sciences [JAMS] 13 (January 1, 2008): 43. http://dx.doi.org/10.24200/jams.vol13iss0pp43-52.
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Length and weight measurement for 31f ish species encountered in the Arabian Sea , o f f t h e Oma n Coast, were collected by demersal trawling during March 2007 and March 2008. A total of 3,261 specimens were measured for total length, or fork length, where appropriate, and green weight. Several commonly caught commercial species undergo onboard processing (dressing) prior to packaging, and dressed weight to green weight regressions and conversion factors were calculated for 12 of these species. The relationships obtained in this study were compared with those of other studies for the same fish species. These data are fundamental to understanding the biological parameters of fishes, and can be applied to fisheries stock assessment and management models.
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Bolser, Derek G., Arnaud Grüss, Mark A. Lopez, Erin M. Reed, Ismael Mascareñas-Osorio, and Brad E. Erisman. "The influence of sample distribution on growth model output for a highly-exploited marine fish, the Gulf Corvina (Cynoscion othonopterus)." PeerJ 6 (September 17, 2018): e5582. http://dx.doi.org/10.7717/peerj.5582.
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Estimating the growth of fishes is critical to understanding their life history and conducting fisheries assessments. It is imperative to sufficiently sample each size and age class of fishes to construct models that accurately reflect biological growth patterns, but this may be a challenging endeavor for highly-exploited species in which older fish are rare. Here, we use the Gulf Corvina (Cynoscion othonopterus), a vulnerable marine fish that has been persistently overfished for two decades, as a model species to compare the performance of several growth models. We fit the von Bertalanffy, Gompertz, logistic, Schnute, and Schnute–Richards growth models to length-at-age data by nonlinear least squares regression and used simple indicators to reveal biased data and ensure our results were biologically feasible. We then explored the consequences of selecting a biased growth model with a per-recruit model that estimated female spawning-stock-biomass-per-recruit and yield-per-recruit. Based on statistics alone, we found that the Schnute–Richards model described our data best. However, it was evident that our data were biased by a bimodal distribution of samples and underrepresentation of large, old individuals, and we found the Schnute–Richards model output to be biologically implausible. By simulating an equal distribution of samples across all age classes, we found that sample distribution distinctly influenced model output for all growth models tested. Consequently, we determined that the growth pattern of the Gulf Corvina was best described by the von Bertalanffy growth model, which was the most robust to biased data, comparable across studies, and statistically comparable to the Schnute–Richards model. Growth model selection had important consequences for assessment, as the per-recruit model employing the Schnute–Richards model fit to raw data predicted the stock to be in a much healthier state than per-recruit models employing other growth models. Our results serve as a reminder of the importance of complete sampling of all size and age classes when possible and transparent identification of biased data when complete sampling is not possible.
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Caraguel, Jean-Marie, Thomas Barreau, Sarah Brown-Vuillemin, and Samuel P. Iglésias. "In vivo staining with alizarin for ageing studies on chondrichthyan fishes." Aquatic Living Resources 33 (2020): 1. http://dx.doi.org/10.1051/alr/2020002.
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Age determination for stock assessments and conservation of cartilaginous fishes is mainly obtained by counting the annual growth bands in vertebrae. Recent studies show numerous inconsistencies and the need for systematic validation. We assessed the effectiveness of the fluorochrome alizarin red S, a common skeleton vital marker used as a time stamp for teleost fishes, on chondrichthyan. Twenty-five captive small-spotted catsharks (Scyliorhinus canicula) were marked by alizarin red S intraperitoneal injections. The fluorochrome produced a wide fluorescent mark on sectioned vertebral centra of all injected fish. Alizarin red S did not have a deleterious effect on growth during three months monitoring. The marks obtained remained stable in vivo for more than four years after injections and were resistant to fading during the observation under the microscope excitation light. Our results suggest that alizarin red S is an effective tool for long time vital marking of chondrichthyans.
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Orio, Alessandro, Ann-Britt Florin, Ulf Bergström, Ivo Šics, Tatjana Baranova, and Michele Casini. "Modelling indices of abundance and size-based indicators of cod and flounder stocks in the Baltic Sea using newly standardized trawl survey data." ICES Journal of Marine Science 74, no. 5 (February 7, 2017): 1322–33. http://dx.doi.org/10.1093/icesjms/fsx005.
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Standardized indices of abundance and size-based indicators are of extreme importance for monitoring fish population status. The main objectives of the current study were to (i) combine and standardize recently performed trawl survey with historical ones, (ii) explore and discuss the trends in abundance, and (iii) the trends in maximum length (Lmax) for cod (Gadus morhua) and flounder (Platichthys flesus) stocks in the Baltic Sea. Standardization of catch per unit of effort (CPUE) from trawl surveys from 1978 to 2014 to swept area per unit of time was conducted using information on trawling speed and horizontal opening of the trawls. CPUE data for cod and flounder stocks were modelled using generalized additive models (GAMs) in a delta modelling approach framework, while the Lmax data were modelled using ordinary GAMs. The CPUE time series of the Eastern Baltic cod stock closely resembles the spawning stock biomass trend from analytical stock assessment. The results obtained furnish evidence of the cod spill-over from Subdivisions (SD) 25–28 to SD 24. The decline of Lmax in recent years was evident for both species in all the stocks analysed indicating that the demersal fish community is becoming progressively dominated by small individuals. It is concluded that the standardization of long time series of fisheries-independent data constitutes a powerful tool that could help improve our knowledge on the dynamics of fished populations, thus promoting a long-term sustainable use of these marine resources.
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Sigler, Mike, Doug DeMaster, Peter Boveng, Michael Cameron, Erin Moreland, Kresimir Williams, and Rick Towler. "Advances in Methods for Marine Mammal and Fish Stock Assessments: Thermal Imagery and CamTrawl." Marine Technology Society Journal 49, no. 2 (March 1, 2015): 99–106. http://dx.doi.org/10.4031/mtsj.49.2.10.
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AbstractNational Oceanic and Atmospheric Administration (NOAA) has adopted an integrated ecosystem research approach to understand climate effects on fish, seabirds, and marine mammals in the Arctic. The integrated ecosystem approach combines traditional oceanography, fisheries, and mammal research techniques to improve scientific understanding of how ecosystems function as a whole. Innovative technologies are being developed to aid in this effort. Two new technologies that NOAA deploys in the Arctic are an advanced thermal imaging technology used to survey ice seal abundance and a high-resolution, nonlethal technology, which integrates cameras and trawls to sample pelagic fishes (CamTrawl). The ice seal surveys relied on thermal imagery to detect warm seal bodies hauled out on cold sea ice. Compared to observer-based surveys, thermal detection surveys require fewer personnel and less postsurvey processing time, can be flown at a higher altitude (reducing disturbance of seals), and yield higher rates of seal detection. The CamTrawl is a self-contained stereo-camera system fitted to the aft end of a trawl at the cod end (i.e., capture bag), which can be left open. By integrating a camera system in the aft portion of a trawl, the CamTrawl concentrates marine organisms and presents this captive group to the cameras without having to recover them for onboard counting, as is done in traditional trawl tows. Compared to traditional survey methods, the CamTrawl more precisely places marine organisms spatially in their environment, which is useful because of small-scale variation in the composition and distribution of fish schools.
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Baelde, Pascale. "Fishers' description of changes in fishing gear and fishing practices in the Australian South East Trawl Fishery." Marine and Freshwater Research 52, no. 4 (2001): 411. http://dx.doi.org/10.1071/mf99149.
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Between the mid 1980s and early 1990s, the concurrence of three major events significantly altered the structure and dynamics of the demersal trawl sector in the Australian South-East Fishery (SEF). These events included marked technological improvement, severe decline of major fish stocks and introduction of an Individual Transferable Quota system. They have led to a switch from maximizing catch volume to maximizing catch composition and quotas, with important associated changes in fishing practices and catches. To better understand these changes and their effect on stock assessment and management, an industry survey asked SEF trawl fishers to describe their fishing gear and fishing practices in detail. This paper is a qualitative synthesis of current trends in fishing that most significantly affect the single-species, logbook-dependent assessment and management of the fishery. It demonstrates how effective collaboration between scientists and fishers can benefit fisheries research and management, by helping scientists make more informed analysis and interpretations of fisheries data.
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Hoff, Ayoe, Hans Frost, Clara Ulrich, Dimitrios Damalas, Christos D. Maravelias, Leyre Goti, and Marina Santurtún. "Economic effort management in multispecies fisheries: the FcubEcon model." ICES Journal of Marine Science 67, no. 8 (June 21, 2010): 1802–10. http://dx.doi.org/10.1093/icesjms/fsq076.
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Abstract Hoff, A., Frost, H., Ulrich, C., Damalas, D., Maravelias, C. D., Goti, L., and Santurtún, M. 2010. Economic effort management in multispecies fisheries: the FcubEcon model. – ICES Journal of Marine Science, 67: 1802–1810. Applying single-species assessment and quotas in multispecies fisheries can lead to overfishing or quota underutilization, because advice can be conflicting when different stocks are caught within the same fishery. During the past decade, increased focus on this issue has resulted in the development of management tools based on fleets, fisheries, and areas, rather than on unit fish stocks. A natural consequence of this has been to consider effort rather than quota management, a final effort decision being based on fleet-harvest potential and fish-stock-preservation considerations. Effort allocation between fleets should not be based on biological considerations alone, but also on the economic behaviour of fishers, because fisheries management has a significant impact on human behaviour as well as on ecosystem development. The FcubEcon management framework for effort allocation between fleets and fisheries is presented, based on the economic optimization of a fishery's earnings while complying with stock-preservation criteria. Through case studies of two European fisheries, it is shown how fishery earnings can be increased significantly by reallocating effort between fisheries in an economically optimal manner, in both effort-management and single-quota management settings.
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Blanco, G., Y. J. Borrell, M. E. Cagigas, E. Vázquez, and J. A. Sánchez Prado. "Microsatellites-based genetic analysis of the Lophiidae fish in Europe." Marine and Freshwater Research 59, no. 10 (2008): 865. http://dx.doi.org/10.1071/mf08038.
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The anglerfish species Lophius piscatorius and Lophius budegassa are among the most valuable fishes sought after by bottom fisheries in western and southern European waters. It is currently believed that there are two stocks for each of the two species, north and south, which determine their assessment and management. A genetic analysis using eight polymorphic microsatellite markers was carried out on samples collected from western European waters and the south-western Mediterranean Sea. The results strongly suggest that the boundary between northern and southern stocks is not genetically supported. However, populations were not genetically homogeneous. Besides a pattern of genetic differentiation between Mediterranean and the rest of the samples, the L. budegassa samples taken from the Spain Atlantic zone and from the Portugal Atlantic zone were genetically distinct, whereas the samples taken in the French Atlantic zone for the L. piscatorius species seem to be different from the rest of the samples under study. This can be indicative of a more subtle genetic structure that deserves more study for guaranteeing adequate fishery management of these species.
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Mohamed, Abdul-Razak M., and Ali H. Al-Hassani. "Growth, mortality and stock assessment of greenback mullet, Planiliza subviridis from northwest Arabian Gulf, Iraq." Archives of Agriculture and Environmental Science 6, no. 2 (June 25, 2021): 142–48. http://dx.doi.org/10.26832/24566632.2021.060205.
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The growth, mortality and stock parameters of greenback mullet, Planiliza subviridis from Iraqi marine waters, northwest Arabian Gulf was assessed using FiSAT II software for length-frequency data collected from February 2020 to January 2021. P. subviridis is one of the species caught in large quantities as commercial by artisanal fishers. Fish samples were collected by the Shaheen steel-hulled dhow and from the artisanal fishermen. The total length and body weight relationship of fish was estimated as W= 0.034L2.670, indicating negative allometric growth. Of 3350 specimens, growth and mortality parameters were evaluated. The asymptotic length (L∞), growth rate (K) and growth performance index (Ø') were 33.8 cm, 0.30 and 2.535, respectively. The total mortality rate (Z), natural mortality rate (M), and fishing mortality rate (F) were 1.11, 0.74 and 0.38, respectively. The present exploitation rate (Epresent) of P. subviridis computed as 0.34. Length at first capture (L50) was 17.47 cm. Recruitment of P. subviridis was observed throughout the year, with a peak during July. The yield per recruit analysis indicates that the current exploitation rate was below the biological target reference points (E0.1 and Emax), which refers to the stock of P. subviridis is underexploited. Virtual population analysis results showed that mid-lengths (16-22 cm) experienced the highest fishing mortality. The length at first capture (L50) was higher than the length at first maturity (Lm) of the species. So, for management purposes, more yields could be obtained by increasing the fishing activities on this species for a substantial harvest.
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Kolpakov, N. V., D. V. Kotsyuk, V. I. Ostrovsky, N. N. Semenchenko, V. N. Koshelev, A. P. Shmigirilov, E. V. Ostrovskaya, et al. "Modern state of aquatic biological resources of the Amur River basin and directions of their research." Izvestiya TINRO 200, no. 3 (October 3, 2020): 499–529. http://dx.doi.org/10.26428/1606-9919-2020-200-499-529.
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Current status of aquatic biological resources in the middle and lower parts of the Amur River basin, including Lake Khanka and the Amursky Liman, is assessed. Generally high abundance of the water organisms is noted, but a downward trend is revealed. In 2015–2019, the total annual catch in the basin by Russian fishermen changed between 15.9–69.6 . 103 t (on average 39.1 . 103 t), with the main portions of pacific salmons (31.9 . 103 t, or 81.6 % of total catch) and smelts (5.5 . 103 t, 14.1 %). After the peak in 2016, the salmons abundance in the Amur has decreased, particularly for summer chum salmon and pink salmon, the number of arctic rainbow smelt Osmerus dentex has decreased gradually in the last 3 years. The stocks of freshwater fish are generally stable, with a slight increase for some species. The program of fisheries research «Amur River Fishes» implemented for 2020–2024 includes intensifying of traditional monitoring of the stocks and their biological state, as well as organization of detailed comprehensive studies for key species. Improvement of data quality on status of the main stocks of pacific salmons, smelts, and freshwater fishes is planned, as the basis for fisheries forecasting. Besides, the program conducts quantitative assessment of the main components of the ecosystem (phyto- and zooplankton, macrozoobenthos, and fish) and their dependence on environmental changes. State of food base for the Amur fish will be evaluated, including the feeding of artificially reproduced juveniles of salmons and sturgeons. Results of these studies will allow to improve approaches to regulation of fishery and to promote development of fishery industry toward organization of effective fishery complex in the Amur River basin.
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Whitmarsh, Sasha K., Charlie Huveneers, and Peter G. Fairweather. "What are we missing? Advantages of more than one viewpoint to estimate fish assemblages using baited video." Royal Society Open Science 5, no. 5 (May 2018): 171993. http://dx.doi.org/10.1098/rsos.171993.
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Counting errors can bias assessments of species abundance and richness, which can affect assessments of stock structure, population structure and monitoring programmes. Many methods for studying ecology use fixed viewpoints (e.g. camera traps, underwater video), but there is little known about how this biases the data obtained. In the marine realm, most studies using baited underwater video, a common method for monitoring fish and nekton, have previously only assessed fishes using a single bait-facing viewpoint. To investigate the biases stemming from using fixed viewpoints, we added cameras to cover 360° views around the units. We found similar species richness for all observed viewpoints but the bait-facing viewpoint recorded the highest fish abundance. Sightings of infrequently seen and shy species increased with the additional cameras and the extra viewpoints allowed the abundance estimates of highly abundant schooling species to be up to 60% higher. We specifically recommend the use of additional cameras for studies focusing on shyer species or those particularly interested in increasing the sensitivity of the method by avoiding saturation in highly abundant species. Studies may also benefit from using additional cameras to focus observation on the downstream viewpoint.
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van Densen, Wim L. T., and Bonnie J. McCay. "Improving communication from managers to fishers in Europe and the US." ICES Journal of Marine Science 64, no. 4 (April 27, 2007): 811–17. http://dx.doi.org/10.1093/icesjms/fsm034.
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Abstract Van Densen, W. L. T., and McCay, B. J. 2007. Improving communication from managers to fishers in Europe and the US. – ICES Journal of Marine Science, 64: 811–817. Communication problems need to be solved if managers are to be more persuasive about the need for limitations on fishing, to protect and restore fish populations. The context is widespread scepticism about the effectiveness of management on both sides of the Atlantic. That scepticism is fuelled by assessment bias as seen in the case of the northern cod of Newfoundland, and by failure to take into account differences in perceptions of stock size and fishing mortality; differences in causal reasoning about fishing pressure and environmental factors influencing stock size; and differences in the capacity to read and understand the mostly graphic information that underlies and is often used to explain management decisions. This analysis is based on interviews and observations in the European Union and the northeastern USA.
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Spengler, Daniel E., Travis W. Schaeffer, Casey W. Schoenebeck, and Michael L. Brown. "The Influence of Symmetrical Feed:Fast Regimes on Oxytetracycline Uptake and Otolith Score in Yellow Perch." Open Fish Science Journal 6, no. 1 (November 29, 2013): 92–98. http://dx.doi.org/10.2174/1874401x01306010092.
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Periods of growth from symmetric feed:fast regimes (i.e., days fed followed by the same number of days fasted) may increase the uptake of oxytetracycline (C22H24N2O9 .HCL[OTC]) compounds in fishes; however, little empirical data exists. Therefore, we experimentally determined if such feeding regimes influenced the concentration of OTC incorporated in muscle and skeletal (e.g., otoliths) tissues. Individually-reared female and batch-reared (male and female), age-1 yellow perch Perca flavescens were subjected to one of four experimental feeding regimes: control (i.e., fed daily), D2 (i.e., 2d feed, 2d deprivation), D6, or D12 symmetrical feed:fast regimes. Following several feeding cycles on these feeding regimes, fish were submersed in a 600mg/L buffered OTC solution; otoliths and muscle tissue were excised and processed to determine OTC uptake via mark quality and concentrations. Ranked otolith scores (mark quality) were significantly lower for the D2 feeding regime than control, D6, and D12 scores for both individual and batch trials suggesting that frequent food deprivation restricts osteogenesis, while daily or extended feeding periods contribute to osteogenesis. In batch-reared fish, total OTC and 4-epioxytetracycline peak concentrations in muscle tissue did not significantly differ among treatments but were significantly greater for smaller individuals within treatments suggesting that the OTC uptake and elimination response is mechanistically related to higher gill ventilation volume and gastric ingestion rate of small fish providing increased chemical assimilation and decreased clearing time following OTC immersions. Increased otolith mark quality derived from such feeding protocols may be of particular interest to fisheries managers conducting stock contribution assessments of yellow perch, but this induction strategy may apply to other species as well as therapies for hatchery stocks.
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Zemeckis, Douglas R., Chang Liu, Geoffrey W. Cowles, Micah J. Dean, William S. Hoffman, David Martins, and Steven X. Cadrin. "Seasonal movements and connectivity of an Atlantic cod (Gadus morhua) spawning component in the western Gulf of Maine." ICES Journal of Marine Science 74, no. 6 (January 15, 2017): 1780–96. http://dx.doi.org/10.1093/icesjms/fsw190.
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Abstract Movement patterns of marine fishes can have considerable impacts on their population dynamics. A thorough understanding of fish movements is therefore required for informing stock identification, stock assessment, and fishery management. This study investigated the seasonal movements and connectivity of a spring-spawning component of Atlantic cod (Gadus morhua) in the western Gulf of Maine. From 2010 through 2013, spawning cod were sampled within an inshore spawning closure and tagged with conventional tags (n = 2368), acoustic transmitters (n = 106), and archival data storage tags (n = 266). Acoustic receivers were deployed on three inshore spawning sites to test for connectivity among sites. Data from archival tags were used to describe seasonal habitat occupancy and movement patterns via geolocation to statistical areas. Tagging data indicated that cod were primarily residential in the western Gulf of Maine, moving inshore to spawn during the spring (April–July), followed by an offshore migration to their feeding grounds for summer and fall. Cod generally inhabited waters from 45 to 175 m, with the deep offshore basins (>150 m) serving as overwintering habitat. Occupied water temperatures ranged from 4.0 to 13.3 °C, with the coldest temperatures experienced from March through July and the warmest temperatures experienced from September through January. Results provided evidence of spawning site fidelity and connectivity among spawning sites, with some fish visiting multiple spawning sites within or between years. The movements observed during and after the spring-spawning season serve as important mechanisms influencing metapopulation dynamics in the Gulf of Maine region, including both fine- and broad-scale population structure. The improved understanding of cod movement patterns will assist fishery managers in developing management plans, including spawning protection measures, and help to address remaining uncertainties with respect to cod population structure in the Gulf of Maine and other regions.
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BABCOCK, RUSSELL C., DANIEL P. EGLI, and COLIN G. ATTWOOD. "Incorporating behavioural variation in individual-based simulation models of marine reserve effectiveness." Environmental Conservation 39, no. 3 (June 1, 2012): 282–94. http://dx.doi.org/10.1017/s0376892912000148.
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SUMMARYEffective spatial management of marine species requires informed planning, as well as ongoing assessment. For mobile species such as fish, knowledge of the scale and variation in movement is central to key planning decisions, such as the size and shape of marine reserves and the interpretation of the response of protected populations. For example, populations of species that require large areas of habitat may not show increases in abundance inside small reserves, but calculating optimal reserve size is complicated by individual variations in behaviour. Fish movements can be used to quantitatively inform marine reserve planning and assessment. An individual based numerical simulation model including acoustic telemetry and census data was used to simulate changes in populations of snapper Pagrus auratus in north-eastern New Zealand. Four behavioural categories and offshore migration were used to represent the observed variability in movement. Age-structures of modelled fish populations in fully exploited areas, marine reserves and virgin populations differed substantially. However, the population structure within reserves resembled a fully fished population more closely than an unfished population. Due to the range of movement types shown by snapper, fish were not ‘locked up’ by reserves, and fish with centres of activity based in reserves were predicted to have a relatively high chance of being caught outside these reserves. Furthermore, the model showed that the response of fish populations within marine reserves was dependent on levels of exploitation in fished areas. For snapper in coastal reef areas, reserves c. 40 km2 or more may be required to achieve abundances > 50% of the unfished stock. On balance, while marine reserves with sizes similar to Leigh and Tawharanui (c. 5 km2) can achieve significant levels of protection for snapper, they are too small to fully protect resident reserve snapper populations.
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Caselle, Jennifer E., Scott L. Hamilton, Donna M. Schroeder, Milton S. Love, Julie D. Standish, Jorge A. Rosales-Casián, and Oscar Sosa-Nishizaki. "Geographic variation in density, demography, and life history traits of a harvested, sex-changing, temperate reef fish." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 2 (February 2011): 288–303. http://dx.doi.org/10.1139/f10-140.
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Geographic variation in ecological and environmental factors may lead to intraspecific differences among populations. For the California sheephead ( Semicossyphus pulcher ), an important predator in kelp forests and a target of commercial and recreational fisheries, we evaluated the degree to which different populations exhibited variation in density, demography, and life history traits. We assessed biogeographic patterns of abundance through underwater visual census at 39 sites spanning a major portion of the species range (southern California, USA, to Baja California, Mexico) and made collections from seven focal sites to investigate geographic differences in demography and life histories. California sheephead densities were significantly greater in the southern part of their range and at offshore islands than along the mainland coast. At the focal sites, we found significant spatial variation in density, fecundity, size structure, growth rates, annual survivorship, and the timing of maturation and sex change. Density- and temperature-dependent effects helped to explain the intraspecific differences in these parameters. Studies such as this one will allow for demographic plasticity to be incorporated into future stock assessments. Management of temperate reef fishes may best be achieved on smaller spatial scales as we increase our understanding of geographic variation among populations.
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Pérez-Lozano, Alfredo, and Barbarino Aniello. "Population parameters of main fishery resources in the basin of the Apure River, Venezuela (2000-2003)." Latin American Journal of Aquatic Research 41, no. 3 (March 8, 2017): 447–58. http://dx.doi.org/10.3856/vol41-issue3-fulltext-8.
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Population parameters, performance index (∅) and exploitation rates (E = F/Z), of the 14 most important commercial fish species, in the Apure River, were estimated from length frequency distributions of commercial catches in the period 2000-2003. Growth parameters were used to determine the status of the principal fisheries resources of the Apure River. The analyzed species represented 83% of the total commercial species. The results showed a predominance of values relativity low of K and high L∞, common in longevity species. This data combined with the high values from estimations of Z and F showed a survival annual high rate and low stock tuner-over rate. The E estimations for the 14 fish species were high. E0,1 (0.50- 0.94). The overfishing indicators to four most fish species abundant (P. mariae, P. tigrinum, M. duriventre y H. littorale), showed that at least three species were heavy exploited. In general the analysis indicate that these 14 fish species have been strongly fished, and the data obtained is a starting point (as biological reference point) to be used for the assessment and management of fisheries resources in the Apure River.
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Tsuboi, Jun-ichi, Kentaro Morita, Thomas Klefoth, Shinsuke Endou, and Robert Arlinghaus. "Behaviour-mediated alteration of positively size-dependent vulnerability to angling in response to historical fishing pressure in a freshwater salmonid." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 3 (March 2016): 461–68. http://dx.doi.org/10.1139/cjfas-2014-0571.
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Positively size-selective vulnerability to fishing is well established in recreational fisheries. Size-selective harvesting can either induce an indirect selection response of behavioural traits that are correlated with size or exert direct selection pressures on behaviours that contribute to vulnerability. In addition, learning to avoid future capture may always happen. Behavioural change caused by fishing may in turn affect the size-selective properties of angling. To test this prediction, field experiments with amago salmon (Oncorhynchus masou ishikawae) were conducted. We demonstrated that, as expected, large fish were more vulnerable than smaller individuals in a low fishing pressure (LP) stream and that positively size-selective angling was not (or no longer) present in a high fishing pressure (HP) stream. Moreover, fish in the HP stream were by far less vulnerable to angling with natural bait than fishes in the LP stream. Laboratory studies showed that offspring from HP streams were intrinsically shyer than offspring collected from LP streams. We propose that the increased timidity of individuals inhibiting HP streams disrupted the generally positive relationship among salmon body size and its vulnerability to angling. Fisheries-induced timidity in response to high exploitation rates reduces catchability, affects the size-selective properties of angling, reduces the value of fishery-dependent stock assessments, and potentially affects trophic interactions.
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Baclayo, Joyce, Matt Alcantara, Laila Holoyohoy, and Letecia Alaba. "Status of Fisheries in Agusan Marsh: Lapaz and Talacogon, Agusan del Sur, Mindanao." Philippine Journal of Fisheries 27, no. 1 (July 1, 2020): 54–82. http://dx.doi.org/10.31398/tpjf/27.1.2019c0002.
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In support to policy formulation of fisheries in Agusan Marsh, a stock assessment was conducted for the period of May 2014 to December 2016 using the data collected from Lapaz and Talacogon, Agusan del Sur within the Agusan Marsh. Results showed that Lapaz contributed 54% of the catch over Talacogon. A total of eighteen species, belonging to 13 genera and 11 families with 7 native and 11 introduced species were found in the marsh. Majority of the total catch consisted of Channa striata, Oreochromis niloticus, and Cyprinus carpio (35%, 27%, and 26%, respectively). Osphronemus laticlavius, Glossogobius celebius and Mugil cephalus were listed as seasonal species. An invasive janitor fish (Pterygoplichthys disjunctivus) was observed as by-catch. A strong pattern of high catch rates occurred during the rainy months of January, February, June, and December. Ten types of commonly used fishing gears were found, majority of which include fish pots, set gillnets, electrofishing and set long lines. Multivariate analysis showed similarity in species composition both in Lapaz and Talacogon. Exploitation of dominant species showed unsustainable level for O. niloticus, C. batrachus, C. caprio, andC. gariepinus, mainly due to excessive capture of immaturesized fishes by major fishing gears. The estimated exploitation rate is beyond the optimum level for O. niloticus and C. carpio in both years and followed by C. striata and C. gariepinus in 2016. Only C. bartachus is estimated to be exploited below the optimum level. Generally, the key species in Agusan Marsh are at risk of overfishing, hence, immediate policy measures must be given high attention.
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Knight, Carey T., Richard T. Kraus, Demetra A. Panos, Ann Marie Gorman, Benjamin S. Leonhardt, Jason Robinson, and Michael Thomas. "Is Barotrauma an Important Factor in the Discard Mortality of Yellow Perch?" Journal of Fish and Wildlife Management 10, no. 1 (December 1, 2018): 69–78. http://dx.doi.org/10.3996/062018-jfwm-056.
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Abstract In physoclistous fishes, barotrauma caused by rapid decompression during capture may be an important source of fishing mortality that is unquantified for some fisheries. We developed a predictive logistic model for barotrauma incidence in Yellow Perch Perca flavescens and applied this model to Ohio's recreational and commercial fisheries in Lake Erie where fisheries managers implicitly consider discard mortality to be negligible in current stock assessment. As expected, capture depth explained most of the variation in incidence, with comparatively small effects of season, sex, and size categories. Measurements of whole body and gonad density provided limited explanation for the categorical effects. Both fisheries spanned a range of depths (7.6 to 16.8 m) that corresponded to a broad range of barotrauma incidence (13 to 74%). Using a recent example, we estimated that additional fishing mortality due to barotrauma in discards was approximately six-fold higher in the commercial than recreational fishery. Overall, this additional mortality was <1% of lake-wide population size estimates. Thus, the assumption that all discarded Yellow Perch survive is unlikely to result in a detectable bias in population estimates. One caveat is that we still do not understand how strong year-classes might influence discard mortality via increased discard rate and barotrauma incidence for small fish.
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Carpi, Piera, Elisabetta B. Morello, Andres Uriarte, Monica Panfili, Beatriz Roel, Alberto Santojanni, Fortunata Donato, and Enrico Arneri. "Impact of the fishery for late-larval European sardine (Sardina pilchardus) on the adult stock in the Adriatic Sea." ICES Journal of Marine Science 74, no. 3 (December 26, 2016): 728–40. http://dx.doi.org/10.1093/icesjms/fsw208.
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Bianchetto [“white” late-larval and juvenile stages (‘fry’) mainly of sardine (Sardina pilchardus)] was fished traditionally along most of the Italian coast. The Gulf of Manfredonia (southwest Adriatic Sea) hosts a sardine nursery which was historically exploited by the bianchetto fishery using trawlnets; the fishery was banned in 2010. Here, we model this larval fishery under different assumptions of catch and natural mortality to assess its impact on the adult sardine stocks in the Adriatic Sea. The results show that the impact of the fishery is heavily dependent on the choice of early-stage natural mortality. The model proposed by Pepin (1991). Effect of temperature and size on development, mortality, and survival rates of the pelagic early life history stages of marine fish. Canadian Journal of Fisheries and Aquatic Sciences, 48: 503–518. was selected as the most plausible. Under this assumption, the direct effect of the bianchetto fishery in the Gulf of Manfredonia on the Adriatic adult sardine stock appears to be low, but not negligible, with impacts estimated as a 0.1–2% increase in the numbers of sardine at age 1 in the absence of a bianchetto fishery. Projections show that a 5% impact on age 1 sardine may be sufficient to bring the adult stock below safe levels. Therefore, given the uncertainties surrounding the impact assessment and the current status of the stock, if this fishery were to be resumed, catches should be kept at the lowest possible level until the underlying processes are better understood.
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Paul, Marchal, Ulrich Clara, Korsbrekke Knut, Pastoors Martin, and Rackham Brian. "Annual trends in catchability and fish stock assessments." Scientia Marina 67, S1 (April 30, 2003): 63–73. http://dx.doi.org/10.3989/scimar.2003.67s163.
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Castellini, Damián L., Daniel Brown, Nicolás A. Lajud, Juan M. Díaz De Astarloa, and Mariano González-Castro. "Juveniles recruitment and daily growth of the southern stock of Mugil liza (Actinopterygii; Fam. Mugilidae): new evidence for the current life-history model." Journal of the Marine Biological Association of the United Kingdom 99, no. 1 (December 7, 2017): 215–21. http://dx.doi.org/10.1017/s0025315417001904.
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Mugil liza is distributed along the western Atlantic coast. It is a commercially exploited species in Argentina, supporting a small-scale fishery conducted by an artisanal fleet. Age determination of fishes constitutes an important key issue for fishery management. The age, growth and recruitment of M. liza juveniles in Mar Chiquita coastal lagoon and Las Brusquitas creek (Buenos Aires, Argentina), were estimated by means of the analysis of the sagittal otoliths of fish collected during January to December of 2014. Ages were estimated by counting and measuring daily growth increments in otoliths under a light microscope. A total of 735 specimens ranging from 19 to 71.5 mm SL and from 67 to 212 days age was analysed. Lengths at previous ages were determined by back-calculation, a linear growth model was fitted to the back-calculated data: SL = 0.2468 + 2.0516; R2 = 0.9945. Two peaks of recruiters were observed from February to March, and from October to November in 2014. Mean ages in days of Querimana and juveniles at the recruitment time were 84.07 ± 14.43 days and 87.56 ± 19.51 days, respectively. The hatching dates of specimens showed two spawning seasons. One was from December 2013 to January 2014, and the second one from July to August 2014. The assessment carried on this work generated age determination values that support previous findings, contributing to make a more accurate description of the life-history model currently used. In addition, valuable information has been generated to give better advice for improving the management of the fishery resource.
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Nurhakim, Subhat. "IMPLIKASI IUU FISHING DALAM PENGELOLAAN SUMBER DAYA IKAN DI INDONESIA." Jurnal Kebijakan Perikanan Indonesia 1, no. 1 (February 3, 2017): 61. http://dx.doi.org/10.15578/jkpi.1.1.2009.61-66.
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Pada tatanan dunia, regional, dan nasional, dewasa ini isu kegiatan yang berkaitan dengan IUU fishing adalah merupakan ancaman utama terhadap sediaan ikan. Telah banyak inisiatif international yang didukung oleh organisasi internasional seperti FAO telah menyiapkan International Plan of Action dari IUU Fishing. Walaupun jumlah negara yang mencoba mengembangkan National Plan of Action dari IUU Fishing terus bertambah, tetapi dalam beberapa hal, kegiatan IUU Fishing merupakan hal yang banyak terjadi dan merupakan ancaman nyata terhadap perikanan lokal. Adalah benar bahwa perhatian dunia terhadap IUU Fishing terus meningkat sebagai akibat yang nyata penurunan sediaan ikan dunia secara drastis. Perkiraan kasar secara keseluruhan menunjukkan bahwa paling tidak 30% dari hasil tangkapan perikanan dunia diperoleh dari kegiatan IUU Fishing. Ini memperlihatkan bahwa masalah IUU Fishing tersebut meningkat dengan kuat, terutama bila dilihat dari percepatan penurunan ketersediaan sumber daya perikanan. Tulisan ini menyajikan hal-hal yang berkaitan dengan pengkajian sediaan dan pengelolaan perikanan seperti juga halnya kegiatan IUU Fishing yang terjadi di Indonesia. Dampak IUU Fishing terhadap hasil pengkajiaan sediaan pada akhirnya digunakan sebagai informasi dasar untuk pengelolaan perikanan juga dibahas. Rekomandasi disampaikan dalam kaitannya untuk mengurangi kegiatan IUU Fishing dan meningkatkan pengkajian sediaan ikan dan pengelolaan perikanan.At global, regional, and national levels, issues associated with IUU fishing activities currently constitute a major world-wide threat to fisheries stocks. There have already been many international initiatives supported by international organizations such as the FAO which have been engaged in the International Plan of Action on IUU fishing. Although an increasing number of countries are trying to develop national plan of actions on IUU fishing, in many parts, IUU fishing practices are still common place and constitute a real threat to local fishers. Indeed, there is increasing global concern about IUU fishing practices due to the fact that global fish stocks are declining drastically. Approximate estimations suggest that overall at least 30% of world-wide fisheries catch is obtained from IUU fishing activities. This shows that the problem is increasingly severe, especially in view of the accelerating overall decline in available fisheries resources. This paper presents briefly regarding stock assessment and fisheries management as well as IUU fishing activities that undertake in Indonesian waters. The impact of IUU fishing to the result of stock assessment, that finally used as basic information for fisheries management is also discuss. Recommendation ismade in relation to eliminate IUU fishing activities and improvement of stock assessment and fisheries management.
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Yuliana, Ernik, and Nurhasanah Nurhasanah. "LAJU EKSPLOITASI IKAN TENGGIRI DAN TONGKOL DI KAWASAN KONSERVASI TAMAN NASIONAL KARIMUNJAWA." Jurnal Matematika Sains dan Teknologi 18, no. 1 (March 14, 2017): 44–55. http://dx.doi.org/10.33830/jmst.v18i1.176.2017.
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Karimunjawa National Park (KNP) is a marine protected area established to preserve ecosystems and natural resources. Scomberomorus commerson (tenggiri) and Euthynnus affinis (tongkol) arethe two species of pelagic fish which are the main catches for artisanal fishery in KNP. This study was aimed to analyze the exploitation rate of S. commerson and E. affinis. Field survey was conducted in KNP District of Jepara, Central Java, in June-September 2016. The exploitation rate is measured by analytical method based on fish’s growth and mortality, through measuring the length of the fish for three months. Totally, as many as 314 individuals of S. Commersonand 499 individuals of E. Affinis were measured. The data were analyzed using Fish Stock Assessment Tools (FISAT II) statistical program. The results indicated that S. Commerson have a body-size trend that tends to increase, with the rate of exploitation (E) was 0,29 (under-exploited), which means there is anopportunity to increase it’s utilization. At the other hand, the size of E. Affinis tends to decrease, with the rate of exploitation (E) = 0,5. It means that the condition of utilizationof E. Affinis was at alarming position. It is necessary to control the tongkol fishing by regulating fishing gear, in order to avoid overfishing situation.
Taman Nasional Karimunjawa (TNKJ) merupakan salah satu kawasan konservasi yang bertujuan melindungi kelestarian ekosistem dan sumber daya alam. Ikan tenggiri (Scomberomorus commerson)dan tongkol (Euthynnus affinis) adalah ikan pelagis yang merupakan tangkapan utama di TNKJ. Tujuan studi ini adalah menganalisis laju eksploitasi ikan tenggiri dan tongkol. Penelitian dilakukan pada bulan Juni-September 2016. Pengukuran laju eksploitasi menggunakan metode analitik didasarkan pada pertumbuhan dan mortalitas ikan, dengan mengukur panjang ikan hasil tangkapan selama tiga bulan. Jumlah ikan tenggiri yang diukur adalah 314 ekor, dan ikan tongkol adalah 499 ekor. Analisis data menggunakan program Fish Stock Assessment Tools (FISAT II). Hasil penelitian menunjukkan tren ukuran ikan tenggiri cenderung meningkat, dengan laju eksploitasi (E) = 0,29 (under exploited), sehingga pemanfaatannya dapat ditingkatkan. Sementara ukuran ikan tongkol cenderung menurun, dengan laju eksploitasi (E) = 0,5. Kondisi pemanfaatan ikan tongkol berada pada posisi mengkhawatirkan. Sehingga perlu dilakukan pengelolaan terhadap penangkapan ikan tongkol agar tidak mengarah ke penangkapan berlebih, dengan mengatur alat tangkap nelayan.
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Andersen, Ken H., Lise Marty, and Robert Arlinghaus. "Evolution of boldness and life history in response to selective harvesting." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 2 (February 2018): 271–81. http://dx.doi.org/10.1139/cjfas-2016-0350.
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Whether intensive harvesting alters the behavioral repertoire of exploited fishes is currently unknown, but plausible. We extend a fish life-history model to account for boldness as a personality trait that affects foraging intensity, which affects energy intake and risk from predation and fishing gear. We systematically investigate life-history and behavioral trait evolution along the boldness–timidity axis in response to the full range of common selectivity and exploitation patterns in fisheries. In agreement with previous studies, we find that any type of harvesting selects for fast life histories and that merely elevated, yet unselective, fishing mortality favors boldness. We also find that timid-selective fishing (which can be expected in species targeted by active gear types) selects for increased boldness. By contrast, increased timidity is predicted when fishing targets bolder individuals common to passive gears, whether in combination with selection on size or not. Altered behavior caused by intensive harvesting should be commonplace in nature, which can have far-reaching ecological, evolutionary, and managerial impacts. Evolution of timidity is expected to strongly erode catchability, which will negatively affect human well-being and influence the reliability of stock assessments that rely on fishery-dependent data.
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Lleonart, Jordi, and Francesc Maynou. "Fish stock assessments in the Mediterranean: state of the art." Scientia Marina 67, S1 (April 30, 2003): 37–49. http://dx.doi.org/10.3989/scimar.2003.67s137.
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Ulltang, Øyvind. "Fish stock assessments and predictions: integrating relevant knowledge. An overview." Scientia Marina 67, S1 (April 30, 2003): 5–12. http://dx.doi.org/10.3989/scimar.2003.67s15.
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Thorson, James T., Robert Fonner, Melissa A. Haltuch, Kotaro Ono, and Henning Winker. "Accounting for spatiotemporal variation and fisher targeting when estimating abundance from multispecies fishery data." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 11 (November 2017): 1794–807. http://dx.doi.org/10.1139/cjfas-2015-0598.
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Estimating trends in abundance from fishery catch rates is one of the oldest endeavors in fisheries science. However, many jurisdictions do not analyze fishery catch rates due to concerns that these data confound changes in fishing behavior (adjustments in fishing location or gear operation) with trends in abundance. In response, we developed a spatial dynamic factor analysis (SDFA) model that decomposes covariation in multispecies catch rates into components representing spatial variation and fishing behavior. SDFA estimates spatiotemporal variation in fish density for multiple species and accounts for fisher behavior at large spatial scales (i.e., choice of fishing location) while controlling for fisher behavior at fine spatial scales (e.g., daily timing of fishing activity). We first use a multispecies simulation experiment to show that SDFA decreases bias in abundance indices relative to ignoring spatial adjustments and fishing tactics. We then present results for a case study involving petrale sole (Eopsetta jordani) in the California Current, for which SDFA estimates initially stable and then increasing abundance for the period 1986–2003, in accordance with fishery-independent survey and stock assessment estimates.
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Hanchet, Stuart M., Ron G. Blackwell, and Alistair Dunn. "Development and evaluation of catch per unit effort indices for southern blue whiting (Micromesistius australis) on the Campbell Island Rise, New Zealand." ICES Journal of Marine Science 62, no. 6 (January 1, 2005): 1131–38. http://dx.doi.org/10.1016/j.icesjms.2005.04.011.
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Abstract This paper develops standardized commercial cpue indices for a highly aggregated spawning fishery in New Zealand waters, and verifies the indices using fishery-independent data. Indices were calculated for all vessels using three different measures of effort, and for vessel subsets based on processing type (surimi and dressed), and relative experience in the fishery. Trends in cpue were consistent with trends in fishery-independent acoustic surveys, age composition of the commercial catch, and recent stock assessment results. In particular, the cpue indices tracked the more than fourfold increase in abundance from 1993 to 1996 associated with the recruitment of the strong 1991 year class, and the decline in relative abundance as this year class was fished down. Despite this being a highly aggregated spawning fishery, there was little evidence for hyperstability. There were also significant differences in fishing strategies of the fleets between periods of high and low fish abundance.
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Bastardie, Francois, J. Rasmus Nielsen, O. R. Eigaard, H. O. Fock, P. Jonsson, and V. Bartolino. "Competition for marine space: modelling the Baltic Sea fisheries and effort displacement under spatial restrictions." ICES Journal of Marine Science 72, no. 3 (December 1, 2014): 824–40. http://dx.doi.org/10.1093/icesjms/fsu215.
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AbstractMaritime spatial planning (MSP) and fishery management may generate extra costs for fisheries by constraining fishers activity with conservation areas and new utilizations of the sea. More energy-efficient fisheries are also likely to alter existing fishing patterns, which already vary from fishery to fishery and from vessel to vessel. The impact assessment of new spatial plans involving fisheries should be based on quantitative bioeconomic analyses that take into account individual vessel decisions, and trade-offs in cross-sector conflicting interests. We use a vessel-oriented decision-support tool (the DISPLACE model) to combine stochastic variations in spatial fishing activities with harvested resource dynamics in scenario projections. The assessment computes economic and stock status indicators by modelling the activity of Danish, Swedish, and German vessels (>12 m) in the international western Baltic Sea commercial fishery, together with the underlying size-based distribution dynamics of the main fishery resources of sprat, herring, and cod. The outcomes of alternative scenarios for spatial effort displacement are exemplified by evaluating the fishers's abilities to adapt to spatial plans under various constraints. Interlinked spatial, technical, and biological dynamics of vessels and stocks in the scenarios result in stable profits, which compensate for the additional costs from effort displacement and release pressure on the fish stocks. The effort is further redirected away from sensitive benthic habitats, enhancing the ecological positive effects. The energy efficiency of some of the vessels, however, is strongly reduced with the new zonation, and some of the vessels suffer decreased profits. The DISPLACE model serves as a spatially explicit bioeconomic benchmark tool for management strategy evaluations for capturing tactical decision-making in reaction to MSP.
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Ye, Guanqiong, Ying Lin, Cuicui Feng, Loke Ming Chou, Qutu Jiang, Panpan Ma, Shengyun Yang, et al. "Could the wild population of Large Yellow Croaker Larimichthys crocea (Richardson) in China be restored? A case study in Guanjingyang, Fujian, China." Aquatic Living Resources 33 (2020): 24. http://dx.doi.org/10.1051/alr/2020025.
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Over 90% of the world's fisheries have been fully exploited or over-fished. Included is the large yellow croaker (Larimichthys crocea), an important commercial fish species in China whose population was nearly depleted prior to the 1980s. Although overfishing and natural resources collapse present a daunting issue, some studies indicate that improved management strategies could aid in natural stock restoration to prevent depletion. We developed an integrated assessment method grounded on an ecosystem-based approach and deigned an integrated index with three key aspects of habitat suitability, natural population status and government & social interventions, to evaluate the potential restoration capacity of the species in a designated “national aquatic germplasm resource protected area” in Guanjinyang based on a data set spanning 1987 to 2015. The results show that although restoration efforts on research and rehabilitation have increased greatly since late 1990s, the effectiveness stays moderate and the natural population remains near depletion.
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Hatch, Joshua, and Yan Jiao. "A comparison between traditional and measurement-error growth models for weakfishCynoscion regalis." PeerJ 4 (September 21, 2016): e2431. http://dx.doi.org/10.7717/peerj.2431.
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Inferring growth for aquatic species is dependent upon accurate descriptions of age-length relationships, which may be degraded by measurement error in observed ages. Ageing error arises from biased and/or imprecise age determinations as a consequence of misinterpretation by readers or inability of ageing structures to accurately reflect true age. A Bayesian errors-in-variables (EIV) approach (i.e., measurement-error modeling) can account for ageing uncertainty during nonlinear growth curve estimation by allowing observed ages to be parametrically modeled as random deviates. Information on the latent age composition then comes from the specified prior distribution, which represents the true age structure of the sampled fish population. In this study, weakfish growth was modeled by means of traditional and measurement-error von Bertalanffy growth curves using otolith- or scale-estimated ages. Age determinations were assumed to be log-normally distributed, thereby incorporating multiplicative error with respect to ageing uncertainty. The prior distribution for true age was assumed to be uniformly distributed between ±4 of the observed age (yr) for each individual. Measurement-error growth models described weakfish that reached larger sizes but at slower rates, with median length-at-age being overestimated by traditional growth curves for the observed age range. In addition, measurement-error models produced slightly narrower credible intervals for parameters of the von Bertalanffy growth function, which may be an artifact of the specified prior distributions. Subjectivity is always apparent in the ageing of fishes and it is recommended that measurement-error growth models be used in conjunction with otolith-estimated ages to accurately capture the age-length relationship that is subsequently used in fisheries stock assessment and management.
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Nardi, Kim, Stephen J. Newman, Michael J. Moran, and Geoffrey P. Jones. "Vital demographic statistics and management of the baldchin groper (Choerodon rubescens) from the Houtman Abrolhos Islands." Marine and Freshwater Research 57, no. 5 (2006): 485. http://dx.doi.org/10.1071/mf05187.
Full textAbstract:
In order to evaluate appropriate management strategies, the life history and demography of the baldchin groper (Choerodon rubescens) was examined from speared samples and commercial catches at the Houtman Abrolhos Islands, Western Australia. Ages were estimated from sections of sagittal otoliths, validated by oxytetracycline labelling of fish recaptured after a minimum of 12 months at liberty. Male C. rubescens (n = 147; 373–639 mm) ranged from ages 5 to 20 years, and females (n = 354; 226–610 mm) ranged from 2 to 13 years. The population underwent a transition in dominance from females to males at age 11–12 years and 500–550 mm total length. Gonad development was seasonal and spawning was evident from spring to summer (September–January), with evidence of aggregation behaviour. Indirect estimates of the annual instantaneous rate of natural mortality (M) ranged from 0.05 to 0.58 and total mortality (Z), ranged from 0.21 to 0.56, rendering stock assessment highly uncertain. The limited geographic range, slow growth, long potential life span, protogynous sex change, aggregative spawning and high discard mortality rates render C. rubescens susceptible to overfishing. In order to manage this mobile species successfully, marine protected areas must continue to be supplemented by strict catch controls in fished areas.
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van Gemert, Rob, and Ken H. Andersen. "Implications of late-in-life density-dependent growth for fishery size-at-entry leading to maximum sustainable yield." ICES Journal of Marine Science 75, no. 4 (January 18, 2018): 1296–305. http://dx.doi.org/10.1093/icesjms/fsx236.
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Abstract Currently applied fisheries models and stock assessments rely on the assumption that density-dependent regulation only affects processes early in life, as described by stock–recruitment relationships. However, many fish stocks also experience density-dependent processes late in life, such as density-dependent adult growth. Theoretical studies have found that, for stocks which experience strong late-in-life density dependence, maximum sustainable yield (MSY) is obtained with a small fishery size-at-entry that also targets juveniles. This goes against common fisheries advice, which dictates that primarily adults should be fished. This study aims to examine whether the strength of density-dependent growth in actual fish stocks is sufficiently strong to reduce optimal fishery size-at-entry to below size-at-maturity. A size-structured model is fitted to three stocks that have shown indications of late-in-life density-dependent growth: North Sea plaice (Pleuronectes platessa), Northeast Atlantic (NEA) mackerel (Scomber scombrus), and Baltic sprat (Sprattus sprattus balticus). For all stocks, the model predicts exploitation at MSY with a large size-at-entry into the fishery, indicating that late-in-life density dependence in fish stocks is generally not strong enough to warrant the targeting of juveniles. This result lends credibility to the practise of predominantly targeting adults in spite of the presence of late-in-life density-dependent growth.
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Jakobsson, Jakob. "Monitoring and Management of the Northeast Atlantic Herring Stocks." Canadian Journal of Fisheries and Aquatic Sciences 42, S1 (December 19, 1985): s207—s221. http://dx.doi.org/10.1139/f85-275.
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The collapse of all the major herring stocks in the Northeast Atlantic in the late 1960s and the early 1970s was undoubtedly the most striking phenomenon in the history of the European fisheries. The events leading to the collapse show similar features for all the herring stocks: a sharp increase in catches over a few years, followed by a rapid decline and a fishing ban. During the period of declining stock abundance, management actions came too late and were not sufficiently restrictive. It appears that managers found it easier to accept a total fishing ban than to agree on severely reduced catches. In many cases it is clear that the fishing ban has been thoroughly enforced, while in other cases illegal fishing has seriously delayed the recovery of the stocks. This has been monitored by various fishery independent methods, such as tagging experiments, trawl surveys, larval surveys, and acoustic surveys. Before advising the reopening of the fishery it has been the general policy of the ICES Advisory Committee for Fishery Management that the spawning stock would be about to reach a minimum target abundance and that there should be firm evidence that recruitment should be on a similar level as it was prior to the collapse. Some stocks are about to or have already fulfilled these criteria, while others are still at a low level and suffering from recruitment failure. When reopening fisheries, setting of total allowable catches (TACs) and national quotas has been universal. Enforcement practices vary greatly within the European countries. In some countries, enforcement of fishing regulations is very strict and carried out on real time bases, while in other countries there appears to be very little enforcement of the existing regulations. Large quantities of herring are sometimes landed and even sold as sprat, whiting, or mackerel. Overshooting TACs is therefore common, and inadequate reporting of catches makes assessment difficult and less reliable than need be. In those cases where fishery regulations are enforced, management is mainly concerned with restricting the activities of the participating vessels so that they do not overfish. In doing so, the best fishing areas have in some cases been closed to fishing, because otherwise the catches would be far too large for the small quantity allocated to each boat. In other cases the catches per boat per night have to be so restricted (because of the large number of participating vessels) that large but unknown quantities of herring are dumped at sea. With the modernized fleets and the large number of boats participating, management has assumed the image of concentrating on "anti-effectiveness." Although the biological management objectives have been well defined and agreed to, the overall management objectives have neither been defined nor agreed to. These must take into account not only the biological objectives but also socioeconomic aspects. A management objective could be to fish the TACs with minimum expense, thus gaining maximum benefit in terms of profits from harvesting the resource. The traditionally free entry and free participation would then be the main obstacle to such an objective. This is especially acute in the case of a schooling species, which can be fished cheaply in large quantities. It is therefore important to develop new methods to restrict effort and investment. This leads to the basic problem of redefining the ownership of the fish stocks. Before an owner is firmly established, management will be under very severe constraints in limiting the entry to the fisheries.
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Calduch-Verdiell, Núria, Brian R. MacKenzie, James W. Vaupel, and Ken H. Andersen. "A life-history evaluation of the impact of maternal effects on recruitment and fisheries reference points." Canadian Journal of Fisheries and Aquatic Sciences 71, no. 7 (July 2014): 1113–20. http://dx.doi.org/10.1139/cjfas-2014-0034.
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Fishing causes dramatic changes in the age and size structure of fish stocks. In particular, the targeting of the largest and oldest individuals in a stock changes the age and size distribution of that stock. A large female produces a higher quantity of eggs than a young female because of its larger size, but recent laboratory evidence further indicates that large females also produce eggs of higher quality, a phenomenon known as maternal effects. However, most traditional management models assume that all female fish contribute equally per unit biomass to future recruitment. Here we investigate whether this assumption is valid by calculating the impact of maternal effects both before and after accounting for density-dependent effects. We find that the contribution of large individuals to reproduction is much more pronounced for unfished than for fished stocks. Fisheries reference points are largely unaffected by maternal effects. Our results indicate that the incorporation of maternal effects into impact assessments of fisheries is not expected to change advice substantially. Important exceptions are stocks whose demography is very vulnerable to fishing (and which therefore have low fishing reference points) for which maternal effects are relevant and necessary to consider.
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Prihatiningsih, Prihatiningsih, Nurainun Mukhlis, and Sri Turni Hartati. "PARAMETER POPULASI IKAN BAWAL PUTIH (Pampus argenteus) DI PERAIRAN TARAKAN, KALIMANTAN TIMUR." BAWAL Widya Riset Perikanan Tangkap 7, no. 3 (December 31, 2015): 165. http://dx.doi.org/10.15578/bawal.7.3.2015.165-174.
Full textAbstract:
Ikan bawal putih (Pampus argenteus) mempunyai nilai ekonomis penting dan sebagai salah satu komoditas unggulan di perairan Tarakan. Informasi tentang biologi perikanan ikan tersebut masih terbatas. Penelitian ini bertujuan untukmengestimasi parameter populasi meliputi pertumbuhan, umur, mortalitas dan tingkat eksploitasi ikan bawal putih. Data frekuensi panjang bulanan dikumpulan pada Februari – Nopember 2013 dengan bantuan enumerator. Sebaran frekuensi panjang ikan dipisahkan kedalam sebaran normal menggunakan metode Bhattacharya pada progran FiSAT (FAO-ICLARM Stock Assessment Tools). Estimasi parameter populasi dengan aplikasi model analitikmenggunakan program ELEFAN-1 (Electronic Length Frequency Analysis). Hasil penelitian menunjukkan ukuran panjang ikan bawal putih berkisar antara 9,0 cm–35,0 cmFL. Hubungan panjangberat ikan bawal putih yang tertangkap dengan jaring insang bersifat allometrik negatif mengikuti persamaan W= 0,187L2,374. Nilai rata-rata panjang ikan pada saat pertama kali tertangkap (Lc) sama dengan ukuran pertama kali matang gonad (Lm). Laju pertumbuhan (K) sebesar 0,52/tahun dan panjang asimptotik (L ) sebesar 37,28 cmFL. Persamaan pertumbuhan dari Von Bertalanffy sebagai Lt = 37,28 (1 – e-0,52(t-+0,07)). Mortalitas alami (M) adalah 1,11/tahun, mortalitas karena penangkapan (F) = ,65/tahun dan mortalitas total (Z) = 1,65/tahun. Laju pengusahaan (E) sebesar 0,60 berarti tingkat eksploitasinya sudah melebihi dari nilai optimal (E=0,5) atau populasi ikan bawal putih dalam keadaan lebih tangkap (over exploited). Untuk itu diperlukan kebijakan pengelolaan secara hati-hati dengan mempertimbangkan aspek biologi dan aspek penangkapan yang sedang berjalan.White pomfret (Pampus argenteus) is one of the economically important fish and includes leading commodity in Tarakan waters. Information of fishing biology of those species were still limited. This study aims to determine the population parameters including growth, age, mortality and exploitation rate of white pomfret. Monthly length frequency data have been collected by enumerator from February to November 2013. Fish lengthfrequency distribution was separated into a normal distribution using the Bhattacharya method with software of FiSAT (FAO-ICLARMStock Assessment Tools). Estimation of population parameters were use analytical model application with ELEFAN-1 (Electronic Length Frequency Analysis) program. The results showed that lengths distribution of white pomfret ranged beetwen 9.0 cm -35.0 cmFL. Length-weight relationship was negatively allometric. Estimating the average length at first captured (Lc) was equal with average length at first maturity (Lm) with growth equation of Lt = 37.28 (1 - e-0, 52 (t +0.07)). Natural mortality (M) was 1.11/year, fishing mortality (F) was 1.65/yearand total mortality (Z) was 1.65/ year. The exploitation rate (E) was 0.60. It is mean that more higher than optimal exploitation so that the white pomfret fish population in a state of over fished. It is necessary to better policy in the management of white pomfret through precaution approach and describing of biologycal and fishing aspect in Tarakan, Kalimantan Timur.