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We investigated blood gas, hematological and biochemical parameters, and gill morphology of Lophiosilurus alexandri juveniles submitted to hypoxia for 48 h, followed by recovery for 48 h. A total of 48 juveniles (360.0 ± 141.6 g) were distributed among eight tanks (120 L) and subjected to hypoxia condition (water with dissolved oxygen at 2.12 ± 0.90 mg L−1) or normoxia (at 5.60 ± 0.31 mg L−1). Blood gas values (pH, PvCO2, PvO2, sO2, HCO3−, stHCO3−, and base excess) in hypoxia were significantly different from normoxia, while for lactate and the electrolytes (K+, Na+, Cl−, and Ca2+) there was no significant change among treatments. The erythrocytes differed significantly between normoxia and hypoxia at 72 h (24 h of recovery), while for hemoglobin and hematocrit there were no significant differences. There was a significant difference in glucose, triglycerides, and cholesterol for both normoxia and hypoxia, while plasma protein remained unchanged. All gill components (epithelial cells, erythrocytes, pillar cells, mucous cells, ionocytes, undifferentiated cells, and blood capillary lumen) differed significantly between normoxia and hypoxia. A reduction in the length of the primary lamella was observed in the hypoxia and recovery treatments, when compared to normoxia. The secondary branchial lamella showed no significant difference for both treatments. Juveniles of Lophiosilurus alexandri adapted well to hypoxia for 48 h, as they were able to adjust most of their physiological variables to survive this stress condition. After 48 h of hypoxia recovery, fish showed parameters similar to animals in normoxia. Thus, the present study shows that the tolerance to hypoxia conditions of L. alexandri, together with other important beneficial characteristics of the species, such as the high meat quality and high commercial value, demonstrates its great potential for production among regional species.

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.

Based on the materials collected in 2019, the authors consider some peculiarities of bottom fish fishing (halibut, stingrays, giant grenadie, cod, lycodes, and broadbanded thornyhead) in the North Okhotsk subzone of the Sea of Okhotsk. The accompanying problems are shown; the measures to optimize fishing are proposed.

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.

Highlight The sex ratio of giant prawns in the waters of fe- male groceries is 3 times higher than that of males. The growth characteristic of male and female giant prawns is negative allometry, but the male and female body shapes are fat. Total mortality, capture mortality, catch rate, male prawns are higher than females. The male infinitive growth is longer than the female,but the female’s growth rate is faster than male. Abstract Giant prawns ( Macrobrachium rosenbergii ) is a crustacean class that has the larg- est size and its habitat in Sembakung waters included brackish water (estuarine) with a salinity variable of 6.5 + 0.5 ppt and a temperature variable of 28.5 + 0.5OC and a variable pH of 6 (acidic). The objective of this research was to analyze the growth and mortality model of giant prawns ( M. rosenbergii ) that was taken from the catch of fisherman in the estuary, Sembakung sub-district, Nunukan Regency, Indonesia. The study was conducted for 3 months from November 2019 to Janu- ary 2020. The sampling was by using a survey method with purposive judgment sampling based on a catch of 14 fishermen who used the bottom fish pot from Sembakung waters, Nunukan Regency (Indonesia). The data collection included data of sex, total length, and the total weight of giant prawns. While analysis was employed for growth pattern, condition index, Von Bertalanffy growth, and mor- tality. The results obtain the sex ratio of male and female giant prawns 1:3.67. The growth pattern of male and female giant prawns were allometric negative. The growth of the von Bertalanffy model for infinitive growth of male giant prawns were 21.219 cm and female were 18.42 cm, respectively the mortality from giant prawns obtain total male mortality is 2,257, catch mortality is 1.92 and natural mortality is 33.75% with an exploitation rate of 0.85 (85%). The total female mor- tality is 1.528, catch mortality is 120.1% and natural mortality is 32.69% with an exploitation rate of 0.786 (78.6%).

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

Life history variation is fundamental to the evolution of Pacific salmon and their persistence under variable conditions. We discovered that Chinook salmon sort themselves into surface- and bottom-oriented groups in tanks within days after exogenous feeding. We hypothesised that this behaviour is correlated with subsequent differences in body morphology and growth (as measured by final length and mass) observed later in life. We found consistent morphological differences between surface and bottom phenotypes. Furthermore, we found that surface and bottom orientation within each group is maintained for at least one year after the phenotypes were separated. These surface and bottom phenotypes are expressed across genetic stocks, brood years, and laboratories and we show that the proportion of surface- and bottom-oriented offspring also differed among families. Importantly, feed delivery location did not affect morphology or growth, and the surface fish were longer than bottom fish at the end of the rearing experiment. The body shape of the former correlates with wild individuals that rear in mainstem habitats and migrate in the fall as subyearlings and the latter resemble those that remain in the upper tributaries and migrate as yearling spring migrants. Our findings suggest that early self-sorting behaviour may have a genetic basis and be correlated with other phenotypic traits that are important indicators for juvenile migration timing.

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.

A new tilefish, Branchiostegus biendong, is described on the basis of three specimens (181–209 mm in standard length [SL]) collected from a local fish market of Quy Nhon on the South China Sea coast of central Vietnam. It can be distinguished from 17 congeners in having the following combination of characters: six diagonal scale rows exposed on cheek; cheek scales moderately large (diameter 2.2–2.5% SL); predorsal ridge black; cheek almost silver with an oval-shaped, yellow blotch along ventral margin of eye; dorsal fin translucent yellowish with narrow black margin overlapping stronger yellowish coloration dorsally; upper lobe of caudal fin with 5–6 yellow stripes and tip with black blotch; and lower lobe of caudal fin navy blue. A key to five species of Branchiostegus from Vietnamese waters is provided.

The present study deals with the design and technical aspects of bottom fish trawl (64 m) locally know as 32 Angali disco dol, operated along the Ratnagiri coast of Maharashtra. The material used for the fish trawl is HDPE (High density polyethylene) and the knot type used for construction is a single trawl knot. Blue colour multifilament netting twine was normally used, having twine diameter of 1.25 mm for construction of netting of wing and square section while 1.00 mm twine was used for the belly, lengthener and cod end section. The mesh size of the wing and square section was 600 mm and gradually reduced down to the cod end section (18 mm). The net was specifically used to catch Ribbonfish, Squid, Croaker, Pomfret etc.

Long-term information on mean annual biomass of the main taxa of bottom and demersal fishes on the shelf and upper continental slope (down to 2025 m) in the Far Eastern Seas and adjacent Pacific waters is summarized. Mean annual biomass of fish in the benthic layer (without pelagic species) is estimated as 9.8 . 10 6 t (60.2 % in the Okhotsk Sea, 20.4 % in the Bering Sea, 11.2 % in the Pacific waters at Kuril Islands, 4.1 % in the Japan Sea, and 4.1 % in the Pacific waters at Kamchatka). Schemes of these species distribution in the pelagic layers are presented, too. Even truly bottom fishes rise to the pelagic layers sometimes (mostly in the nighttime). Eggs, larvae and juveniles of many demersal and benthic species dwell mainly in the pelagic layers, transported by currents everywhere including the open waters beyond the continental shelf and slope; elder fish, from the stage of fingerlings, are able for migrations, even against stream. Biomass of the species majority is proportional to square of shelf and slope, with exception of the species associated with complicated bottom topography (rocks, canyons, guyots, etc.), in particular at steep slopes.

Data on mean annual biomass (t) of the bottom macrofauna groups and main species in the Far-Eastern Seas and adjacent waters of the Pacific Ocean, by bathymetric ranges, and on density of their distribution (t/km 2 ) are summarized. The average density of distribution for bottom and demersal fish varies from 5.8 to 26.9 t/km 2 in the range 0-200 m, from 8.6 to 26.9 t/km 2 in the range 200-500 m, from 3.6 to 14.7 t/km 2 in the range 500-1000 m, and from 3.4 to 15.7 t/km 2 in the range 1000-2000 m. The average density for bottom invertebrates varies within 4.0-12.6, 4.7-19.6, 1.7-10.2, and 0.6-3.0 t/km 2 , respectively. The density usually increases in the transitional zone between the continental shelf and a slope (200-500 m). Aggregations of total macrofauna are the densest in this bathymetric range and reach 32.3 t/km 2 in the Bering Sea, 15.2 t/km 2 in the Japan Sea, and 41.4 t/km 2 in the Pacific waters at Kuril Islands. However, the concentrations in this zone in the Okhotsk Sea (maximum 13.3 t/km 2 ) and the Pacific waters at Kamchatka (31.5 t/km 2 ) are lower than that ones on the continental shelf.

Giant prawns (Macrobrachium rosenbergii) has high economic value with a price range between IDR. 40,000 to IDR. 75,000 that it was one of the main catches of fishing gear used by the society in Muara Tepian Sembakung. This research aims to analyze the growth model composition of giant prawns (M. rosenbergii) in Muara Tepian Sembakung, Nunukan. The objective was conducted for 5 months from October 2019 to February 2020. The research was designed by using quantitative descriptive with a case study approach. The determination of the study location was applied with a purposive random sampling method by following the fishermen who used the bottom fish pots catch. The sampling of giant prawns at Muara Tepian Sembakung was done by taking a survey method adhered to a fisherman with repetition as 10 times of sampling at a different time. The data of Giant prawns that were collected involved sex, total weight, and total length using a laboratory-scale method in the Laboratory of fisheries biology, Fisheries and marine science faculty, Universitas Borneo Tarakan. The research variable was the von Bertalanffy model and age structure of male and female giant prawns. The results obtained that the sex ratio of giant prawns (Macrobrachium rosenbergii) between males and females was 1: 1.83 with a percentage of a male was 35.33% and female was 78.6%. The growth of Von Bertalanffy model in getting the infinitive growth for male giant prawns was 24.185 cm at 132 days then T0 was -1.1088 and growth rate was 0.0877 cm/day with correlation value was 0.88431 (88.431% = very strong correlation) and female giant prawns amounted to 18.470 cm at 101 days whileT0 was -1.0734 days and the growth rate was 0.1019 cm/day with a correlation value was 0.90626 (90.626% = very strong correlation).

The society of Tepian Muara Sembakung village, Nunukan Regency (Indonesia) render Sembakung waters as a potential resource that can be used as one of their income. The fisherman used Bubu Dasar fishing gear (Bottom fish pots). This research aims to analyze the economic feasibility business model of Bubu Dasar fishing gear (Bottom fish pots) in Tepian Muara Sembakung, Nunukan Regency, Indonesia. The sampling was conducted for 3 months, from November 2019 to January 2020. The research used a quantitative descriptive method with a case study approach. The Data was collected using survey with interview, observation based on catches from bottom fish pots as many as 14 times, and laboratory-scale method by doing identification of main catch, such as giant prawns (Macrobrachium rosenbergii) and by-catch composition like mangrove crab (Scylla serrata); catfish (Pangasius hypophthalmus); crossbreed fish (Plotosus canius); cand hopstick fish (Toxotes jaculatrix). The results obtained an average daily income of fishermen was IDR 379,286 with an average gross income in each month was IDR. 3,792,857 with total expenses in the form of maintenance costs, depreciation costs and operational costs of IDR. 444,868, so the average profit of fishermen in each month was IDR. 3,347,990. The business analysis can be seen from the average ROI index value as 33.4; the average BEP index value was 12.4 and the average benefit cost ratio (B/C ratio) index was 8.5, so the results of the three indices explain that the bottom fish pots business analysis results are profitable and worthy of profit catching giant prawns (M.rosenbergii) using bottom fish pots in Tepian village, Sembakung subdistrict, Nunukan district.

In this study we attempted to determine the effect of various feeding methods (bottom and surface feeding) used in the hatchery, on the survival and growth rates of hatchery-reared sea trout (Salmo trutta trutta L.) in the wild. Rearing was performed in two variants: a bottom-fed group (BFG) and a surface-fed group (SFG). At the end of the rearing time, we observed that BFG fish gathered at the bottom of tank, as opposed to SFG fish, which swam in the whole water column. After 4 weeks of rearing, the fish were released into two similar streams. After about 2 months the fish were captured and the foodbase of the streams were examined. 30 fish from each group have been randomly selected for stomach contents analysis. In the shallow stream the growth rates were better for the BFG fish than the SFG and also a significantly higher number of typical benthic taxa was found in stomachs of the BFG fish than the SFG fish. In the deeper stream more food was found in the stomachs of the SFG fish than in the BFG fish. The analyzed results showed that factors such as stream depth, current velocity, and turbulence can also affect the rearing success of juvenile salmonids in hatchery streams. Bottom feeding fish during rearing has a positive impact only on the fish in shallow watercourses, where there is no turbulence, and the food is not carried by the current drift or washed out from the bottom into the drift.

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.

We tested the hypothesis that humpback whales aggregate at the southern flank of Stellwagen Bank (SB) in response to internal waves (IWs) generated semidiurnally at Race Point (RP) channel because of the presence of their preferred prey, planktivorous fish, which in turn respond to zooplankton concentrated by the predictable IWs. Analysis of synthetic aperture radar (SAR) images indicates that RP IWs approach the southern flank of SB frequently (∼62% of the images). Published reports of whale sighting data and archived SAR images point to a coarse spatial coincidence between whales and Race Point IWs at SB's southern flank. The responses of whales to IWs were evaluated via sightings and behavior of humpback whales, and IWs were observed in situ by acoustic backscatter and temperature measurements. Modeling of IWs complemented the observations, and results indicate a change of ∼0.4 m/s in current velocity, and ∼1.5 Pa in dynamic pressure near the bottom, which may be sufficient for bottom fish to detect the IWs. However, fish were rare in our acoustic observations, and fish response to the IWs could not be evaluated. RP IWs do not represent the leading edge of the internal tide, and they may have less mass-transport potential than typical coastal IWs. There was large interannual variability in whale sightings at SB's southern flank, with decreases in both numbers of sightings and proportion of sightings where feeding was observed from 2008 to 2013. Coincidence of whales and IWs was inconsistent, and results do not support the hypothesis.

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.

The main aim of this study was to biomonitor mercury (Hg), arsenic (As), cadmium (Cd), lead (Pb) and copper (Cu) concentrations in the Arvand River using Heteropnestis fossilis and Parasesarma persicum. Comparison of heavy metals among the stations indicated that the concentrations of Hg, As, Cd, Cu and Pb in sediment samples were apparently different among the stations. The results of linear regression analyses showed that there were significant correlations ( p < 0.05) between Hg, As and Pb elements in sediment and hepatopancreas of P. persicum and between As in sediment and liver of H. fossilis. These findings showed that P. persicum could be considered as a biomonitor of Hg, As and Pb and H. fossilis as a biomonitor of As contamination in sediment of the Arvand River.

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.

This study was aimed at analyzing the fishermen and the fish farmers household economic conditions living around the coal mining activity site and comparing them to those living in the site of no coal mining activity. Tanah Laut Regency has many fishermen and fish farmers and there are also coal mining activities.The study found that the mining companies operating on the study site was small-scaled companies, but that operating around the villages was large-scaled one. This mining operations contribute to the carrying capacity of environmental conditions, especially fish farming activities. Shrimp pond activities in the study area have always failed in the last several years that caused the fishermen and the fish farmers have to move to other work in order to meet their household economic needs and even there were some fish ponds sold.The small-scaled coal mining companies in this area have not conducted the empowerment program for surrounding communties despite providing some non-skill working opportunies for few local people, such as security staff and other loading and unlouding labors.Small-scaled fishermen (

This study uses a 30-year time series of standardized bottom trawl survey data (1982–2011) from the eastern Bering Sea shelf to model patterns of summer spatial distribution for various bottom fishes and crabs in response to changes in the areal extent of the cold pool, time lag between surveys, and fluctuations in population abundance. This investigation is the first to include data for the 2006–2010 cold period and to use between-year comparisons of local and shelf-wide spatial indices to test specific responses to three different isothermal boundaries within the cold pool. Distributional shifts in population varied considerably among species and directional vectors for some species were greater in magnitude to the east or west than to the north or south; however, in general, eastern Bering Sea shelf populations shifted southward in response to the increasing cold pool size, and after accounting for differences in temperature and population abundance, there was still a temporal northward shift in populations over the last three decades despite the recent cooling trend. Model results for local and shelf-wide indices showed that survey time lag and cold pool extent had a greater effect on spatial distribution than population abundance, suggesting that density-independent mechanisms play a major role in shaping distribution patterns on the eastern Bering Sea shelf. The area enclosed by the 1 °C isotherm most commonly affects both local and shelf-wide spatial indices suggesting that 1 °C is a more important boundary for describing temperature preferences of eastern Bering Sea bottom fishes and crabs than is the 2 °C isotherm used for designating the physical boundary for the cold pool.

A rocky ramp fishway is one of the Nature like fishway, comprises a long sloping channel and boulders on a slope (Katopodis et al., 2001). The turbulence and backwater around the boulders creates refuges of decreased local flow where fish can rest. However, recent studies have shown that turbulent flow may influence fish migration (Smith et al., 2006). This paper is focused on boulder arrangement and height of boulder on rocky ramp fishway. The swimming performance of char ( Salvelinus richardson ) and freshwater sculpin ( Cottus pollux ) around boulders on experimental channel were observed using ultra-high-speed cameras, and the appropriate arrangement of boulders for each species was considered. In total, 27 hydraulic conditions were assessed considering variable distributions, shapes, heights of the boulders as well as variable flow depths by observing swimming behavior for each condition. Laboratory measurement shows that sculpin, which are bottom fish, require a density, and several linear arrangements of boulders to allow migration. As increasing the vertical low-velocity area, which is created behind high boulders does not always result in a good outcome for sculpin. However, this solution is not suitable for char; therefore, a diverse arrangement of boulders is required on individual rocky ramp fishways to allow the movement and migration of multiple species. We propose to add cloister in the fishway for free migration of weak swimmer.

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.

Correlations have been revealed between the distribution of the different ichthyoplankton species and the fluctuations of the environmental factors along transects in the Baltic Sea during the autumn of 2005 and spring and autumn of 2006. The early ontogenetic stages of the cod and other bottom fish species were confined to the Bornholm Basin located in the southwestern part of the sea with near-bottom salinity of more than 16‰ and the absence of an oxygen deficiency in the isohaline zone of 11–14‰. Eggs and larvae of the Baltic sprat were distributed in June throughout all the deep-sea regions with near-bottom water salinity of no less than 8%., up to the western Gulf of Finland. In the spring of 2006, the abundance of sprat eggs was found to drop significantly compared with the average long-term data for the recent period; this was due to the cold winter of 2006.

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.

Information on tissue distribution of Dechlorane Plus (DP) and its dechlorinated analogs in wildlife is scarce. DP isomers and two dechlorinated compounds, anti-Cl11-DP and anti-Cl10-DP, were examined in the muscle, liver, and brain tissues of two bottom fish species collected from an electronic waste recycling site, South China. The median levels of syn-, anti-, and anti-Cl11-DP isomers in the tissues ranged 0.18–39.1, 0.22–52.9, and 0.01–5.63 ng/g wet wt, respectively. Anti-Cl10-DP was only detected in one muscle sample of mud carp (0.01 ng/g wet wt), although it was consistently detected in the sediments (0.42–0.83 ng/g dry wt). Preferential distribution in liver relative to muscle was observed for syn-DP and anti-Cl11-DP. However, a high persistent retention in the brain compared to the liver was observed for anti-DP, suggesting that this isomer can across the blood–brain barrier of fish, and may cause adverse effects to the nervous system in the exposed biota.

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.

Understanding the links between large scale spatial structuring of fish assemblages and shaping factors is essential to develop comprehensive ecosystem-based fisheries management. In this study, we investigated spatial patterns of bottom fish assemblages in the North Sea in relation to prevailing water masses in the region. We based our analysis on catch data from the German Small-Scale Bottom Trawl Survey conducted between 1987 and 2005 and used both ordination techniques and Mantel tests. Spatial variability of bottom fish assemblages was larger than inter-annual variability. Five significantly different bottom fish assemblages were associated with the following prevailing hydrographical regimes: i) the English Channel, ii) Continental Coastal, iii) central North Sea, iv) northern North Sea, and v) northern Atlantic water masses. Associations were generated by gradients in relative proportions of abundant species such as grey gurnard (Eutrigla gurnardus), dab (Limanda limanda), whiting (Merlangius merlangus), haddock (Melanogrammus aeglefinus) and Norway pout (Trisopterus esmarki). Taking into account large scale spatial structuring of catch data Mantel tests confirmed significant correlation between the fish assemblages and hydrographical variables. In summary, our results strongly support the hypotheses that hydrographical features such as water masses, fronts, and residual currents could shape bottom fish associations in the North Sea. Spatial demarcations of bottom fish assemblages indicated by this study can be used to support ecosystem-based fisheries management strategies.

Though a sand banking method is known to be effective to improve an environment of bottom sediment, there is no common method of construction or monitoring investigation. Duration of effect is also not clear. In this study, we verified the duration of effect of sand banking method based on monitoring investigation for 17 years in Tsuda Bay. As a result, it became clear that the effect lasted 17 years on improvement of sediment, elution of phosphorus, and a habitat of bottom fish.

The bottom-fish stocks of the Main Hawaiian Islands (MHI) are intensively fished, both commercially and recreationally. Recent assessments of the Bottomfish Management Unit Species (BMUS) complex suggested overfishing, and expressed concerns about missing non-commercial data. We used reported commercial time-series data and estimation ratios to indirectly estimate non-commercial catches for non-pelagic species (i.e., excluding tuna and billfishes) for 1950–2005. Using adjustment ratios, we also accounted for commercial under-reporting, which suggested that total commercial non-pelagic catches were 28–128% higher than reported commercial catches for any given year. Estimated non-commercial catches for 1950–2005 were 2.1 times higher than reported commercial catches. Reported catches underestimated likely total catches (reported and un-reported commercial plus non-commercial) of non-pelagic species and BMUS components for 1950–2005 by a factor of 3.9 and 2.9, respectively. We incorporated the reconstructed BMUS non-commercial catches into stock assessments of the officially reported commercial BMUS catches via a Schaefer production model. Total catch increased by 2.5–3.5 times with the addition of non-commercial BMUS catch estimates, which in turn increased model estimates of MSY and carrying capacity (k) by approximately four times compared to analyses with reported commercial data alone. As the CPUE data lacked information to resolve the confounding between large, unproductive and small, productive stocks, an informative prior was used for fishing mortality rate to attain MSY (FMSY). To address uncertainty in key management parameters, independent estimates of exploitation rate, or fisheries independent estimates of abundance, and informative trends in recreational effort or catches are required.

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.

We assessed mercury levels in the feathers of little tern (Sternula albifrons) chicks from hatching to fledging and in their prey captured by adults in three main foraging habitats: lagoon, salinas, and adjacent sea. These data were used to model mercury concentration in chick feathers through food ingestion, in order to explore the effects that changes in diet would have on the mercury burden of chicks as they aged. The mercury concentration in feathers of chicks raised in sandy beaches was higher than in those raised in salinas. Lagoon prey had a significantly higher mercury concentration (0.18 +/- 0.09 microg g(-1) dry weight [d.w.]) than prey from salinas and the adjacent sea (both 0.06 +/- 0.03 microg g(-1) d.w.). In relation to prey species group, mercury content was significantly higher for bottom fish (0.17 +/- 0.10 microg g(-1) d.w.) than for pelagic (0.08 +/- 0.06 microg g(-1) d.w.), euryhaline fish (0.04 +/- 0.02 microg g(-1) d.w.), and crustacea (0.08 +/- 0.03 microg g(-1) d.w.). To understand the importance of mercury content of each prey group, we ran several theoretical scenarios assuming that chicks were fed on only one species at a time. Considering a diet restricted to lagoon (mostly benthic) prey, A- and B-chicks may encounter health problems with an excess of mercury. On the contrary, a diet restricted to marine (mostly pelagic) prey would decrease the mercury concentration in chick feathers; the fast growth rate and the related mercury dilution effect in little tern chicks seem to decrease mercury levels in their feathers. Our study supports the fact that marine pelagic prey are important for estuarine seabirds because they provide a food resource with lower contamination levels. This model may have a wider application in similar seabird species and coastal environments.

Selected metals were evaluated in surface sediments from Cadeia and Feitoria Rivers (Brazil), potentially affected by tanneries. Statistical factor analysis of sediment data allowed the identification of critical} metals and priority areas for biological monitoring, i.e., chromium and mercury at the lower course of Feitoria River. Non-piscivorous bottom-fish from the species Rineloricaria cadeae (violinha) were collected at reference and contaminated sites. Chromium was undetected} in fish tissues, and mercury accumulated in individuals living in contact with contaminated deposits. Mercury contents in fish were below World Health Organization quality standard for human consumption (0.5 μg/g). The ratio of total mercury content in fish (wet weight) to sediment (dry weight

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.

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 263 trawl hauls completed during October 1999 and September to November 2001, 116 fish species were collected in Davis Strait and the southern Baffin Bay (61°44.1′ N–73°52.8′ N, depths of 145–1484 m). The abundance data for the 80 benthic species were used for analyses of the fish fauna diversity and fish assemblages. As a first step, seven 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 seven clusters. The spatial distribution of the conditional probabilities for each cluster (assemblage) was mapped by means of a geostatistical tool. Each assemblage was further defined by indicator species, depth, and temperature. Four of the assemblages were found in Baffin Bay, two in Davis Strait and one mainly in Davis Strait but scattered into Baffin Bay.

Based on the data of two summer surveys carried out in 2002, the biomass of bottom fishes of the West Kamchata Shelf was assessed. The obtained results were considered within the series of similar annual assessments conducted since 1996. It was displayed that against the background of some increase in the total biomass of bottom fishes, the biomass of the plaices prevailing there, which had previously been the two dominating species had decreased. As a result of the quantitative variations that occurred, the present community structure differs considerably from that observed over the past twenty years.