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The location and timing of spawning play a critical role in pelagic fish survival during early life stages and can affect subsequent recruitment. Spawning patterns of Pacific herring (Clupea pallasii) were examined in Prince William Sound (1973–2019) where the population has failed to recover since its collapse in 1993. Abrupt shifts in spawn distribution preceded the rapid increase in population size in the 1980s and later its collapse by one and two years, respectively. Following the population collapse, spawning contracted away from historical regions towards southeastern areas of the Sound, and the proportion of occupied spawning areas declined from 65% to

Climate change is anticipated to have multiple consequences for aquatic ectotherms. Warming temperatures, for example, are predicted to reduce body size in many fish species. Smaller sizes may be caused by physiological constraints associated with respiration, life-history responses to faster growth and concomitant earlier age at maturity, and interactive effects of fishing and climate change on evolution. Here, using a phylogenetically broad dataset of 100 marine species, we explore how natural mortality might respond to a 10% reduction in asymptotic length (L∞). We find that this decrease in size (predicted to be associated with a 1 °C ocean temperature increase) is likely to exacerbate natural mortality (M) for most marine fishes, albeit not all, on Canada’s Scotian Shelf. Across all bony fishes (Actinopterygii), the median proportional increase in natural mortality is 10.5%; limited data suggest that chondrichthyans are less affected. Smaller-bodied fish species experienced greater absolute increases in M than larger-bodied species. Among commercially exploited species for which sufficient data are available, M is predicted to increase by 0.14 for Atlantic mackerel (Scomber scombrus), 0.08 for Silver hake (Merluccius bilinearis), 0.04 for Atlantic herring (Clupea harengus), and 0.02 for Atlantic cod (Gadus morhua) and Pollock (Pollachias virens). The present study offers a simple means of exploring the mortality consequences of reduced body size hypothesized to result from globally warming water temperatures, thus contributing a potential tool for climate-change vulnerability assessments of marine fishes.

Parasites of spawning pacific herring (Clupea pallasii Valenciennes in Cuvier et Valenciennes, 1947) from the Taui population are explored on the samples caught on two spawning grounds located in the Ola lagoon and Amakhton Bay (Tauiskaya Guba Bay, Okhotsk Sea), and 17 species of helminthes are found, including 6 trematodes, 5 cestodes, 4 nematodes, and 2 acanthocephalans. Some differences in species composition of helminthes and their infestation were found between these estuarine and marine spawning grounds. In the Ola lagoon, 16 species of helminthes were identified, including 5 species of cestodes, whereas only 13 species of helminthes, including 3 species of cestodes, were found in the Amakhton Bay. The Taui population of herring is distinguished from the Okhotsk and Gizhiga-Kamchatka populations by presence of nematodes Hysterothylacium aduncum, l, and Ascorophis pacificus with rather high rates of invasion (occurence = 52.9 %; mean abundance = 4.16) and trematode Bucephaloides spp. On the other hand, the herring from the Taui population has common dangerous parasites with other populations in the Okhotsk Sea, as trematode Brachyphallus crenatus and nematode Anisakis spp. (larvae), with high degree of infestation.

Food limitation can dampen the survival and growth of fish species during early development. To investigate prey diversity important to the planktivorous larval longfin smelt (Spirinchus thaleichthys) and Pacific herring (Clupea pallasii) from the San Francisco Estuary, we used DNA metabarcoding analysis of the cytochrome oxidase I gene on the guts of these fishes and on environmental zooplankton samples, in comparison with results from abundance analyses of zooplankton samples. Overall, both fish consumed the prey that were commonly available and relatively abundant: Diets were dominated by arthropods but also included soft‐bodied and difficult to identify organisms. Prey taxa substantially overlapped between the two species (Schoener's index = 0.66), and alpha diversity analysis suggested high variability in the content of guts from different individuals. Abundant prey taxa in both fish species included the copepods Eurytemora carolleeae, Acanthocyclops americanus, and A. robustus; Acanthocyclops spp. are difficult to distinguish morphologically. Differential abundance analysis suggested that both species consumed the most abundant zooplankton in lower proportions than their availability in the environment. A few uncommon prey observed in the diets may hint at feeding strategies employed by the larvae, such as herring DNA in the longfin smelt diets, suggesting feeding on eggs near substrates or schooling behavior. Herring consumed the small (

The aim of this study was to determine the effect of heat treatment on the antioxidant properties of herring meat and then subjecting it to hydrolysis with Alcalase® and testing these activities in...

Using ten microsatellite loci, the analysis of genetic variability and differentiation of the Pacific herring Clupea pallasii over a wide geographic range in the Sea of Okhotsk, the Bering, Chukchi, Kara, Barents, and White seas was performed. A similar level of genetic variability is shown for the herring belonging to three geographical subspecies. The genetic structure at a large scale is most pronounced between the three geographical subspecies of herring, with the different level of genetic differentiation within each of the subspecies. Herring of the Pacific distribution range is differentiated only at the level of large basins, the Sea of Okhotsk and Bering Sea, which indicates a significant level of gene exchange, as in the southeastern part of the Barents Sea and in the Kara Sea. However, the gene flow in the White Sea herring is limited to a very small spatial scale.

In the last decades, high concentrations of flame retardants (PBDE) in marine organisms have caused increasing concern among scientists with regards to their biomagnification potential and to human health. Poly-Brominated Diphenyl Ethers have been widely used in the past as flame retardants in various industrial sectors, and their presence in the biota has been associated with different toxicological effects. In this study, concentrations of 9 congeners of PBDE (183, 85, 153, 154, 99, 100, 47, 66 and 28) and morphometric parameters (Total Length, TL; Fork Length, FL in cm and weight) have been measured in muscle of males and females of Atlantic herring (Clupea harengus). Results showed no statistical differences between the concentrations of most of the congeners analysed between the two sexes, except for PBDE 153 (Mean ± standard error in males = 0.034 ± 0.005 μg/kg and in females = 0.086 ± 0.040 μg/kg; p = 0.003). This research contributes to better comprehend the ecotoxicological properties of these molecules and their implications for human consumption.

Preliminary evidence suggests that Chinook salmon Oncorhynchus tshawytscha from the Yukon River may be more susceptible to Ichthyophonus sp. infections than Chinook from stocks further south. To investigate this hypothesis in a controlled environment, we experimentally challenged juvenile Chinook from the Yukon River and from the Salish Sea with Ichthyophonus sp. and evaluated mortality, infection prevalence and infection load over time. We found that juvenile Chinook salmon from a Yukon River stock were more susceptible to ichthyophoniasis than were those from a Salish Sea stock. After feeding with tissues from infected Pacific herring Clupea pallasii, Chinook salmon from both stocks became infected. The infection was persistent and progressive in Yukon River stock fish, where infections sometimes progressed to mortality, and histological examinations revealed parasite dissemination and proliferation throughout the host tissues. In Salish Sea-origin fish, however, infections were largely transient; host mortalities were rare, and parasite stages were largely cleared from most tissues after 3-4 wk. Susceptibility differences were evidenced by greater cumulative mortality, infection prevalence, parasite density, proportion of fish demonstrating a cellular response, and intensity of the cellular response among fish from the Yukon River stock. These observed differences between Chinook salmon stocks were consistent when parasite exposures occurred in both freshwater and seawater. These results support the hypothesis that a longer-standing host-pathogen relationship, resulting in decreased disease susceptibility, exists among Salish Sea Chinook salmon than among Yukon River conspecifics.

A comparative analysis of the biological and morphometric characteristics of the Pacific herring Clupea pallasii from different parts of the range, from the White Sea to the Yellow Sea, was performed. Forming of the modern species range, covering the waters of the Arctic, boreal, and subtropical zoogeographic zones, was preconditioned by the system of adaptations developed during the long evolution in the specific conditions of the northern Pacific Ocean. The results of multivariate discriminant analysis indicated relatively small differences in the complex of meristic features when comparing the samples from the Pacific Ocean and the samples obtained in the Arctic Ocean and the north-eastern Atlantic Ocean.

Understanding the competitive interactions of ecological similar species is essential to determine their role and niche in the ecosystem. Using both conventional dietary methods and stable isotope analysis, we examined the feeding ecology, trophic position and possible niche partitioning of Northeast Atlantic mackerel (Scomber scombrus), Icelandic summer spawning (ISS) herring (Clupea harengus), and Norwegian spring spawning (NSS) herring from Icelandic waters during the spring and summer 2012 and 2014. The stomach analysis showed differences in prey preferences among the species during summer, where mackerel diets were almost exclusively calanoid copepods, while herring ate larger zooplankton, i.e. euphausiids and amphipods. Analysis of isotopic diet contribution of mackerel and herring using Bayesian mixing models, representing mainly the spring consumption, revealed that euphausiids were the main dietary contributor of both mackerel and herring. Fish prey were also an important dietary source for ISS herring, and amphipods were important to the diet of NSS herring. In addition, mackerel encompassed a broad isotopic niche, whereas the two herring stocks had narrower and separated niches from each other. The results from this analysis reveal new and holistic information into the diet of these species, which have various ecological implications.

PurposeThe aim of the study was to analyse the quality changes in marinated herring meat depending on the moment of adding milk thistle.Design/methodology/approachOne control (C) and two experimental groups were investigated: MH (milk thistle added to a marinade solution) and FH (fillets rubbed with milk thistle before marination). The basic chemical composition, the meat colour, heavy metals concentration, fatty acids profile, quality of lipids and antioxidant capacity were determined.FindingsThe occurrence of Fe, Mn, Cu and Zn was higher in the experimental group than in the control group throughout the marinating process. The peroxide value was higher from the first day in the control group than in the experimental groups. On the last day of the study, the peroxide value in the control group exceeded the maximum acceptable value. The highest level of Thiobarbituric Acid Reactive Substances was determined in the control group on the first day, and the lowest in the FH group. On the first day, the highest percentage of DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical quenching was recorded in the FH group.Originality/valueThe results are the first to find that the addition of milk thistle to herring fillets in marinating process maintains or even improves the quality of the marinades. The process of previously coating the fillets in milk thistle and then marinating achieves a lower peroxide value, higher content of polyunsaturated fatty acids and a higher content of elements such as iron and manganese, which are very valuable for human health.

The population genetic structure of Pacific herring Clupea pallasii in the northwestern Pacific Ocean is studied based on the polymorphism analysis of 11 microsatellite loci. Significant genetic differences are found between lacustrine and marine forms of herring (FST 0.0197−0.0521). The herring of lakes Ainskoe and Vilyui are separate populations. Based on the genetic differentiation index FST (0.0086−0.0218), the samples of marine forms are divided into two geographical groups: the Sea of Okhotsk and the Sea of Japan group, and the Bering Sea group. Within these groups, five population groups are differentiated: (1) Peter the Great Gulf, (2) northwestern Sea of Okhotsk (Okhotsk), (3) Shelikhov Gulf Shelikhova (Gizhiginsk), (4) Karaginsky Gulf, and (5) northern Bering Sea. During a period of high abundance, herring lacks clear ecological boundaries; its population structure can change over several generations on a significant part of the distribution range. The modern population structure of the marine forms was formed by a depression of the Bering Sea population and a population explosion in the Sea of Okhotsk.

Age at maturation is linked to population productivity and directly impacts forecasts of population biomass and resultant harvest limits set by management agencies. Based on the original concept that scale growth can be used as an index of body growth (length) from Johan Hjort and his collaborators, the current study examined a new way of estimating maturity empirically using scales for Pacific herring. We hypothesized that Pacific herring that will spawn in a particular year (spring) will have reached a sufficient size and have reduced growth (length) the summer prior, compared to immature herring, as energy will be allocated to reproduction rather than somatic length. Model results suggested that there was no difference in the measurement of all scale growth prior to the last increment (growth up until the summer prior) nor in the outer ring measurement (growth the summer prior to spawning) of immature and mature female herring; using scales to estimate maturity empirically was not successful in this study. It is possible that the sample size in this study may have been too low to detect differences in growth or differences in growth may be better represented by changes in length-specific mass.

The Paleo-Tokyo Bay (Kanto Plateau) that persisted during the transgression periods in the Middle-Late Pleistocene is known for its rich marine fauna that accommodated both the warm and cold water taxa brought by the Kuroshio and Oyashio Currents, respectively. However, little is known on the paleoichthyofauna in this area and the processes shaping the marine ichthyofauna of modern southern Kanto. We used fossil fish otoliths and teeth discovered in the Sha’ana Tuffaceous Sand Member belonging to the Chibanian Miyata Formation, exposed at Sha’ana-dai, Miura City, Kanagawa Prefecture, Japan, to reconstruct the paleoichthyofauna and its associated paleoenvironment and explore the content of fish assemblages during this period. The Sha’ana Tuffaceous Sand Member was composed of upper sandy mud and lower muddy sand horizons at the exposure. A total of 1,675 fish remains were collected from this site, of which 1,389 were assigned to 62 distinct taxa (20 orders, 31 families). The taxonomic composition revealed taxa from various environments, including shallow continental shelf, epi- to meso-pelagic settings, and the majority were from a generally temperate climatic zone. Paleoenvironmental analyses suggested that the fish assemblages were from the continental shelf (approximate depth of 100–200 m) in a temperate sea where both warm Kuroshio and cold Oyashio Currents had an influence on the biota. The analysis also showed that two boreal fishes, namely Clupea pallasii and Theragra chalcogramma, once had a wider distribution that extended to the southwestern areas of the Paleo-Tokyo Bay. This study provides a more complete view of the related paleobiogeography of marine fishes during the Chibanian and is essential for reconstructing the evolutionary processes of the rich ichthyofauna in the southern Kanto.

One hundred and ninety-three staphylococcal strains were isolated from samples of alaska pollock meat (Theragra chalcogramma), atlantic mackerel meat (Scomber scombrus), atlantic herring meat (Clupea harengus), and femoral muscle samples of the wild pheasants (Phasianus colchicus), wild rabbits (Oryctolagus cuniculus) and bryndza cheese. Phenotypic manifestations typical of individual staphylococcal species were detected in these isolates. Species identification was also performed by matrix-assisted-laser-desorption-ionization-mass-spectrometry on the basis of which 5 species of staphylococci were determined: S. aureus, S. epidermidis, S. capitis, S. haemolyticus, S. warneri. Subsequently, the presence of the 16S rDNA gene was confirmed by PCR assay; a specific sequence for S. aureus species; putative transcriptional regulator gene serp0107, a specific sequence of the sodA gene was used to identify S. epidermidis and to identify S. warneri, S. haemolyticus, S. capitis species. When comparing the results of identification by PCR assay and matrix-assisted-laser-desorption-ionization-mass-spectrometry, the identification at the genus level was identical in all cases (100%). However, the discrepancies in results were confirmed at the species level, where congruence for identification of isolates by PCR assay and matrix-assisted-laser-desorption-ionization-mass-spectrometry was only 80%. For these isolates, the score value ranged from 1.953 to 2.564.

There are few resources available for assessing historical change in fish trophic dynamics, but specimens held in natural history collections could serve as this resource. In contemporary trophic ecology studies, trophic and source information can be obtained from compound‐specific stable isotope analysis of amino acids of nitrogen (CSIA‐AA‐N).We subjected whole Sebastes ruberrimus and Clupea pallasii to formalin fixation and 70% ethanol preservation. We extracted tissue samples from each fish pre‐fixation, after each chemical change, and then in doubling time for 32–64 days once placed in the final preservative. All samples were subjected to CSIA‐AA‐N, and their glutamic acid and phenylalanine profiles and associated trophic position were examined for differences over time by species.Glutamic acid and phenylalanine values were inconsistent in direction and magnitude, particularly during formalin fixation, but stabilized similarly (in 70% ethanol) among conspecifics. In some cases, the amino acid values of our final samples were significantly different than our initial pre‐preservation samples. Nonetheless, significant differences in glutamic acid, phenylalanine, and estimated trophic position were not detected among samples that were in 70% ethanol for >24 hr.Our results suggest that the relative trophic position of fluid‐preserved specimens can be estimated using CSIA‐AA‐N, and CSIA‐AA‐N estimates for fluid‐preserved specimens should only be reported as relative differences. Timelines of trophic position change can be developed by comparing specimens collected at different points in time, revealing trophic information of the past and cryptic ecosystem responses., How can we detect historical change in fish trophic position? We can use compound specific stable nitrogen isotope analysis of fluid‐preserved museum specimens. Due to preservation effects, we should compare similarly preserved fish by species and report relative change in trophic position.

Life-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.

In high latitude coastal regions, benthic scavenger communities are largely composed of invertebrates that play a key role in the cycling of organic matter. Factors including temperature and depth can structure Arctic and Subarctic fjord benthic communities, but the response of scavenging communities to these factors is poorly known. To address this, we compared scavenging fauna in eight fjords with different physical characteristics in Svalbard and northern Norway using time-lapse imagery of scavengers consuming Atlantic herring (Clupea harengus) bait. Fjords influenced by relatively warm Atlantic waters, both in Norway and Svalbard, had high scavenger richness. However, Svalbard fjords with negative bottom temperatures had the lowest species richness and were dominated by lysianassoid amphipods and ophiuroids. In these cold Svalbard fjords, the mean carrion removal rates were almost 20 times higher than mean values noted elsewhere, except in the warm Norwegian fjord Kaldfjorden. Amphipods and ophiuroids quickly reduced the bait to bones (207.6–304.7 g removed per hour (g h−1); mean 290.6 ± 7.3 g h−1, n = 4) in cold Svalbard fjords. In the warmer Svalbard fjords, carrion removal rates were low (0–51.5 g h−1; mean 14.6 ± 9.0 g h−1, n = 5). Carrion removal rates in Kaldfjorden were higher than other Atlantic Water influenced fjords (132.1 and 372.5 g h−1, n = 2) owing to the scavenging activity of Atlantic cod (Gadus morhua). The results demonstrate potential ecosystem responses to warming in Arctic and Subarctic fjords, particularly effects related to range expansion of boreal species. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

The study was carried out to determine the effect of garlic extract on the proximate composition and microbial activity of cold and hot smoked Clupea harangus (Atlantic herring fish). In the study, fresh atlantic herring was thawed, eviscerated, weighed, washed properly and folded. Garlic extract was prepared at 100 ml, 75 ml, 50 ml and control with no garlic extract, each treatments were prepared in duplicates and in three batches. The folded atlantic herring was dipped into the garlic extract at the different concentration, the first batch of treatments was oven dried for 40°C for 6 hours (cold smoked), the second batch was oven dried for 65°C for 12 hours (cold smoked) and the third batch was oven dried for 75°C for 18 hours (hot smoked). After oven drying, it was allowed to cool for 20 minutes, samples for microbial analysis was immediately taken in a foil paper and stored in the fridge for a month while the remaining sample was immediately used for proximate analysis. At all hours of drying period, the moisture content decreases and protein content increases with increasing concentration of garlic extract, the lipid content was highest at 75 ml garlic extract and the ash content was highest at 50 ml garlic extract. Total bacteria count decreases with increasing concentration of garlic, increasing temperature and increasing hour of drying. No fungi growth was recorded at all hours of drying period.

Based on the materials collected in 2020, the catch, some biological and behavioral features of herring inhabiting the northern part of the Sea of Okhotsk are considered. The problems encountered in the herring fishing are shown, and measures to optimize the fishery are proposed.

An eDNA assay for the detection of Pacific herring (Clupea pallasii) in water samples was developed using quantitative PCR (qPCR) technology. Species-specific primers and a minor groove binding (MGB) probe were designed based on the mitochondrial cytochrome b gene sequence. Upon conducting a cross-species test, the target species DNA was not only detected at low concentrations but also with high specificity. The assay was validated using field-collected water samples from aquatic environments known to be inhabited by Pacific herring and tested positive in samples from Pacific herring-inhabited sites. Our in silico, in vitro, and in situ results highlight the sensitivity of our proposed eDNA-based procedure for the detection of C. pallasii DNA, and could provide a non-invasive and non-destructive approach to detect this species and characterize its distribution in the Jinhaeman Bay, Korea.

An experience on the creation of artificial spawning grounds for Pacific herring in Tauyskaya Bay of Sea of Okhotsk in 2014 is presented. A necessary area of artificial spawning grounds is calculated based on the volume of the substituted damage. It is shown that it is possible to compensate the damage to aquatic living resources, caused by economic activity with the suggested method.

The geographical structure and dynamics of introgressive hybridization with Atlantic herring Clupea harengus were studied for the Pacific herring Clupea pallasii based on long-term monitoring of genetic variation of C. pallasii from the White, Barents, and Kara seas using multivariate statistical analysis procedures in the Structure and NewHybrids programs. An unequal level of introgression of the Atlantic herring’s genes have been reported for the population of the White Sea summer-spawning and spring-spawning herring as well as for the Chesha-Pechora herring. The factors involved in supporting the hybridization of herring species in the zone of their secondary contact were considered. The predominant role of hybridization and introgression of genes in the formation of intraspecific genetic diversity of the Pacific herring was revealed.

Summary The study analyses for the first time the diet composition of grey seals inhabiting the Polish Baltic Sea coast. Samples of seal scat were collected in the Mewia Łacha Nature Reserve at the mouth of the Vistula River. Using genetic and osteological methods, the remains of organisms included in the grey seals diet were analysed for their taxonomy (families and species). Based on the analysis of 49 scat samples from grey seals, 761 hard parts that could be identified by taxon were isolated. The predominant species in the samples were perch, Perca fluviatilis (almost 78% of samples); pikeperch, Sander lucioperca (67%); lamprey, Lampetra fluviatilis (almost 35% of samples); Baltic cod, Gadus morhua callarias (almost 31% of samples) and sea trout, Salmo trutta trutta (26.5%). Genetic analysis confirmed the presence of Atlantic cod DNA in 69% and sea trout in 63% of samples. The genetic material of the Atlantic herring, Clupea harengus has not been identified in the analysed scat samples. Information on grey seals feeding on river lampreys seems to be valuable in the context of lack of knowledge on the occurrence of lampreys in the Vistula River. The methodology used showed that seals fed on species that were the most abundant in the area which is directly associated with the migration cycle of fish. The results of our study allowed the conclusion that the grey seal is an opportunistic predator and its diet reflects and exploits the variations in its habitat.

This study aimed at limiting hemolysis of fish red blood cells (RBCs) as a strategy to limit hemoglobin (Hb)-induced lipid oxidation during post-mortem handling and processing. Effects of varying temperature, salinity, and mechanical impact were studied using washed resuspended RBCs (wr-RBCs) and whole blood (WB) from rainbow trout (Oncorhynchus mykiss) and herring (Clupea harengus). The wr-RBCs were most stable avoiding mechanical stress, keeping isotonic conditions (0.9–1.3% NaCl) and low temperature 0–6 °C, with predicted minimum at 2.5 °C. When compared at the same salinity, it was found that hemolysis was more pronounced in herring than trout wr-RBCs. Furthermore, WB was more stable than wr-RBCs, showing protecting the effects of blood plasma. Studying individual plasma components, stabilizing effects were found from glucose, proteins, and ascorbic acid. This study indicates that small adjustments in the early handling and processing of fish such as changing salinity of storage and rinsing solutions could minimize Hb contamination of the fish muscle and thereby improve quality.

1. During this study, the effects of epiphytic filamentous algae on the survival of demersal spawned fish eggs were investigated in one of the most important spawning grounds of herring in the western Baltic Sea, which is subject to intense and ongoing eutrophication. 2. In coastal marine ecosystems all over the world, eutrophication is a primary water quality issue, often resulting in mass developments of bloom-forming algae. Macro-algal blooms have immense ecological effects, as they alter the structure and the function of an ecosystem. Numerous fish species are affected, as they depend on those coastal areas for spawning and as juvenile habitats. 3. A comparison of the survival of herring eggs on two natural spawning beds revealed an immense impact of a filamentous algal bloom. The mortality rate reached nearly 100% in the area with massive occurrence of filamentous brown algae. 4. Hypothesizing that the presence of filamentous algae facilitates herring egg mortality, field and laboratory experiments were conducted and revealed particular effects of distinct algal species. The survival rate of artificially spawned eggs on algal substrates and control substrates was compared. Whereas filamentous forms of the green alga Ulva intestinalis induced no immediate effect, significantly higher egg mortality was documented in experiments with the filamentous brown alga Pylaiella littoralis. 5. Considering the ecological and economical importance of herring and other coastal spawners on the one hand and the persisting and increasing effects of eutrophication and climate change on the other hand, the results of our study clearly underpin the necessity to increase global efforts to reduce nutrient loads in coastal waters.

The lack of any abundant recruiting year class of Norwegian spring-spawning (NSS) herring between 2005 and 2015 contributed to an approximate reduction of 40% in the spawning-stock biomass since 2009, i.e. from 7 to 4 million tonnes. Warming of the North Atlantic is suggested to contribute to this reduction in recruitment. In the past, a warm phase induced by a positive Atlantic Multidecadal Oscillation (AMO) in the North Atlantic was positively correlated to the NSS herring stock size. Recent unprecedented ocean warming in the Norwegian Sea ecosystem, besides elevated temperatures due to a positive AMO, seems to be outside optimal environmental conditions for early life history stages of NSS herring. We analysed 28 years of survey data using generalized additive models to reconstruct environmental conditions for drifting yolksac and preflexion stage larvae. Our results indicate that strong recruitment years were more likely when the larvae occurred simultaneously with a negative AMO during positive temperature anomalies. The transition from yolksac stages towards preflexion stages occurred while there was a slow increase in water temperature during the larval drift. Weak recruitment years generally occurred when larvae experienced elevated temperatures during the life stage transition under a positive AMO. These results augment evidence that the historical positive relationship between AMO and stock dynamics is reversed between 1988 and 2015. Albeit not implying any specific mechanistic biological interactions, we can assume that the unprecedented warming has modified the ecosystem drivers that negatively affect drifting larvae. Since 2016, the North Atlantic is shifting into a negative AMO phase, possibly resulting in the 10-year recruitment suppression of NSS herring ending soon.

An analysis of the size and age composition of the Pacific herring Clupea pallasii from Peter the Great Bay in 1941, 1944, and 1947−2017 has shown the categories of large-, medium-, and small-sized fish that statistically significantly differ in linear size. Their proportions in year-classes are subject to long-term and interannual variations. The identified groups of fish are distinguished by life cycle duration, timing of sexual maturity, and abundance dynamics, but they do not have a complete reproductive isolation. In the long-term dynamics of proportions of the size categories, large- and medium-sized individuals with positive linear growth deviations dominate the considered year-classes during the periods of stock increase; groups of small- and medium-sized fish with negative deviations of growth indices prevail in the years of low abundance.

Fish is an important part of the human diet, are at the top of the aquatic food chain with a high propensity to accumulating contaminants like heavy metals and polychlorinated biphenyls (PCBs) which are toxic to humans. The objective of this study was to evaluate the relationship between condition factor (physiologic wellbeing) of the fishes, PCBs, and heavy metal accumulation.Ten adult fish species three each of Chrysichthys nigrodigitatus, Trachinotus teraia, Liza dumerilli, Tilapia guieensis, Pseudotolithus elongatus, Pomadasys jubelini, Polydactylus quadrifilis, Caranx hippos, Sphyreana barracuda, Arius heudoloti,were acquired at Epe Lagoon. Ten adult fish species three each of Argentina silus, Gadus chalcogrammus, Gadus morhua, Atlantic mackerel, Micropogonias undulatus, Urophycis sp., Chrysichthys nigrodigitatus, Oreochromis niloticus, Clupea harengus, Trachurus trachurus, imported into Lagos were purchased. The fish species’ condition factor was determined. The heavy metals were determined using AAS while PCB level was determined using GC-MS. Iron, mercury, zinc, arsenic, nickel and copper levels correlated positively with the condition factor in the local fishes while in the imported fishes, cadmium, iron, zinc, nickel, copper and lead levels correlated positively to the condition factor. The levels of PCBs in both the local and imported fishes were non-detectable. It is concluded that the lead, copper, arsenic, zinc, mercury and cadmium in both the imported and local fishes were within permissible limits compared with the FAO/WHO maximum permissible limits. The positive correlation of some heavy metals to the fishes’ condition factor infers that these metals might be altering physiologic activities in the fishes. Keywords: Condition factor; Heavy metals; Polychlorinated biphenyl; Fish

Senescence is the age-specific decline in fitness of adult organisms principally associated with a decline in survival rate (actuarial senescence) and fecundity (reproductive senescence). Although common in natural populations of many taxa, there are few examples in fishes. A recent study found age-specific increases in the relative frequency of macroscopically non-reproductive Atlantic herring (Clupea harengus Linnaeus, 1758), consistent with reproductive senescence in a number of Canadian populations. However, a non-adaptive explanation for these patterns, unrelated to senescence, could not be definitively ruled out. Here, we present the results of histological examination of herring gonads undertaken to examine this and another hypothesis. The sample size of macroscopically senescent gonads was small (n = 4 females), a function of the low abundance of large, older, purportedly senescent, herring in these populations subjected to high mortality rates, and constraints on obtaining fresh samples. The results indicate that these fish were senescent and not merely skip spawning, providing further evidence of senescence and the occurrence of a post-reproductive period in herring in Atlantic Canada. Based on existing theory for the evolution of senescence, observations of actuarial senescence in Norwegian spring-spawning herring suggest that this population may also experience reproductive senescence and that the phenomenon may occur broadly in the species.

Fish are adapted to spawn where their larvae will be retained in, or transported to, suitable juvenile habitat. Variability in circulation and behaviour produces variation in larval transport with consequences for recruitment. A biophysical model was used to simulate early larval dispersal of Celtic Sea herring (Clupea harengus) during wintertime in 6 years (2002, 2003, 2004, 2005, 2008, 2010). After 30 days, particles occurred in three areas: inshore Celtic Sea, offshore Celtic Sea, and southern Irish Sea, with the majority (70%–78% on average) of particles retained in the Celtic Sea. Inclusion of tidal forcing increased transport to the Irish Sea and decreased transport offshore, as did release during a spring tide. Retention in the Celtic Sea was increased by diel vertical migration and decreased by horizontal diffusion. Strong and frequent west to southwest winds increased transport offshore, while strong and frequent east to south-southeast winds increased inshore retention in the Celtic Sea and transport into the Irish Sea. The study shows how tides, winds, and behaviour influence larval transport and retention and highlights potential impacts of climate change on population persistence.

Pacific herring Clupea pallasii Val. — an important commercial species, the range of which covers not only the boreal waters of the Asian and American coasts of the Pacific Ocean, but also extends to the coastal waters of northern Eurasia. The article examines the features of the ecological, biological, morphological variability of the Pacific herring in the extended range from the White to the Yellow Seas, covering the waters of the Arctic, boreal, subtropical zones. The modern habitat of the Pacific herring is represented by two subunits: the ancient range (about 5 million years old) (the coastal area of the North Pacific) and the newly formed range (about 6 thousand years old) — (shelf zones of the Bering, Okhotsk, Yellow Seas, the Arctic coast of Eurasia). The highest growth rate is characteristic of herring in the boreal zone; the lowest values were found for herring from the Kara Sea and the White Sea spring-spawning herring. The results of multivariate discriminant analysis illustrate the similarity of Pacific herring in different areas of the range in terms of a set of meristic characters. The features of changes in the temporal characteristics of the spawning period in Pacific herring in different parts of the range are considered.

For marine fishes of commercial interest, defining how individuals vary in certain attributes, through ontogeny, and across space and time, can help expose the structure of harvested populations and guide their management. The chemical markers locked within otoliths are, in principle, ideal for such applications, providing life-long, bio-environmental records for individuals and populations. However, substantial uncertainty still surrounds how intrinsic (i.e., within-individual) and extrinsic (i.e., environmental) processes shape chemical incorporation into otoliths, constraining our ability to predict marker variability when sampling is patchy. To tackle these issues, we measured otolith elemental (Li, Mg, Ca, Mn, Zn, Sr, Ba) and stable isotopic (δ13C, δ18O) concentrations from juvenile Atlantic herring (Clupea harengus) captured in Icelandic nursery sites, and built models to isolate ontogenetic (i.e., age-, growth-related) from environmental influences on otolith chemistry. Otolith Li:Ca, Mg:Ca, Mn:Ca and Sr:Ca declined with age within sites. Age slopes differed among sites for Li:Ca and Mg:Ca, and Sr:Ca was lower in larger fish within an age-class. Individual-level variation (i.e., within site, within age-class) was high for all markers, our models highlighting the importance of temperature and salinity (or proxies these represent) in explaining population-level δ13C and δ18O trends. Age- and year-specific predictions for each marker, at each site, generally accorded well with empirical observations, providing inference on island-wide heterogeneity in otolith chemistry across the juveniles’ full distributional range. Such ‘isoscapes’, generated from mechanistically-focused models as presented here, might benefit investigations of population structure for other exploited species, particularly where sampling limitations hamper fishery-management efforts.

Polymorphism in the variable fragment of the mtDNA control region (D-loop, 373 bp) and four microsatellite loci in 683 specimens of the Pacific herring Clupea pallasii sampled at different locations from the Asian part of range has been studied. It is shown that the Pacific herring lake forms inhabiting the three lakes on Sakhalin Island (Ainskoe) and in the Kamchatka Peninsula (Vilyuy and Nerpiche) have significantly diverged from the marine forms according to the data on the mtDNA and nDNA markers. The genetic variations among the herring forms inhabiting different lakes (FST = 0.034−0.066) and between the lake herring forms and marine herring forms (FST = 0.004−0.055) are revealed. The level of the genetic differentiation among the lake herring forms is much higher than that among the samples of the marine herring forms, which may be explained by the founder effect. Evolution of the lake forms occurred along with the geological processes producing the lakes.

The prevalence of Ichthyophonus infection in Pacific herring Clupea pallasii was spatially heterogeneous in the southern Salish Sea, Washington State, USA. Over the course of 13 mo, 2232 Pacific herring were sampled from 38 midwater trawls throughout the region. Fork length was positively correlated with Ichthyophonus infection at all sites. After controlling for the positive relationship between host size and Ichthyophonus infection, the probability of infection was approximately 6-fold higher in North Hood Canal than in Puget Sound and the northern Straits (12 vs. 2% predicted probability for a 100 mm fish and 30 vs. 7% predicted probability for a 180 mm fish). Temporal changes in Ichthyophonus infection probability were explained by seasonal differences in fish length, owing to Pacific herring life history and movement patterns. Reasons for the spatial heterogeneity remain uncertain but may be associated with density-dependent factors inherent to the boom-bust cycles that commonly occur in clupeid populations.

Clupea pallasii Valenciennes, 1847. Pacific Herring. To 46 cm (18 in) TL (Miller and Lea 1972). Korea and Japan to Arctic Ocean off Alaska to northern Baja California; Arctic Canada as far east as Queen Maud Gulf (Coad in Coad and Reist 2018). Scattered populations in Norwegian Barents Sea and Russian White and Pechora Seas (Whitehead 1985, J��rstad et al. 1994, J��rstad 2004, Laakkonen et al. 2015). This species hybridizes with Clupea harengus Linnaeus, 1758 in northern Europe (Laakkonen et al. 2015). Marine, brackish waters and, very occasionally, fresh waters (Moyle 2002); depth: surface to 250 m (820 ft) (Whitehead 1985). There are a number of deeper capture records (e.g., 723 m, 2,371 ft, Bradburn et al. 2011; 1,033 m, 3,388 ft, 1,068 m, 3,503 ft, NWFSC-FRAM) all recorded from bottom trawl catches. In these circumstances it is not possible to ascertain if these fish were caught on the bottom or in midwaters during net deployment or recovery. Almost always captured above 150 m (492 ft) (Whitehead 1985)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 43, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Miller, D. J. & Lea, R. N. (1972) Guide to the coastal marine fishes of California. California Department of Fish and Game Fish Bulletin, 157.","Coad, B. W. & Reist, J. D. (Eds.). (2018) Marine Fishes of Arctic Canada. University of Toronto Press, Toronto.","Whitehead, P. J. P. (1985) FAO Species Catalogue. Volume 7. Clupeoid Fishes of the World (Suborder Clupeoidei). Part 1. Chirocentridae, Clupeidae and Pristigasteridae. FAO Fisheries Synopsis No. 125, FAO, Rome.","Jorstad, K. E., Dahle, G. & Paulsen, O. I. (1994) Genetic comparison between Pacific herring (Clupea pallasi) and a Norwegian fjord stock of Atlantic herring (Clupea harengus). Canadian Journal of Fisheries and Aquatic Sciences, 51, 233 - 239.","Jorstad, K. E. (2004) Evidence for two highly differentiated herring groups at Goose Bank in the Barents Sea and the genetic relationship to Pacific herring, Clupea pallsi. Environmental Biology of Fishes, 69, 211 - 221. https: // doi. org / 10.1007 / 978 - 94 - 007 - 0983 - 6 _ 17","Laakkonen, H. M., Strelkov, P., Lajus, D. L. & Vainola, R. (2015) Introgressive hybridization between the Atlantic and Pacific herrings (Clupea harengus and C. pallasii) in the north of Europe. Marine Biology, 162, 39 - 54. https: // doi. org / 10.1007 / s 00227 - 014 - 2564 - x","Moyle, P. B. (2002) Inland Fishes of California. Revised and Expanded. University of California Press, Berkeley.","Bradburn, M. J., Keller, A. A. & Horness, B. H. (2011) The 2003 to 2008 U. S. West Coast bottom trawl surveys of groundfish resources off Washington, Oregon, and California: estimates of distribution, abundance, length, and age composition. National Marine Fisheries Service Technical Memorandum, NMFS-NWFSC- 114."]}

Pacific herring (Clupea pallasii Valenciennes, 1847) is a commercially important species that inhabits the coastal waters of the North Pacific from Korea to California, USA. This study analyzed the target strength (TS, dB re 1 m2) of Pacific herring individuals (n = 14, total length (LT) = 21.3–32.3 cm) at 38 and 120 kHz using ex-situ measurements and the Kirchhoff-ray mode (KRM) model. The least-squares regressions of the TS–LT relationship for the ex-situ measurements were TS38kHz = 20 log10(LT) − 70.10 (r = 0.17) and TS120kHz = 20 log10(LT) − 70.59 (r = 0.10). The least-squares regressions for the KRM model were TS38kHz = 20 log10(LT) − 68.39 (r = 0.40) and TS120kHz = 20 log10(LT) − 69.74 (r = 0.49). The b20 value of the KRM model was 1.71 dB higher than that of the ex-situ measurement at 38 kHz but similar at 120 kHz. These results provide basic data to evaluate the distribution and abundance of Pacific herring using fisheries’ acoustic technology.

Simple Summary Pathogen surveillances in wild marine fish populations need to be carefully designed to address specific research or management objectives. Surveillance strategies should be designed around host life history characteristics, host and pathogen geographic ranges, laboratory diagnostic tools that are specific to the epidemiology of each pathogen, and the goal of the surveillance program. We demonstrate how the potential impacts of viral hemorrhagic septicemia can be under-appreciated in populations of Pacific herring by comparing results from opportunistically collected samples with those from more targeted epidemiological investigations that were focused on times and locations with high disease probability. Abstract Throughout a 20 year biosurveillance period, viral hemorrhagic septicemia virus was isolated in low titers from only 6/7355 opportunistically sampled adult Pacific herring, reflecting the typical endemic phase of the disease when the virus persists covertly. However, more focused surveillance efforts identified the presence of disease hot spots occurring among juvenile life history stages from certain nearshore habitats. These outbreaks sometimes recurred annually in the same temporal and spatial patterns and were characterized by infection prevalence as high as 96%. Longitudinal sampling indicated that some epizootics were relatively transient, represented by positive samples on a single sampling date, and others were more protracted, with positive samples occurring throughout the first 10 weeks of the juvenile life history phase. These results indicate that viral hemorrhagic septicemia (VHS) epizootics in free-ranging Pacific herring C. pallasii are more common than previously appreciated; however, they are easily overlooked if biosurveillance efforts are not designed around times and locations with high disease potential.