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1
Setiaji, J., J. Hariwitonang, T. I. Johan, and Heriyanto. "Antibacterial Activity of Ethanolic Extracts from Jeringau (Acorus calamus)." IOP Conference Series: Earth and Environmental Science 1118, no. 1 (December 1, 2022): 012006. http://dx.doi.org/10.1088/1755-1315/1118/1/012006.
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Abstract Increased resistance of pathogenic bacteria due to the use of antibiotics has become a major concern in the aquaculture industry. Environmentally friendly products are urgently needed to replace antibiotics for the treatments of fish diseases. This study aims to determine the activity of extract of Jeringau (Acorus calamus) as an antibacterial towards Aeromonas hydrophila, Pseudomonas aeruginosa and Vibrio alginolyticus. The A. calamus extract was obtained by maceration using ethanol as a solvent. This extract was tested for its phytochemical content and its antibacterial activity was tested using the agar diffusion method. The treatments used were concentrations of A. calamus extract 200, 300, 400, 500 and 600 mg mL-1. Phytochemical test results of A. calamus extract produced alkaloids, phenolic compounds, saponins, terpenoids and flavonoids. The results of the inhibition test showed that A. calamus extract with a concentration of 200 was able to inhibit the growth of Aeromonas hydrophila bacteria by 13.9 mm, 300 (14.4 mm), 400 (14.8 mm), 500 (16.2 mm), 600 (16.5 mm). On Pseudomonas aeruginosa, the concentrations were 200 (13.9 mm), 300 (14.5 mm), 400 (15.2 mm), 500 (15.5 mm), 600 (16.2 mm). On Vibrio alginolyticus, the concentrations were 200 (15.5 mm), 300 (15.7 mm), 400 (16.4 mm), 500 (18.7 mm), 600 (19 mm). In conclusion, A. calamus extract can be used to inhibit the growth of pathogenic bacteria in fish.
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Khyl, A. M., and S. B. Peredera. "Toxicological properties of plant-based disinfectants." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 26, no. 113 (February 24, 2024): 140–44. http://dx.doi.org/10.32718/nvlvet11321.
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The article presents the results of research on the toxicity determination of phytopreparations in the composition of common powdery mildew + calamus + pear Late November + bischofite; common powdery mildew + calamus + bischofite; pear Late November + bischofite, which have a universally broad spectrum of bactericidal action against Staphylococcus aureus and Escherichia coli. When studying the toxicity of phytopreparations on guppy fish, it was found that when adding the infusion to water in the composition of common powdery mildew + calamus + pear Late November + bischofite with exposures of 30 minutes and 60 minutes, all fish in a group of 10 had an adverse reaction. With an exposure of 24 hours, mortality reached up to 20 %. The highest fish mortality occurred at 24 hours in the composition of common powdery mildew + calamus + bischofite, with a mortality rate of 40 %. The composition of pear in late November + bischofite showed no signs of toxicity; all fish in the group remained alive during the study. Visually, motor activity, behavioral reactions, changes in skin pigmentation, and breathing intensity were average. The survey of skin-irritating effects of phytopreparations was conducted on laboratory animals in 20 individuals – Alaska breed rabbits. It was established that during the observation period, the following signs were absent: the presence of temperature; moderately expressed, expressed, and sharply expressed erythema; pain (with a slight thickening of the skin followed by flaking); pain, swelling, and ulcers (thickening of the skin in the application area on the rabbit). After applying phytopreparations to the skin of rabbits with exposures of 1 hour, 24 hours, 48 hours, and 72 hours, no behavioral and visual changes of an inflammatory nature were detected. When applied to the animal's skin, the investigated plant-based disinfectants do not cause irritating, necrotic, or absorptive effects. Throughout the observation period, no visible changes were observed in laboratory animals' experimental and control groups. The conducted research indicates the possibility of safe application of these plant-based disinfectants in the presence of animals.
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Burton, Michael L., Jennifer C. Potts, Ariel Poholek, Jordan Page, and Dalton Knight. "Age, Growth, and Natural Mortality of Whitebone Porgy, Calamus Leucosteus, From the Southeastern United States." Aquatic Science and Technology 9, no. 2 (March 25, 2021): 22. http://dx.doi.org/10.5296/ast.v9i2.16220.
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Ages of whitebone porgy (Calamus leucosteus) (n = 559) from southeastern U. S. commercial and recreational fisheries from 1975 – 2017 were determined using sectioned otoliths. Opaque zones were annular, forming April – July (peaking in June). Ages ranged from 2 – 19 years, and the largest fish measured 513 mm TL (total length, mm). Body size relationships were: TL = 1.09 FL + 16.07 (n = 469, r2 = 0.97), FL = 0.89 TL – 6.39 (n= 469, r2 = 0.97), W = 2.8 x 10-5 TL2.91 (n = 462), and W = 6.8 x 10-5 FL2.82 (n = 417) where W is total weight (grams, g) and FL is fork length (mm). The von Bertalanffy growth equations were Lt = 365 (1 - e-0.35 (t + 1.37)) (n = 559) for all areas combined, Lt = 365 (1 - e-0.55(t + 0.00)) (n = 185) for fish from North Carolina through Cape Canaveral, Florida, and Lt = 368 (1 - e-0.25 (t + 2.51)) (n = 374) for fish from southeast Florida. Mean size-at-age was significantly different between regions for ages 4 – 9, (92% of total samples). Point estimates of natural mortality were M = 0.22 and M = 0.30 for northern- and southern-region fish, respectively, while age-specific estimates of M were 0.85 – 0.55 y-1 for ages 2– 19 for the northern region and 0.41 – 0.26 (ages 2-14) for southern region fish. This study presents updated life history parameters for whitebone porgy from the Atlantic waters off the southeastern United States.
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Burton, Michael L., Jennifer C. Potts, Jordan Page, and Ariel Poholek. "Age, growth, mortality and reproductive seasonality of jolthead porgy, Calamus bajonado, from Florida waters." PeerJ 5 (September 8, 2017): e3774. http://dx.doi.org/10.7717/peerj.3774.
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Ages of jolthead porgy (Calamus bajonado Schneider 1801) (n = 635) from Florida commercial and recreational fisheries from 2008–2016 were determined using sectioned sagittal otoliths. We determined, using edge-type analysis, that opaque zones were annular, forming March–June (peaking in April). Jolthead porgy ranged from 1–13 years, and the largest fish measured 680 mm TL (total length, mm). Body size relationships for jolthead porgy were TL = 1.09FL + 20.44 (n = 622, r2 = 0.99), FL = 0.90 TL –14.26 (n = 622, r2 = 0.99), and W = 1.1 × 10−5 TL3.06 (n = 577), where W is total weight (grams, g) and FL is fork length (mm). The von Bertalanffy growth equation for jolthead porgy was Lt = 737(1 − e−0.14(t+2.02)) (n = 635). Point estimate of natural mortality was M = 0.32, while age-specific estimates of M ranged from 0.58–0.17 y−1 for ages 1–13. Catch curve analysis estimated the instantaneous rate of total mortality Z = 0.70, while instantaneous rate of fishing mortality F was 0.38. Macroscopic staging of female gonads indicated the presence of hydrated oocytes from December–March, and GSI data indicates that peak spawning in females occurs during March. This study presents the first published findings of life history parameters for jolthead porgy from the Atlantic waters off the southeastern United States.
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Cruces, Celso Luis, Jhon Darly Chero, Gloria Sáez, and José Luis Luque. "Redescripción de Haliotrematoides mediohamides (Monogenea: Dactylogyridae), un parásito branquial del sargo Calamus brachysomus (Perciformes: Sparidae) del océano Pacífico oriental." Revista Mexicana de Biodiversidad 93 (December 7, 2022): e933960. http://dx.doi.org/10.22201/ib.20078706e.2022.93.3960.
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The monogenean Haliotrematoides mediohamides Kritsky & Mendoza-Franco, 2009 (Monogenea: Dactylogyridae) is redescribed based on examination of the type specimen (paratypes) and newly collected specimens parasitizing the gills of the Pacific porgy, Calamus brachysomus (Lockington, 1880) (Perciformes: Sparidae) (type host), a neritic fish captured off the coastal zone of Puerto Pizarro, Tumbes, Peru. Even though this monogenean was described 12 years ago, that description did not report some of the unique morphological features of H. mediohamides and neither did it offer a whole-mount drawing of this species. The most important characteristics of H. mediohamides are: 1) a male copulatory organ with hook-shaped distal end, 2) a non-coiled vaginal duct, 3) numerous secretory gland-cells associated with the peduncle, 4) a chandelier-shaped extrinsic adductor muscles articulated with superficial roots of the anchors, 5) a single tadpole-shaped prostatic reservoir, and 6) a vas deferens anteriorly convoluted. In addition, the first whole-mount drawing of H. mediohamides, as well as morphometric data are provided. Haliotrematoides mediohamides represents the first record of Haliotrematoides in South America. Haliotrematoides mediohamides is the third dactylogyrid species recorded to infect C. brachysomus in Peru.
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NORMAN, MARK D., and F. G. HOCHBERG. "The "Mimic Octopus" (Thaumoctopus mimicus n. gen. et sp.), a new octopus from the tropical Indo-West Pacific (Cephalopoda: Octopodidae)." Molluscan Research 25, no. 2 (2005): 57–70. http://dx.doi.org/10.11646/mr.25.2.1.
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In recent years considerable media attention has been focussed on the “Mimic Octopus”, an Indo-West Pacific long-armed species which impersonates numerous poisonous or dangerous animals. This distinctive octopus is here described. A combination of unique morphological characters justify this octopus being placed in a new genus. These characters include: absence of a calamus on the copulatory organ, absence of enlarged suckers in either sex; long narrow arms capable of arm autotomy at a set level near the base; and distinctive base components of colour patterns including a white teardrop ring on the mid-dorsal mantle and a distinct white “U” patch on the posterio-dorsal mantle. Thaumoctopus mimicus n. gen. et sp. is reported primarily from the Indo-Malayan Archipelago from New Caledonia to Indonesia, Malaysia and the Philippines. Photographic records from the Red Sea extend the distribution to the western Indian Ocean. This octopus occurs in shallow waters (0.5–37 m) on soft sediment substrates where it is day-active, foraging for small fish and crustaceans. It is delineated from other long-armed genera and species complexes within the genus Octopus. Other undescribed species are flagged as potential members of the new genus Thaumoctopus. Links between habitat preference and the origins of this unique mimicry are explored.
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Bhavani, M., and M. Elumalai. "Phytoconstituents Profile of Acorus calamus, Cardiospermum halicacabum and Solanum nigrum as Potential Source of Fish Feed Supplementation with Reference to the Bioactive Compounds." International Journal of Zoological Investigations 9, no. 1 (2023): 845–57. http://dx.doi.org/10.33745/ijzi.2023.v09i01.095.
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López-Rocha, Jorge A., Laura Vidal-Hernández, and Arturo Bravo-Calderón. "Length-based indicators for the management of sport fishery in Yucatan, Mexico." Latin American Journal of Aquatic Research 48, no. 4 (September 1, 2020): 637–48. http://dx.doi.org/10.3856/vol48-issue4-fulltext-2414.
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Sportfishing is an activity of increasing popularity that involves a large number of users and high levels of fishing effort. In Yucatan, most of the target species in sport fishing are the same as those of commercial fisheries. However, there is no record of fishing effort or catch volumes. Thus the impact of sport fishing on these populations is unknown. This study analyzes the catches made by users of sport fisheries of nine species (Epinephelus morio, Haemulon plumieri, Seriola dumerili, Lutjanus synagris, Ocyurus chrysurus, Calamus bajonado, Sphyraena barracuda, S. guachancho and Mycteroperca bonaci) through length-based indicators. Samples of species’ sizes were obtained from the catches made during 10 fishing tournaments held in Yucatan's three-port towns (Sisal, Yucalpeten, and Telchac) between 2015 and 2016. The catch variables that were evaluated included: the number of mature individuals Pmat, optimal length Popt, and the number of mega-spawners Pmega. Length measures were derived from 1,252 individuals. Only H. plumieri, L. synagris, and S. guachancho exhibited sustainable indicator values, while E. morio and C. bajonado demonstrated extremely low values. In most species, sport fishing affects a high proportion of juveniles. The results suggest that sportfishing contributes to the fishing pressure of a species and commercial fishing, due to the capture of juveniles of economically important fish. It is essential to establish a systematic monitoring method of such activities and increase the priority level of the evaluation and management of this fishery.
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Bøgwald, Isak, Simon Herrig, Alice Marie Pedersen, Sileshi Gizachew Wubshet, and Karl-Erik Eilertsen. "Effect of Calanus finmarchicus Hydrolysate Inclusion on Diet Attractiveness for Whiteleg Shrimp (Litopenaeus vannamei)." Fishes 9, no. 4 (April 13, 2024): 134. http://dx.doi.org/10.3390/fishes9040134.
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Shrimp feed formulations have moved towards less fish meal and more of the readily available and cheaper plant proteins. To counteract the lower attractiveness and palatability of plant proteins, feeds are supplemented with ingredients known to have chemoattractive properties that will increase feed intake. This study investigated the putative chemoattractive effect of Calanus finmarchicus hydrolysate, when used as a dietary supplement in shrimp feeds. C. finmarchicus is a zooplankton species native to the northern Atlantic Ocean and is a novel and sustainable raw material for shrimp feed products. Diet attractiveness was evaluated in a 24-day feeding trial with whiteleg shrimp (Litopenaeus vannamei) by measuring the intake of 12 diets with various levels of fish meal, calanus hydrolysate, and krill (Euphausia superba) meal. Higher inclusion rates of both ingredients resulted in increased feed intakes, and supplementing the high fish meal diet with calanus hydrolysate gave a statistically significant higher feed intake. Low molecular weight peptides, chemoattractive amino acids, and the water-soluble nature of the hydrolysate could explain the chemoattractive properties observed in the study.
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Aarflot, Johanna Myrseth, Hein Rune Skjoldal, Padmini Dalpadado, and Mette Skern-Mauritzen. "Contribution of Calanus species to the mesozooplankton biomass in the Barents Sea." ICES Journal of Marine Science 75, no. 7 (December 15, 2017): 2342–54. http://dx.doi.org/10.1093/icesjms/fsx221.
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Abstract Copepods from the genus Calanus are crucial prey for fish, seabirds and mammals in the Nordic and Barents Sea ecosystems. The objective of this study is to determine the contribution of Calanus species to the mesozooplankton biomass in the Barents Sea. We analyse an extensive dataset of Calanus finmarchicus, Calanus glacialis, and Calanus hyperboreus, collected at various research surveys over a 30-year period. Our results show that the Calanus species are a main driver of variation in the mesozooplankton biomass in the Barents Sea, and constitutes around 80% of the total. The proportion of Calanus decreases at low zooplankton biomass, possibly due to a combination of advective processes (low C. finmarchicus in winter) and size selective foraging. Though the Calanus species co-occur in most regions, C. glacialis dominates in the Arctic water masses, while C. finmarchicus dominates in Atlantic waters. The larger C. hyperboreus has considerably lower biomass in the Barents Sea than the other Calanus species. Stages CIV and CV have the largest contribution to Calanus species biomass, whereas stages CI-CIII have an overall low impact on the biomass. In the western area of the Barents Sea, we observe indications of an ongoing borealization of the zooplankton community, with a decreasing proportion of the Arctic C. glacialis over the past 20 years. Atlantic C. finmarchicus have increased during the same period.
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Opdal, Anders Frugård, and Frode B. Vikebø. "Long-term stability in modelled zooplankton influx could uphold major fish spawning grounds on the Norwegian continental shelf." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 2 (February 2016): 189–96. http://dx.doi.org/10.1139/cjfas-2014-0524.
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Early life stages of fish spawned on the Norwegian continental shelf have long been suggested to depend on eggs and nauplii from the crustacean zooplankton Calanus finmarchicus for survival. Calanus finmarchicus overwinters in the deep basins of the Norwegian Sea, and gravid females must be advected onto the shelf prior to spawning if eggs and nauplii larvae are to serve as food for fish larvae. In this study, cross-shelf advection of C. finmarchicus is simulated over 52 years (1960–2011) using a numerical ocean model coupled with an individual-based model. The results suggest that cross-shelf transport of C. finmarchicus is surprisingly stable across years and that transport is particularly concentrated immediately upstream of the two major spawning areas for the Northeast Arctic cod (Gadus morhua) and the Norwegian spring-spawning herring (Clupea harengus), namely Lofoten and Møre, respectively. Two large topographical features, the Træna Trough and the Norwegian Trench, appear to be funnelling C. finmarchicus onto the shelf in these two areas. This could suggest that the fish spawning grounds outside Møre and Lofoten are, in part, maintained owing to stable interannual food supply in spring.
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Zagorodnyaya, Yu A., and I. V. Vdodovich. "Identifying nauplial stages of the Black Sea copepods of Calanidae family in fish larvae guts." Marine Biological Journal 4, no. 3 (September 30, 2019): 101–3. http://dx.doi.org/10.21072/mbj.2019.04.3.10.
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Nauplial stages of copepods are known to be the main food items for fish larvae. Their identification in fish larvae guts is usually a difficult task and a time-consuming procedure. Original approach to identification of larvae and juvenile fish common food items – nauplial stages of the Black Sea copepods of family Calanidae – is proposed. This work is a continuation of the initiated studies on the developing a method for determining the juvenile copepod stages from fish larvae guts. On the example of nauplial stage III of Calanus euxinus Hulsemann, 1991, specific features that can be used in identifying nauplial stages of three species of the Black Sea copepods from fish larvae guts are shown.
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Eilertsen, Hans Chr, Edel Elvevoll, Ingeborg Hulda Giæver, Jon Brage Svenning, Lars Dalheim, Ragnhild Aven Svalheim, Birthe Vang, et al. "Inclusion of photoautotrophic cultivated diatom biomass in salmon feed can deter lice." PLOS ONE 16, no. 7 (July 29, 2021): e0255370. http://dx.doi.org/10.1371/journal.pone.0255370.
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The aim of this study was to evaluate the potential of diatom (microalgae) biomass as a lice-reducing ingredient in salmon feed. The original hypothesis was based on the fact that polyunsaturated aldehydes (PUAs), e.g. 2-trans, 4-trans decadenial (A3) produced by diatoms can function as grazing deterrents and harm copepod development. Salmon lice (Lepeophtheirus salmonis) is a copepod, and we intended to test if inclusion of diatom biomass in the feed could reduce the infestation of lice on salmon. We performed experiments where salmon kept in tanks were offered four different diets, i.e. basic feed with diatoms, fish oil, Calanus sp. oil or rapeseed oil added. After a feeding period of 67 days a statistically representative group of fishes, tagged with diet group origin, were pooled in a 4000L tank and exposed to salmon lice copepodites whereafter lice infestation was enumerated. Salmon from all four diet groups had good growth with SGR values from 1.29 to 1.44% day-1 (increase from ca. 130 g to 350 g). At the termination of the experiment the number of lice on salmon offered diatom feed were statistically significantly lower than on salmon fed the other diets. Mean lice infestation values increased from diatom feed through Calanus and fish oil to standard feed with terrestrial plant ingredients. Analysis of the chemical composition of the different diets (fatty acids, amino acids) failed to explain the differences in lice infestation. The only notable result was that diatom and Calanus feed contained more FFA (free fatty acids) than feed with fish oil and the control feed. None of the potential deleterious targeted polyunsaturated aldehydes could be detected in skin samples of the salmon. What was exclusive for salmon that experienced reduced lice was diatom inclusion in the feed. This therefore still indicates the presence of some lice deterring ingredient, either in the feed, or an ingredient can have triggered production of an deterrent in the fish. An obvious follow up of this will be to perform experiments with different degrees of diatom inclusion in the feeds, i.e. dose response experiments combined with targeted PUA analyses, as well as to perform large scale experiments under natural conditions in aquaculture pens.
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Vega-Cendejas, María Eugenia, Mirella Hernandez de Santillana, and Steven Norris. "Habitat characteristics and environmental parameters influencing fish assemblages of karstic pools in southern Mexico." Neotropical Ichthyology 11, no. 4 (2013): 859–70. http://dx.doi.org/10.1590/s1679-62252013000400014.
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Fish assemblage structure was evaluated and compared among 36 karstic pools located within protected areas of the Calakmul Biosphere Reserve (southern Mexico) and unprotected adjacent areas beyond the Reserve. Nonmetric multidimensional scaling (MDS), indicator species analysis (ISA), and canonical correspondence analysis (CCA) were used to identify which environmental factors reflected local influences and to evaluate the correlation of these variables with fish assemblages structure. Thirty-one species were encountered in these karstic pools, some for the first time within the Reserve. These aquatic environments were separated into three groups based on physico-chemical characteristics. Although CCA identified significant associations between several fish species (based on their relative abundance) and environmental variables (K, NH4, NO3, and conductivity), the most abundant species (Astyanax aeneus, Poecilia mexicana, and Gambusia sexradiata ) occur in most pools and under several environmental conditions. Baseline data on fish diversity along with a continued monitoring program are essential in order to evaluate the conservation status of fish assemblages and their habitats, as well as to measure the influence of anthropogenic impacts on pristine habitats such as the karstic pools of the Calakmul Biosphere Reserve.
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Landaeta, Mauricio F., Javier Vera-Duarte, María José Ochoa-Muñoz, Claudia A. Bustos, and Fernando Balbontín. "Feeding ecology of fish larvae from Chilean Patagonia during austral winter." Revista de Biología Marina y Oceanografía 54, no. 2 (September 13, 2019): 221. http://dx.doi.org/10.22370/rbmo.2019.54.2.1906.
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Feeding habits of the ichthyoplankton from Chilean Patagonia (44-46°30’S) were studied during June-July 2012 (austral winter). Ichthyoplankton assemblage was composed by 10 species, with low abundance (3.8 to 16.73 ind. 1000 m-3). Most abundant larvae were Maurolicus parvipinnis, Leptonotus blainvilleanus and Sprattus fuegensis. These three species fed mainly on calanoid copepodites, Paracalanus indicus and Calanus sp. copepodites, and cyphonautes. Trophic overlap among dominant fish larvae was high (Schoener’s D > 0.69) and no significant differences were detected in prey composition and size. Therefore, no resource partitioning occurred in planktonic fish larvae during winter 2012 in Chilean Patagonia.
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Petursdottir, Hildur, Stig Falk-Petersen, and Astthor Gislason. "Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis." ICES Journal of Marine Science 69, no. 7 (September 1, 2012): 1277–88. http://dx.doi.org/10.1093/icesjms/fss125.
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Abstract Petursdottir, H., Falk-Petersen, S., and Gislason, A. 2012. Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis. – ICES Journal of Marine Science, 69: . A trophic study was carried out in August of 2007 and 2008 on the pelagic ecosystem in the Subarctic Iceland Sea. Carbon and nitrogen stable isotopes and fatty acid biomarkers were used to study trophic linkages and the trophic ecology of the most important pelagic species in this ecosystem, with emphasis on capelin (Mallotus villosus). According to 15N enrichment results, there are 3–4 trophic levels in this ecosystem excluding organisms of the microbial loop and birds and mammals. The primarily herbivorous copepod Calanus hyperboreus occupies the lowest trophic level of the animal species studied, and adult capelin and blue whiting (Micromesistius poutassou) occupy the highest level. Calanus spp. proved to be an important dietary component of most of the species studied, the euphausiid species Thysanoessa inermis and T. longicaudata being exceptions. The chaetognath Eukrohnia hamata is a pure carnivore, feeding heavily on Calanus spp., whereas most of the other zooplankton species studied practice an omnivorous–carnivorous feeding mode. The amphipod species Themisto libellula is important in the diet of adult capelin. Adult capelin and blue whiting share the same feeding habits and could therefore be competing for food.
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Dalheim, Lars, Jon Brage Svenning, and Ragnar Ludvig Olsen. "In vitro intestinal digestion of lipids from the marine diatom Porosira glacialis compared to commercial LC n-3 PUFA products." PLOS ONE 16, no. 6 (June 9, 2021): e0252125. http://dx.doi.org/10.1371/journal.pone.0252125.
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Marine sources of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) are in high demand for use in health supplements. Mass cultivated marine microalgae is a promising and sustainable source of LC n-3 PUFA, which relieves pressure on natural fish stocks. The lipid class profile from cultivated photosynthetic algae differ from the marine organisms currently used for the production of LC n-3 PUFA. The objective of this study was to compare in vitro intestinal digestion of oil extracted from the cold-adapted marine diatom Porosira glacialis with commercially available LC n-3 PUFA supplements; cod liver oil, krill oil, ethyl ester concentrate, and oil from the copepod Calanus finmarchicus (Calanus® oil). The changes in the free fatty acids and neutral and polar lipids during the enzymatic hydrolysis were characterized by liquid and gas chromatography. In Calanus® oil and the Ethyl ester concentrate, the free fatty acids increased very little (4.0 and 4.6%, respectively) during digestion. In comparison, free fatty acids in Krill oil and P. glacialis oil increased by 14.7 and 17.0%, respectively. Cod liver oil had the highest increase (28.2%) in free fatty acids during the digestion. Monounsaturated and saturated fatty acids were more easily released than polyunsaturated fatty acids in all five oils.
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González-Quirós, R., J. Cabal, F. Álvarez-Marqués, and A. Isla. "Ichthyoplankton distribution and plankton production related to the shelf break front at the Avilés Canyon." ICES Journal of Marine Science 60, no. 2 (January 1, 2003): 198–210. http://dx.doi.org/10.1016/s1054-3139(03)00009-2.
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Abstract The overall objective of this study was to search for spatial differences in primary production and its transference towards larval fish related with the distribution of water masses at shelf break of the Avilés Canyon. High primary production and ichthyoplankton abundance were associated with a shelf break front at the Avilés Canyon. Egg distributions of Scomber scombrus, Sardina pilchardus and Trachurus trachurus, coupled with topography, the associated physical structure and phytoplankton productivity, suggested adaptive spawning strategies. The distribution of copepod stages, which are considered the trophic link between primary producers and fish larvae, was not related with the position of the front. Moreover, the egg production of two abundant species (Calanus helgolandicus and Acartia clausi) was not significantly related with phytoplankton abundance and productivity.
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Cleary, Alison C., Janne E. Søreide, Daniela Freese, Barbara Niehoff, and Tove M. Gabrielsen. "Feeding by Calanus glacialis in a high arctic fjord: potential seasonal importance of alternative prey." ICES Journal of Marine Science 74, no. 7 (July 25, 2017): 1937–46. http://dx.doi.org/10.1093/icesjms/fsx106.
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Abstract The copepod species Calanus glacialis is an important component of arctic marine food webs, where it is the numerically dominant zooplankton grazer and serves as a major prey item for fish, seabirds, and other predators. These copepods are typically considered to be phytoplanktivorous, although they are also known to feed on microzooplankton, and little is known about their diet in fall and winter. To investigate their feeding, C. glacialis gut contents were analyzed over an annual cycle in a seasonally ice covered arctic fjord using next generation sequencing of 18S rDNA. During the spring bloom, diatoms, particularly Thalassiosira spp., were important contributors to the dietary sequence reads. In addition to diatoms, Chytridiomycetes, fungal parasites of diatoms, also made up a large proportion of dietary sequence reads during this productive season. This provides one of the first indications of the potential importance of the mycoloop in marine environments. Just prior to the spring bloom, chaetognath sequences dominated the prey sequence reads from C. glacialis, suggesting potential predation on eggs or other early life stages of chaetognaths by C. glacialis. Other indications of omnivorous feeding outside of the spring bloom period included sequence reads from polychaetes in summer, at the time of peak polychaete larval abundance, and from Metridia spp. (Copepoda) in winter in prey sequences from C. glacialis. Incorporating such predation into our knowledge of Calanus spp. behaviour may help refine our understanding of Calanus spp. ecology, and potential responses of C. glacialis to ongoing climate change.
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van Deurs, Mikael, Marja Koski, and Anna Rindorf. "Does copepod size determine food consumption of particulate feeding fish?" ICES Journal of Marine Science 71, no. 1 (September 5, 2013): 35–43. http://dx.doi.org/10.1093/icesjms/fst090.
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Abstract van Deurs, M., Koski, M., and Rindorf, A. Does copepod size determine food consumption of particulate feeding fish? – ICES Journal of Marine Science, 71: . The climate-induced reduction in the mean copepod size, mainly driven by a decrease in the abundance of the large Calanus finmarchicus around 1987, has been linked to the low survival of fish larvae in the North Sea. However, to what extent this sort of reduction in copepod size has any influence on adult particulate feeding fish is unknown. In the present study, we investigated the hypothesis that the availability of the large copepods determines food consumption and growth conditions of lesser sandeel (Ammodytes marinus) in the North Sea. Analysis of stomach content suggested that food consumption is higher for fish feeding on large copepods, and additional calculations revealed how handling time limitation may provide part of the explanation for this relationship. Comparing stomach data and zooplankton samples indicated that lesser sandeel actively target large copepods when these are available. Finally, we observed that the length of lesser sandeel began to decrease in the late 1980s, simultaneously with the C. finmarchicus decline.
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Ceyhan, Tevfik, Okan Akyol, T. Murat Sever, and Ali Kara. "Diet composition of adult twaite shad (Alosa fallax) in the Aegean Sea (Izmir Bay, Turkey)." Journal of the Marine Biological Association of the United Kingdom 92, no. 3 (June 9, 2011): 601–4. http://dx.doi.org/10.1017/s0025315411000750.
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Specimens of twaite shad, Alosa fallax were sampled from commercial purse seiners and trammel netters in Izmir Bay during November and December 2007. A total of 287 prey items from 14 taxa from 208 stomachs were recorded. The primary food of twaite shad was found to be fish, especially anchovy Engraulis encrasicolus, which was the most frequent (%F = 66.11) and abundant (%N = 63.64) prey item, and also had the highest percentage by weight (%W = 81.91). Decapoda, Isopoda, Ostracoda and Copepoda (Calanus spp., Candocia armata, Temora stylifera from Calanoida and Corycaeus spp. from Cyclopodia), were recorded occasionally with low values for all indices. The study showed that in the Aegean Sea Alosa fallax is a predator of small pelagic fish, E. encrasicolus, A. boyeri, S. pilchardus, and some crustaceans. Benthopelagic P. acarne and demersal S. hepatus were first recorded in diet of twaite shad.
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Kristiansen, Inga, Eilif Gaard, Hjálmar Hátún, Sigrún Jónasdóttir, and A. Sofia A. Ferreira. "Persistent shift of Calanus spp. in the southwestern Norwegian Sea since 2003, linked to ocean climate." ICES Journal of Marine Science 73, no. 5 (December 17, 2015): 1319–29. http://dx.doi.org/10.1093/icesjms/fsv222.
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Abstract The southwestern Norwegian Sea is characterized by an inflow of warm and saline Atlantic water from the southwest and cold and less saline East Icelandic Water (EIW), of Arctic origin, from the northwest. These two water masses meet and form the Iceland-Faroe Front (IFF). In this region, the copepod Calanus finmarchicus plays a key role in the pelagic ecosystem. Time-series of C. finmarchicus and Calanus hyperboreus in May and September, extending back to the early 1990s, were studied in relation to phytoplankton bloom dynamics and hydrography. The main reproductive period of C. finmarchicus started consistently earlier south of the IFF, resulting in different life cycles and stage compositions in the two water masses. In 2003, a sudden shift occurred north of the IFF, resulting in a similar phenology pattern to south of the IFF. Before this, only one generation of C. finmarchicus was produced in the Arctic water, but the earlier reproduction enabled the species to produce two generations after 2003. Simultaneously, C. hyperboreus, an expatriate in the EIW, largely disappeared. Food availability is unlikely the reason for the phenological differences observed across the front, as the typical pattern of the phytoplankton spring bloom showed an earlier onset north of the IFF. Temperature and salinity peaked at record high values in 2003 and 2004, and therefore possible links to oceanography are discussed. The dominant role of Calanus spp. and the potential linkages to water mass exchanges may herald strong effects on the ecosystem and pelagic fish in this subpolar Atlantic region under expected climate change.
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Sakınan, Serdar, and Ali Cemal Gücü. "Spatial distribution of the Black Sea copepod, Calanus euxinus, estimated using multi-frequency acoustic backscatter." ICES Journal of Marine Science 74, no. 3 (November 6, 2016): 832–46. http://dx.doi.org/10.1093/icesjms/fsw183.
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The copepod Calanus euxinus is a key prey species for fish in the Black Sea. To estimate the distribution and biomass of the late developmental stages of this species in July 2013, we analysed multi-frequency (38, 120, and 200 kHz) echo-sounder data from a fisheries survey of the Black Sea. The dependence of acoustic backscatter on frequency, i.e. the frequency response, was estimated for daytime scattering layers, which were confirmed by net catches to be dense, post-copepodite-stage (C4) aggregations of C. euxinus with prosome lengths greater than 2 mm. The high-resolution acoustic observations revealed that the nighttime, shallow distribution was bounded by the lower portion of the thermocline and that the daytime, deep distribution was bounded by oxygen. The dense and isolated aggregations were observed in seawater with a specific density, σT, of between 15.2 and 15.9 kg m−3. These results show that fisheries acoustic surveys, typically targeting only commercially exploited fish species, may also provide information on the lower trophic levels and thereby serve as an ecosystem-monitoring tool.
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Vanegas-Ríos, James Anyelo, Alexander Urbano-Bonilla, and Gian Carlo Sánchez-Garcés. "A new species of Chrysobrycon Weitzman & Menezes, 1998 (Characiformes, Characidae, Stevardiinae) with remarkable sexually dimorphic pigmentation from the upper Río Vaupés basin, Colombian Amazon, with taxonomic key." Zoosystematics and Evolution 100, no. 2 (May 28, 2024): 675–89. http://dx.doi.org/10.3897/zse.100.121499.
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This study describes Chrysobrycon calamar, a new stevardiine fish from the upper Río Vaupés basin in Colombia. The new species differs from its congeners by the following combined characters: adult males have a dark vertical blotch on the abdominal flanks that is confined to a small area immediately dorsal to the urogenital region and anterior to the third anal-fin ray; adult males with a well-developed vertically humeral blotch, numerous tiny bony hooks on nearly all the upper lobe caudal-fin rays (except C. guahibo, C. hesperus, and C. mojicai), and bony hooks on nearly all branched anal-fin rays (except C. hesperus); the number of vertebrae (43 vs. 38–42); an elongated maxillary anterior process, representing 40% or more of the total length of the bone (vs. with a shorter maxillary anterior process, representing less than 40% of that length); and the posterior portion of the maxilla not reaching the vertical through the anterior border of the eye when the mouth is closed (except from C. yoliae). Additionally, C. calamar differs from C. mojicai by the number of maxillary teeth (2–4 vs. 9–17) and shape of the distal tips of most maxillary teeth (straight along their lengths vs. lateroventrally curved). Remarks on the interspecific color variation associated with sexual dimorphism and other characteristics of the genus are provided. A key to the species of Chrysobrycon is presented. The discovery of C. calamar is a key advance in the understanding of fish biodiversity associated with endemism-rich regions that could be explored after the guerrilla demobilized in Colombia.
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Hop, H., W. M. Tonn, and H. E. Welch. "Bioenergetics of Arctic cod (Boreogadus saida) at low temperatures." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 8 (August 1, 1997): 1772–84. http://dx.doi.org/10.1139/f97-086.
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The Arctic cod (Boreogadus saida), a key component of the marine food web of Canadian high Arctic waters, occurs at temperatures close to or below zero. We established a complete energy budget for this Arctic fish, based on laboratory measurements of consumption (C), growth (G), respiration (R), egestion (F), and excretion (U) at about 0°C. An average (N = 3) energy budget for individual juvenile Arctic cod fed live Arctic zooplankton was 100C = 50G + 24R + 9SDA + 3F + 6U + 8Z, where SDA is specific dynamic action (derived from previously published studies) and Z included activity and unaccounted energy. Eight determinations of total energy budgets for fish fed to satiation accounted for 72-104% of the energy consumed. Maximum daily rations and growth rates were dependent on fish size and the energy content of prey. Although maximum daily rations were similar for small fish fed different prey, diets of Calanus copepods (high energy content) resulted in faster growth rates than diets of Themisto amphipods or capelin (Mallotus villosus) fillets. Both consumption and respiration rates were low at temperatures close to 0°C. The net result was slow growth rates, although the assimilation efficiency was about 80%. Because of slow growth of individuals, the relatively high annual production of Arctic cod mainly reflects their large standing biomass.
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Bollens, Stephen M., and Bruce W. Frost. "Zooplanktivorous fish and variable diel vertical migration in the marine planktonic copepod Calanus pacificus." Limnology and Oceanography 34, no. 6 (September 1989): 1072–83. http://dx.doi.org/10.4319/lo.1989.34.6.1072.
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Kaartvedt, S. "Life history of Calanus finmarchicus in the Norwegian Sea in relation to planktivorous fish." ICES Journal of Marine Science 57, no. 6 (December 2000): 1819–24. http://dx.doi.org/10.1006/jmsc.2000.0964.
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Stebniki, Samanta, Iván González, Alejandro D’Anatro, and Franco Teixeira de Mello. "Relaciones entre variables ambientales y la comunidad de peces en el río Uruguay bajo, Uruguay." Aqua-LAC 8, no. 1 (March 31, 2016): 62–67. http://dx.doi.org/10.29104/phi-aqualac/2016-v8-1-07.
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Los peces son fundamentales en el funcionamiento de los ecosistemas acuáticos, determinando los flujos de energía en dichos ambientes. El río Uruguay es uno de los sistemas más importantes de la cuenca del río de la Plata, recibiendo gran presión antrópica. En el presente estudio se analiza la variación espacio-temporal de la comunidad de peces y su relación con variables ambientales en tres sitios del Río Uruguay bajo, a lo largo del período 2007-2014. Los individuos fueron colectados utilizando ocho redes nórdicas, caladas doce horas en cada uno de los sitios en los meses de noviembre (primavera) y abril (otoño) de cada año. Los peces fueron identificados taxonómicamente, medidos, pesados, y clasificados en grupos tróficos. Se registraron en total 120 especies, distribuidas en 9 órdenes y 30 familias. En relación a la biomasa total, las especies detritívoras fueron dominantes (34%), seguidas por las omnívoras (30%), bentívoras (23%) y piscívoras (13%). A lo largo del periodo de estudio se observó una tendencia significativamente decreciente en la biomasa total y relativa de especies bentívoras y un aumento en la biomasa relativa de omnívoros. La temperatura y la altura del río serían los principales factores determinantes de la dinámica comunitaria observada.
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Fields, David M., Nils Olav Handegard, John Dalen, Christiane Eichner, Ketil Malde, Ørjan Karlsen, Anne Berit Skiftesvik, Caroline M. F. Durif, and Howard I. Browman. "Airgun blasts used in marine seismic surveys have limited effects on mortality, and no sublethal effects on behaviour or gene expression, in the copepod Calanus finmarchicus." ICES Journal of Marine Science 76, no. 7 (August 7, 2019): 2033–44. http://dx.doi.org/10.1093/icesjms/fsz126.
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Abstract Seismic surveys use airguns that emit low frequency high magnitude sound to detect subsea resources and to map seabed geology. The effect of seismic blasts on Calanus spp., a key food source for commercially important fish, was assessed in field experiments. Immediate mortality of copepods was significantly different from controls at distances of 5 m or less from the airguns. Mortality 1 week after the airgun blast was significantly higher—by 9% relative to controls—in the copepods placed 10 m from the airgun blast but was not significantly different from the controls at a distance of 20 m from the airgun blast. The increase in mortality—relative to controls—did not exceed 30% at any distance from the airgun blast. Only two genes changed in response to the airgun blast; however, their function is unknown. There were no sublethal effects of the seismic blasts on the escape performance or the sensory threshold needed to initiate an escape response at any of the distances from the airgun blast that were tested. Results from these experiments suggest that seismic blasts have limited effects on the mortality or escape response of Calanus sp. within 10 m of the blast and no measurable impact at greater distances.
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Möbius, Wiebke, Julia Patzig, Klaus-Armin Nave, and Hauke B. Werner. "Phylogeny of proteolipid proteins: divergence, constraints, and the evolution of novel functions in myelination and neuroprotection." Neuron Glia Biology 4, no. 2 (May 2008): 111–27. http://dx.doi.org/10.1017/s1740925x0900009x.
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The protein composition of myelin in the central nervous system (CNS) has changed at the evolutionary transition from fish to tetrapods, when a lipid-associated transmembrane-tetraspan (proteolipid protein, PLP) replaced an adhesion protein of the immunoglobulin superfamily (P0) as the most abundant constituent. Here, we review major steps of proteolipid evolution. Three paralog proteolipids (PLP/DM20/DMα, M6B/DMγ and the neuronal glycoprotein M6A/DMβ) exist in vertebrates from cartilaginous fish to mammals, and one (M6/CG7540) can be traced in invertebrate bilaterians including the planktonic copepod Calanus finmarchicus that possess a functional myelin equivalent. In fish, DMα and DMγ are coexpressed in oligodendrocytes but are not major myelin components. PLP emerged at the root of tetrapods by the acquisition of an enlarged cytoplasmic loop in the evolutionary older DMα/DM20. Transgenic experiments in mice suggest that this loop enhances the incorporation of PLP into myelin. The evolutionary recruitment of PLP as the major myelin protein provided oligodendrocytes with the competence to support long-term axonal integrity. We suggest that the molecular shift from P0 to PLP also correlates with the concentration of adhesive forces at the radial component, and that the new balance between membrane adhesion and dynamics was favorable for CNS myelination.
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Gislason, Astthor, Kristinn Gudmundsson, Solveig R. Olafsdottir, and Hildur Petursdottir. "Inter-annual and decadal variability of Calanus finmarchicus and C. hyperboreus in Subarctic waters north of Iceland 1990–2020." ICES Journal of Marine Science 78, no. 10 (November 16, 2021): 3735–47. http://dx.doi.org/10.1093/icesjms/fsab218.
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Abstract This study compares inter-annual dynamics of the two biomass dominant copepods in the Iceland Sea, the North Atlantic species Calanus finmarchicus and the Arctic C. hyperboreus, in an era of relatively low temperatures in the beginning of the study period (1990-1995) and higher temperatures thereafter. Samples were collected annually in May along a cross-shore transect of eight stations. The long-term variability in abundance of the two Calanus species was analysed in relation to hydrography, nutrients and phytoplankton dynamics, and large-scale climatic changes in the North Atlantic Ocean. Sea surface temperatures showed an increasing trend from the beginning to the end of the time series for all stations. From the end of the 1990s, C. finmarchicusshowed an increasing trend at the outermost station, whereas C. hyperboreus generally showed a decreasing trend along the whole transect from the mid-2000s. For both species, temperature was the single most important environmental factor explaining variance in abundance, however with opposite effects for the Arctic (C. hyperboreus) and the Atlantic (C. finmarchicus) species. It is hypothesized that warming north of Iceland may lead to increase of C. finmarchicus abundance through increased recruitment and advection, and decreased C. hyperboreus abundance. The change in species composition may in turn influence upper trophic levels, e.g. the capelin, the region’s main planktivorous fish.
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Eisner, Lisa B., Elizabeth C. Siddon, and Wesley W. Strasburger. "Spatial and temporal changes in assemblage structure of zooplankton and pelagic fish in the eastern Bering Sea across varying climate conditions." Izvestiya TINRO 181, no. 2 (June 30, 2015): 141–60. http://dx.doi.org/10.26428/1606-9919-2015-181-141-160.
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Zooplankton and pelagic fish samples collected on the eastern Bering Sea shelf in late summer 2003-2010 were used to evaluate spatial and temporal changes in the plankton and nekton community structure. The zooplankton were sampled by vertical towing of a Juday net (168 μm mesh) and oblique towing of a Bongo net (505 μm mesh), and pelagic fish were caught by midwater rope trawl. The communities were compared across climate regimes (in relatively warm and cold years), by latitude (in the northern and southern parts of the shelf), and by water depth (in the inner, middle, and outer domains of the shelf). Zooplankton were dominated by the small copepod Oithona spp. in warm years but relatively larger copepods Pseudocalanus spp. and Acartia spp. in cold years. Notably, the large copepod Calanus spp., an important energy-rich prey for fish, were more abundant in cold years than warm years. Age-0 walleye pollock Gadus chalcogrammus were more abundant in warm years, while capelin Mallotus villosus were abundant within cold-year communities over the northern shelf. Latitudinal variations in communities were more prominent in the cold years, particularly in 2007 and 2010. Cross-shelf variations were evident, particularly for large zooplankton and fish, with communities corresponding to specific oceanographic domains. Outer shelf communities varied less than inner and middle shelf communities between warm and cold periods, suggesting that this region may be less impacted by climate variability. An understanding of the overlap of zooplankton (prey) and fish communities within specific shelf regions or climate regimes may provide information for ecosystem-based approaches to fisheries management.
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Alheit, J., C. Möllmann, J. Dutz, G. Kornilovs, P. Loewe, V. Mohrholz, and N. Wasmund. "Synchronous ecological regime shifts in the central Baltic and the North Sea in the late 1980s." ICES Journal of Marine Science 62, no. 7 (January 1, 2005): 1205–15. http://dx.doi.org/10.1016/j.icesjms.2005.04.024.
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Abstract The index of the North Atlantic Oscillation, the dominant mode of climatic variability in the North Atlantic region, changed in the late 1980s (1987–1989) from a negative to a positive phase. This led to regime shifts in the ecology of the North Sea (NS) and the central Baltic Sea (CBS), which involved all trophic levels in the pelagial of these two neighbouring continental shelf seas. Increasing air and sea surface temperatures, which affected critical physical and biological processes, were the main direct and indirect driving forces. After 1987, phytoplankton biomass in both systems increased and the growing season was extended. The composition of phyto- and zooplankton communities in both seas changed conspicuously, e.g. dinoflagellate abundance increased and diatom abundance decreased in the CBS. Key copepod species that are essential in fish diets experienced pronounced changes in biomass. Abundance of Calanus finmarchicus (NS) and Pseudocalanus sp. (CBS) fell to low levels, whereas C. helgolandicus (NS) and Temora longicornis and Acartia spp. (CBS) were persistently abundant. These changes in biomass of different copepod species had dramatic consequences on biomass, fisheries, and landings of key fish species: North Sea cod declined, cod in the CBS remained at low levels, and CBS sprat reached unprecedented high biomass levels resulting in high yields. The synchronous regime shifts in NS and CBS resulted in profound changes in both marine ecosystems. However, the reaction of fish populations to the bottom-up mechanisms caused by the same climatic shift was very different for the three fish stocks.
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Sulistiono, M. Robiyanto, M. Brodjo, and C. P. Simanjuntak. "Study on food habits of herring (Clupea fimbriata) in Ujung Pangkah Waters, East Java." Jurnal Akuakultur Indonesia 9, no. 1 (January 1, 2010): 38. http://dx.doi.org/10.19027/jai.9.38-45.
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<p>Herring <em>C</em><em>lupea fibriata</em> is an important fishery resource in Indonesia. This species is found in large number in Ujung Pangkah Waters. This study aims to investigate food habits of the species. The study was done from July to December 2005, in Ujung Pangkah Waters (Gresik, East Java Province), using samples of 313 individuals consisting of 147 males and 166 female fish, collected by gill net and fix net. Study result shows that food habit of the herring was consisted of Bacillariophyceae (7 genera), Crustacea (3 genera), Ciliate (2 genera), Dynophycea (2 genera), and detritus. Bacillariophyceae is a main food, Crustacea is additional food, and Ciliata and detritus is complementary food both for male and female fish. Electivity indeks of the fish varied from -0,99 to 0,45 (male) and -0,98 to 0,51 (female). According to the index, <em>Skeletonema</em> and <em>Calanus </em>are the dominant food of the fish collected in the Ujung Pangkah Waters.</p> <p>Key words: Food habits, herring (<em>Clupea fibriata</em>), Ujung Pangkah, Gresik</p> <p> </p> <p>ABSTRAK</p> <p>Ikan tembang (<em>C</em><em>lupea fibriata</em>) merupakan salah satu sumberdaya perikanan yang cukup penting di Indonesia. Jenis ikan ini cukup banyak ditemukan di perairan Ujung Pangkah. Penelitian bertujuan untuk menganalisis makanan ikan tembang yang tertangkap di daerah tersebut. Penelitian dilaksanakan sejak Juli sampai Desember 2005, di daerah Perairan Ujung Pangkah (Gresik, Jawa Timur), dengan pengambilan sampel ikan sebanyak 313 ekor yang terdiri atas 147 ekor jantan dan 166 ekor betina, menggunakan alat tangkap jaring insang (<em>gill net</em>) dan jeger (<em>fix net</em>). Hasil pengamatan menunjukkan bahwa ikan tembang memiliki makanan yang terdiri atas Bacillariophyceae (7 jenis), Crustacea (3 jenis), Ciliata (2 jenis), Dynophycea (2 jenis), dan detritus. Kelompok Bacillariophyceae merupakan kelompok makanan utama, Crustacea merupakan makanan pelengkap, dan Ciliata dan detritus merupakan makanan tambahan baik pada ikan jantan maupun ikan betina. Indeks pilihan makanan ikan tembang berkisar antara -0,99 sampai 0,45 (pada ikan jantan) dan -0,98 sampai 0,51 (pada ikan betina). Berdasarkan indeks tersebut, <em>Skeletonema</em> dan <em>Calanus </em>merupakan jenis yang banyak dimakan ikan tembang di perairan Ujung Pangkah.</p> <p>Kata kunci: Makanan, ikan tembang (<em>Clupea fibriata</em>), Ujung Pangkah, Gresik</p>
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Prokopchuk, Irina, and Evgeniy Sentyabov. "Diets of herring, mackerel, and blue whiting in the Norwegian Sea in relation to Calanus finmarchicus distribution and temperature conditions." ICES Journal of Marine Science 63, no. 1 (January 1, 2006): 117–27. http://dx.doi.org/10.1016/j.icesjms.2005.08.005.
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Abstract Diets of Norwegian spring-spawning herring, mackerel, and blue whiting in the Norwegian Sea are investigated in relation to the distribution of plankton and hydrographic conditions. Fish stomachs and zooplankton samples were collected during summer (June and July) cruises in 2001 and 2002. Calanus finmarchicus was the principal prey of mackerel, accounting for 53–98% of total stomach content by weight. The diet composition of herring varied depending on feeding area and availability of food under various environmental conditions. C. finmarchicus was important prey for herring only in July 2001 (about 77% by weight) in the central part of the sea and in June 2002 (about 82% by weight) near the Lofotens. In July 2002 appendicularians (Oikopleura spp.), amphipods (mainly Parathemisto abissorum), and euphausiids were important in the diet of herring, and at some stations cannibalism was observed. The main prey of blue whiting were amphipods (10–34% by weight), appendicularians (11–34%), and euphausiids (8–47%), as they usually feed deep in the water column, though C. finmarchicus was important, particularly in June 2002, when blue whiting were caught in the upper layers of the sea. Higher water temperatures indirectly affect pelagic fish through accelerated development of their prey and favourable conditions for migration farther north.
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Pershing, Andrew J., Charles H. Greene, Jack W. Jossi, Loretta O'Brien, Jon K. T. Brodziak, and Barbara A. Bailey. "Interdecadal variability in the Gulf of Maine zooplankton community, with potential impacts on fish recruitment." ICES Journal of Marine Science 62, no. 7 (January 1, 2005): 1511–23. http://dx.doi.org/10.1016/j.icesjms.2005.04.025.
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Abstract We used principal component analysis (PCA) to explore interannual changes in a time-series lasting more than 40 years of zooplankton abundance from NOAA's Continuous Plankton Recorder (CPR) survey. This analysis identified a complex of taxa, including Centropages typicus, Oithona spp., Pseudocalanus spp., and Metridia lucens that followed a common pattern of interdecadal variability characterized by a dramatic increase in these taxa around 1990, followed by a rapid decline in 2002. All of these taxa showed a large proportional increase in winter abundance between the 1980s and 1990s. These changes could be driven by increased primary productivity during winter, caused by a large-scale freshening of the Northwest Atlantic Shelf. In addition to the “community shift” mode, the analysis found a strong mode of interannual variability attributed to previously described changes in the abundance of late-stage Calanus finmarchicus. To explore the impact of these modes on higher trophic levels, we correlated the zooplankton modes with recruitment time-series from 12 fish stocks from the Gulf of Maine region. Several significant correlations were found, suggesting that the changes in the zooplankton modes may reflect broad changes in the Gulf of Maine ecosystem.
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Dinisia, Amelian, Enan M. Adiwilaga, and Yonvitner. "KELIMPAHAN ZOOPLANKTON DAN BIOMASSA IKAN TERI (Stolephorus spp.) PADA BAGAN DI PERAIRAN KWATISORE TELUK CENDERAWASIH PAPUA (Abundance of Zooplankton and Biomass of Anchovy (Stolephorus spp.) of Liftnet at Kwatisore Bay, Cendrawasih Gulf, Papua)." Marine Fisheries : Journal of Marine Fisheries Technology and Management 6, no. 2 (October 7, 2016): 143. http://dx.doi.org/10.29244/jmf.6.2.143-154.
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ABSTRACT<br /><br />Millions of organisms can be found in the Cenderawasih Gulf National Park area, especially in the waters of the Kwatisore Bay, Nabire and has been well-known to almost all over the world. Large zooplankton is an important food for migrated fish larvae and all kinds of fish including anchovies. Anchovy is the food of large and small pelagic fish groups. Groups of fish that use plankton as food were included anchovy. The main catch product of lift net at the Kwatisore bay is anchovy (Stolephorus spp.). This study aims to assess the level of availability of anchovy in relation to the abundance of zooplankton as food and to analyze the influence of anchovy fishing activities with lift net fishing gear. The results were obtained 51 species of zooplankton, which consists of 44 types holoplankton and 7 types of meroplankton. There were 17 species of zooplankton were found in the stomach of anchovy with the subgroup dominated by copepods (73.51 %). Among 17 species of zooplankton there 2 types that were found in all four sampling periods, namely Calanus sp. 2 and Euterpina acutifrons. There is a relationship between the abundance of individual zooplankton in the waters of the anchovy biomass and also between the abundance of zooplankton and biomass of anchovy.<br /><br />Keywords: abundance of zooplankton, biomass of anchovy, lift net at Kwatisore<br />-------<br /><br />ABSTRAK<br /><br />Jutaan organisme dapat ditemukan dalam kawasan Taman Nasional Teluk Cenderawasih khususnya di perairan Kwatisore, Nabire dan telah terkenal sampai hampir ke seluruh dunia. Zooplankton berukuran besar merupakan makanan penting bagi ikan-ikan yang bermigrasi dan larva semua jenis ikan termasuk didalamnya ikan teri. Ikan teri merupakan makanan dari kelompok ikan pelagis besar dan kecil. Kelompok ikan-ikan yang banyak memanfaatkan plankton dari kelompok ikan pelagis kecil diantaranya ikan teri. Hasil tangkapan utama bagan penangkap ikan pelagis kecil di perairan Kwatisore ialah jenis teri (Stolephorus sp.). Tujuan penelitian ini adalah untuk mengkaji tingkat ketersediaan ikan teri dalam kaitannya dengan kelimpahan zooplankton sebagai makanannya serta menganalisis pengaruh dari aktivitas penangkapan ikan teri dengan alat tangkap bagan. Secara keseluruhan dari seluruh stasiun dalam setiap periode sampling, diperoleh 51 jenis zooplankton yang terdiri atas 44 jenis holoplankton dan 7 jenis meroplankton. Terdapat 17 jenis zooplankton yang ditemukan dalam lambung ikan teri dengan didominasi oleh Sub-grup Copepoda (73,51%). Diantara ke-17 jenis zooplankton tersebut terdapat 2 jenis yang ditemukan pada keempat periode sampling yaitu Calanus Sp.2 dan Euterpina acutifrons. Hasil analisis regresi linier antara biomassa ikan teri hasil tangkapan bagan dan kelimpahan maupun antara biomassa ikan teri hasil tangkapan bagan dan jumlah jenis zooplankton menunjukkan adanya korelasi positif.<br /><br />Kata kunci: kelimpahan zooplankton, biomassa ikan teri, bagan di Kwatisore
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Pershing, Andrew J., and Karen Stamieszkin. "The North Atlantic Ecosystem, from Plankton to Whales." Annual Review of Marine Science 12, no. 1 (January 3, 2020): 339–59. http://dx.doi.org/10.1146/annurev-marine-010419-010752.
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Compared with terrestrial ecosystems, marine ecosystems have a higher proportion of heterotrophic biomass. Building from this observation, we define the North Atlantic biome as the region where the large, lipid-rich copepod Calanus finmarchicus is the dominant mesozooplankton species. This species is superbly adapted to take advantage of the intense pulse of productivity associated with the North Atlantic spring bloom. Most of the characteristic North Atlantic species, including cod, herring, and right whales, rely on C. finmarchicus either directly or indirectly. The notion of a biome rests inherently on an assumption of stability, yet conditions in the North Atlantic are anything but stable. Humans have reduced the abundance of many fish and whales (though some recovery is underway). Humans are also introducing physical and chemical trends associated with global climate change. Thus, the future of the North Atlantic depends on the biome's newest species, Homo sapiens.
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Dvoretsky, Vladimir G., and Alexander G. Dvoretsky. "Coastal Mesozooplankton Assemblages during Spring Bloom in the Eastern Barents Sea." Biology 11, no. 2 (January 27, 2022): 204. http://dx.doi.org/10.3390/biology11020204.
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Mesozooplankton play an important role in Arctic shelf ecosystems as a trophic link and a key food source for many larval fish species. The distribution of mesozooplankton in the eastern Barents Sea was studied along a 500 nautical mile-long transect in May 2016 during the spring bloom. Mesozooplankton were sampled using a Juday net hauled from the surface to the bottom at 12 stations. We found good correspondence between the distribution of water masses and mesozooplankton assemblages. Mesozooplankton abundance (mean 73·103 individuals m−2) in Novaya Zemlya coastal water was dominated by Copepoda ova and nauplii, Thyssanoessa spp. nauplii and Oithona similis. Parasagitta elegans and Calanus finmarchicus comprised most of the total mesozooplankton biomass (mean 0.9 g dry mass m−2) in that water mass. A second assemblage (mean abundance 171·103 individuals m−2) was associated with the colder Barents Sea water, with Oithona similis, Copepoda nauplii, Fritillaria borealis and Cirripedia nauplii being the most numerous. In that water mass, C. finmarchicus, Metridia longa, Cirripedia nauplii and Calanus glacialis contributed most to the total biomass (mean 3 g dry mass m−2). The dominance of young stages of Copepoda and a high proportion of meroplankton were typical of spring mesozooplankton assemblages. The spatial distribution of mesozooplankton abundance and biomass was strongly correlated with latitude, longitude and chlorophyll a concentration, which together explained 10% of the total variance in mesozooplankton density. The present investigation is a baseline study for the assessment of the spring mesozooplankton assemblage in the eastern Barents Sea, and for an evaluation of the possible impact of future environmental changes on the Arctic shelf marine ecosystem.
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Khan, Md Shahzad Kuli, Sheikh Aftab Uddin, and Mohammed Ashraful Haque. "Abundance and composition of zooplankton at Sitakunda coast of Chittagong, Bangladesh." Research in Agriculture Livestock and Fisheries 2, no. 1 (April 27, 2015): 151–60. http://dx.doi.org/10.3329/ralf.v2i1.23053.
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Correction: Table 1 and Table 2 were omitted in from the PDF of this article. On 29th April 2015 the two tables were included in the PDF and the page numbers were changed from 151-158 to 151-160.Eight groups of zooplankton were found at Sitakunda coast, Chittagong, northeastern part of the Bay of Bengal during January to June 2007. The identified groups were Appendicularia (2.46%), Chaetognatha (2.45%), Cladocera (2.31%), Copepoda (26.05%), Ctenophora (5.86%), Crustacean zooplankton (21.64%), Ichthyoplankton (17.77%) and Meroplankton (21.45%). Abundance of zooplankton varied from 413 to 7730 individuals/m3.Mangrove vegetate area (station- VI) has the highest abundant possibly due to the organic and inorganic matters dissolved in the water while ship breaking area (station- IV) has the lowest abundant. Zooplankton population was significantly (p>0.05) higher in the mangrove vegetate area than the fishermen community area and ship breaking area. The mangrove vegetate area has the highest composition (57.06%) of zooplankton than the fishers community area and ship breaking area (29.77% and 13.16%, respectively). Calanus sp. (12.29%) belonging to Copepods and fish eggs (9.25%) belonging to Ichthyoplankton were the most abundant and Oikopleura albicans (0.66%) from Appendicularia, Metapenaeus brevicornis (0.71%) and Metapenaeus monoceros (0.90%) belonging to Crustacean larvae were the lowest abundant species found at three major investigated area.Res. Agric., Livest. Fish.2(1): 151-160, April 2015
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Drinkwater, Kenneth F., Franz J. Mueter, and Sei-Ichi Saitoh. "Shifting boundaries of water, ice, flora, fauna, people, and institutions in the Arctic and Subarctic." ICES Journal of Marine Science 75, no. 7 (December 1, 2018): 2293–98. http://dx.doi.org/10.1093/icesjms/fsy179.
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Abstract An international Open Science Meeting entitled Moving in, out, and across the Subarctic and Arctic marine ecosystems: shifting boundaries of water, ice, flora, fauna, people, and institutions, took place 11–15 June 2017 in Tromsø, Norway. Organized by the Ecosystem Studies of Subarctic and Arctic Seas programme and cosponsored by the International Council for the Exploration of the Sea and the North Pacific Marine Science Organization, the primary aim of the meeting was to examine past, present, and future ecosystem responses to climate variability and ocean acidification (OA) and their effect on fishing communities, the fishing industry and fisheries management in the northern Pacific and Atlantic oceans and the Arctic. This symposium issue contains several papers from the meeting covering topics from climate and OA, ecosystem responses to environmental change, and fisheries management including: a synthesis of the ecosystem responses to the AMO-linked cold period of the 1970s and 1980s;a novel approach to understand responses to OA in northern climes using natural carbonate chemistry gradients, such as CO2 vents, methane cold seeps, and upwelling area;the possibility that warm temperatures are allowing two generations of Calanus finmarchicus per year to be produced;a new hypothesis suggesting that in areas where sea ice disappears there could be an increase of fish species with swim bladders;results from laboratory experiments on the effects of temperature and food on Arctic and boreal fish larvae;the application of ecosystem-based management in northern regions; anda description of the United States National Oceanic and Atmospheric Administration approach to marine conservation and how it affects fish populations and fisheries.
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Provan, Jim, Gemma E. Beatty, Sianan L. Keating, Christine A. Maggs, and Graham Savidge. "High dispersal potential has maintained long-term population stability in the North Atlantic copepod Calanus finmarchicus." Proceedings of the Royal Society B: Biological Sciences 276, no. 1655 (September 23, 2008): 301–7. http://dx.doi.org/10.1098/rspb.2008.1062.
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The cool-water copepod Calanus finmarchicus is a key species in North Atlantic marine ecosystems since it represents an important food resource for the developmental stages of several fish of major economic value. Over the last 40 years, however, data from the Continuous Plankton Recorder survey have highlighted a 70 per cent reduction in C. finmarchicus biomass, coupled with a gradual northward shift in the species's distribution, which have both been linked with climate change. To determine the potential for C. finmarchicus to track changes in habitat availability and maintain stable effective population sizes, we have assessed levels of gene flow and dispersal in current populations, as well as using a coalescent approach together with palaeodistribution modelling to elucidate the historical population demography of the species over previous changes in Earth's climate. Our findings indicate high levels of dispersal and a constant effective population size over the period 359 000–566 000 BP and suggest that C. finmarchicus possesses the capacity to track changes in available habitat, a feature that may be of crucial importance to the species's ability to cope with the current period of global climate change.
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Kouwenberg, J. H. M., H. I. Browman, J. A. Runge, J. J. Cullen, R. F. Davis, and J. F. St-Pierre. "Biological weighting of ultraviolet (280-400 nm) induced mortality in marine zooplankton and fish. II. Calanus finmarchicus (Copepoda) eggs." Marine Biology 134, no. 2 (July 7, 1999): 285–93. http://dx.doi.org/10.1007/s002270050546.
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Kuznetsova, Natalia A. "Feeding and food supply of juvenile fishes in the eastern Bering Sea in 2003-2012." Izvestiya TINRO 181, no. 2 (June 30, 2015): 129–40. http://dx.doi.org/10.26428/1606-9919-2015-181-129-140.
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Feeding of fish juveniles in the eastern Bering Sea is investigated for the periods of 2003-2006 considered as relatively «warm» and 2007-2012 considered as relatively «cold». Small- and medium-sized zooplankton was the dominant prey in the 2003-2006, in particular copepods prevailed in the food of walleye pollock (41.5 %), pacific herring (48.3 %), and sand lance (71.7 %) juveniles, which in turn were the prey for pollock, herring and cod yearlings and other predators. On the contrary, large-sized zooplankton was more abundant in the 2007-2012, so arrowwarms ( Sagitta sp.), large-sized copepods (in particular Calanus marshallae ), euphausiids (mainly Thysanoessa raschii ), hyperiids, and pteropods were the prey for young fish: C. marshallae - for juveniles of pollock (40-45 % by weight) and capelin (32-34 %), Th. raschii - for yearlings of pollock (51 %) and herring (36-46 %), cold-water hyperiid T. libellula - for adult pollock (24 %), juvenile cod (9-18 %) and juvenile herring (9-11 %), whereas portion of fish in the diets was insignificant. In the warm period (2003-2006), juvenile pollock, herring, sand lance and capelin were zooplankton-eaters with the diets similarity 67 %, while yearlings of pollock and juveniles of cod, herring, sandfish, and atka mackerel were fish-eaters preying upon pollock juveniles. In the cold period (2007-2012), the diets of juvenile pollock, juvenile and adult capelin, and juvenile sand lance were also similar at 85-70 % but they preferred large-sized copepods and euphausiids ( C. marshallae and Th. raschii ), while yearlings of pollock, yearlings and adults of herring, and juveniles of sand fish and cod had the diets of 70 % similarity with Th. raschii prevalence. Feeding intensity was high for all species: the mean stomach fullness was 150-200 ‱ for pollock juveniles and yearlings, 200-250 ‱ for cod juveniles, 200-258 ‱ for sand lance juveniles, 302 ‱ for herring juveniles, and 178-250 ‱ for juvenile atka mackerel. The fullness had diurnal rhythm with three peaks: at noon - up to 179 ‱, in evening - up to 213 ‱, and at night - up to 204 ‱ (the data for walleye pollock juveniles in «cold» years only). Daily food ration of juvenile pollock is estimated as 6.7 % of its body weight in the «warm» years and 7.0 % in the «cold» years.
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Mahipe, Firgiani V. N., Rose O. S. E. Mantiri, and Ruddy D. Moningkey. "Zooplankton Community In Coastal Malalayang Waters Manado." JURNAL ILMIAH PLATAX 5, no. 1 (March 3, 2017): 77. http://dx.doi.org/10.35800/jip.5.1.2017.15808.
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The purpose of this study was to identify the zooplankton, to know the relative density of zooplankton, and to analyze their community structure, such as Diversity Index (H') and Dominance Index (C).Sampling was conducted on September 30th, 2016 at the depth of 50 cm-withdrawn slowly along 40 meter (2x20 meter back and forth) in each station. The water left in the cod end (reservoir bottle) put into a sample bottle, with alcohol 95%, and taken to the laboratory for identification.Based on the identification, there were 25 species of zooplankton (19 adults, one final larval stage brachyura, 4 larvae of mollusks and worms, and 1 fish larvae 1 unidentified), namely: Oncaea sp. [1], Oncaea sp. [2], Oncaea sp. [3], Diastylis sp., Monstrilla sp., Euchaetomera sp., Euchaeta sp., Ibacus sp., Oithona sp., Synchaeta sp., Farranula sp., Macrosetella sp., Eurydice sp., Calanus sp., Lucifer sp., Eucalanus sp., Scolecithricella sp., Lucicutia sp., Lepidasthenia sp., megalops brachyura, zoea brachyura, larvae of eulimella, larvae of echinospira, larvae of corethra and larvae of fish. Relative density was the highest in Oncaea sp. (34.21%) and Diversity Index (H') was classified as moderate. The diversity index showed that the zooplankton community was less diverse. Dominance Index (C) was also low indicating no species was dominant in the coastal waters of Malalayang.Keyword : Community, zooplankton, Malalayang DuaAbstrak Tujuan penelitian ini adalah untuk mengetahui jenis–jenis zooplankton, mengetahui kepadatan relatif zooplankton, dan menganalisa struktur komunitas zooplankton seperti Indeks Keanekaragaman (H’) dan Indeks Dominasi (C).Pengambilan sampel dilakukan pada 30 September 2016 dengan cara memasukkan plankton net sedalam 50 cm, kemudian ditarik sambil berjalan secara perlahan sepanjang 40 meter (2x20 meter bolak-balik) di tiap stasiun. Air yang tersaring dalam cod end (botol penampungan) dituangkan di dalam botol sampel dan ditambahkan/diawetkan dengan alkohol 95%. Selanjutnya, sampel tersebut dibawa ke Laboratorium untuk diidentifikasi.Berdasarkan hasil identifikasi diperoleh 25 jenis zooplankton (19 dewasa, 1 organisme muda [tahap akhir larva] zooplankton, 4 larva zooplankton dan 1 larva ikan yang tidak teridentifikasi) yaitu: Oncaea sp. [1], Oncaea sp.[2], Oncaea sp.[3], Diastylis sp., Monstrilla sp., Euchaetomera sp., Euchaeta sp., Ibacus sp., Oithona sp., Synchaeta sp., Farranula sp., Macrosetella sp., Eurydice sp., Calanus sp., Lucifer sp., Eucalanus sp., Scolecithricella sp., Lucicutia sp., Lepidasthenia sp., Megalopa Brachyura, Zoea Brachyura, Larva Eulimella, Larva Echinospira, Larva Corethra dan Larva Ikan. Kepadatan Relatif tertinggi terdapat pada Oncaea sp. sebesar 34,21% Nilai Indeks Keanekaragaman (H’) zooplankton di tiga Stasiun tergolong sedang. Nilai tersebut menunjukkan bahwa komunitas organisme dalam kondisi yang kurang beragam. Hasil Indeks Dominasi (C) termasuk kriteria dominasi rendah, menunjukkan bahwa tidak ada spesies yang mendominasi di perairan pantai Malalayang.Kata kunci : Komunitas, zooplankton, Malalayang Dua
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Utne, Kjell Rong, Solfrid Sætre Hjøllo, Geir Huse, and Morten Skogen. "Estimating the consumption of Calanus finmarchicus by planktivorous fish in the Norwegian Sea using a fully coupled 3D model system." Marine Biology Research 8, no. 5-6 (April 25, 2012): 527–47. http://dx.doi.org/10.1080/17451000.2011.642804.
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Ferreira, ASA, LC Stige, AB Neuheimer, B. Bogstad, N. Yaragina, I. Prokopchuk, and JM Durant. "Match-mismatch dynamics in the Norwegian-Barents Sea system." Marine Ecology Progress Series 650 (September 17, 2020): 81–94. http://dx.doi.org/10.3354/meps13276.
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A key process affecting variation in the recruitment of fish into fisheries is the spatio-temporal overlap between prey and predator (match-mismatch hypothesis, MMH). The Northeast Arctic cod Gadus morhua and its dominant prey, the copepod Calanus finmarchicus, have long been studied in the Norwegian-Barents Sea system. However, the mechanistic explanation of how cod survival is affected by MMH dynamics remains unclear. Most MMH studies have focused on either the time synchrony or the spatial overlap between trophic levels. Here, we used G. morhua larvae and C. finmarchicus data collected in the Norwegian-Barents Sea via ichthyoplankton surveys from 1959-1992 to assess the effect of the predator-prey relationship on predator recruitment to the fisheries at age 3 (as a measure of survival) and to develop a metric of predator-prey overlap using spatio-temporal statistical models. We then compared the interannual variability of the predator-prey overlap with the predator’s abundance at recruitment to assess how MMH dynamics explain the survival of cod during its early life stages. We found that the amount of overlap between cod larvae (length: 11-15 mm) and their prey explained 29% of cod recruitment variability. Positive correlations between predator-prey overlap and subsequent recruitment were also found for predators of 6-10 and 16-20 mm, but not for 21+ mm. This improved predator-prey overlap metric is thus (1) useful to better understand how predator-prey dynamics at early life stages of fish impact the survival of later stages; and (2) a valuable tool for assessing the state of an ecosystem.
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Hirai, J., K. Yamazaki, K. Hidaka, S. Nagai, Y. Shimizu, and T. Ichikawa. "Characterization of diversity and community structure of small planktonic copepods in the Kuroshio region off Japan using a metabarcoding approach." Marine Ecology Progress Series 657 (January 7, 2021): 25–41. http://dx.doi.org/10.3354/meps13539.
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Small copepods are important prey for fish larvae in the Kuroshio region off southern Japan. However, revealing entire community structures of small copepods is difficult using conventional methods. We applied a metabarcoding method to size-fractionated community samples of epipelagic copepods (small: 0.1-0.5 mm, medium: 0.5-1.0 mm, and large: 1.0-2.0 mm). Samples were collected from 2013 to 2016 from the shoreward (Kuroshio Slope, KS) and oceanic (Kuroshio Gyre, KG) sides of the Kuroshio Current at 138° E; the results were compared with those in the center of the subtropical gyre (SG). The KS and KG sites showed both spatial differences and seasonal changes, with distinct differences between winter-spring and summer-autumn in each size-fractionated community. Water temperature markedly influenced copepod diversity and community structure, especially in the small size fraction. Warm-water species in the SG intruded into the Kuroshio regions during high-temperature periods, leading to high diversity in summer-autumn. Inter-annual environmental variations influenced by temperature and productivity were evident in KS, leading to clear changes in the sequence proportions of dominant small copepods including Paracalanus sp. and immature stages of the large copepod Calanus sinicus. Immature stages of medium/large copepods formed a substantial proportion of small-copepod communities in the Kuroshio regions (KS: 28.8%; KG: 24.7%; SG: 11.9%; based on average proportions of sequence reads). Because of their ecological importance and sensitivity to environmental changes, monitoring communities of small copepods with high taxonomic resolution may provide further insights into marine ecosystems, including fish recruitment, in the Kuroshio region.
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Post, S., SH Jónasdóttir, H. Andreasen, AH Ólafsdóttir, and T. Jansen. "Blue whiting Micromesistius poutassou diel feeding behaviour in the Irminger Sea." Marine Ecology Progress Series 678 (November 11, 2021): 1–16. http://dx.doi.org/10.3354/meps13918.
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With warming ocean temperatures, the abundance of blue whiting Micromesistius poutassou is increasing in the waters around Greenland. However, in this region, knowledge about the species’ trophic role in the ecosystem is scarce. Consequently, we investigated the diet composition and diel feeding behaviour of blue whiting in the north-eastern part of the Irminger Sea in Greenland waters by analysing their stomach contents and the vertical position/movements of their prey from zooplankton samples and hydroacoustic measurements. We collected the data during a designated experimental survey in July 2016 with repeated sampling at the same location. Results from the stomachs of 624 blue whiting individuals ranging from 22-39 cm long (total length) showed that the highest food intake took place from noon until late evening, with minimum feeding occurring in the morning. The most essential prey groups consisted of euphausiids, copepods, amphipods and fish, in that respective order. Regarding copepod prey, blue whiting had a strong affinity for Calanus hyperboreus and Paraeuchaeta spp. and showed potential for local depletion of these large copepods. On the other hand, the more abundant but smaller C. finmarchicus was almost absent in the fish stomachs, in contrast to findings in other regions. This new understanding provides an early indication of some of the emerging trophodynamics in the Irminger Sea and similar subarctic zooplankton communities with increasing numbers of blue whiting. Our results confirm the importance of accounting for diel and size-specific differences in blue whiting feeding when studying various aspects of its food intake.
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Kuznetsova, N. A., and M. A. Shebanova. "Feeding of walleye pollock and its feeding base in the Chukchi Sea in summer-autumn period." Izvestiya TINRO 203, no. 1 (April 5, 2023): 179–99. http://dx.doi.org/10.26428/1606-9919-2023-203-179-199.
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Data on feeding of walleye pollock <i>Gadus chalcogrammus</i> (3–70 cm long) in the Chukchi Sea in summer-autumn of 2017–2020 are presented. The food base includes zooplankton, benthic invertebrates and fish. The juveniles in the northwestern part of the sea consumed 0.033 t/km2 of prey per day, mainly fish (30.9 %), mysids (20.1 %) and amphipods (13.9 %), whereas the portion of copepods and euphausiids was 5.0–7.6 % of the diet. In the southwestern part of the sea, the juveniles consumption was much higher, as 0.200 t/km2 of prey per day, and included mainly euphausiids and copepods (24.9–51.1%). The adults with length 40–70 cm long dominated in the southwestern Chukchi Sea and consumed on average 13.2 t/km2 of prey per day, shared between fish (42 %), euphausiids (20 %), copepods (6 %), and decapods (11 %). Composition and structure of plankton was different between the main water masses on the shelf occupied the northern and the southern parts of the sea. In the northwestern Chukchi Sea, zooplankton distributed with the mean spatial density of 56.3 t/km2, formed mostly by chaetognaths (35.3 t/km2) and copepods (12.6 t/km2). In the southwestern Chukchi Sea, the mean spatial density of zooplankton was 49.2 t/km2, mostly euphausiids (17.3 t/km2), chaetognaths (15.8 t/km2) and copepods (9.2 t/km2). The total density was close to the level observed in the 2000s, but slight decreasing in biomass of chaetognaths and copepods was observed, mainly due to the recent lack of cold-water species <i>Calanus glacialis</i>, whereas the biomass of euphausiids, in particularly <i>Thysanoessa inermis</i>, had almost doubled. Biomass of the main groups of zooplankton prevailing in the diet in the Chukchi Sea in summer-autumn, as copepods and euphausiids, exceeded daily consumption of these groups by walleye pollock in 6–11 times that may indicate a sufficient food supply for this species. Besides, walleye pollock dwelled at the sea bottom and fed on shrimps, gammarids, bottom polychaetes, echiurids, mollusks, and also bottom fish. Total fullness of the pollock stomachs was in the range of 218–228 ‱ that also suggested successful feeding.