Sea Herring Research Articles

Explaining major shifts in early-modern economies: the causes for the decline of the North Sea Fisheries of Southwest Denmark, 1537–1657

ABSTRACT In the early modern period, the region of southwest Jutland, Denmark, faced international competition and climate change. By the early sixteenth century, the region enjoyed remarkable wealth thanks to a booming fish trade. Catches peaked at levels not surpassed before the twentieth century, and the trade in North Sea herring, haddock, cod, plaice, and skate supported thousands of fishers and merchants. Fishing benefitted from favourable environmental conditions and strong demand from the nearby German market. In the seventeenth century, the region began to decline, primarily because of changes in the international market with competing supplies and declining prices for whitefish relative to agricultural products. Environmental forces had both positive and negative effects on the fishery. The shocks of the Swedish occupation of 1628–29 and the flood of 1634 exacerbated the decline. The demise of North Sea fishing coincided with a shift in urban wealth from middle-class fish merchants to a small group of cattle-trading patricians and led to a general contraction and emigration of the human population along the North Sea coast. The study shows that economic factors and environmental forces must be considered to get a full picture of the region as it faces international competition and climate change.

Local reflects global: Life stage-dependent changes in the phenology of coastal habitat use by North Sea herring.

Climate warming is affecting the suitability and utilization of coastal habitats by marine fishes around the world. Phenological changes are an important indicator of population responses to climate-induced changes but remain difficult to detect in marine fish populations. The design of large-scale monitoring surveys does not allow fine-grained temporal inference of population responses, while the responses of ecologically and economically important species groups such as small pelagic fish are particularly sensitive to temporal resolution. Here, we use the longest, highest resolution time series of species composition and abundance of marine fishes in northern Europe to detect possible phenological shifts in the small pelagic North Sea herring. We detect a clear forward temporal shift in the phenology of nearshore habitat use by small juvenile North Sea herring. This forward shift might be linked to changes in water temperatures in the North Sea. We next assessed the robustness of the effects we found with respect to monitoring design. We find that reducing the temporal resolution of our data to reflect the resolution typical of larger surveys makes it difficult to detect phenological shifts and drastically reduces the effect sizes of environmental covariates such as seawater temperature. Our study therefore shows how local, long-term, high-resolution time series of fish catches are essential to understand the general phenological responses of marine fishes to climate warming and to define ecological indicators of system-level changes.

Determination of the quality of smoked sea herring (Sardinella maderensis) produced by three smoking processes practiced in Ivory Coast

Determination of the quality of smoked sea herring (Sardinella maderensis) produced by three smoking processes practiced in Ivory Coast

Современное состояние биологии, запасов и промысла атерины (Atherina boyeri caspia (Eichwald)) в западной части Среднего и Северного Каспия

The article considers the original results of observations and analysis of the catches of atherina (Atherina boyeri caspia (Eichwald)) by months by stationary nets in the Terek-Caspian fishery subarea (Republic of Dagestan). The size-weight and age indicators of the spawning stocks of atherina have been characterized. For the first time in recent years the conditions for atherina spawning in the western part of the Middle and Northern Caspian are described. All biostatistical indicators of atherina obtained in the recent years (2016–2021) are listed: average linear weight parameters, average fatness coefficient according to Fulton (0.944) indicate a high fattening of fish. Size and weight composition of females and males, age-related fluctuations in length and weight, comparative analysis of atherina concentrations, characteristics of atherina reproduction in the conditions of the Northern and Middle Caspian, fecundity of different age groups, quantitative distribution of roe, larvae and fry of atherina, as well as dynamics of the age composition from catches prove a satisfactory state of stocks of this fish species. Comparative analyses of autumn concentrations of atherina in the Middle Caspian in 1958–1963 and in 2018–2021 are presented, as well as spp/h of trawling, age-related fluctuations in the length and weight in the autumn period (2016–2021). It has been found that atherina in the Caspian Sea is the main object of by-catch when fishing for kilka with stationary seines (in average 56.3 tons per year); it plays an important role as a food component for many fish species (sea herring, sturgeon) and mammals (Caspian seal) living in the waters of the Caspian Sea. Prospective volumes of processing atherina for fishmeal are also considered for the first time. On the scale of the Caspian Sea, with intensive kilka fishing by stationary seines as by-catch, it is possible to catch atherina in the amount of 150–200 tons. Despite the small volumes, they would significantly cover the deficit in the fish feed. Due to the increasing population of atherina in the natural conditions it is required to actively involve atherina in the fishing processes of the organizations in order to maximize the development of the commercial stock.

Marine migrating herring of the Caspian Sea

In the Russian water area of the Caspian Sea, after a long period of prohibition of marine net fishing, there is an increase in the intensity of catching marine migratory herring. Long-term monitoring studies confirm that the three species of the most massive herring (Dolginsky herring, Caspian puzanok, Big-eyed puzanok) are characterized by the stability of the biomass of the stock, the structure of populations by age and size-weight composition, the distribution of concentrations on spawning grounds, the yield of new generations. Sea herring is one of the underutilized resources of the Caspian Sea. Possible ways of solving the problem of development of fishing reserves are considered. The current state of reserves makes it possible to increase the annual industrial withdrawal of sea herring to 15,4 thousand tons.

Role of protozooplankton in the diet of North Sea autumn spawning herring (Clupea harengus) larvae

The role of small prey (< 200 µm) in larval marine fish nutrition is largely understudied. Here, we explore the contribution of protozooplankton (PZP 20–200 µm) to larval fish diets, compared to metazoan microzooplankton (MZP 55–200 µm). More specifically, we tested whether the contribution of PZP increased during the low productivity season and decreased as larvae grow. We used North Sea autumn spawning herring (Clupea harengus) as a case study, as it is a key species with high commercial and ecological importance. In autumn and winter, the potential PZP and MZP prey was dominated by cells < 50 µm (mainly Gymnodiniales, Pronoctiluca pelagica,Tripos spp. and Strombidium spp.), while copepod nauplii and copepodites where more abundant in autumn than in winter. Based on their trophic enrichment (∆15 N), larvae preferentially grazed on small MZP < 50 µm rather than PZP both in autumn and winter. Larvae of different body size (range 8–14 mm standard length) fed at the same trophic level but on different prey (similar δ15N but different δ13C). Growth rates (based on RNA/DNA estimates) were similar in autumn and winter, suggesting that growth was not affected by station-specific differences in the composition of the prey field. Our results not only underscore the important role of MZP on larval herring diets both in autumn and wintertime, but also emphasize the limitations of bulk stable isotope analysis. Given the current low recruitment in North Sea herring, these results provide significant information for future monitoring approaches relevant to stock assessment of this species.

The more the merrier? Testing spatial resolution to simulate area closure effects on the pelagic North Sea autumn spawning herring stock and fishery

Spatially explicit bio-economic models that are age-structured and dynamic become increasingly important, being used for different purposes including spatial management measure evaluation. One of the reasons why those complex models are still rare is the extensive data need. FishRent incorporates highly resolved economic information of multiple fleets at the same time linking this to a detailed age-structured biology of multiple species simultaneously. Additionally, it follows the European Data Collection Framework (DCF) data structure, hence the data is relatively easy to implement We adapted the temporal (annual) version of the pelagic FishRent model to be spatially explicit and incorporated seasonal migration patterns of North Sea herring. During this process, we showed the effects of increasing the spatial resolutions on simulated stock biomass and simulated fleet behaviour. When interested in the general, annual population development over the years, a relatively low resolution might suffice. Spatial effects of the fleet behaviour are, however, better captured with a higher resolution. Further, we closed the major spawning grounds at different resolutions. By doing so, we illustrated the need to incorporate a dynamic behaviour of fishing fleets and to increase fleets’ flexibility by increasing the amount of accessible areas for each fleet.

THE CURRENT STATE OF THE KEFAL FAMILY (MUGILIDAE) IN THE COASTAL ZONE OF THE DAGHESTAN COAST OF THE CASPIAN SEA

For more than a century of active commercial exploitation and environmental changes in the Caspian Sea, the structure of the population of marine fish species has undergone significant qualitative and quantitative changes. In this group of fish until 1960, the main role in the fishery was played by sea herring, which provided up to 50–70% of the total fish catch in the region. Interest in the study of marine fish of the Caspian Sea, using the example of mullets, Black Sea acclimatizers, is due to the fact that under new conditions, as well as a result of deep negative changes in the ecology of this reservoir under the influence of natural and anthropogenic factors, especially recently. At present, among marine fish, one of the main and promising fishing objects is mullet, which, since the period of acclimatization, has formed a high abundance in the coastal zone of the Daghestan coast of the Caspian Sea. Mullet are euryhaline fish that can live both in sea, salty water, and freshwater bodies. In this regard, the objects of this study were mullet (singil), the study of their commercial catches and stocks in the Caspian Sea.

The influence of feeding on muscle tissues composition in cage reared bluefin tuna (Thunnus thynnus)

Capture-based tuna aquaculture rates as one of the most important aquaculture activities in Cro-atia, where juvenile tuna are reared in cages for over a year long period in order to increase substan-tially their weight. The aim of this study was to assess the effect of length and intensity of feeding on biochemical composition (total fat, moisture, dry matter, carbohydrates and protein content) of tuna (Thunnus thynnus) white muscle tissues in newly caught tuna prior to feeding (NCTPF) versus far-med tuna kept in rearing circular cages in the Vela Grska Bay, Adriatic Sea (LAT 43°17’40,6984”N, LONG 016°28’58,4315”E (WGS84)) between 2001 and 2004. Farmed tunas from all cages were fed with the feed consisting of domestic small pelagic fish, or with mixtures containing North Sea herring (Clupea harengus) and Sardina pilchardus, for five months (cage 3), eight months (cage 4) or 21 months (cages 1 and 2). A low content of moisture and high content of dry matter including fat was observed in farmed tuna muscles compared to wild-caught tuna. In farmed tuna muscles, measured moisture was 55.26% in cage 1, 39.95% in cage 2, 54.64% in cage 3 and 49.70% in cage 4. These results are significantly lower than moisture measured in NCTPF (80.36%). Content of dry matter found in farmed tuna muscles also differed greatly between wild tuna (19.64%) and far-med tuna, but also between the cages (44.74% in cage 1, 60.05% in cage 2, 45.36% in cage 3 and 50.30% in cage 4). In NCTPF, muscle tissues total fat encompassed less than 1% of the total body weight, while it reached over 20% of total body mass in farmed fed tuna (20.62% in cage 1, 42.50% in cage 2, 20.97% in cage 3 and 20.57% in cage 4). These results demonstrate that high fat content can be achieved already after five months of intensive feeding. Higher content of proteins was also found in aquacultured tuna (18.60% in cage 1, 16.00% in cage 2, 15.09% in cage 3 and 20.58% in cage 4) compared to wild-caught tuna (13.77%). There were no differences in carbohydrates con-tent between tuna farmed in different cages and NCTPF tuna, indicating glycogen as a less optimal indicator of muscle tissue quality in farmed tuna of the present study.

Biophysical models reveal the role of tides, wind, and larval behaviour in early transport and retention of Atlantic herring (Clupea harengus) in the Celtic Sea

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.

Lake or Sea? The Unknown Future of Central Baltic Sea Herring

The understanding of natural variability of harvestable fish stocks is of fundamental interest for their management; however, time series are often biased by the impact of fisheries. Observations show that the mean weight of central Baltic Sea herring (Clupea harengus), a quantity unbiased by fisheries, is indirectly influenced by the Atlantic Multi-decadal Oscillation (AMO) via a complex mediator chain, in which a transition from a marine to a freshwater state plays a major role. This observed trend is also projected for the future in regional climate change scenarios. The consequence of increasing precipitation is a reduction in the marine habitat, a change in the prey community and a decrease in the mean weight of three-year-old central Baltic Sea herring from 50-70 g in the late 1970s to 25-30 g today. The reduction in weight over this period represents a reduction in landings of approximately one million tons of herring and an economic loss of the order of €100 million.

A new semi-parametric method for autocorrelated age- and time-varying selectivity in age-structured assessment models

Selectivity is a key parameter in stock assessments that describes how fisheries interact with different ages and sizes of fish. It is usually confounded with other processes (e.g., natural mortality and recruitment) in stock assessments and the assumption of selectivity can strongly affect stock assessment outcome. Here, we introduce a new semi-parametric selectivity method, which we implement and test in Stock Synthesis. This selectivity method includes a parametric component and an autocorrelated nonparametric component consisting of deviations from the parametric component. We explore the new selectivity method using two simulation experiments, which show that the two autocorrelation parameters for selectivity deviations of data-rich fisheries are estimable using either mixed-effect or simpler sample-based algorithms. When selectivity deviations of a data-rich fishery are highly autocorrelated, using the new method to estimate the two autocorrelation parameters leads to more precise estimations of spawning biomass and fully selected fishing mortality. However, this new method fails to improve model performance in low data quality cases where measurement error in the data overwhelms the pattern caused by the autocorrelated process. Finally, we use a case study involving North Sea herring (Clupea harengus) to show that our new method substantially reduces autocorrelations in the Pearson residuals in fit to age composition data.

Measuring Potential Rents in the North Sea Herring Fishery

AbstractThis paper assesses the potential for rent generation in the North Sea herring fishery. The assessment distinguishes between rents and intra‐marginal profits—the sum of which constitutes variable profits in the fishery. A bioeconomic model combining fish population dynamics and the economics of the fishery is constructed to allow the computation of these different components of profits. In order to assess the dynamics of both rents and intra‐marginal profits, the model is computed under various assumptions with regard to price, costs, and discount rates. Potential total profits are measured at £88 to £89 million annually, of which rents make up about £87 million with intra‐marginal profits measured in the order of only £2 million. The study further shows that, in this fishery, rent is dissipated mainly due to excess effort but also due to suboptimal stock size.

Northern Europe Processing Technique, Nutritional Composition, Quality and Safety, Flavour Compounds," Bio-Chemical Change During Pickle Curing of North Sea Herring (Clupea harengus) of Britain

Northern Europe Processing Technique, Nutritional Composition, Quality and Safety, Flavour Compounds," Bio-Chemical Change During Pickle Curing of North Sea Herring (Clupea harengus) of Britain

Spatial and Temporal Variability in the Abundance and Size Structure of Larvae of the White Sea Herring (Clupea pallasii marisalbi) in Onega and Kandalaksha Bays of the White Sea

According to the data of ichthyological surveys conducted in Onega and Kandalaksha bays of the White Sea in June 2015, the abundance and pattern of spatial distribution of larvae of the White Sea herring Clupea pallasii marisalbi are comparable with those of 2012. Aggregations of herring larvae detected at a distance of 12−14 km from the coast in the apex part of Kandalaksha Bay are probably the result of their mass drift caused by fresh floodwater discharge. In coastal waters of the bays adjacent to the littoral part, the abundance of herring larvae above the depths less than 5 m varies considerably due to their drift under effect of alongshore and/or tidal currents. The White Sea herring larvae reach high abundance only in the inlets (Chupa, Knyazhaya, Belaya, and Maikova inlets) with the river runoff; their length increases with the distance from spawning grounds. In different years, the main bulk of herring larvae in Knyazhaya Inlet is concentrated at depths about 12–15 m at 6−8°C, or moved to the upper 5-m quasi-homogeneous layer when the water temperature at the depth was 0−1°C.

May Fermented Baltic Sea Herring help in conditions of gut disorders, such as gastric catarrh and heartburn?

Bakground - It has been suggested that disruption of the gut microbiota can be significant with respect to pathological intestinal conditions, like irritable bowel syndrome (IBS), gastric catarrh (GC), and heartburn (HB). Through history, an essential part of the colonization of the human gut took place by ingestion of food preserved by fermentation. The natural replenishment of microbes via food and beverage is today low because food is “sterilized” through boiling, broiling and pasteurization. Modulating the gut microbiota with fermented food products may hence be considered as a strategy to treat such conditions. Fermented Baltic Sea herring (FBSH) is an example of a Lactobacillus-fermented food product, which was tested in the present study. Methods - A 30-day open study was performed in 42 volunteers with IBS, GC, or HB. Volunteers were recruited by advertisements in daily newspapers. The volunteers were provided with gelatin capsules for the study, each containing approximately 100 mg freeze dried FBSH. They were also provided with forms that contained columns and rows for every test day where the volunteers were ask to fill in number of capsules taken, and to report possible improvements according to a 0-10 scale, where 10 stands for full recovery. Results - The most reported common disorder symptom was IBS and 7of 14 of these volunteers reported recovery, with a mean recovery of 4.4. Nine of 9 volunteers reported recovery from GC, with a mean recovery of 8.4. Five of 6 volunteers reported recovery from HB, with a mean recovery of 6.8. Conclusion - Although the present study is a small open study, the overall results are exciting and merits further studies in volunteers, ideally in a double-blind placebo-controlled manner.

Inter-annual variability in distribution and spatial abundance of sprat, Norway pout and small herring in the North Sea

Spatial explicit ecology and new regulations call for continuous spatiotemporal data. For marine species, such data hardly can be obtained from observation but need to be modelled from point data. A promising approach is regression kriging that addresses biological response to environmental conditions and spatial autocorrelation in data. Here it was applied to abundance data of North Sea prey fish sprat, Norway pout and herring. Results show seasonal and inter-annual variability of distribution limits, core areas and high abundance areas of all three species. Core areas of sprat and Norway pout are complementary bordering roughly along the 50 m isobaths. Small overlap of the two core areas were found only off the northern English coast. The comparison of North Sea-wide sums with assessment estimates show that the regression kriging approach can reproduce inter-annual dynamics. The outcomes allow assessing the magnitude of the catchability of the employed fishing gear and give evidence of seasonal variation of catchability. Capabilities and restrictions of the applied model and data are discussed in the light of niche theory. Results are of potential use in the assessment of the effects of changed utilization of marine areas in the marine spatial planning framework.

Genetic variations among pacific herring (&lt;i&gt;Clupea pallasii Val&lt;/i&gt;.) from the Okhotsk Sea and Lake Ainskoye by microsatellite loci

Genetic variation among spawning groups of pacific herring from different spawning grounds in the northwestern Okhotsk Sea and Lake Ainskoye (Sakhalin Island) is assessed by 11 microsatellite loci. All loci were polymorphic. Genetic differentiation of the herring from the Okhotsk Sea was statistically significant, the pairwise genetic differentiation F ST varied in the range of 0.0-0.4 that suggested existence of at least two local stocks. The herring from Lake Ainskoye was clearly different from the Okhotsk Sea herring.

Temporal Trends and Geographical Differences of Perfluoroalkyl Acids in Baltic Sea Herring and White-Tailed Sea Eagle Eggs in Sweden.

Temporal and spatial trends of perfluoroalkyl acids (PFAAs) were investigated in Baltic Sea herring liver (Clupea harengus) from three sites, and white-tailed sea eagle (WTSE) eggs (Haliaeetus albicilla) from two freshwater and two marine areas in Sweden. Trends of most quantifiable PFAAs increased over the monitored period (1980-2014 in herring, 1960s/1980s-2010 in WTSE). No significant decreasing trends were observed for the most recent ten years for any substances, except perfluorooctane sulfonamide (FOSA). Concentrations of perfluorooctanesulfonic acids (PFOS) in herring showed a distinct decreasing spatial trend moving from the more southern site toward the more northern site, indicating main input of PFOS into the southern Baltic Sea. For WTSE, PFOS concentration was higher in the marine compared to the freshwater environment, explained by the cumulative historic contamination of the Baltic Sea. Similarly, concentrations in WTSE were lower in the northern part of the Baltic Sea compared to further south. Concentrations of PFUnDA, representing long-chain perfluoroalkyl carboxylic acids (PFCAs), showed a more homogeneous spatial distribution compared to PFOS for both herring and WTSE, indicating that atmospheric inputs (via precursors) of the long-chain PFCAs are important contributors in the study areas.

Feeding strategy of Downs herring larvae (Clupea harengus L.) in the English Channel and North Sea

This study aims to characterize the larval feeding strategy of the Downs sub-population of North Sea herring (Clupea harengus L.). Diet composition, vacuity rate and prey selectivity of larvae from 8 to 15mm collected during the International Bottom Trawl Survey (IBTS) - MIK sampling from 2008 to 2013 were assessed by direct observation of their gut contents using Scanning Electron Microscopy (SEM). The high contribution of protists and small zooplanktonic prey observed in the gut contents proved the relevance of SEM to study the diet of first feeding larvae. The relatively low vacuity rate of 45% suggests that food may not be a limiting factor for Downs herring larvae in winter. These larvae appeared to be omnivorous and there was a clear shift in term of prey composition at a size of 13mm. Smaller larvae (8–12mm) fed on a higher diversity of small prey, mainly small copepods (Oncaea spp. and Euterpina acutifrons), invertebrate eggs, diatoms (Psammodicthyon panduriforme and Coscinodiscus spp.) and dinoflagellates (Dinophysis acuminate and Prorocentrum micans) whereas bigger larvae (13–15mm) fed on a lower diversity of larger prey, mainly copepods (Temora longicornis and Paracalanus parvus) and dinoflagellates (Gonyaulax spp.). Downs herring larvae had clear prey preferences as some dinoflagellates (Pyrophacus spp., Gonyaulax spp., P. micans and Porocentrum lima), invertebrate eggs, copepods (Oncaea spp. and nauplii) and diatoms (Thalassiosira curviseriata) were positively selected and other diatoms (Nitzschia spp., Thalassiosira tenera, Thalassiosira spp. and Chaetoceros spp.) and copepods (Pseudocalanus elongatus, T. longicornis and Unidentified calanoid) were negatively selected. We argue that this shift in term of prey preferences occurring at a size of 13mm constitutes the critical period for Downs herring larvae.