Beryx Splendens Research Articles

Feeding habits of splendid alfonsino Beryx splendens in the vicinity of Kuroshio, the south of Japan

AbstractGut contents and nitrogen isotope ratio (δ15N) analyses were conducted on splendid alfonsino Beryx splendens collected in the vicinity of Kuroshio from May 2015 to November 2016 (n = 708) to identify their feeding habits in the Western North Pacific. Micronektonic fish, shrimp, and squid were the dominant prey species, with the Decapoda Acanthephyra quadrispinosa, Prehensilosergia prehensilis, Cephalopoda Enoploteuthis chunii, Chiroteuthis calyx, Teleostei Sigmops gracilis, and Gonostoma elongatum. These micronektons are common in the Kuroshio Current; thus, B. splendens is a possible opportunistic feeder. Gut content weight (GCW), occurrence (%O) of fish and squid, and δ15N were significantly increased with the fork length (FL) of B. splendens. Only the %O of shrimp does not show a significant relationship with the FL of B. splendens. These indicated the ontogenetic shift of dominant prey from shrimp to fish. Fattened specimens could also prey on a greater number of fish. The seasonality of GCW and %O values was high in spring and autumn and low in summer and winter. This seasonality indicated that the feeding habits of B. splendens are controlled by primary productivity in the surface layer and/or by maturity. When the Kuroshio flowed in the north of Hachijojima Island, the GCW was significantly increased, and some organisms, including C. calyx, G. elongatum, and S. gracilis, were preyed on more. While the offshore area of the Kuroshio has low productivity, B. splendens can actively prey in this area, indicating that it is an important feeding ground for this species.

Patterns of variability of species composition of catches from the russian fishing vessels in the south-eastern Pacific ocean for 2015–2022

The work provides information on the patterns of species composition of catches from the Russian fishing vessels conducted fishing of jack mackerel (Trachurus murphyi Nichols 1920), chub mackerel (Scomber japonicus Houttuyn 1782) and redbait (Emmelichthys spp.) in the South-Eastern Pacific Ocean outside the economic zones of the coastal States. According to scientific observations, an analysis of the composition of species caught by the Russian fishing vessels is given. When fishing in the pelagic zone over ocean depths, jack mackerel was the main target species, chub mackerel formed the bycatch. At the same time, the proportion of chub mackerel in catches in the northern parts was higher than in the southern ones. When fishing on seamounts of the Nazca Ridge, catches were dominated by redbait with jack mackerel and alfonsino (Beryx splendens Lowe, 1834) as bycatch. According to the similarity of the species composition of catches, three areas – 1) all the Southern and Central subareas and part of the Northern subarea; 2) seamounts of Nazca ridge; 3) part of the Northern subarea near the border of the EEZ of Peru between 17–20°S, were singled out using the cluster analysis method.

Fish Nutrition at the Underwater Mountains of the Whale Ridge (Southeastern Atlantic). 3. Structure of Fish Accumulations and Fish Feeding

Pelagic accumulations of fish are formed above the underwater mountains of the Whale Ridge in the evening and at night, but not observed during daylight hours. The study of such an accumulation above one of the mountains reveals its structure. The central part of the cluster consists of splendid alfonsino Beryx splendens, silver scabbardfish Lepidopus caudatus and oilfish Ruvettus pretiosus tend to keep on the periphery of the splendid alfonsino accumulation. Previously, it was found that food of splendid alfonsino, silver scabbardfish, rosefish Helicolenus mouchezi, Richardson’s boarfish Pentaceros richardsoni, and Cape bonnetmouth Emmelichthys nitidus consisted of organisms forming sound-scattering layers (SSL) above the underwater mountains. The composition of food and the daily dynamics of feeding of the listed commercial fish species indicate that they use two feeding tactics. In the first case, rosefish, Richardson’s boarfish, and Cape bonnetmouth forage for most of their food during the day at the bottom, when the SSL-forming organisms descend to the top of the underwater mountain during the diel migration. In the second case, splendid alfonsino, silver scabbardfish, and oilfish as part of a structured pelagic aggregation feed at night on the organisms rising into the upper layers of the water and forming sound-scattering layers. This tactic expands the possibilities for feeding fish that form pelagic aggregations in the dark hours of the day and allows the use of organisms both brought by the current to the mountain top and those that descended here earlier during the diel migration and then stayed until the beginning of the evening.

Determination of dietary essential fatty acids in a deep-sea fish, the splendid alfonsino Beryx splendens: functional characterization of enzymes involved in long-chain polyunsaturated fatty acid biosynthesis

The splendid alfonsino Beryx splendens is a commercially important deep-sea fish in East Asian countries. Because the wild stock of this species has been declining, there is an urgent need to develop aquaculture systems. In the present study, we investigated the long-chain polyunsaturated fatty acid (LC-PUFA) requirements of B. splendens, which are known as essential dietary components in many carnivorous marine fish species. The fatty acid profiles of the muscles, liver, and stomach contents of B. splendens suggested that it acquires substantial levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from its natural diet. The functional characterization of a fatty acid desaturase (Fads2) and three elongases (Elovl5, Elovl4a, and Elovl4b) from B. splendens confirmed their enzymatic capabilities in LC-PUFA biosynthesis. Fads2 showed Δ6 and Δ8 bifunctional desaturase activities. Elovl5 showed preferential elongase activities toward C18 and C20 PUFA substrates, whereas Elovl4a and Elovl4b showed activities toward various C18-22 substrates. Given that Fads2 showed no Δ5 desaturase activity and no other fads-like sequence was found in the B. splendens genome, EPA and arachidonic acid cannot be synthesized from C18 precursors; hence, they can be categorized as dietary essential fatty acids in B. splendens. EPA can be converted into DHA in B. splendens via the so-called Sprecher pathway. However, given that fads2 is only expressed in the brain, it is unlikely that the capacity of B. splendens to biosynthesize DHA from EPA can fulfill its physiological requirements. These results will be useful to researchers developing B. splendens aquaculture methods.

Trends in abundance indices derived from commercial fisheries for priority marine stocks in the Azores.

Large-scale assessments of fish and shellfish populations may be valuable for identifying the impacts of fishing pressure on stocks, but they are rarely possible due to a lack of long-term datasets. In this study, a two-part mixed-effect model for lognormal data was used to obtain historical abundance indices for 16 priority fish and shellfish stocks in the Azores region derived from catch per unit effort (kg per day at sea per vessel) and landing per unit effort (kg per landing per vessel). This data was obtained over the past 30 years under the EC Data Collection Framework and, in addition to information on effort and catch, included details about the fishing operation such as quarter, vessel length and fishing gear. This information was analysed to investigate how abundance indices changed over the years, verify if trends from different data sources were different and, if possible, relate these results to the population and fishery dynamics. The abundance indices derived from both datasets were generally in agreement with each other. Declining trends have been observed for some commercially important species, such as forkbeard Phycis phycis, European conger Conger conger, parrotfish Sparisoma cretense, red scorpionfish Scorpaena scrofa, offshore rockfish Pontinus kuhlii, common spiny lobster Palinurus elephas, splendid alfonsino Beryx splendens and alfonsino B. decadactylus, which is concerning because they are particularly slow-growing, long-lived and have low natural mortality, making them susceptible to overfishing. The results of this study are very important and should help future stock assessment and management initiatives.

Feeding of Fish at the Seamounts of the Whale Ridge (South-Eastern Atlantic Ocean). 2. Splendid alfonsino Beryx splendens (Berycidae)

The feeding characteristics of splendid alfonsino Beryx splendens from the seamounts of the Whale Ridge have been studied. A wide range of food organisms in feeding of splendid alfonsino has been confirmed, comprising meso- and macroplankton of the sound-scattering layers of the mesopelagial. Benthic organisms have not been found in the food spectra of splendid alfonsino. The food spectra of splendid alfonsino differ in populations inhabiting distant groups of the seamounts of the Whale Ridge due to the difference in the composition of the available food items and environmental conditions, fish body size, season, and sampling period. Splendid alfonsino has a pronounced diurnal feeding dynamics: the fish feed most intensively in the evening and at the beginning of the night, when the organisms of the sound-scattering layers migrate to the upper water layers. At this time, maximum feeding and minimum digestion of food are noted. Splendid alfonsino selects organisms of 0.9–130.0 mm (on average, 36.1 mm) in size for feeding. As the body length increases, splendid alfonsino switches to feeding on larger prey, while the ratio of the size of the prey to the size of splendid alfonsino changes little (9.7–11.5%).

Dietary characteristics of the ecologically-important fish species Centroberyx gerrardi, including discussion of resource partitioning among species of Berycidae in Australia

Data for the Berycidae, collected during extensive past scientific surveys, were used to quantify the depth distributions of the four species of Centroberyx and two of Beryx found in Australian coastal waters and thus elucidate the extent to which these species are partitioned by region and depth. The dietary, jaw and dentitional characteristics of the ecologically and fishery-important Centroberyx gerrardi were then determined, providing the first such account for any Centroberyx species. While Centroberyx gerrardi, Centroberyx lineatus, Beryx splendens and Beryx decadactylus are found throughout southern Australia, the last two species extend further up the west and east coasts. Centroberyx australis occurs on the lower half of the west coast eastwards to the central south coast and Centroberyx affinis on the lower half of the east coast. The four Centroberyx species typically occur at depths <350 m and the two Beryx species at >350 m. On the south coast of Western Australia, depth distributions undergo an overlapping progressive gradation, from C. lineatus in inshore and nearshore shallow waters, to C. gerrardi and C. australis in nearshore deep waters, and then B. splendens and B. decadactylus in offshore deep waters. The main dietary categories of C. gerrardi change with increasing body size from crabs and isopods in small fish to teleosts in the largest fish, in which volumetrically they constituted >60% of the stomach contents. The wide range of teleost prey (at least 39 species from 33 families) ingested by C. gerrardi would be valuable to this species if continuing climate change or other anthropogenic effects lead to alterations in the composition of potential prey. Differences between depth distributions account for the fish prey of C. gerrardi comprising nearshore species, such as those of clupeids, congrids, pomacentrids and platycephalids, whereas those of B. splendens (from studies elsewhere) are dominated by myctophids, which are abundant in deeper waters. The combination of a large mouth and numerous, exclusively small teeth (edentulate morphotype) strongly suggest that C. gerrardi is a suction feeder adapted to engulfing larger prey. While the co-occurring and likewise commercially-fished Oplegnathus woodwardi also ingests substantial volumes of crabs and teleosts, its diet is distinguished from C. gerrardi by large volumes of poriferans and appreciable volumes of echinoderms, likewise reflecting feeding specialisations. Although differing in depth distributions and dietary compositions, berycid species in general are close to the apex of the food web.

Life history baseline of unexploited populations: The case of Beryx splendens from the Sierra Leone Rise

This study examines for the first time the biology of alfonsino (Beryx splendens) from three small seamounts of the Sierra Leone Rise (SLR), an unexploited and fragile ecosystem in the Atlantic, using data from an experimental survey carried out in 2001 by Spanish longliners. In general, the lack of rigorous baseline data limits the implementation of efficient management and conservation plans in fisheries strategies. Therefore, the main aim of present study was to provide baseline information on basic biological parameters of the alfonsino population associated with an unexploited ecosystem. A total of 17296 individuals of alfonsino were sampled from SLR. Alfonsino is gonochoric and presented an unbalanced sex ratio, there were significantly more females than males. Taking into account the results in stage of maturity of alfonsino and the gonadosomatic index values during studied period, we can conclude that at least one reproductive period in these seamounts was in the late spring and early summer. The spawning stage was attained at a minimum fork length of 23 and 25 cm for males and females, respectively. The size at which 50% of the population attains sexual maturity was approximately 28 and 27 cm for males and females, respectively. The stock structure of alfonsino showed a segregation of the size with the depth, as they increase in size they move into the deeper water.

A Model that Forecasts Future Values of Reproductive Success for the Pacific Stock of Splendid Alfonsino

A Model that Forecasts Future Values of Reproductive Success for the Pacific Stock of Splendid Alfonsino

Can we consider the stocks of alfonsinos Beryx splendens and Beryx decadactylus from the Azores a discrete fishery management unit?

This paper summarises the detailed information on catch, fork length, weight, sex and maturity of alfonsinos Beryx splendens and Beryx decadactylus collected from targeted surveys in Azores waters, complemented by fishery data, over the past c. 20 years. To date, it was not possible to define if the Azorean component of the population can be considered as a discrete local management unit. The reason for this is the lack of available information for these resources covering the entire spatial distribution of the species in the North Atlantic Ocean. Additionally, there are some conflicts between the different genetic results available, poor understanding about the species movements and data from the Azores show some discrepancies in aspects of reproduction. Consequently, there is no analytical assessment for this resource and the stock of Beryx spp. is currently managed based on the precautionary approach. Outputs of recent analyses are presented in this study and possible assumptions and strategies for the assessment are discussed.

Megabenthos and benthopelagic fishes on Southeast Atlantic seamounts

In a descriptive study of megafauna of several Southeast Atlantic seamounts, multiple video-transects on upper slopes and summits documented the occurrence of benthic invertebrate taxa, primarily corals, regarded as indicators of vulnerable marine ecosystems (VMEs) as defined in international guidelines. At Schmitt-Ott Seamount there was a pronounced dominance of gorgonian corals (seafans, Alcyonacea). In all other study areas the diversity was greater, and more scleractinians (stony corals, Scleractinia) were observed. Scleractinian corals were mainly dead, and much of the coral framework and rubble may have been ancient. In the Valdivia complex and on Ewing Seamount, which are open to fisheries, scleractinians seemed restricted to some slopes of knolls, and on Valdivia Bank and the subarea denoted Valdivia West the summit substrate was mostly bare rock. Pelagic armourhead Pseudopentaceros richardsoni and splendid alfonsino Beryx splendens (two targets of commercial fisheries in the area) were observed at a few sites, but did not appear to be abundant in the main former fishing areas of the Valdivia area. Orange roughy Hoplostethus atlanticus was common in video records around the summit at Ewing Seamount. The deep-sea red crab Chaceon erytheiae was abundant in the Valdivia area and at Ewing Seamount, and crabs were distributed across a more extensive depth range than the fishes. In areas with high densities of live coral, the video records suggested that the benthic communities were intact and not impacted by fishing. Evidence of past fishing activities included observations of lost pots and rope at Vema Seamount and in the Valdivia area.

Long-term changes in the diversity, abundance and size composition of deep sea demersal teleosts from the Azores assessed through surveys and commercial landings

To obtain important baseline information about population dynamics and to provide valuable insights about the possible effects of artisanal fishing on the demersal fish community, this study had three specific objectives: (1) to update the annotated list of demersal teleost species occurring in the Azores (mid-North Atlantic); (2) to describe their depth distribution and related fishery information; and (3) to evaluate annual changes in their observed abundance and length composition. To do this, a time series with about 25 years of scientific data from the commercial fishery and surveys was analyzed. The demersal teleost community was represented by 213 species, predominantly deep-water species, reflecting the main marine habitat in the Azores region. Fishery takes place mainly in the intermediate strata (200–600 m), where the most commercially important species occur. No changing in the fork length (LF) distribution toward small individuals caused by size-selective fishing was detected in this study. The high variability observed in the LF data indicates the need for more accurate studies considering alternative statistical analyses (e.g., generalised linear models) to examine the possible factors (e.g. depth coverage, gear configuration, soak time, and fishing area) that cause this variability. On the other hand, the abundance indices of some commercially important species appear to have declined (Phycis phycis, Pontinus kuhlii, Conger conger, Beryx splendens and B. decadactylus), while others appear to be more stable (Helicolenus dactylopterus) or even increasing (Mora moro). Although the available data are insufficient for a formal assessment on the status of exploited populations, the long-term analysis of commercial landings and survey data was used as a basis to assess deep sea demersal teleost fisheries of the Azores, under a precautionary approach.

Comunity structure and habitat characterization of Neoschrammeniella cf. bowerbankii (Porifera, Corallistidae) aggregations in the Cantabrian Sea

Comunity structure and habitat characterization of Neoschrammeniella cf. bowerbankii (Porifera, Corallistidae) aggregations in the Cantabrian Sea

A new record and biological evidence supporting the establishment of Beryx splendens (Actinopterygii: Beryciformes: Berycidae) in the western Mediterranean basin

A new record and biological evidence supporting the establishment of Beryx splendens (Actinopterygii: Beryciformes: Berycidae) in the western Mediterranean basin

Albatross chicks reveal interactions of adults with artisanal longline fisheries within a short range

Incidental capture in fisheries (“bycatch”) is a major threat to global marine biodiversity, especially to those species with low fecundity, such as albatrosses. Efforts to reduce bycatch have been undertaken in industrial fisheries, but the scale of seabird interactions with artisanal or small-scale fleets remains largely unknown. The island of Torishima (Japan) is an important breeding site for two albatross species (short-tailed Phoebastria albatrus and black-footed P. nigripes) and also lies in the range of the artisanal longline fishery for the splendid alfonsino Beryx splendens. In February–March 2017, we tracked 23 foraging trips of adult P. nigripes feeding chicks by Global Positioning System (GPS) and monitored the prevalence of fishing gear at the nests using a metal detector. The foraging range of these albatrosses was a maximum of 280 km from Torishima, and only 3.7% of the GPS locations occurred over the shallow habitats targeted by the alfonsino fishery (water depth 150–500 m), suggesting relatively low risks of interaction. However, 190 (54.3%) nests of P. nigripes contained fishing gear, among which 12 (3.4%) nests or chicks contained a hook or an unidentified metallic object. Six hooks were also collected from P. albatrus nests. All found hooks, except one, originated from the alfonsino fishery, indicating that both targeted albatross species actually interacted with this fishery at sea. Both research approaches provided data from returning birds only and did not reflect possible lethal cases at sea. Monitoring the sub-lethal effects of bycatch and encouraging small-scale fisheries to report gear lost at sea are two possibilities to further help quantify and reduce the impact of fisheries on seabirds.

Bizionia berychis sp. nov., isolated from intestinal tract of a splendid alfonsino (Beryx splendens).

A Gram-stain-negative, non-motile, aerobic and rod-shaped bacterial strain, designated RA3-3-1T, was isolated from splendid alfonsino (Beryxsplendens) collected from the North Pacific Ocean. Strain RA3-3-1T grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 1.0-3.0 % (w/v) NaCl. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain RA3-3-1T belonged to the genus Bizionia, clustering with the type strain of Bizionia fulviae. Strain RA3-3-1T exhibited 16S rRNA gene sequence similarities of 98.7, 97.6 and 97.3 % to the type strains of B. fulviae, Bizionia paragorgiae and Bizionia saleffrena, respectively, and of 95.5-96.4 % to the type strains of the other Bizionia species. Strain RA3-3-1T contained MK-6 as the predominant menaquinone and anteiso-C15 : 0, iso-C16 : 0 3-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH, iso-C15 : 0 and C17 : 0 2-OH as the major fatty acids. The major polar lipids detected in strain RA3-3-1T were phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid. The DNA G+C content of strain RA3-3-1T was 34.1 mol% and its DNA-DNA relatedness values with the type strains of B. fulviae, B. paragorgiae and B. saleffrena were 12-29 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain RA3-3-1T is separate from recognized species of the genus Bizionia. On the basis of the data presented, strain RA3-3-1T is considered to represent a novel species of the genus Bizionia, for which the name Bizionia berychis sp. nov. is proposed. The type strain is RA3-3-1T (=KCTC 62140T=NBRC 113024T).

Prey use by three deep-sea fishes in the Emperor Seamount waters, North Pacific Ocean, as revealed by stomach contents and stable isotope analyses

We analyzed the stomach contents and nitrogen and carbon stable isotope ratios of three deep-sea fishes Pentaceros wheeleri (North Pacific armorhead), Beryx splendens (splendid alfonsino), and Allocyttus folletti (oxeye oreo)—to elucidate interspecific and intraspecific differences in prey use among demersal fishes in the Emperor Seamount waters (North Pacific Ocean). Principal component analysis using an index of relative importance revealed interspecific differences in prey use: P. wheeleri preyed on plankton and benthos; B. splendens on micronekton and plankton, and A. folletti on micronekton. The relationship between the index of relative importance in B. splendens and body length also indicated ontogenetic shifts in prey use. High percentage of empty stomachs and low stomach fullness index in P. wheeleri indicated this species’ limited feeding ability during its demersal life on seamount. Nitrogen isotope ratio analysis suggested that the trophic level of A. folletti was the highest, followed by large B. splendens, small B. splendens, and P.wheeleri. Variation in carbon isotope ratio values were small, indicating that primary producers were similar. Differences in nitrogen isotope ratio (trophic level) coincided with differences in prey use by the three fishes. Thus, these species are likely able to coexist in seamount waters by partitioning their use of benthos, plankton, and micronekton food resources. They might be supported by food supplied from the surrounding water columns by horizontal flux of plankton or vertical migration of micronekton in the deep scattering layer because except for the benthic prey of P. wheeleri they consumed plankton and micronekton.

Rapid fish stock depletion in previously unexploited seamounts: the case of Beryx splendens from the Sierra Leone Rise (Gulf of Guinea)

Fish stocks associated with seamounts may be particularly susceptible to overexploitation. From January to July 2001, the Spanish Oceanographic Institute (IEO) conducted an experimental fishing survey entitled ‘Palguinea-2001’ on the seamounts of the Sierra Leone Rise. Beryx splendens (commonly called alfonsino) is the main commercial demersal fish associated with this area. The aim of this study was to investigate the effects of a demersal longline fishery targeting B. splendens on the previously unexploited small Machucambo Seamount over a short time-scale, and also to consider trends in pooled catch rate at another four seamounts. During 110 fishing days at Machucambo, a total catch of 207 tonnes of B. splendens was taken with a fishing effort of 1 309 070 hooks. A spectral analysis and red-noise spectra procedure (REDFIT) algorithm was used to identify the red-noise spectrum from the gaps in the observed time-series of catch per unit effort by weight. Our results show the potential impact of longline fishing pressure on an unexploited ecosystem – after approximately 50 fishing days, the stock appeared to decline substantially, as reflected by a marked drop in catch per unit effort. The apparent rapid decline of the stock might be related to the small size and the virgin state of the Sierra Leone seamounts. The results could be extrapolated to similar small seamounts elsewhere.

MtDNA 調節領域の塩基配列により推定されたキンメダイの集団構造

キンメダイは世界中の温帯亜熱帯域の水深 300-1300 m に生息し，底魚漁業において重要な魚種の一つである。しかし，キンメダイの集団構造の詳細は明らかになっていない。北太平洋 4 地点，南インド洋 3 地点，北大西洋 1 地点から集めたキンメダイについて，mtDNA の調節領域の塩基配列分析を行い，集団間に遺伝的な差異があるか調べた。それぞれの大洋内において集団間に差はなかったが，大洋間で差があった。このことから，大洋ごとに一つの大きな集団を形成していると推測された。

Studies of the age and growth of alfonsino Beryx splendens (Berycidae) in the area of the Azores Banks compared to other areas of its habitation

Methods of determining age of alfonsino Beryx splendens in the area of the Azores Banks are described. On otoliths of the beryx, spawning marks form in the period of intensive spawning (June–September); those of hyaline zone form in the season of lowest water temperature in the considered area (January–March); and those of opaque zone form in the prespawning (April–May) and postspawning (October–December) periods. The growth of alfonsino in the northern part of the Atlantic is close to an isometric one. The rate of linear growth of alfonsino in the area of the Azores Banks in the first year of life is higher than in fish of the New Anyo Seamount and Vavilov Ridge but lower than at the Angular Seamount. Beginning from the second year of life, the rate of growth slows down and becomes lower than at the New Anyo and Angular seamounts, but it remains higher than the rate of growth of fish of the Vavilov Ridge.