Artigos de revistas: "Fish Mortality"

1

Ellis, Tim, Iain Berrill, Jeff Lines, James F. Turnbull e Toby G. Knowles. "Mortality and fish welfare". Fish Physiology and Biochemistry 38, n.º 1 (16 de setembro de 2011): 189–99. http://dx.doi.org/10.1007/s10695-011-9547-3.

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Suprayitno, Eddy. "THE INFLUENCE OF FISH MORTALITY ON THE FRESHNESS OF FISH". International Journal of Research -GRANTHAALAYAH 6, n.º 2 (28 de fevereiro de 2018): 80–85. http://dx.doi.org/10.29121/granthaalayah.v6.i2.2018.1547.

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Fish is one of the freshly prepared high-protein foodstuffs. Fish protein needs by the body to speed up the digestion process by the similar function as human proteins. Protein has a function as growth, regulatory and former energy. Moreover, fish is the perishable product which is easy to spoil and cause decreasing quality. One of the factors that the caused the decreasing quality of fish is death method. Where fish that the long process of decay death proved more rapid than the fish that quickly intervening died calmly. This research was conducted to investigate the effect of fish mortality on the old phase of deterioration in fish quality. The method was used in this experiment was Completely Randomized Design (CRD) with 6 treatments rooms is left alone, the medulla oblongata stabbed, beaten hard objects, broken spine, given freshwater ice, and smeared with kluwak. The result showed that there was no significant effect (P> 0.05) on the phase of deterioration of fish quality. Which is the longest phase of fish deterioration in the treatment of fish stabbed medulla oblongata with an average value of 2137.8 minutes.

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Hedström, Per, David Bystedt, Jan Karlsson, Folmer Bokma e Pär Byström. "Brownification increases winter mortality in fish". Oecologia 183, n.º 2 (3 de dezembro de 2016): 587–95. http://dx.doi.org/10.1007/s00442-016-3779-y.

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FOTIS (Γ. ΦΩΤΗΣ), G., e I. KIRKOUDIS (Ι. ΚΥΡΚΟΥΔΗΣ). "Clostrìdìum botulinum - A cause of fish mortality". Journal of the Hellenic Veterinary Medical Society 52, n.º 1 (31 de janeiro de 2018): 65. http://dx.doi.org/10.12681/jhvms.15409.

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Clostridium botulinum type E proliferates in dead aquatic animals and sediments and it is distributed by water currents and infected fish. Botulism is a disease with great significance for both aquacultured fish and humans. The existing data about the subject are very few, and the aim of the present paper is to warn fish farmers and pathologists about the possibility of outbreaks in Greece.

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JANCIN, BRUCE. "Fish Oil Cuts Heart Failure Morbidity, Mortality". Internal Medicine News 41, n.º 19 (outubro de 2008): 36. http://dx.doi.org/10.1016/s1097-8690(08)71105-3.

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6

Auld, Garry. "Fish consumption and cardiovascular mortality in Canada". Journal of Nutrition Education 21, n.º 1 (fevereiro de 1989): 10. http://dx.doi.org/10.1016/s0022-3182(89)80229-8.

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TARAZONA, J. V., MaJ MUŃOZ, J. A. ORTIZ, MaO NUNÉZ e J. A. CAMARGO. "Fish mortality due to acute ammonia exposure". Aquaculture Research 18, n.º 2 (abril de 1987): 167–72. http://dx.doi.org/10.1111/j.1365-2109.1987.tb00135.x.

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Nandan, S. Bijoy, e P. K. Abdul Azis. "Fish Mortality from Anoxia and Sulphide Pollutions". Journal of Human Ecology 6, n.º 2 (maio de 1995): 97–104. http://dx.doi.org/10.1080/09709274.1995.11907139.

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9

Craig, J. F. "Aging in fish". Canadian Journal of Zoology 63, n.º 1 (1 de janeiro de 1985): 1–8. http://dx.doi.org/10.1139/z85-001.

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Theories on aging are well advanced but empirical data lag far behind them mainly because few fish populations are unexploited and are allowed to reach old age. There is more evidence supporting the theory of genetic aging controlled by a biological clock than aging by random damage, but the two are probably interconnected. Growth and natural mortality are closely correlated between and within species and populations. Fast growth and early maturity curtail the life-span; slow growth and late maturity have the reverse effect. There appears to be a trade-off between reproductive effort and longevity to ensure the production of the maximum number of progeny over the life-span of the mature adults. This trade-off is influenced by a feedback system dependent on reproductive success. Genetic control of growth and thus mortality is not well understood and is obscured by environmental factors. Anatomical and physiological changes with age are similar to those of mammals and include the appearance of malignant tumors. Changes in growth and natural mortality have an important influence on yield and recruitment in fisheries. The understanding of aging processes lies in an improved knowledge of bioenergetic processes and the environmental factors that control them.

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Septiyawati, Septiyawati, Muhammad Fauzi e Deni Efizon. "Analisis dinamika populasi ikan selar kuning (Selaroides leptolepis) dalam upaya pengelolaan sumberdaya ikan pelagis kecil di perairan Bintan, Provinsi Kepulauan Riau". Depik 9, n.º 3 (9 de outubro de 2020): 428–34. http://dx.doi.org/10.13170/depik.9.3.17351.

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This raw fish is used as fisheries products such as salted fish, grilled fish, fishmeal and surimi. This study aims to analyze mortality and recruitment of yellowstipe scad (Selaroides leptolepis) and the information about management of small pelagic fisheries resources in Bintan Waters. This research was carried out in February-June 2019 at the Barek Motor Fish Landing Area (TPI) with fishing areas in Bintan waters. The number of fish studied was 2.550 with a length of 102-215 mm and a weight of 15-102 gr. The highest recruitment peak occurred in Mei of 18.11% and June of 19.48%. The highest and lowest condition factors are 0.83 and 1.09. The total mortality rate (Z) of yellow strait fish is 4.61 per year with a natural mortality rate (M) of 1.66 per year and the capture mortality rate of 2.95 per year so that the exploitation rate is 0.63. The death of yellowstipe scade in the Bintan Sea most of the caused by fishing activities (F) of 2.95 per year.Keywords:Yellowstipe scad Bintan WatersRecrutmentCondition factorsMortalityABSTRAKIkan selar kuning merupakan salah satu jenis ikan ekonomis penting. Ikan ini banyak dimanfaatkan sebagai bahan baku produk olahan perikanan seperti ikan asin, ikan bakar, pindang, tepung ikan dan surimi. Penelitian ini bertujuan untuk menganalisis, mortalitas dan rekrutmen ikan selar kuning (Selaroides leptolepis) dan informasi tentang pengelolaan sumberdaya ikan pelagis kecil di Perairan Bintan. Penelitian ini telah dilaksanakan bulan Februari-Juni 2019 di Tempat Pendaratan Ikan (TPI) Barek Motor dengan wilayah penangkapan di perairan Bintan. Jumlah ikan yang diteliti 2.550 ekor dengan panjang 102-215 mm dan berat 15-102 gr. Puncak rekrutmen tertinggi terjadi bulan Mei sebesar 18,11% dan Juni sebesar 19,48%,. Nilai tertinggi dan terendah faktor kondisi yaitu 0,82 dan 1,09. Laju mortalitas total (Z) ikan selar kuning 4,61 per tahun dengan laju mortalitas alami (M) 1,66 per tahun dan laju mortalitas penangkapan 2,95 per tahun sehingga diperoleh laju eksploitasi 0,63. Kematian ikan selar kuning di laut Bintan sebagian besar diakibatkan oleh aktivitas penangkapan (F) sebesar 2,95 per tahun.Kata kunci:Ikan selar kuning Perairan Bintan Rekrutmen Faktor kondisi Mortalitas

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11

Davis, M. W. "Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish". ICES Journal of Marine Science 64, n.º 8 (27 de junho de 2007): 1535–42. http://dx.doi.org/10.1093/icesjms/fsm087.

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Abstract Davis, M. W. 2007. Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish. – ICES Journal of Marine Science, 64: 1535–1542. Development of efficient methods to predict discard and escapee mortality in fishing operations is essential to the conservation of sensitive fish stocks. For a few fisheries, mortality data are available from fishing experiments in the field; these require long-term holding or monitoring of fish in tanks, cages, or tag and recapture experiments to detect delayed mortality. A different approach to predicting discard and escapee mortality is to use reflex action mortality predictors (RAMP) consisting of relationships between mortality and reflex impairment for species of interest. Fish were towed in a net in the laboratory and then either restrained in foam-lined holders and rapidly tested for reflex impairment five minutes after towing, or held for up to 60 days to determine delayed mortality. Delayed mortality occurred up to 20 days after towing. RAMP was related to mortality with biphasic sigmoid functions. As fishing stressors increased in intensity, the first phase showed an increase in RAMP with no concomitant mortality. In the second phase, RAMP continued to increase, while mortality became apparent and increased. The measurement of RAMP in restrained fish on board fishing vessels during experiments to predict discard mortality and in caged free swimming fish to predict escapee mortality is feasible and advisable.

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12

Zhang, Bo, Ke Xiong, Jing Cai e Aiguo Ma. "Fish Consumption and Coronary Heart Disease: A Meta-Analysis". Nutrients 12, n.º 8 (29 de julho de 2020): 2278. http://dx.doi.org/10.3390/nu12082278.

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Epidemiological studies on the impact of fish consumption on coronary heart disease (CHD) incidence have shown inconsistent results. In addition, in terms of CHD mortality, although previous meta-analyses showed that fish consumption reduces the risk of CHD, six newly incorporated studies show that fish consumption has no impact on CHD. Therefore, the results still need to be verified. The purpose of this study is to quantitatively evaluate the impact of fish consumption on CHD incidence and mortality. Relevant studies were identified from PubMed, Web of Science, and Embase databases up to October 2019. The multivariate-adjusted relative risks (RRs) for the highest versus the lowest fish consumption categories and the 95% confidence intervals were computed with a random-effect model. A restricted cubic spline regression model was used to assess the dose–response relationship between fish consumption and CHD incidence and mortality. Forty prospective cohort studies were incorporated into research. Among them, 22 studies investigated the association between fish consumption and CHD incidence (28,261 cases and 918,783 participants), and the summary estimate showed that higher fish consumption was significantly associated with a lower CHD incidence [RR: 0.91, 95% CI: (0.84, 0.97); I2 = 47.4%]. Twenty-seven studies investigated the association between fish consumption and CHD mortality (10,568 events and 1,139,553 participants), and the summary estimate showed that higher fish intake was significantly associated with a lower CHD mortality [RR: 0.85, 95% CI: (0.77, 0.94); I2 = 51.3%]. The dose–response analysis showed that the CHD incidence and mortality were reduced by 4%, respectively, with a 20 g/day increment in fish consumption. This meta-analysis indicates that fish consumption is associated with a lower CHD incidence and mortality.

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13

Davis, Michael W. "Key principles for understanding fish bycatch discard mortality". Canadian Journal of Fisheries and Aquatic Sciences 59, n.º 11 (1 de novembro de 2002): 1834–43. http://dx.doi.org/10.1139/f02-139.

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The mortality of discarded fish bycatch is an important issue in fisheries management and, because it is generally unmeasured, represents a large source of uncertainty in estimates of fishing mortality worldwide. Development of accurate measures of discard mortality requires fundamental knowledge, based on principles of bycatch stressor action, of why discarded fish die. To date, discard mortality studies in the field have focused on capture stressors. Recent laboratory discard experiments have demonstrated the significant role of environmental factors, size- and species-related sensitivity to stressors, and interactions of stressors, which increase mortality. In addition, delayed mortality was an important consideration in experimental design. The discard mortality problem is best addressed through a combination of laboratory investigation of classes of bycatch stressors to develop knowledge of key principles of bycatch stressor action and field experiments under realistic fishing conditions to verify our understanding and make predictions of discard mortality. This article makes the case for a broader ecological perspective on discard mortality that includes a suite of environmental and biological factors that may interact with capture stressors to increase stress and mortality.

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14

Wishkovsky, A., N. Garber e R. R. Avtalion. "The effect of fish age on the mortality caused by selected fish pathogens". Journal of Fish Biology 31, sa (dezembro de 1987): 243–44. http://dx.doi.org/10.1111/j.1095-8649.1987.tb05324.x.

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15

JANCIN, BRUCE. "Fish Oil May Cut Heart Failure Mortality, Morbidity". Clinical Psychiatry News 36, n.º 10 (outubro de 2008): 39. http://dx.doi.org/10.1016/s0270-6644(08)70728-8.

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16

Jacobsen, Nis S., e Timothy E. Essington. "Natural mortality augments population fluctuations of forage fish". Fish and Fisheries 19, n.º 5 (19 de abril de 2018): 791–97. http://dx.doi.org/10.1111/faf.12290.

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17

Myers, Ransom A., e Noel G. Cadigan. "Density-Dependent Juvenile Mortality in Marine Demersal Fish". Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 8 (1 de agosto de 1993): 1576–90. http://dx.doi.org/10.1139/f93-179.

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We examine the hypothesis that population variability is created and regulated in the juvenile stage for demersal marine fish. Juvenile mortality is examined for 17 populations of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), yellowtail flounder (Pleuronectes ferrugineus), and sole (Solea vulgaris) in the North Sea, Irish Sea, Barents Sea, Baltic Sea, and Northwest Atlantic. A latent variable covariance analysis of recruitment time series with measurement error is used to test hypotheses. We found strong evidence of density-dependent mortality within cohorts during the juvenile stage for cod, plaice, sole, and whiting; density-dependent mortality appears to be related to the log of juvenile abundance. There is evidence of negative autocorrelation between adjacent cohorts of cod; this pattern is consistent with density-dependent mortality between adjacent cohorts. The autocorrelations are positive for the flatfish examined. It is possible to obtain estimates of estimation error variances for populations if there are multiple research surveys of the same population. We conclude that the juvenile stage is very important for population regulation in most species but that the source of the variability in year class strength is in the larval stage or very early juvenile stage.

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Norell, S. E., A. Ahlbom, M. Feychting e N. L. Pedersen. "Fish consumption and mortality from coronary heart disease." BMJ 293, n.º 6544 (16 de agosto de 1986): 426. http://dx.doi.org/10.1136/bmj.293.6544.426.

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Turunen, A. W., P. K. Verkasalo, H. Kiviranta, E. Pukkala, A. Jula, S. Mannisto, R. Rasanen, J. Marniemi e T. Vartiainen. "Mortality in a cohort with high fish consumption". International Journal of Epidemiology 37, n.º 5 (25 de junho de 2008): 1008–17. http://dx.doi.org/10.1093/ije/dyn117.

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Garcia, F., F. R. Moraes e M. L. Martins. "Challenge of pacu (Piaractus mesopotamicus) fed diets supplemented with vitamins C and E by Aeromonas hydrophila under different temperature". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 61, n.º 2 (abril de 2009): 378–85. http://dx.doi.org/10.1590/s0102-09352009000200014.

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Pacu Piaractus mesopotamicus fed diets supplemented with three vitamins C and E levels (zero, 250, and 500mg vitamin/kg diet) were challenged with Aeromonas hydrophila under different temperatures. Fish were kept in 300L plastic tanks and fed during the first 60 days with diets without vitamins C and E, in an attempt to reduce vitamin sources. After this period, fish were maintained at an initial density of 14 fish/tank and test diets were offered during 60 days. At the end of the experiment, all fish were infected with 6×10(6)CFU of A. hydrophila/fish, intraperitoneally injected. No interaction of dietary levels of vitamin C vs. E on mortality was observed. Supplementation with vitamins C and E did not decrease the mortality rate of fish challenged with A. hydrophila. Regardless of vitamin supplementation, after challenge, smaller fish showed higher mortality than larger ones and the fish group maintained in an environment under higher temperatures showed higher mortality rate.

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Chadijah, Andi, e Sulistiono Sulistiono. "Pertumbuhan dan Mortalitas Ikan Endemik Opudi (Telmatherina prognatha Kottelat, 1991) di Danau Matano, Sulawesi Selatan". Jurnal Ilmu Pertanian Indonesia 26, n.º 1 (7 de dezembro de 2020): 92–97. http://dx.doi.org/10.18343/jipi.26.1.92.

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Lake Matano is an ancient lake that has a high endemicity. Opudi fish (Telmatherina prognatha) is an endemic fish that is vulnerable to extinction and needs to be preserved. The threat of invasive species and habitat degradation can cause a decrease in opudi fish populations. This study aimed to examine the growth parameters associated with growth coefficients and mortality in Lake Matano so that population can be sustainable. The study was conducted at Lake Matano from March 2018 to February 2019. Samples of fish were caught using a net bag measuring 30 m long, 2 m wide with a mesh size of 0.5 inches. Analysis of fish growth was based on total length-frequency data. These data were analyzed using the FISAT II software. The sizes of male and female opudi fish obtained ranged from 30-70 mm. Growth patterns of von Bertalanffy butina in male fish are male Lt = 76.50 [1-e-0.46 (t + 0.47)] and female fish Lt = 74.05 [1-e-0.51 (t + 0.52)]. The total mortality value of male fish was higher (Z = 1.65) compared to female fish (Z = 1.50), the natural mortality value of male opudi fish was lower (M = 0.84) compared to that of female fish (M = 0.91). Keywords: endemic fish, growth, mortality, Telmatherina prognatha

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Czarkowski, Tomasz K., e Andrzej Kapusta. "The impact of angling experience on the efficiency of float fishing using different hook types". Fisheries & Aquatic Life 27, n.º 1 (1 de março de 2019): 41–46. http://dx.doi.org/10.2478/aopf-2019-0005.

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Abstract The aim of the study was to compare the catch efficiency of novice and experienced anglers float fishing with different hook types. The mortality of fish that were caught and released was determined based on the experience of the angler and the type of hook used. The mean catch rates of the experienced angler was 46.7 fish per hour, while that of the novice angler was 33.7 fish per hour. The landing efficiency of fish using hooks with micro-barbs was higher than that with barbless hooks. Angling experience had a significant impact on the mean time required to unhook caught fish and also on the mortality of the fish released. The lowest mortality was noted in fish caught by experienced anglers fishing with barbless hooks. The results of the study suggest that angling experience does not have a great impact on parameters characterizing the quality of angling catches. The efficiency of float fishing performed by novice and experienced anglers was similar. Differences were noted in the time required to unhook the fish and in the mortality of the fish released.

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Loftus, Andrew J., William W. Taylor e Myrl Keller. "An Evaluation of Lake Trout (Salvelinus namaycush) Hooking Mortality in the Upper Great Lakes". Canadian Journal of Fisheries and Aquatic Sciences 45, n.º 8 (1 de agosto de 1988): 1473–79. http://dx.doi.org/10.1139/f88-172.

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Investigation of lake trout (Salvelinus namaycush) hooking mortality was conducted in Lakes Michigan, Huron, and Superior during 1984 and 1985. Fish were caught and handled by charterboat operators and sport fishermen. Mortality was estimated by returning hooked fish to the lake after tethering them to a line–buoy system. Overall hooking mortality was estimated to be 14.9% (95% C.I. = 7.4–25.7). Significantly higher mortalities occurred in fish that were not discovered to have been hooked and in fish of smaller size classes. In addition, lake trout that were hooked in internal regions produced a mortality of 71.4% whereas those hooked in the upper or lower jaw had a mortality of 6.9%. The depth from which the fish was angled, the temperature differential from this depth to the surface, gear type, and handling times had no significant impact on survival. These results support the use of size limits, creel limits, and season restrictions as effective methods to reduce sport fishing mortality of lake trout.

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Jiang, Honghua, Cavell Brownie, Joseph E. Hightower e Kenneth H. Pollock. "Estimating Fishing Mortality, Natural Mortality, and Selectivity Using Recoveries from Tagging Young Fish". North American Journal of Fisheries Management 27, n.º 3 (agosto de 2007): 773–81. http://dx.doi.org/10.1577/m06-127.1.

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Ostrand, Kenneth G., Michael J. Siepker e David H. Wahl. "Effectiveness of Livewell Additives on Largemouth Bass Survival". Journal of Fish and Wildlife Management 2, n.º 1 (1 de junho de 2011): 22–28. http://dx.doi.org/10.3996/092010-jfwm-037.

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Abstract Livewell conditions during competitive angling events are thought to affect fish mortality. We examined the effects of livewell additives on initial and delayed mortality of largemouth bass Micropterus salmoides. We applied three treatments (salt, ice, or salt and ice) to livewells during tournaments conducted on lakes in Illinois, United States, as well as in laboratory and pond experiments designed to examine the effects of fish size and ambient water temperature on mortality. Fish were collected after tournament weigh-in procedures were completed and monitored for delayed mortality every 24 h for 5 d. Initial mortality did not differ among livewell additives during these field experiments. Although delayed mortality was high (35%), it was not significantly different among livewells that contained salt (56%), ice (48%), ice and salt (40%), and controls (30%). Additives administered during the laboratory experiments, at cool water temperatures, resulted in significantly lower delayed mortalities than those observed during the field experiments when ambient water temperatures were warmer. Initial and delayed mortality did not differ among livewell additives during the laboratory experiments. Larger fish in field experiments had significantly greater delayed mortality than smaller fish in the pond experiments even though initial and delayed mortality did not differ among livewell additives. Our results suggest that fish size and ambient water temperature have a greater influence on delayed mortality observed during competitive angling events than the specific livewell additives studied here.

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Jacobsen, Nis S., James T. Thorson e Timothy E. Essington. "Detecting mortality variation to enhance forage fish population assessments". ICES Journal of Marine Science 76, n.º 1 (13 de novembro de 2018): 124–35. http://dx.doi.org/10.1093/icesjms/fsy160.

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Abstract Contemporary stock assessment models used by fisheries management often assume that natural mortality rates are constant over time for exploited fish stocks. This assumption results in biased estimates of fishing mortality and reference points when mortality changes over time. However, it is difficult to distinguish changes in natural mortality from changes in fishing mortality, selectivity, and recruitment. Because changes in size structure can be indicate changes in mortality, one potential solution is to use population size-structure and fisheries catch data to simultaneously estimate time-varying natural and fishing mortality. Here we test that hypothesis, using a simulation experiment to test performance for four alternative estimation models that estimate natural and fishing mortality from size structure and catch data. We show that it is possible to estimate time-varying natural mortality in a size-based model, even when fishing mortality, recruitment, and selectivity are changing over time. Finally, we apply the model to North Sea sprat, and show that estimates of recruitment and natural mortality are similar to estimates from an alternative multispecies population model fitted to additional data sources. We recommend exploring potential trends in natural mortality in forage fish assessments using tools such as the one presented here.

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Alós, Josep. "Influence of anatomical hooking depth, capture depth, and venting on mortality of painted comber (Serranus scriba) released by recreational anglers". ICES Journal of Marine Science 65, n.º 9 (16 de setembro de 2008): 1620–25. http://dx.doi.org/10.1093/icesjms/fsn151.

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Abstract Alós, J. 2008. Influence of anatomical hooking depth, capture depth, and venting on mortality of painted comber (Serranus scriba) released by recreational anglers. – ICES Journal of Marine Science, 65: 1620–1625. Immediate (4–5 h) and delayed (10 d) hooking mortality for released fish kept in tanks was evaluated for painted comber (Serranus scriba) taken by the recreational fishery of the Balearic Islands (western Mediterranean). Results showed low rates of immediate (10.8%) and delayed (3.3%) hooking mortality, a total mortality of 14.1%. Anatomical hook location and capture depth were the most significant predictors of mortality; 70.4% of fish caught with a deep location of hook died as a consequence of the damage caused, bleeding, and long unhooking times. Fish caught in depths >16 m showed evidence of external barotrauma caused by rapid decompression, which increased the probability of death. The most common forms of barotrauma were swimbladder enlargement and stomach inversion. For fish vented with the aid of a hypodermic needle to extract excess gas, mortality was reduced by half. Factors such as surface temperature, fish size, and hook type (“J” hook vs. circle hook) could not explain the mortality of fish released into tanks. Therefore, the results confirm that a practice of catch-and-release (voluntary or mandatory) for S. scriba needs to be promoted among recreational anglers.

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Pepin, Pierre. "An Appraisal of the Size-Dependent Mortality Hypothesis for Larval Fish: Comparison of a Multispecies Study with an Empirical Review". Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 10 (1 de outubro de 1993): 2166–74. http://dx.doi.org/10.1139/f93-242.

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This study presents an assessment of the size-dependent mortality hypothesis for larval fish from a multispecies survey of Conception Bay, Newfoundland, Canada. Mortality rates are estimated using a length-based method (per millimetre). The results from this survey are consistent with previous studies which indicate that losses decrease with increasing size of fish. However, for each species within this survey, mortality rates are constant. Comparison of mortality rates within species among surveys indicates that as the range of size categories sampled increases, the estimated mortality rates decrease, despite evidence of adequate fit to the length-based model. The findings indicate that previous relationships between size or stage and mortality of larval fish should be reevaluated. Length-based methodology used to estimate mortality rates of larval fish appears to provide biased estimates of this vital characteristic. It is suggested that using size as a proxy for biological age (i.e., assuming a constant growth rate) may be an invalid assumption. Future surveys will need to provide accurate information about the age structure of larvae sampled in order to properly estimate mortality rates.

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Sanches, R. A. K., e P. A. Piana. "The influence of catch-and-release on mortality of Salminus brasiliensis (Cuvier, 1816)". Brazilian Journal of Biology 80, n.º 4 (dezembro de 2020): 705–10. http://dx.doi.org/10.1590/1519-6984.204168.

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Abstract Catch-and-release (CR) angling has been used to assist management programs seeking to promote the conservation and recovery of some recreational fish stocks by decreasing mortality from fishing. However, without appropriate fish handling, this activity may cause damage and injuries to individual fish, causing mortality. Therefore, CR should be allowed under some circumstances that ensure higher rates of survival to achieve the goals of the conservation measures. Thus, we experimentally tested the CR effects on dourado (Salminus brasiliensis) by comparing caught-and-released fish (CR fish) with uncaught fish (control fish) in a pond and estimating individual mortality rates related to seven air exposure times (AET: 120 s, 240 s, 360 s, 480 s, 600 s, 720 s and 840 s). We also determined a safe limit for fish handling and investigated the length and weight gain variations. We found that an increase in AET affects fish survival and that the limit of handling time for this species was 546 s; after this threshold, the individual probability of death exceeds 5%. The length and weight gain of CR fish did not differ significantly from the control fish. We believe that CR is efficient for S. brasiliensis because it does not significantly impair their organic growth and causes little or no mortality if handling is performed properly; thus, it could be employed to assist conservation programs.

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Molnár, József, Balázs Csorbai, Gergely Bernáth, Levente Várkonyi, Béla Urbányi e Zoltán Bokor. "Optimizing fish structure in angling ponds focusing on white fish". Acta Agraria Debreceniensis, n.º 1 (23 de maio de 2019): 33–36. http://dx.doi.org/10.34101/actaagrar/1/2366.

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According to new amendments of laws, commercial fishing licenses of natural waters shall not be issued from the calendar year 2016 in Hungary. However, the most settlement of white fish to angler ponds originated from natural waters. Currently, there is no sufficient quantity of fish species belonging to this group available to fulfil the settlement commitments of fish farmers. The aim of this recent study is to develop a breeding and production technology that is suitable for settlement of large quantities of this fish species of appropriate length of (4–5 cm). The following methods are investigated: aquaculture cage system (pond-in-pond system), monoculture and mixed population with different ratio of white fish in fish structure. Due to the different environmental needs of different fish species, many parameters need to be investigated, for example: stocking density, feeding, oxygen level, monoculture or mixed populations, growth potential and mortality. A preliminary experiment was carried out following the artificial propagation of ide (Leuciscus idus) following a 21-day larval rearing experiment in which the effect of different stoking density was investigated for mortality and growth. On the basis of the expected results, the optimal conditions for the aquaculture cage system will be described, regarding to the white fish stock.

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Schultz, Eric T., David O. Conover e Amir Ehtisham. "The dead of winter: size-dependent variation and genetic differences in seasonal mortality among Atlantic silverside (Atherinidae: Menidia menidia) from different latitudes". Canadian Journal of Fisheries and Aquatic Sciences 55, n.º 5 (1 de maio de 1998): 1149–57. http://dx.doi.org/10.1139/f97-320.

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Genetic differences among populations of Atlantic silverside (Menidia menidia) are hypothesized to be evolutionary responses to intense, size-selective winter mortality at high latitudes. Three experiments were conducted to test features of winter mortality. In the first experiment, we varied size and whether food was provided or withheld; temperatures were permitted to follow ambient (New York) wintertime fluctuations. Mortality and depletion of energy reserves were more rapid in the units receiving no food. Small fish died before larger fish in these units, but not in the units receiving food. Energy depletion of fish in the no-food treatment resembled that of fish in the wild. In the second experiment, we varied size and population of origin, representing high-latitude (Nova Scotia), midlatitude (New York), and low-latitude (South Carolina) populations. These fish were provided food and showed minimal depletion of energy reserves, but mortality rates were high when water temperatures were low. Mortality did not vary with size in New York and South Carolina fish, but was highest in intermediate-size fish from Nova Scotia. There was a pronounced population difference in survival rate (Nova Scotia > New York > South Carolina). In the third experiment, food was withheld and extreme low temperatures were moderated. Energy depletion was rapid and small fish died before large fish. We conclude that populations in seasonal environments are likely to be subject to size-selective winter mortality when energy reserves are depleted and that juvenile growth rates have evolved in response to this selection pressure. In addition, high-latitude populations have evolved greater tolerance to other winter stresses associated with low temperatures.

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Maraja, Mafrian Kris, Netty Salindeho e Jenki Pongoh. "PENANGANAN IKAN NILA (Oreochromis niloticus) HIDUP DENGAN DENGAN MENGGUNAKAN ES SEBAGAI PENGAWET". MEDIA TEKNOLOGI HASIL PERIKANAN 5, n.º 3 (3 de agosto de 2017): 80. http://dx.doi.org/10.35800/mthp.5.3.2017.16849.

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Imotilization of fish is one way of handling techniques by using low temperature (cooling). Cooling (cold chain) is applied to transport live fish so that the weight of the load during transportation could be reduced and fish do not experience stress during transportation. This technique is more advantageous when compared with the wet transportation system by using water. After the fish fainted, fish could be re-awakened by returning the fish to the pond with the aid of sufficient aeration to facilitate fish regain consciousness. This study aims to determine the rate of stunning, the speed of awareness, and mortality of nile tilapia fish which was treated and stored at different temperatures and times. This study used a factorial completely randomized design (RAL) with 2 treatments namely, storage method (A) treatment consisting of 2 storage levels (Temperature 10-12 ° C and 14-16 ° C); and storage time (B) consisting of 4 levels (2, 4, 6 and 8 hours). The optimum time of fainting fish is at a temperature of 14-16 ° C that is 8.19 min. For re-awakening, the optimum time is 48 seconds when fish was stored for 2 hours. The best mortality rate was achieved at storage temperature ± 14-16 ° C because after 6 hours storage the mortality rate was only 20.8%, but by the maximum storage (8 hours) the mortality has reached 87.5%, Meanwhile at a storage temperature of ± 10-12 ° C, the mortality has reached 50% after 6 hours and 100% at 8 hours.Pemingsanan ikan merupakan salah satu cara teknik penanganan dengan pengunaan suhu rendah (pendinginan). Pemingsanan dengan suhu rendah diaplikasikan untuk transportasi ikan hidup dengan tujuan mengurangi berat beban selama transportasi dan supaya ikan tidak mengalami stress selama transportasi. Teknik ini lebih menguntungkan jika dibandingkan dengan transportasi sistem basah dengan menggunakan air. Setelah dipingsankan ikan kembali disadarkan dengan mengembalikan ikan ke kolam air habitatnya dengan dibantu aerasi yang cukup agar ikan kembali sadar. Penelitian ini bertujuan untuk mengetahui kecepatan pemingsanan, kecepatan penyadaran, dan mortalitas ikan nila yang dipingsankan dan disimpan pada suhu dan waktu berbeda. Penelitian ini menggunakan rancangan acak lengkap (RAL) faktorial dengan 2 perlakuan yaitu, perlakuan metode penyimpanan (A) yang terdiri atas 2 taraf penyimpanan (Suhu 10–12°C dan 14–16°C); perlakuan lama penyimpanan (B) yang terdiri atas 4 taraf (2, 4, 6 dan 8 jam). Waktu optimum kecepatan pingsan adalah pada suhu 14–16°C yaitu 8,19. Untuk penyadaran kembali, waktu optimumnya adalah 48 detik, pada ikan nili yng disimpan 2 jam. Pada penyimpanan suhu ±14-16°C didapat tingkat mortalitas terbaik karena sampai penyimpanan 6 jam tingkat mortalitasnya hanya 20,8%, namun sampai penyimpanan maksimum ( 8 jam) sudah mencapai 87,5%, sedangkan pada suhu penyimpanan ±10-12°C , setelah 6 jam mortalitasnya sudah mencapai 50% dan saat 8 jam tingkat mortalitasnya sudah mencapai 100%.

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Pepin, P. "Influence of Alternative Prey Abundance on Pelagic Fish Predation of Larval Fish: A Model". Canadian Journal of Fisheries and Aquatic Sciences 44, n.º 1 (1 de janeiro de 1987): 222–27. http://dx.doi.org/10.1139/f87-031.

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In this model of predation on larval fish by pelagic fish, I postulate that variations in the abundance of the more numerous alternative prey population can determine the time required by a predator to attain its maximum ration. The model predicts that larval fish mortality should be a direct function of the abundance of their predator scaled relative to alternative prey abundance. A test of the model using data from the California Current reveals that mortality of larval northern anchovy (Engraulis mordax) shows a significant relationship with the predator-to-prey ratio (pelagic fish biomass/Zooplankton biomass). Other possible interpretations of this result and problems of model parameterization are discussed.

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McFarlane, Gordon A., e Richard J. Beamish. "Effect of an External Tag on Growth of Sabiefish (Anoplopoma fimbria), and Consequences to Mortality and Age at Maturity". Canadian Journal of Fisheries and Aquatic Sciences 47, n.º 8 (1 de agosto de 1990): 1551–57. http://dx.doi.org/10.1139/f90-175.

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Tagged juveniles from a strong year-class of sablefish (Anoplopoma fimbria) were sampled for 9 yr Tagged females were approximately 6 cm larger than untagged females at 50% maturity. Males showed little difference because of their slower growth rate. Untagged males and females matured one and 2 yr earlier than tagged males and females. From this same year-class length-at-age of untagged males and females was significantly larger than for tagged and recaptured fish. Untagged males and females were 6.5 and 8 cm larger than tagged fish by age seven. Smaller tagged fish were recaptured at lower rates than larger tagged fish, indicating that slower growth reduced recapture percentage, which we believe indicates a higher mortality rate. Because smaller size was associated with increased mortality and tagged fish grew slower than untagged fish, we concluded that tagged fish had higher rates of mortality than untagged fish. The increased age and size at 50% maturity and the increased juvenile mortality indicated the potential response of a population of sablefish and possibly other species to a reduction in individual fish growth. If our results apply to other species and other types of tags, investigators should be cautious in extrapolating from tagged to untagged populations.

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Rassweiler, Andrew, e Thomas Rassweiler. "Does rapid scavenging hide non-predation mortality in coral-reef communities?" Marine and Freshwater Research 62, n.º 5 (2011): 510. http://dx.doi.org/10.1071/mf10194.

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Predation is assumed to be a principal cause of adult fish mortality on coral reefs, and therefore a main pathway by which biomass is passed to higher trophic levels. However, the strength of predation has mostly been demonstrated on juvenile fish, and even with juveniles, when predators are excluded, substantial mortality still occurs. Mortality from causes other than predation is rarely considered, because carrion is not common on coral reefs, but the strength of this inference depends crucially on the rate of scavenging. We tested the hypothesis that removal of carrion through scavenging may be very rapid by placing undamaged fish carcasses of a range of species and sizes on reefs in Curaçao, monitoring their rate of disappearance. All carrion was consumed within 24 h and at such rapid rates that, if non-predation mortality were occurring, it would leave little evidence on the reef. Carcasses were consumed almost exclusively by fish, mainly reef-associated piscivores, indicating that scavenged biomass is tightly recycled within the reef fish community. The results of this study suggest that more attention should be paid to quantifying the role of non-predation sources of fish mortality in reef ecosystems.

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Gordoa, Ana, e Carlos M. Duarte. "Size-Dependent Density of the Demersal Fish off Namibia: Patterns within and among Species". Canadian Journal of Fisheries and Aquatic Sciences 49, n.º 10 (1 de outubro de 1992): 1990–93. http://dx.doi.org/10.1139/f92-221.

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The density of the 40 most abundant demersal fish species off Namibia is inversely scaled to their average length, similar to the scaling of mortality to fish length. However, the density of individual fish species is, on average, scaled to the −2 power of average fish length in the aggregates, indicating that biomass increases (slope > −3) during the growth of most species examined. These findings indicate that size structure of these fish populations is primarily determined by mortality.

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Jørgensen, Christian, Bruno Ernande, Øyvind Fiksen e Ulf Dieckmann. "The logic of skipped spawning in fish". Canadian Journal of Fisheries and Aquatic Sciences 63, n.º 1 (1 de janeiro de 2006): 200–211. http://dx.doi.org/10.1139/f05-210.

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That sexually mature fish skip reproduction, especially in response to poor condition, has been documented in many species. We present results from an energy-allocation life history model that shed light on the underlying logic of skipped spawning, based on the Northeast Arctic stock of Atlantic cod (Gadus morhua). The model predicts that skipped spawning is a regular phenomenon, with up to 30% of the sexually mature biomass skipping spawning. Spawning should be skipped if the expected future gain in reproductive output, discounted by survival, more than balances the expected reproductive success the current year. Skipped spawning was most common (i) among potential second-time spawners and (ii) early in life, (iii) when fishing mortality at the spawning grounds was high, (iv) when fishing mortality at the feeding grounds was low, (v) when natural mortality was low, and (vi) when the energetic and mortality costs associated with migration and spawning were high. Cod skipped spawning more often when food availability was both increased (opportunities for better growth) and decreased (too little energy for gonad development), and this pattern interacted with mortality rate. We conclude that skipped spawning may be more widespread than appreciated and highlight potential consequences for the understanding of stockrecruitment relationships.

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Wanja, Daniel W., Paul G. Mbuthia, Robert M. Waruiru, Janet M. Mwadime, Lilly C. Bebora, Philip N. Nyaga e Helena A. Ngowi. "Fish Husbandry Practices and Water Quality in Central Kenya: Potential Risk Factors for Fish Mortality and Infectious Diseases". Veterinary Medicine International 2020 (19 de março de 2020): 1–10. http://dx.doi.org/10.1155/2020/6839354.

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Fish mortality has an enormous impact on the aquaculture industry by reducing fish production and slowing industrial growth. A cross-sectional study was carried out in Kirinyaga County, Central Kenya, to evaluate potential risks of fish mortality and disease transmission and suitability of pond water for rearing fish. A semistructured questionnaire that focused on general information, management practices, and disease history was administered to 92 small-scale fish farmers. Parasitological examination of fish sampled from selected farms (farms that were reporting mortality at the time of sampling) was done by following the standard procedure. Water quality parameters for 33 ponds were evaluated in situ (recorded on pond site) and ex situ (analysed at the laboratory) following the standard methods. The risks were assessed by adjusted odds ratio based on univariate regression analysis. Prevalent fish husbandry practices that were found to be associated with fish mortality and acquisition of pathogens in the study area were the use of raw livestock manure (0R = 1.500), high fish stocking density (0R = 1.168), and feeding fish on homemade rations (0R = 1.128). Parasitological investigation found infestation with Diplostomum spp., Dactylogyrus spp., Clinostomum spp., and Piscicola leeches. Water temperature and pH were found fit for rearing fish. Of the 33 fishpond water samples tested, 1 (3%) and 6 (18%) exceeded the recommended limits of <100 mg/L and <0.2 mg/L of nitrate and nitrite, respectively. Of the 29 fishpond water tested, 15 (59%) exceeded the recommended limits of <100 mg/L of total ammonia. The findings show that the use of raw livestock manure, high fish stocking density, high nitrates and nitrites, and high ammonia levels in fishponds are potential risk factors for fish mortality and acquisition of infectious pathogens in a pond environment in a rural setup, in Central Kenya. There is a need to address the above factors in small-scale farming practices to minimize fish loss and also to prevent the occurrence and spread of infectious pathogens.

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Soudijn, Floor H., P. Daniël van Denderen, Mikko Heino, Ulf Dieckmann e André M. de Roos. "Harvesting forage fish can prevent fishing-induced population collapses of large piscivorous fish". Proceedings of the National Academy of Sciences 118, n.º 6 (2 de fevereiro de 2021): e1917079118. http://dx.doi.org/10.1073/pnas.1917079118.

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Fisheries have reduced the abundances of large piscivores—such as gadids (cod, pollock, etc.) and tunas—in ecosystems around the world. Fisheries also target smaller species—such as herring, capelin, and sprat—that are important parts of the piscivores’ diets. It has been suggested that harvesting of these so-called forage fish will harm piscivores. Multispecies models used for fisheries assessments typically ignore important facets of fish community dynamics, such as individual-level bioenergetics and/or size structure. We test the effects of fishing for both forage fish and piscivores using a dynamic, multitrophic, size-structured, bioenergetics model of the Baltic Sea. In addition, we analyze historical patterns in piscivore-biomass declines and fishing mortalities of piscivores and forage fish using global fish-stock assessment data. Our community-dynamics model shows that piscivores benefit from harvesting of their forage fish when piscivore fishing mortality is high. With substantial harvesting of forage fish, the piscivores can withstand higher fishing mortality. On the other hand, when piscivore fishing mortality is low, piscivore biomass decreases with more fishing of the forage fish. In accordance with these predictions, our statistical analysis of global fisheries data shows a positive interaction between the fishing mortalities of forage-fish stocks and piscivore stocks on the strength of piscivore-biomass declines. While overfishing of forage fish must be prevented, our study shows that reducing fishing pressures on forage fish may have unwanted negative side effects on piscivores. In some cases, decreasing forage-fish exploitation could cause declines, or even collapses, of piscivore stocks.

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Henry, Theodore B., John M. Grizzle, Carol E. Johnston e Jason A. Osborne. "Susceptibility of Ten Fish Species to Electroshock-Induced Mortality". Transactions of the American Fisheries Society 133, n.º 3 (maio de 2004): 649–54. http://dx.doi.org/10.1577/t03-070.1.

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Vanni, Michael J., Chris Luecke, James F. Kitchell, Yvonne Allen, Jo Temte e John J. Magnuson. "Effects on lower trophic levels of massive fish mortality". Nature 344, n.º 6264 (março de 1990): 333–35. http://dx.doi.org/10.1038/344333a0.

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Tsou, Tien-Shui, e Jeremy S. Collie. "Estimating predation mortality in the Georges Bank fish community". Canadian Journal of Fisheries and Aquatic Sciences 58, n.º 5 (1 de maio de 2001): 908–22. http://dx.doi.org/10.1139/f01-044.

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Multispecies virtual population analysis (MSVPA) is one of the most successful methods of including predation in fishery models. By applying MSVPA to nine important fish species on Georges Bank, we estimated predation mortality of prey species, fishing mortality, and population abundance from 1978 to 1992. One of the inputs to the MSVPA, relative stomach content, was estimated by fitting gamma distributions to the logarithmic predator-to-prey size ratios. Chi-square tests indicated that the gamma distributions fit the observed ratios well. Predation mortality was highest at ages 0 and 1. Total biomass of all species remained relatively constant with decreasing predator biomass and increasing prey biomass. MSVPA requires extensive input data, and the uncertainty in the inputs will propagate into the model output. The sensitivity of MSVPA to perturbations in the inputs was assessed with a two-level fractional factorial design. Results of the sensitivity test indicated that MSVPA outputs were most sensitive to predator consumption rates and terminal fishing mortalities. With ±25% perturbations to the input parameters, MSVPA outputs varied within ±10% of the levels from the base run. Therefore, MSVPA appears to be relatively robust to uncertainty in the input data.

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Hightower, Joseph E., e Julianne E. Harris. "Estimating Fish Mortality Rates Using Telemetry and Multistate Models". Fisheries 42, n.º 4 (27 de março de 2017): 210–19. http://dx.doi.org/10.1080/03632415.2017.1276347.

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Myers, Ransom A., e Noel G. Cadigan. "Is Juvenile Natural Mortality in Marine Demersal Fish Variable?" Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 8 (1 de agosto de 1993): 1591–98. http://dx.doi.org/10.1139/f93-180.

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We test the hypothesis that the interannual variability of the density-independent component of juvenile natural mortality is a major source of variability in abundance of marine demersal fish. Our tests use data on populations for which there are research surveys consisting of two simultaneous estimates of abundance of young juveniles soon after settlement and two more simultaneous estimates of the same cohort a year later. We applied our test to 14 populations of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and sole (Solea vulgaris). We conclude that, in all populations examined except North Sea sole, there was very little or no interannual variability in the density-independent component of juvenile mortality.

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Padilla, D., F. Acosta, F. Rodríguez, V. Gómez, S. Déniz e F. Real. "Mortality Caused byStaphylococcus xylosusin Red Porgy (Pagrus pagrus) Fish". Journal of Applied Animal Research 19, n.º 2 (junho de 2001): 203–8. http://dx.doi.org/10.1080/09712119.2001.9706724.

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Tomasallo, Carrie, Henry Anderson, MaryLee Haughwout, Pamela Imm e Lynda Knobeloch. "Mortality among frequent consumers of Great Lakes sport fish". Environmental Research 110, n.º 1 (janeiro de 2010): 62–69. http://dx.doi.org/10.1016/j.envres.2009.09.008.

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Siple, Margaret C., Andrew O. Shelton, Tessa B. Francis, Dayv Lowry, Adam P. Lindquist e Timothy E. Essington. "Contributions of adult mortality to declines of Puget Sound Pacific herring". ICES Journal of Marine Science 75, n.º 1 (7 de junho de 2017): 319–29. http://dx.doi.org/10.1093/icesjms/fsx094.

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Abstract Forage fish undergo dramatic changes in abundance through time. Long-term fluctuations, which have historically been attributed to changes in recruitment, may also be due to changes in adult mortality. Pacific herring, a lightly exploited forage fish in Puget Sound, WA, have exhibited shifts in age structure and decreases in spawning biomass during the past 30 years. Here, we investigate changes in adult mortality as a potential explanation for these shifts. Using a hierarchical, age-structured population model, we indicate that adult natural mortality for Puget Sound Pacific herring has increased since 1973. We find that natural mortality has increased for every age class of adult (age 3+), especially age 4 fish, whose estimated mortality has doubled over the survey time period (from M = 0.84–1.76). We demonstrate that long-term shifts in mortality explain changes in age structure, and may explain biomass declines and failure to reach management thresholds for two spawning sites in Puget Sound (Cherry Point and Squaxin Pass). Temporal shifts in natural adult mortality could have negative implications for herring and herring predators. We demonstrate that adult mortality, in addition to recruitment variation, is an important driver for forage fish, which face exceptionally high natural mortality compared with other fishes.

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Anderson, Deena A., e Frederick S. Scharf. "The effect of variable winter severity on size-dependent overwinter mortality caused by acute thermal stress in juvenile red drum (Sciaenops ocellatus)". ICES Journal of Marine Science 71, n.º 4 (11 de abril de 2013): 1010–21. http://dx.doi.org/10.1093/icesjms/fst041.

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Abstract Mortality during winter can impact the population dynamics of fish at temperate latitudes. The red drum (Sciaenops ocellatus) supports valuable coastal fisheries throughout its range in the southeastern United States. At the northern edge of its distribution, severe winters may cause considerable overwinter loss and size-selective mortality among juveniles. We conducted a series of laboratory experiments to quantify overwinter survivorship of age 0 fish. To determine thermal tolerance, fish were exposed to various minima (1, 3, or 5°C) for up to 14 d. The effect of winter severity on survivorship was then evaluated by exposing fish to simulated cold-front events of varying frequency and duration. Body size was incorporated as a factor into each set of experiments. Age 0 red drum were intolerant of even brief exposure to temperatures ≤3°C and experienced mortality after prolonged exposure to 5°C. Higher frequency of simulated cold-front events impacted survivorship more than longer-event duration, and recovery time between events improved survivorship. Size-dependent mortality was only evident for fish exposed to mild and moderate winter severity conditions, with larger fish surviving longer. For juvenile red drum, severe winters may cause high mortality independent of body size, whereas size-dependent year-class restructuring may occur during milder winters.

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Skrodenytė-Arbačiauskienė, Vesta, Nijolė Kazlauskienė, Milda Vosylienė e Tomas Virbickas. "Aeromonas salmonicida infected fish transfer disease to healthy fish via water". Open Life Sciences 7, n.º 5 (1 de outubro de 2012): 878–85. http://dx.doi.org/10.2478/s11535-012-0066-8.

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AbstractExperimental studies of infection transmission via water from infected to healthy fish were conducted. The dark-brown bacterial colonies typical for Aeromonas salmonicida on tryptone soya agar (TSA) have been isolated and counted (from 3.0±0.6×102 to 3.5±0.5×105 c.f.u. g−1) from the internal organs of naturally infected (NI) and experimentally infected (EI) perch and sea trout. No significant differences in dark-brown bacterial counts were detected between EI perch and EI sea trout. The assessment and comparison of the alterations of the biological parameters of EI European perch and sea trout with bacterium Aeromonas salmonicida subsp. salmonicida with naturally infected perch were conducted. No mortality was recorded in groups of EI perch and sea trout. Whereas, the mortality of NI perch (collected from the main sites of outbreak of disease) was observed from the second day of the experiments. Changes in morphophysiological parameters of EI perch and sea trout were similar. Different alterations in blood cell parameters of EI fish were observed, and the most noticeable was the decrease (P≤0.01) in white blood cell count (WBC) of EI perch and sea trout. Based on these results it can be deduced that there is infection transmission of bacterium A. salmonicida from European perch via water to other fish species.

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Hurst, Thomas P., e David O. Conover. "Winter mortality of young-of-the-year Hudson River striped bass (Morone saxatilis): size-dependent patterns and effects on recruitment". Canadian Journal of Fisheries and Aquatic Sciences 55, n.º 5 (1 de maio de 1998): 1122–30. http://dx.doi.org/10.1139/f98-017.

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Winter mortality plays a significant role in the dynamics of some temperate fish populations and has been shown to be size-dependent for some species, but not for others. Our objective was to determine how winter mortality affects the recruitment dynamics of Hudson River striped bass (Morone saxatilis). We used catch-per-unit-effort data from three separate surveys targeting young-of-the-year (YOY), overwintering, and age 1 striped bass. Age 1 abundance was negatively correlated with the severity of winter. In contrast, the abundance of age 0 fish was not correlated with age 1 abundance, suggesting that winter mortality greatly modifies year-class strength. A progressive increase in the mean length of YOY fish, coupled with a decrease in the coefficient of variation in length, occurred during some winters. Laboratory experiments showed that growth in length requires temperatures in excess of 10°C; hence, these changes likely result from selective mortality of smaller fish. Direct evidence of size-dependent mortality was obtained from a laboratory experiment that exposed fish to ambient conditions throughout the winter. Accounting for interannual differences in the severity and size dependency of winter mortality may improve our ability to evaluate striped bass year-class strength in the Hudson River.

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