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An analysis of red king crab bycatch in bottom-trawl fisheries in the Russian exclusive economic zone (EEZ) in the Barents Sea based on data collected from 2010 to 2019 shows an annual range of 2.2–9.8 thousand tonnes of crab bycatch from 2010 to 2018, which is 0.7–2.9% of the total biomass of red king crab in the EEZ. It was found that the catch of commercially valuable male crabs in the bottom-trawl fishery ranged from 1.4 to 6.5 thousand tonnes, which is ∼0.7–3.3% of the total commercial stock. A protected area created in 2006 is estimated to prevent the catch of 1.1–4.8 thousand tonnes of crab; however, protective measures do not take into account the peculiarities of the current distribution of crab populations and the geography of the fishing area. This work offers suggestions for improving the regulatory measures to protect the king crab stock in Russian waters of the Barents Sea.

International audience; Lagoon soft-bottoms are key habitats within coral reef seascapes. Coral reef fish use these habitats as nurseries, feeding grounds and transit areas. At present, most soft-bottom sampling methods are destructive (trawling, longlining, hook and line). We developed a remote, unbaited 360° video sampling method (RUV360) to monitor fish species assemblages in soft bottoms. A low-cost, high-definition camera enclosed in a waterproof housing and fixed on a tripod was set on the sea floor in New Caledonia from a boat. Then, 534 videos were recorded to assess the efficiency of the RUV360. The technique was successful in sampling bare soft-bottoms, seagrass beds, macroalgae meadows and mixed soft-bottoms. It is easy to use and particularly efficient, i.e., 88% of the stations were sampled successfully. We observed 10,007 fish belonging to 172 species, including 45 species targeted by fishermen in New Caledonia, as well as many key species. The results are consistent with the known characteristics of the lagoon soft bottom fish assemblages of New Caledonia. We provide future users with general recommendations and reference plots to estimate the proportion of the theoretical total species richness sampled, according to the number of stations or the duration of the footage.

The benthic zone of Lake Malombe was sampled for invertebrates, fungi and bacteria using an Ekman Grab measuring 15.2 cm by 15.2 cm. Thirty-six stations were surveyed for macro-invertebrates which were identified to the lowest taxa and enumerated to estimate abundance for the lake. Snails were the most dominant macro fauna, belonging to four genera Melanoides, Bellamya, Bulinus and Lanistes with the mean densities of 177.5, 34.7, and 4.3 and 0.1 m-2 individuals, respectively. Blood worms and Tubifex were also present. Although there are few such studies in Malawi, it was generally postulated that dominance of snails is a recent phenomenon following previous studies which showed that the invasion of a form of Melanoides of Asian origin; its success might be responsible for its proliferation. The benthic substrate was mainly composed of mud, clay granules, sand and bedrock. The biomass of macro-fauna is being reported here for the first time and coincides with a decline in fish catches on Lake Malombe. The prevalence of Melanoides species and other high pollution tolerance species suggests that there is high ecosystem modification due to anthropogenic activities including sediment and nutrient loading from agricultural practices in the surrounding area. Compared to Lake Malawi and Upper Shire, Lake Malombe is by far the most productive. There were significantly higher (P

This study was conducted in the fishing community of the Cabedelo municipality (NE Brazil, Paraiba) and characterized the socioeconomic profile of the fishers, their local ecological knowledge and their main usage of fish species. Overall, 80 fishers were interviewed. Snowball, direct observation, guided tours, free interviews and structured and semi-structured questionnaires were used for data collection, which occurred from December 2010 to June 2011 in fortnightly visits to the city of Cabedelo. Most fishers ranged from 36 to 45 years, with low education and low income levels, and approximately 87% fished in the municipality. At least 33 fish species were recorded as important for family consumption and trade. The most commonly caught fish families were Carangidae, Mugilidae, Lutjanidae and Scombridae. The fishes most used for commerce were Lutjanidae, Scombridae, and Serranidae. Fishers demonstrated a high knowledge about the temporal distribution of fishes and categorized them as “fishes of summer”, “fishes of winter” and “fishes around all year”; fishes' vertical distributions were categorized as either “bottom fish” or “water flower”. Fishers also classified eating habits, some types of behavior and reproduction of most exploited species. Fishermen's understanding of the fish stocks distribution and fish ecology is potentially imperative for scientific knowledge and future shared management plans.

Исследовано современное состояние популяций основных промысловых видов бычковых рыб в Шаболатском лимане. Установлено, что после экологической катастрофы 1992 г. и последующего периода ограниченной связи лимана с морем его экологическое состояние ухудшилось, что отразилось на популяционных характеристиках кругляка и травника. Вместе с тем полученные характеристики бычков свидетельствуют о том, что их популяция в лимане в последние годы постепенно восстанавливается, а её состояние значительно улучшилось, There was studied the modern condition of populations of main industrial species of goby fish in Shabolatsky liman. The ecological catastrophe took place in 1992. As a result of the global suffocation, mass death of bottom fish (especially, gobies) was observed in the Southern-Western part of the water body. In the further period the ecological condition of Shabolotsky liman worsened because of the limited link with the sea. Several physical-chemical parameters of the water environment changed: salinity increased, organic content in water and bottom sediments grew, transparency decreased. The oxygen content in the near-bottom horizon decreased, hydrogen sulfide emissions were observed.The anthropogenic transformation of the liman ecosystem influenced qualitative and quantitative indicators of main groups of hydrobionts. The biological diversity and biomass of animal plankton and zoobenthos decreased, associations of macrophytes disappeared, the bloom of liman was observed the whole year round as a result of the progressing euthrophication. The renewal of the liman ecosystem took place only in 1997-2003. The reconstruction and continuous work of channels that connect Shabolatsky and Dnestrovsky limans and the regular work of a maritime channel provided normalization of the hydrologic-hydrochemical regime, restoration of biocenoses and forage reserve. The anthropogenic transformation of the ecosystem of Shabolatsky liman was reflected on population characteristics of melanostomus legs and thriver – the most mass species of neogobius in the liman. Their distribution in the liman water area, age and size-mass structure of populations, fatness, reproduction effectiveness and nutrition features changed. Most of these indicators differ from the previous period today. Along with it the received characteristics of neogobius melanostomus legs and thriver testify to the fact that their population in Shabolatsky liman is gradually renewed last years and its condition essentially improves

The Saharan Bank (21–26°N) is a wide subtropical continental shelf and a highly productive upwelling ecosystem. The bottom communities are dominated by octopus and sparid fish, which are the main targets of bottom-trawl fishing fleets. To investigate resource partitioning within the bottom fish community, adult fish from 14 of the most abundant species were investigated for stomach content analysis. Samples were collected during two periods: October 2003 and May 2007. The diet of the analysed species showed more variation between periods than between size classes, suggesting that temporal or spatial variability in prey availability appears to play a significant role in their diet. Multivariate analysis and subsequent clustering led to a grouping of the species within five trophic guilds. Two species were fish feeders, and the others mainly fed on benthic invertebrates, where epibenthic crustaceans, lamellibranchs and fish were the most important groups in defining trophic guilds. We found that the studied species had a high rate of overlapping spatial distributions and overlapping trophic niches. In this highly productive upwelling ecosystem, where food resources may not be a limiting factor, inter-specific competition did not appear to be an important factor in structuring bottom fish communities. For the species that showed differences in the proportions of prey categories in comparison with other ecosystems, the rise of the proportion of epibenthic crustaceans in their diet was a common feature; a possible consequence of the benthic productivity of this highly productive upwelling ecosystem.

The Antarctic plunderfishes (Artedidraconidae) are a poorly known component of the bottom fish fauna inhabiting the continental shelf of the High Antarctic Zone. Biological data on these fishes are still rather scarce and generally based on only a few specimens. To increase the knowledge of this group, we investigated the reproductive biology and population age structure of Artedidraco skottsbergi and Dolloidraco longedorsalis, the most abundant plunderfishes collected during the 2013/2014 expedition of the RV Polarstern in the Weddell Sea. Based on macroscopic and histological analyses, we found that both species exhibited prolonged gametogenesis and produced few eggs. Estimates of absolute and relative fecundity were lower in A. skottsbergi than in D. longedorsalis, ranging from 69 ± 7 oocytes per female and 11.4 ± 4.3 oocytes/g, and from 209 ± 73 oocytes per female and 13.5 ± 3.7 oocytes/g, respectively. Female size at first spawning was estimated to be 9.5 and 11 cm in A. skottsbergi and D. longedorsalis, respectively. Age and growth were assessed through otolith readings, and estimates of age ranged between 6 and 14 years in A. skottsbergi and between 3 and 14 years in D. longedorsalis. The von Bertalanffy growth parameters were only estimated for D. longedorsalis (L ∞ = 12.5 cm, k = 0.27, t 0 = −0.06). The results of this study provide insights into some of the biological aspects of these species and shed new light on their life strategies, which show similarities to those of other notothenioids.

Feeding of yellowfin sole Limanda aspera is studied in the Sea of Okhostsk and Bering Sea in summer–autumn. Age variation of the food spectrum is analyzed with consideration of ecological characteristics of prey. By the composition of food, the sole is a benthophage–polyphage: it consumes Mollusca, Polychaeta, Echiuridea, Amphipoda, Decapoda, Pisces, Priapulida, Echinodermata, and Mysidacea. Depending on individual length, the values of trophic level vary within 3.06–4.56 and define it as a consumer of the second and third order. During the first year of life, the principal source of organic matter for the yellowfin sole is the pasture trophic chain. After transition to the bottom mode of life, it is changed into a detrital one. Predominant feeding on leading groups of the infaunal and onfaunal invertebrates result in biotic success of this species expressed in a leading position among Pleuroctiformes and other bottom fish belonging to the detrital network.

The distribution pattern of benthic meiofauna in freshwater ecosystems reflects a trade-off between residences in the high-risk, but productive, sediment surface versus the safer, but physiologically harsher, conditions deeper in the sediment. In this study, we used field enclosures and exclosures in a natural freshwater pond to investigate the effects of the juvenile common carp (Cyprinus carpio) on the distribution patterns of meiofaunal assemblages. Carp fed voraciously on meiofauna, reducing within few days the density and biomass of nematodes, oligochaetes, and microcrustaceans but not of rotifers, in the upper (0–2 cm) as well as deeper (2–4 cm) sediment layers. However, fish predation had less impact on the populations of nematodes and oligochaetes in the deeper sediment than in the surface sediment, as evidenced by reductions of 65 versus 80%, respectively. An analysis of the gut contents of carp indicated a high degree of omnivory, including the frequent consumption of meiofaunal organisms and also demonstrated the importance of meiobenthic invertebrates as prey for juvenile bottom-feeding fishes.

This study presents a spatial analysis of species richness of soft-bottom bony and cartilaginous fish species in the Colombian Caribbean. The dataset consisted of 625 species distributed among 15651 georeferenced occurrences. The global richness completeness analysis suggests that the list is close to completion but that probably more species await being registered at greater depths. In spatial terms, our knowledge of fish richness remains incomplete as none of the spatial units, in which the general area was divided reached 100 % completeness and few reached 70 % or higher completeness probably due to the incidence of numerous rare species. The Guajira, Palomino, Tayrona and Golfo de Salamanca zones, displayed the highest observed and predicted richness. The Galerazamba, Arco (coralline archipelago) and Arboletes zones were predicted to have high species richness. In view of the results, marine protected areas need to be expanded to include soft-bottom habitats. Future research efforts should focus on the high species richness areas observed and predicted and surveys should include more extensively depth locations. Este estudio presenta un análisis espacial de la riqueza de especies de peces óseos y cartilaginosos de fondos blandos del Caribe Colombiano. El conjunto de datos consiste de 625 especies distribuidas en 15651 registros georeferenciados. El análisis de completitud global de riqueza sugiere que la lista está próxima a estar completa pero que probablemente mas especies están pendientes de ser registradas a mayores profundidades. En términos espaciales el conocimiento de la riqueza de especies se mantiene incompleto ya que ninguna de las unidades espaciales en que el área general fue dividida, alcanzo el 100 % de completitud y pocas alcanzaron el 70 % o mas, probablemente debido a la influencia de muchas especies raras. Las zonas Guajira, Palomino, Tayrona y el Golfo de Salamanca mostraron la mayor riqueza observada y esperada. Para las zonas Galerazamba, Arco (archipiélago coralino) y Arboletes se predice alta riqueza de especies. En vista de los resultados, las áreas marinas protegidas deben expandirse para incluir hábitats de fondos blandos. Esfuerzos futuros de investigación deben enfocarse en las áreas de alta riqueza de especies tanto observada como esperada e incluir más extensamente localidades profundas.

According to results of integrated record summer-autumn trawl surveys performed in 2004, 2005, and 2008 in the shelf-continental region of the northwestern Bering Sea from Cape Olyutorsky to Bering Strait in the range of depths 14–563 m, eight bottom communities of fish and fish-like were distinguished and their structure was described. In the composition of communities, 142 species from 29 families were recorded, among which Cottidae, Pleuronectidae, Zoarcidae, Agonidae, Stichaeidae, and Liparidae dominate by the number of species. According to biotopic belonging, bottom fish of elittoral, mesobenthal, and sublittoral complexes dominate in catches; according to zoogeographic belonging, wide boreal, arctic-boreal, and high boreal species dominate. Spatial change in the species structure of fish communities proceeds in correspondence with main regularities of life distribution in the ocean—principles of vertical and latitudinal zonality. The strongest relation of spatial variation of bottom fish communities was established with depth. Using multivariate nonmetrical scaling, five fish communities corresponding to different bathymetric ranges (sublittoral, elittoral, transitory shelf-bathyal, α-bathyal, and β-bathyal) were distinguished. Within sublittoral, elittoral, and shelf-bathyal communities, latitude zonal groups of Olyutorsky-Navarin and Anadyr regions having a lower hierarchic status were distinguished. In an interannual aspect, stability of the number of separated bottom fish communities and similarity of their spatial distribution in the examined sea areas is traced.

Using the critical thermal maximum technique with heating at 18°C /hour and from very different temperatures acclimation, the lethal temperature values and loss of equilibrium temperatures in eight pampasic species were identified. The results show a physiological relationship with the various “ecological types” in relation to temperature. The open-water fish and shore fish show greater tolerance than lower bottom fish, according to the stability of the environment.

Summary One of the main concerns of shrimp fisheries is the associated impact on ecosystem biodiversity, particularly on fish assemblages that are poorly characterized yet likely very relevant to the health of the ecosystem. The continental shelf along the eastern coast of the mouth of the Gulf of California is a region of high biodiversity that harbors highly productive fisheries. This study aimed to analyze the changes in the soft bottom fish assemblages caught as bycatch in the shrimp fishery located in this region. Sampling was conducted with commercial trawls at 16 fixed stations during the 2006–2007 shrimp-fishing season. A total of 103 fish species from 80 genera and 47 families were collected. The ecological and taxonomic diversity as well as the composition and abundance of the fish community caught as bycatch in the shrimp trawl fishery were found to be significantly different in the autumn and winter. Ordination and similarity analyses also revealed differing patterns. Species abundance was strongly associated with sea bottom temperature, depth and latitude. The effects of these abiotic variables on the observed diversity patterns and the possible influences of the fishery are discussed.

In the coming decades, artificial defence structures will increase in importance worldwide for the protection of coasts against the impacts of global warming. However, the ecological effects of such structures on the natural surroundings remain unclear. We investigated the impact of experimentally introduced tetrapod fields on the demersal fish community in a hard-bottom area in the southern North Sea. The results indicated a significant decrease in fish abundance in the surrounding area caused by migration effects towards the artificial structures. Diversity (HB) and evenness (E) values exhibited greater variation after the introduction of the tetrapods. Additionally, a distinct increase in young-of-the-year (YOY) fish was observed near the structures within the second year after introduction. We suggest that the availability of adequate refuges in combination with additional food resources provided by the artificial structures has a highly species-specific attraction effect. However, these findings also demonstrate that our knowledge regarding the impact of artificial structures on temperate fish communities is still too limited to truly understand the ecological processes that are initiated by the introduction of artificial structures. Long-term investigations and additional experimental in situ work worldwide will be indispensable for a full understanding of the mechanisms by which coastal defence structures interact with the coastal environment.

Although it is recognized that marine wild-capture fisheries are an important source of food for much of the world, the cost of sustainable capture fisheries to species diversity is uncertain, and it is often questioned whether industrial fisheries can be managed sustainably. We evaluated the trade-off among sustainable food production, profitability, and conservation objectives in the groundfish bottom-trawl fishery off the U.S. West Coast, where depletion (i.e., reduction in abundance) of six rockfish species (Sebastes) is of particular concern. Trade-offs are inherent in this multispecies fishery because there is limited capacity to target species individually. From population models and catch of 34 stocks of bottom fish, we calculated the relation between harvest rate, long-term yield (i.e., total weight of fish caught), profit, and depletion of each species. In our models, annual ecosystem-wide yield from all 34 stocks was maximized with an overall 5.4% harvest rate, but profit was maximized at a 2.8% harvest rate. When we reduced harvest rates to the level (2.2% harvest rate) at which no stocks collapsed ( 30% of total sustainable yield, whereas yield lost from stock depletion was 3% of total sustainable yield. There are clear conservation benefits to lower harvest rates, but avoiding overfishing of all stocks in a multispecies fishery carries a substantial cost in terms of lost yield and profit.

Biota-sediment accumulation factors (BSAFs) for Dechlorane Plus (DP), a highly chlorinated flame retardant, were determined in three bottom fish species, i.e., crucian carp, mud carp, and northern snakehead from an electronic waste recycling site in South China. The average BSAFs are 0.007, 0.01, and 0.06 for syn-DP, and 0.003, 0.025, and 0.001 for anti-DP in crucian carp, mud carp, and northern snakehead, respectively, suggesting low bioaccumulation potential of DP isomers in these fish. However, the bioaccumulation factors (BAFs) determined previously in the same sample set indicated that both DP isomers were highly bioaccumulative (BAFs>5000) in most of the samples. This implies that BSAF values may be inherently inconsistent affecting their reliability as a bioaccumulation indicator. The BSAFs for DP isomers are two orders of magnitude lower than those (average of 0.43–2.28) for extremely hydrophobic polychlorinated biphenyls (CBs 199, 203, 207 and 208), but are comparable to those (average of 0.0001–0.009) for decabromodiphenyl ether (BDE 209) determined in the same sample set. Despite of the different chemical structures of the three compound classes, significantly negative correlations between logarithm of octanol–water partition coefficients (log KOWs) and BSAFs of these chemicals were found, indicating that hydrophobicity is one of the key factors influencing the bioaccumulation of these compounds. Keywords: Dechlorane Plus, Biota-sediment accumulation factors, Bioaccumulation, Flame retardant, Electronic waste

The bathymetry of Baffin Bay with shallow sills both to the north and south creates a relatively isolated body of deep polar water, unique among the Arctic Seas. During 105 trawl hauls completed during autumn 2004, 45 fish species were collected in the northern Baffin Bay between 72o 02' N – 76o 55' N, depth 150–1 418 m. As a first step the abundance data for the 40 benthic species were used for analyses of the fish fauna diversity and fish assemblages. Two species, Greenland halibut (Reinhardtius hippoglossoides) and the sea snail Liparis fabricii were very common and represented in large numbers in almost all trawl hauls. The two species dominated the outcome of the first run of the analysis and were removed from the analysis to allow an analysis of the remaining species. For those remaining 38 species, five assemblages were found by a standard type of cluster analysis. A Bayesian multinomial logit model was then applied to calculate vectors of probabilities defining the likelihood of each haul belonging to each of the five clusters. By means of a geostatistical tool the spatial distribution of the conditional probabilities for each cluster (assemblage) was mapped. Each of the five assemblages was further defined by indicator species, depth and temperature. The study is a continuation of a similar study using the same vessel, sampling scheme and analytical methods previously conducted in the southern part of Baffin Bay and Davis Strait.

The current study is on East Calcutta Wetland (ECW) which is a model for multi-use resource recovery system with activities like pisciculture and agriculture. The entire city's soluble waste is disposed into the raw sewage canals which finally drains into the shallow, flat bottom fish ponds called Bheri. These sewage fed fisheries act simultaneously for the purification process like removal of heavy metals, coliform reduction as well as fish production at a commercial scale. The fishes from these Bheri are analyzed for the extent of metal accumulation in them as compared with those collected from the fresh water ponds around Calcutta. This comparative study was done to access the risk involved, if any, in fish cultivation and its subsequent consumption from these wastewater fed fisheries. Two types of commonly consumed fishes were chosen for the study namely Labeo rohita and Cirrhinus mrigala. Analysis of elements like P, S, Cl, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr and Pb was done by Energy Dispersive X Ray Fluorescence (EDXRF) in order to quantify the level of accumulation. The analysis inferred that elements like Cr, Cu, Rb, Pb shows accumulation in substantial amount in both type of fishes collected from the sewage fed as well as freshwater sources. The uptake of these fishes by human population thereby causes the consumption of these elements in relatively higher level as compared to the Recommended Dietary Allowance (RDA). Thus consumption of waste water cultivated fishes pose no additional health hazard. The accumulation of these metals in fishes from both Bheri as well as fresh water pond put forth a plausible action of diverse microscopic population and certain geochemical factors acting beneath the phenomenon of sedimentation as well as biomagnification of metal in the fish pond and their subsequent uptake in the aquatic food chain.

Variability in tropical estuarine sandy bottom fish faunas was investigated along a 200 km section of the northeast coast of tropical Australia at 3 nested spatial scales: among bays, among adjacent estuaries within bays, and among replicates within estuaries. Sampling was confined to a single habitat type, shallow sandy habitats, and a single class of estuaries, those with extensive areas of shallow sand in their lower reaches. This approach was employed to minimise the biases inherent in sampling estuaries containing varying proportions of the disparate habitat types that occur in tropical estuaries. The results showed: (1) the compositions of samples from all 9 estuaries in November 1999 were quite distinct from those in July 1999, July 2000 and July 2001; (2) there were no clear differences among estuaries during November 1999, but strong differences among estuaries every July, which were greater than differences among years; and (3) there was a greater difference at the scale of estuaries than at the larger spatial scale of ‘bays’, such that the differences among estuaries within bays were consistently greater than differences among bays. This pattern was consistent between seasons and among years in the same season. The clear estuary-to-estuary variability suggests that fauna of adjacent estuaries are likely to be no more similar than the faunas of estuaries hundreds of kilometres apart. This implies that no single estuary can be assumed to be a control site that can be used as a baseline against which to judge change in a different ‘impacted’ estuary.

During 2006 and 2008 two bottom trawl surveys were conducted at East Greenland to 72°N covering depths down to 1500 m. In the 149 trawl hauls in total 113 fish species were recorded of which 37 were considered pelagic and excluded from the analyses. As a first step the abundance data for the 76 benthic species were used for analyses of the fish fauna diversity and fish assemblages. Nine assemblages were found by a standard type of cluster analysis. A Bayesian multinomial logit model was then applied to calculate vectors of probabilities defining the likelihood of each haul belonging to each of the nine clusters. By means of a geostatistical tool the spatial distribution of the conditional probabilities for each cluster (assemblage) was mapped. Each of the nine assemblages was further defined by indicator species, depth and temperature. The assemblages were well defined regarding geographical distribution, species composition, temperature and depth. Three of the assemblages were located in the cold Iceland Sea while six were found in the somewhat warmer Irminger Sea

Studies on the fishways of Nagaragawa Estuary Barrage and migratory fish species that passed the barrage were conducted when the estuary barrage project was planned, before and during the construction of the barrage, and before the barrage went into operation. After the barrage went into operation, its monitoring began, and it is still being carried on. The investigations and studies conducted at the planning stage and before the commencement of barrage construction yielded information on the habitats and helped the development of seed production techniques of ayu (sweetfish) and satsukimasu salmon, which were likely to be affected by barrage operation. Through subsequent studies conducted during the construction of the barrage, knowledge was gained about the habitat of migratory bottom fish species, and the type of fishway structure to be adopted was determined according to the study results. Before the gates went into operation, findings from the studies and deliberations conducted thus far were verified through test operations. In the monitoring of the estuary barrage after it went into service, the migratory habits of fish species likely to be affected by barrage operation were studied, and effectiveness of the fishways was confirmed.

From bibliographical information on bathymetric and latitudinal distribution of 110 marine fish species of western Patagonia (42º-57ºS), the ichthyogeographic zonation of the area is discussed. The bathymetric distribution of the fish species shows a species association distributed at depths less than 100 m, a second association between 50 and 500 m, and a third association below 500 m depth. This third one is interpreted as a transitional situation of the second one, because of the scarcity of endemic species. These associations present similar latitudinal zonation patterns, including separation into a northern sector, characterized by species of lower latitudes, a southern sector with characteristic and endemic elements of that zone, and an intermediate transition sector considered as an independent association by its large extension and species composition. The Straits of Magellan represent an important faunistic exchange zone between the bottom fish communities of the Southwestern Atlantic and the Southeastern Pacific. A partir de la información, principalmente bibliográfica, sobre distribución batimétrica y latitudinal de 110 especies de peces marinos de la Patagonia occidental (42º-57ºS), se presenta un esquema de zonación ictiogeográfica para el área. La distribución batimétrica de las especies muestra la existencia de una asociación de peces distribuida entre 0 y 50 m de profundidad, una segunda asociación entre 50 y 500 m de profundidad y una tercera asociación a más de 500 m de profundidad. Esta tercera asociación es interpretada como situación de transición de la segunda asociación, a causa de la escasez de especies endémicas. Estas asociaciones presentan un patrón similar de distribución latitudinal, que incluye un sector norte, caracterizado por elementos de latitudes menores, un sector sur, con elementos característicos del área y un sector intermedio de transición considerado como una unidad independiente por su extensión y composición íctica, confirmando los resultados de revisiones biogeográficas anteriores. El Estrecho de Magallanes destaca como sector de intercambio faunístico entre el Atlántico suroccidental y el Pacífico suroriental.

Neoplasm epizootics in fish from a wide variety of freshwater, marine, and estuarine locations have been associated with genotoxins in sediment or water. The majority of cases have involved benthic or bottom feeding fish living in habitats with sediment contaminated by PAHs. The most common lesions involved in such epizootics include liver neoplasms, both biliary and hepatic, and skin neoplasms. Laboratory research has demonstrated the ability of fish to metabolize carcinogenic PAHs such as B(a)P into the ultimate carcinogen with the resulting formation of DNA adducts. Fish dosed with B(a)P or sediment extracts containing carcinogenic PAHs have developed skin and liver neoplasms. In the Black River, OH, neoplasm prevalence in wild brown bullhead has reflected PAH exposure as the latter has changed due to coke plant closures and remedial dredging activity. The weight of evidence supports a cause-and-effect relationship between exposure to genotoxins in sediment and water and neoplasm epizootics in wild fish populations.

The mean trophic level of the species groups reported in Food and Agricultural Organization global fisheries statistics declined from 1950 to 1994. This reflects a gradual transition in landings from long-lived, high trophic level, piscivorous bottom fish toward short-lived, low trophic level invertebrates and planktivorous pelagic fish. This effect, also found to be occurring in inland fisheries, is most pronounced in the Northern Hemisphere. Fishing down food webs (that is, at lower trophic levels) leads at first to increasing catches, then to a phase transition associated with stagnating or declining catches. These results indicate that present exploitation patterns are unsustainable.

Experiments were conducted to examine the dynamics of the sediment-associated polychlorinated biphenyl (PCB) using a benthic-based trophic transfer model (sediments to benthic copepods to juvenile fish). Field-collected benthic copepods were exposed to sublethal levels of PCB in sediments for 96 h. Accumulation of PCB was measured in the copepods, and these contaminated copepods were fed to the juvenile fish predator Leiostomus xanthurus in uncontaminated sediments. After gut clearance, whole fish were homogenized and examined for PCB accumulation. Similar experiments with L. xanthurus in which meals of uncontaminated copepods were fed in PCB-contaminated sediments were conducted to determine the relative roles of contaminated sediments and contaminated copepod prey ingestion to PCB transfer. Total PCB transfer as well as PCB congener group contributions were examined. A total of 30 congeners were grouped according to log K{sub ow} increments and according to chlorine homologue groups. Copepods exposed to PCB-contaminated sediments to 90 {micro}g/g accumulated PCBs to 326 {micro}g/g dry weight. Accumulation of PCB in fish feeding in contaminated sediments was five times higher than that in fish feeding on contaminated prey in uncontaminated sediments (p = 0.0498). In terms of congener patterns, log K{sub ow} grouping provided clearer discrimination between groups. Congener patternsmore » were similar in PCB stock solution, sediments, and copepods and were different in the two fish treatments. K{sub ow} group relative accumulation patterns in fish were mixed. The chlorine homologue groups revealed that the fish preferentially accumulated the tetrachlorinated congeners relative to copepods and sediments.« less

Periphytic bacteria found on the carapace and gills of crabs collected from near a tannery effluent outlet were shown to be able to concentrate chromium. By concentrating Cr, the bacteria contributed to the total Cr concentration of the crabs. Since crabs and other crustaceans are eaten by bottom feeding fish, bacteria may be contributing to the passage of Cr up the food chain.

Submersible data from two areas along the Carolina-Virginia continental slope reveal a Hatteras upper middle slope (HMS) (35.30’N, 74.50’W) demersal fish fauna remarkable for diminutive size of individuals within and across species, a fauna which is accordingly termed ‘Lilliputian’. Contrast of HMS submersible data with Virginia trawl and submersible data support this finding. The four top-ranking HMS fishes, Lycenchelys verrillii, Glyptocephalus cynoglossus, Myxine glutinosa and Nezumia bairdii, are all significantly smaller than on the Virginia upper middle slope. Also peculiar to the HMS is the dominance of sedentary benthic species, rarity of active benthopelagic foragers, and markedly elevated fish population density. Species composition of the HMS fauna differs from that of the general Middle Atlantic Bight fauna; notably absent are species of otherwise continuous distribution along the U.S. East Coast (e.g. Synaphobranchus affinis, Nezumia aequalis). Since HMS megafaunal and macrofaunal invertebrate communities are also anomalous, the Lilliputian phenomenon among HMS bottom fishes provides a characteristic biotic signature of a pervasively re-structured benthic boundary layer community. The authors hypothesize that the HMS faunal anomaly reflects a limiting factor, episodic sediment surface hypoxia, peculiar to this region of high particulate organic carbon flux from surface waters. Results indicate that substantial changes in fish faunal composition and structure can occur on a small geographic scale on the open soft-Substrate continental slope.

Interactive effects of three alternating normoxia-hypoxia cycles on benthic prey exploitation by mobile fish (spot, Leiostomus xanthurus; and hogchoker, Trinectes maculatus) and a burrowing crustacean (Squilla empusa) were investigated in the York River, Chesapeake Bay, Virginia, USA, in 1989. Predators collected in four depth strata (A: 5 to 10 m; B: 10 to 14 m; C: 14 to 20 m; D:>20 m) variously affected by hypoxia were separated into size classes (three for spot and two each for hogchoker and mantis shrimp) to examine potential ontogenetic influences in prey selection. The most severe effects of hypoxia on the benthos occurred in the two deepest strata (C and D) and decreased in shallower strata (B>A), with Stratum A never affected by low oxygen. Predators investigated exhibited dietary evidence of optimal prey exploitation during or immediately after hypoxic events. In most instances gut contents contained significantly larger, deeper-burrowing prey during periods of low oxygen than during alternating peroids of normal oxygen levels. Spot consumed a greater biomass (45 to 73%) of polychaetes than other prey, with crustaceans initially also constituting a main dietary component but decreasing in importance later in the study period. The deep-burrowing anemone, Edwardsia elegans, was an important prey species for spot, particularly in the lower depth strata affected by hypoxia. Prey consumed by 10-to 15-cm-long spot increased significantly in size during some hypoxic events, suggesting a sublethal effect of hypoxia on large benthic species. Polychaetes (primarily Glycera americana, Notomastis latericeus and Loimia medusa) were dominant dietary components in hogchoker, making up between 85 and 98% of the diet. Bivalve siphons became important prey for hogchoker in the three deepest strata and were only consumed after the August hypoxia. Stomach contents of mantis shrimp were difficult to identify in most instances due to the near complete mastication of consumed prey. Crustaceans were important prey initially but became less conspicuous in the diet subsequent to the July hypoxia event, when hydroids became more dominant. Overall, predator species exhibited optimal exploitation of moribund or slowly recovering benthos affected by hypoxia. The sublethal effects of hypoxia through increased availability of benthos to resident predators can have important consequences for energy flow in areas such as the York River which experience periodic low-oxygen cycles.

This paper describes the pollution status of North Sea sediments, and is based on results of sediment testing conducted during the Bremerhaven Workshop designed to test various methods (chemical and biological) for assessing the status of North Sea waters, sediments and biota. Testing comprised 2 transects, one down current from an abandoned drilling site, and the other across the German Bight from the mouth of the Elbe northwest. Sediment methods focused on tox~clty testing, chemical analyses, and measures of in sltu benthic community structure Together these 3 methods comprise the Sediment Quality Triad. Using the Triad In a burden-of-evidence approach, ~t was determined that sediments nearest the Elbe are moderately polluted (pollution is defined as contamination. toxicity and benthic community alteration), and that sediments offshore and at Dogger Bank are unpolluted. Sediments nearest the drilllng site show evidence of relatively low level toxicity and benthic community alteration. Limited chemical measurements did not indicate contamination. Observed laboratory toxicity and alterations in benthic infauna community structure may be due to unmeasured toxic chemicals. Anticipated effects due to drilling were not observed and appear to have been amellorated by natural deposition of clean sediment. North Sea sediments away from point sources of pollution (e.g. coastal areas, drilling platforms) are expected to be unpolluted. Lesions in bottom fish in such offshore areas (e.g, the Dogger Bank) cannot be attributed to sediment pollution in these areas, but if they are truly indicative of anthropogenic pollution, could be due to other factorjs) such as exposure of plankton~c larvae to sea surface microlayer chemical contamination and toxicity. Integrative assessments such as the Triad are essential for adequately assessing the status of European marine ecosystems. Although relatively expensive, such complete studies determine and prioritise problem areas such that managers, regulators and the public have access to the best possible information for decisionmaking and resource allocation.

Over the past 25 years, there have been an increasing number of fish tumor epizootics recognized in discrete geographical areas in North America. This is consistent with an association between tumor development in fish and exposure to waterborne contaminants as a result of increased industrialization. Reports of fish tumor epizootics from the literature, plus acquisitions at the Registry of Tumors in Lower Animals, Smithsonian Institution originate from 41 geographical regions in North America. Epizootics of hemic, neural, connective tissue, and gonial neoplasms seem unrelated to environmental pollution, but epizootics of hepatic and epidermal neoplasms appear to be caused or strongly influenced by environmental pollution. The 14 species with epizootic liver tumors are all bottom feeding fish, and tumor-bearing fish are generally located in areas where chemical contaminants are concentrated. Epidermal neoplasms are also found in fish near polluted areas, but a direct cause-and-effect link with chemical carcinogens is not clear.

Concern has existed for years that the Los Alamos National Laboratory (LANL), a complex of nuclear weapons research and support facilities, has released polychlorinated biphenyls (PCBs) to the environment that may have reached adjacent bodies of water through canyons that connect them. In 1997, we began measuring PCBs in fish in the Rio Grande upstream and downstream of ephemeral streams that cross LANL and later began sampling fish in Abiquiu and Cochiti reservoirs, which are situated on the Rio Chama and Rio Grande upstream and downstream of LANL, respectively. In 2005, six species of fish from Abiquiu and Cochiti reservoirs were collected and the edible portion (fillets) was analyzed for 209 possible PCB congeners. Fish from the reservoirs were last sampled in 2001. Mean total PCB concentrations in fish from Abiquiu Reservoir ({mu} = 2.4 ng/g) were statistically similar ({alpha} = 0.01; P (T{le}t) [range = 0.23-0.71]) to mean total PCB concentrations in fish from Cochiti Reservoir ({mu} = 2.7 ng/g), implying that LANL is not the source of PCBs in fish in Cochiti Reservoir. The levels of PCBs in fish from Cochiti Reservoir generally appear to be declining, at least since 2001, which is when PCB levels might havemore » peaked resulting from storm water runoff after the Cerro Grande Fire. Although a PCB ''fingerprinting'' method can be used to relate PCB ''signatures'' in one area to signatures in another area, this method of implicating the source of PCBs cannot be effectively used for biota because they alter the PCB signature through metabolic processes. Regardless of the source of the PCBs, certain species of fish (catfish and carpsuckers) at both Abiquiu and Cochiti reservoirs continue to harbor levels of PCBs that could be harmful to human health if they are consistently eaten over a long period of time. Bottom-feeding fish (carpsucker and catfish) from Cochiti Reservoir contained statistically higher levels of total PCBs ({mu} = 4.25 ng/g-fillet-wet) than predator fish (walleye, northern pike, bass) ({mu} = 1.67 ng/g) and the bottom-feeding fish had levels of PCBs that fall into a restricted consumption category in U.S. Environmental Protection Agency (EPA) charts. Similarly, bottom-feeding fish from Abiquiu Reservoir also contained statistically higher levels of total PCBs ({mu} = 4.25 ng/g-wet) than predator fish (walleye, bass) ({mu} = 0.68 ng/g-wet) and only the bottom-feeding fish had levels of PCBs that fall into a restricted consumption category in the EPA charts.« less

Publisher Summary This chapter discusses the scallops in Venezuela. The Venezuelan coast, in the southwestern Caribbean Sea, is a tropical region that supports a high diversity of bivalve molluscs. Most of these scallops are small and only Nodipecten nodosus and Euvola ziczac are exploited by coastal populations for local consumption, and a drag fishery exploits Amusium papiraceum, Amusium Laurenti, and Argopecten nucleus. Euvola ziczac forms small beds on sandy bottoms in areas of upwelling. It is a functional hermaphrodite and is unusual among tropical bivalves because of its markedly seasonal reproduction. Populations of N. nodosus along the northeast coast of Venezuela show even lower generic variability than E. ziczac, as the frequency of polymorphic loci is 1.92% and mean heterozygosity is 0.0016. A. papyraceum forms the major scallop beds in Venezuela and is fished commercially. It is part of a multi-species bottom trawl fishery, which targets shrimps, bottom fish, and molluscs. The large size of the adductor muscle of Euvola ziczac and Nodipecten nodosus suggests that they should be good species for aquaculture and a number of studies have evaluated their growth and survival in suspended and bottom culture.

Experiments were conducted to examine the dynamics of a sediment-associated pesticide azinphosmethyl (APM) using a sublethal benthic based trophic transfer model (meiobenthic copepods to juvenile fish). Two predominant pathways for contaminant transfer during feeding, prey ingestion and sediment ingestion, were examined to determine their relative contributions to APM transfer and subsequent effects on fish brain AChE inhibition. Experiments were conducted in 1993 and in 1994. Field collected benthic copepods were exposed to 14-C labeled APM, a potent acetylcholinesterase (AChE) inhibitor, in sediments for 96 h. APM burdens were measured in the copepods, and these contaminated copepods were fed to the juvenile fish predator Leiostomus xanthurus in uncomtaminated sediments. After gut clearance, fish were examined for brain AChE activity and APM residues in the liver, heart, gut, muscle, gill, and remains. Similar experiments were conducted in which meals of uncontaminated copepods were fed to spot in APM contaminated sediments, to determine the relative contribution of contaminated sediments to APM transfer. Copepods exposed to APM at a mean sediment concentration of 1223 ng/g dry weight accumulated APM at the level of 2.5mgr;g/g dry tissue. Brain AChE activity was significantly depressed (23%) in the 1993 fish fed one meal of contaminated copepods, however there was no significant decline in AChE activity in the fish tested during 1994. APM accumulation in fish feeding in contaminated sediments was generally greater than in fish feeding on contaminated prey. Significant accumulation was found in bodily remains, gills, gut, and muscle in fish that fed in contaminated sediments. No significant APM accumulation was found in fish fed the contaminated copepods.

Nektons refer to the aquatic organisms that have fully developed mobile organs and a strong ability to swim. They can overcome water current resistance and migrate a long distance and are virtually not affected by water current movement. They are gregarious and constitute an ecological group. Marine nektons include most species of marine fishes (Chondrichthyes and Osteichthyes, etc.) and of marine mammals, some species of Cephalopoda and Crustacea, and a few species of Reptilia and Aves.

Concentrations of 14 elements (Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, V, and Zn) were measured in the dorsal muscle of omnivorous white suckers and brown bullheads, fish likely to ingest sediment while feeding. The fish were collected in two acidic Adirondack lakes known to have elevated concentrations of several of these elements in their surface sediment. Trace element concentrations in the muscle of the white suckers and brown bullheads were compared with government guidelines for edible fish and survey data for concentrations present in commercial species. Only the largest white sucker exceeded the U.S. Food and Drug Administration's guidelines for Hg in food of 1 ppm (wet wt). Concentrations of all the other elements measured were at low or innocuous levels in the edible muscle. A significant positive correlation was found between body weight and Hg concentrations in both species. Zinc was negatively correlated for the same parameters in white suckers. With the possible exception of Hg, our results indicate that elevated levels of potentially toxic elements in the surface sediment of the two acidic Adirondack lakes are not reflected in the edible muscle of the omnivorous bottom feeding fish present in these systems.

The Hyuga Nada (Hyuga High Sea) when taken in wide sense extends off the eastern and east-southern coasts of Kyushu Island, viz., from up north the Bungo Strait down to south the Osumi Penninsula, and abounds, amoungst others, in red gurnards, of which economically important are the following five species; Chelidonichthys kumu, Pachytrigla alata, Lepido-trigla japonicus, L, guntheri and L, microptera. Examination of their stomach contents reveal that they devour by far Crustaceans and those small fishes as hidden in sand-mud or crawling on sea bottom (Table 2). Voracious as they are, their stomach was often found stuffed with food, which weighed 3-4% of the body at maximum. Table 3 and Fig. 1, A-F give the results of the statistical observation of their egg. Ova measuring over 1.0mm in diameter are characterized by having one or three oil globules and almost complete transparency and were taken as mature eggs. The degree of maturity was defined by ratio of mature ova to the whole ovary in weight and is given in Table 6. Single mature ovum weighs about 0.0011gr in Chelidonichthys kumu and about 0.00095gr in Pachytigla alata. Number of ova to be liberated at first spawning is estimated 10, 000-25, 000 in C, kumu, and 2, 000-3, 500 in P, alata.

This study was based on an examination of approximately 290,000 fishes that comprised 151 species collected from southern California coastal waters, 1969 to 1976. Approximately 5 percent of the fishes were affected with external signs of disease, such as fin erosion, tumors, color anomalies, and attached macroparasites. Fin erosion diseases were reported in the greatest number of species and occurred at the highest frequencies. Fin erosion in Dover sole is the only disease that appears to be directly associated with discharge of municipal waste waters in southern California. It occurs primarily at one site, the Palos Verdes shelf, and appears to result from exposure to contaminated sediments at that site. The occurrence of skin tumors on young Dover sole covers an even wider geographic area, and the disease is quite similar to that which affects pleuronectids as far north as Bristol Bay, Alaska. The lack of association with specific waste discharge conditions coupled with an apparent relation to the life cycle of the Dover sole suggest that changes in waste discharge practices will have little impact on the prevalence of these tumors unless the changes affect survival rates and distributional patterns of young fish. The lack of infestation of Pacificmore » sanddabs by the parasite P. cincinnatus at Palos Verdes is curious and deserves further study. It is possible that the high levels of chlorinated hydrocarbons in the tissues of bottom fish at Palos Verdes are inimical to this and, possibly other, attached macroparasites.« less

Four types of field experiments were carried out in order to study the effects of fish predation on different size groups of burrowing larval dragonflies Onychogomphus uncatus (CHARP.). (1) The effects of the bottom feeding fish Barbatula (Nemacheilus) barbatula (L.) on three size groups of O. uncatus in three types of substrate: sand, gravel and stones, were recorded using field enclosure cages. The densities of small sized larvae inhabiting cages with stones and gravel were reduced in the presence of fish compared with fish-free controls. No effects due to fish presence were found in larger larvae. (2) The colonisation of sand, gravel and stones in the field by different size groups of O. uncatus was studied using frames filled with substrates. Substrate as well as size specific effects were found. The low density of small larvae in coarse substrates is interpreted mainly as a direct effect of predation by B. barbatula which exclusively colonised these substrates. (3) To test the effect of exclusion of all fish on colonisation of O. uncatus, frames filled with stones were exposed in a running water and half of these were protected by cages. The densities of very small and medium sized larvae in the protected substrates were higher than in those without cages. (4) In cages with a wide mesh size, which allowed a free exchange of dragonfly larvae and B. barbatula but prevented predation by large fish, the density of small larvae of O. uncatus was reduced. B. barbatula were found exclusively inside the cages. It is suggested that predation by B. barbatula using the cages as a shelter against predation by large fish was responsible for this reduction.

The development of commercial fisheries in the Aleutian area, particularly the catching of salmon in the open sea with drifting gill nets, has stimulated interest in the food of the Pribilof seal (Callorhinus ursinus) in the Bering Sea. Added interest results from the decline in the salmon runs in Bristol Bay. Fisheries investigators believe that at least part of the salmon migrating to rivers entering Bristol Bay pass through areas in the Bering Sea where fur seals feed intensively. No pelagic investigation of the food of fur seals while in the Bering Sea has been made since Alexander's in 1892. This was summarized by Lucas (1899) who wrote that "In Bering Sea during August and September the pollack (Theragra chalcogramma) forms the staple article of food, a squid (Gonatus amoenus) coming next in importance, while some salmon and a few species of small fish are also eaten." Lucas quotes Alexander in stating that "material which has been found in the stomachs of seals taken in different parts of Bering Sea indicates that only a small percentage is composed of fish which inhabit deep water. It is only reasonable to suppose that when seals are in shallow water they feed on both bottom fish and those near the surface." Lucas footnoted the latter part of this statement, saying: There is, however, no evidence of this except in the rare presence of cottoids. . ." On the basis of stomachs collected from the killing fields, Kenyon (1956) has verified Alexander's statement. Most of the content of these stomachs (94 per cent) was composed of sand fish (Trichodon trichodon), which burrow in sand in relatively shallow water. The sturgeo -lik sea poacher (Agonus acipenserinus), second in importance, is also a bottom dweller. Fro 17 June to 20 July 1955, 204 fur seals were collected pelagically in the Bering Sea from Unimak Pa s and Unalaska to the Pribilof Islands. Most of the seals were collected by the authors by shooting with buckshot from the deck of a halibut schooner, the M/S Paragon. On the rare calm days two men worked from a dory powered with a 10horsepower utboard. In good weather this was as effective as the larger vessel, and fewer animals were lost when hunting with the dory. Throughout the period, seals were most abundant in or near Unimak Pass. Near the Pass were also Steller sealions (Eumetopias jubata), numerous humpback whales (Megaptera novaeangliae), and vast numbers of shearwaters (Puffinus spp.). It is reasonable to presume that the rich food supply attracted all thes forms. Pregnant females predominated among the seals collected, comprising 71 per cent of the total. Females without fetuses composed 16 per cent and males 13 per cent of the collection. Table 1 gives the food contained in the stomachs of 204 seals collected pelagically and of three others in the commercial kill at St. Paul Island where empty stomachs are the normal condition among the thousands we have examined. Capelin was the predominant food species in Unimak Pass and near the Aleutian Islands. It appears that concentrations of capelin are available for the seals during extensive portions of their northward migration. Scheffer (in Taylor, Fujinaga, and Wilke, 1955) found that capelin made up more

Immature heterocheilid nematodes, usually Contracaecum or Anisakis, are commonly found encysted in commercial fish brought to the Seattle docks. Sites of predilection are the serosal surfaces of the stomach, pyloric caeca, and adjacent intestine, the ventral mesentery, and less commonly, somatic musculature in contact with these areas or along the vertebrae. The heaviest parasite load occurs in bottom fish, such as rock fish, cod, and flat fish, which may carry several hundred parasites per host. Herring and salmonids are usually more lightly infected. Criteria for specific identification of the immature nematodes in this group are not established. Anisakis adults have been reported as occurring in various marine mammals (pinnipeds and cetaceans), and occasionally from marine birds. Recently, immature stages were reported from man (Hitchcock, 1950). There is nothing to suggest that more than one species of Anisakis is present in the material from the intermediate hosts encountered in Seattle. Adult Contracaecum occur locally in marine mammals, birds, and fish (Sebastodes, cod, etc.). Since a temperature of 37? C. is lethal in vitro for most excysted Contracaecum from fish in this area, it seems likely that the common final host is a piscivorous fish. No published material dealing specifically with death by freezing has been found for this group. The only example of encysted nematode larva investigated with respect to freezing is that of Trichinella spiralis, which has been the subject of repeated testing to establish a basis for control of trichinosis. This literature has been most recently reviewed by Gould and Kaasa (1949). Discrepancies among the opinions expressed have been attributed to the type of freezer employed, the medium surrounding the sample, the size of the sample, the rate of cooling, the age of the larvae, individual differences in the larvae, and the host in which they are encysted. It seems probable from this work that trichina larvae may survive for two weeks or more at - 10? C., less than 3 days at - 20? C., and only a few hours at - 30? C. Studies to determine the effect of freezing on heterocheilids were initiated following inquiries from the Woodland Park Zoo, Seattle, where frozen herring are fed to seal, cormorants, and other potential hosts. Interest has also been expressed in this problem by animal breeders using fish scrap, and by individuals with public