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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.

This study aimed to develop a detailed behavior observation method for deep water fish using pingers and a quantitative echo sounder. We focused on alfonsino (Beryx splendens) inhabiting deep water. The survey was conducted at two locations: one where fishermen operate (experimental area) and another where they do not (control area). First, we set 10 grid survey lines in each survey area and ran using a quantitative echo sounder. The volume backscattering strength was smaller maximum 10 dB than in the experimental area. Second, following the grid survey, we used vertical longlines for confirmation of the fish species with corded pingers and a depth water temperature logger. We measured catch depth of the target. In this study, we observed the detailed behavior of the fishing gear in real time; integrating this information with the catch results could lead to more accurate measurements of the habitat range of deep water fishes.

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 ...

Research trawling surveys and visual observations aboard manned underwater vehicles carried out at Whale Ridge revealed 116 species of bottom, near-bottom, over-bottom, and over-bottom-pelagic fish of 46 families. The data on the distribution, number, and behavior, along with some data on biology of the mass fish species, are given in the present paper. The following species prevail by number and biomass: splendid alfonsino Beryx splendens; boarfish Pseudopentaceros richardsoni; redbait Emmelichthys nitidus; flintperch Hoplostethus atlanticus; Helicolenus mouchezi; and fish of families Gempylidae, Oreosomatidae, Macrouridae, Moridae, Alepocephalidae, etc. All these species are subject to fisheries but the boarfish and alfonsino are most commercially important.

A benthic community constituted by an assemblage of at least four species of deep-sea corals collected in only one trawl carried-out on the summit of the O'Higgins I seamount, central Chile. The corals were collected in only one trawl carried-out during a Chilean-Japanese cruise onboard the R/V" Koyo Maru" in December 29, 2004. Presence of oxygenated and cold Antarctic Intermediate Water (>400 m depth) on the plateau was recorded under of the Equatorial Subsurface Water associated to the oxygen-minimum zone (OMZ

Fish is considered by nutritionists as the main source of omega 3 (n-3) polyunsaturated fatty acids which is not available in common edible plant oils. However, methylmercury (MeHg) in fish is considered as the major contributor from food. Risk benefit analysis of MeHg and n-3 fatty acids became a hot topic in the past decade. Different risks and benefit analysis on the consumption of fish have been reported, but most of the analyses were based on the data extracted from different databases. This study provided the levels of n-3 fatty acids, MeHg, and total mercury (tHg) of different fish species commonly consumed in Hong Kong. Among the sampled 88 species of fresh/frozen whole fish, all samples were found to contain quantifiable amount of n-3 fatty acids, MeHg, and tHg. The levels of n-3 fatty acids (EPA plus DHA) in local or imported fish species are ranging from 0.31 to 20.6 mg per g while the highest level was found in Atlantic salmon. For MeHg, the highest content was found for alfonsino at the level of 0.827 μg per g. A modified AOAC 990.08 was single laboratory validated and used for analysis n-3 fatty acids content of fish samples. This paper presents the n-3 fatty acids and MeHg content in 88 fish species. These original results are consistent with overseas findings and are useful in risk/benefit assessment of fish consumption recommendations in general.

A method is proposed for estimating two instantaneous mortality coefficients, and rate of effective survivors to number of tagged fish released, using exact times at liberty from multiple sets of tagging experiments. Effective survivors are defined here by the product of survivors immediately after releasing and reporting rate of recaptures. A least-squares method was applied to estimate the parameters using statistical models expressing the numbers of effective survivors, which were calculated by a principle similar to virtual population analysis. In order to investigate the statistical performance of the method, simulation trials using operating models were carried out. The method was applied to data of tagging experiments for alfonsino Beryx splendens from 1957 to 1969, off Kanagawa Prefecture. In most of the results of simulation trials, the method yielded estimates of natural mortality coefficient of which expected values were within ±12% of true values. Estimates of natural mortality coefficient, fishing coefficient and the rate of effective survivors for alfonsino are 0.57 (per year, 95% confidence limits [CL] 0.40–0.69), 0.094 (per year, 0.03–0.25) and 0.39 (0.12–1.00), respectively. Modifications for the generalization of the method and notes on its applications are discussed.

Age and growth of alfonsino Beryx splendens from South-West Indian Ocean seamounts were studied based on whole otolith readings. Ages of the fish under study ranged between one year and 14 years (15.5–43.5cm fork length). Age distribution was related to depth. The von Bertalanffy growth parameters for males were L&#8734= 49.1cm, K = 0.099 year –1 and t 0 = –4.11 years, and L&#8734 = 57.1cm, K = 0.081 year –1 and t 0 = –4.16 years for females, obtained by length-age pair values. For all individuals the von Bertalanffy growth parameters were L&#8734 = 53.5cm, K = 0.085 year –1 and t 0 = –4.33 years. There were no differences in the growth parameters between males and females. Also, the growth parameters of the alfonsino under study did not differ between those of alfonsino from New Caledonia and the Izu Islands (Japan), but they differed significantly from those from New Zealand. Keywords: age, alfonsino, Beryx splendens, growth, Indian Ocean African Journal of Marine Science 2006, 28 (1): 33–40

The sequences spanning 307 bp of the mitochondrial cytochrome b gene were determined for 45 sepcimens of Beryx splendens and seven specimens of B. mollis collected in Japan, resulting in identification of 11 and three haplotypes in the two species, respectively. The parsimony tree was constructed from the determined sequences and those registered into the GenBank data-base as species A and W of B. splendens collected in New Caledonia, featuring with two clades. The first clade comprised species W from New Caledonia and B. mollis in the present study, whereas the second one contained species A from New Caledonia and B. splendens in the present study. These results demonstrate a large geographic distribution for both B. splendens and B. mollis. Some of the haplotypes found in Japan were identical to those of New Caledonia for both B. mollis and B. splendens, suggesting levels of gene flow at the trans-oceanic scale.

The distribution of mercury in the muscle and other tissues was determined in 23 species of fishes and invertebrates. This study reveals species-specific patterns of mercury accumulation in the muscle of tuna and alfonsino. Consistently high levels of total mercury were found in Beryx splendens (0.78±0.56 μg/g), Atlantic Thunnus thynnus (0.42±0.06 μg/g), Pacific T. thynnus (0.59±0.34 μg/g), Thunnus obesus (0.98±0.34 μg/g), Makaira nigricans (0.56±0.05 μg/g), Tetraptrus audax (0.51±0.08 μg/g), and Xiphias gladius (0.47±0.24 μg/g). Other fish species had lower levels of total mercury or methylmercury in muscle than the maximum permitted level of mercury in fish in Japan (0.4 μg/g). Total mercury and methylmercury levels in the muscles of T. thynnus, T. obesus, and B. splendens were closely correlated with body weight.

The genetic variability shown by geographically distant populations of the alfonsino Beryx splendens off the Macaronesian archipelagos (the Canary Islands, Madeira and the Azores) was surveyed by examining polymorphisms in three mitochondrial DNA regions (cytochrome b, rRNA 16S and control region). Particular DNA polymorphisms were detected in fish specimens from the three archipelagos. Two single nucleotide substitutions in the rRNA 16S region and one in the control region served to identify the Azorean populations, while one cytochrome b substitution was sufficient to discriminate specimens fished off the coast of Madeira. Specimens from the Canary Islands could be identified by a distinct Sau3AI restriction enzyme pattern found in the mitochondrial control region. To test the congruence of these molecular observations with the morphological and meristic discriminatory analyses generally used in fisheries research, a pilot study was conducted to distinguish between two of our sampling areas: Canaries and Madeira. Analyses based on both morphometric and meristic data were more reliable than those based solely on morphometric data. The discriminating factors identified were cephalic length and number of soft rays in the anal fin. The proportions of specimens correctly classified were in the range 67.2–70.7%. Although previous hypotheses suggest genetic homogeneity at the inter-oceanic scale consistent with the long pelagic stage of marine species, discriminatory haplotypes were detected according to the three mitochondrial gene fragments despite the relative geographical closeness of the Macaronesian archipelagos (Canaries, Madeira and Azores). These geographical differences were also supported by biometric data. Discrimination among populations of the three archipelagos suggests limited genetic flow between them, such that they should really be considered as independent stocks for fisheries. © 2005 Elsevier B.V. All rights reserved.

Age and growth of alfonsino Beryx splendens (Lowe) were studied using counts of presumed daily incremental growth rings on the transverse section of otoliths of fish collected from the Kanto District, central Japan. Microstructural growth increments were observed from the core to the outermost margin of the broadest of approximately 50 branches formed on the surface of an otolith. Of 98 otoliths examined, 46 were readable. The number of increments and fish lengths ranged from 448 (218 mm fork length [FL]) to 3701 (411 mm FL). The ages of these fish were estimated to be 1 year, 2 months and 10 years, 2 months, respectively, assuming that an increment was formed daily. The von Bertalanffy growth equation combined for males and females was expressed as follows: Lt = 542 {1 − exp [−0.133(t + 2.00)]}, where Lt is fork length (mm) at yearly age t. The results of the present study were compared with those of other researchers who had studied alfonsino from central Japan.

Summary This paper provides comparative information on the reproductive biology of the alfonsino, Beryx splendens Lowe, 1834, species with commercial interest in the Azores, Madeira and the Canary Islands. A total of 846 individuals from Azores (14.0–42.0 cm fork length), 621 from Madeira (17.2–50.0 cm fork length) and 643 from the Canaries (18.2–38.9 cm fork length) were used for the study. The alfonsino is gonochoric with no evidence of sexual dimorphism. Females are more abundant than males; this dominance probably reflects certain differences in the spatial distribution and/or the catchability of males and females in the Macaronesian archipelagos. The spawning season was distinct for the three Macaronesian areas, with an observed North–South variation in the reproductive period: September–March in the Azores, March–June in Madeira and July–September in the Canary Islands. The size at sexual maturity estimated for Madeira and the Canary Islands is similar (32 and 30 cm fork length, respectively), while for the Azores it is reached at smaller length (23 cm fork length). The differences observed in the size at sexual maturity can be explained by the different exploitation levels in each archipelago. Life-history parameters of the alfonsino suggest that this species has a specialistic life-history strategy and fisheries based on this species are more susceptible to growth overfishing and population depletion.

The mitochondrial 16S rRNA gene was amplified by polymerase chain reaction usingtotal DNAas a template from muscle tissues of alfonsino and related fish species of alfonsino belong-ing to the genus Beryx , B.splendens , B.mollis and B.decadactylus . While the sequence of the 16SrRNA gene consisted of 492 nucleotides irrespective of the three species, three, nine and eight inter-specific variations were shown between B.splendens and B.mollis , between B.splendens and B.decadactylus , and between B.mollis and B.decadactylus , respectively. The pelagic eggs, which werecollected off Izu Islands and showed morphological characteristics typical to the genus Beryx wereall identified as those of B.splendens from the nucleotide sequence of the mitochondrial 16S rRNA gene. KEY WORDS: 16S rRNA , alfonsino, Beryx , mitochondrial DNA, pelagic eggs, species identification. *Corresponding author: Tel: 81-468-82-2313. Fax: 81-468-81-7903. Email: akimoto@agri.pref.kanagawa.jpReceived 28 December 2001. Accepted 4 June 2002.

Deep water fisheries resources in the Indian Ocean ekslusive economic zone of Indonesia, has been investigated extensively in the year of 2004 to 2005. Recently a fishing operation of deep sea bottom trawl vessel F/B.

Levels of total mercury (tHg) and mono-methylmercury (MeHg) were measured in 280 different fish, including fresh/frozen raw whole fish of 89 different species and canned tuna fish of three different species, that are traded mainly in Hong Kong, China. These samples were purchased from different commercial outlets between April and August 2007. All samples of raw whole fish were identified at species level by the Agriculture, Fisheries and Conservation Department. The range for tHg and MeHg of all samples were 3-1370 and 3-1010 µg kg(-1), respectively, with medians of 63 and 48 µg kg(-1), respectively. The results show that, according to Hong Kong legislation, the products on the market are generally 'safe'. A total of 277 samples (99?) contained tHg and MeHg below the legal limit of 500 µg kg(-1). The remaining three samples of alfonsino (species: Beryx splendens) were found to contain tHg and MeHg at levels higher than 500 µg kg(-1) (tHg: 609-1370 µg kg(-1); MeHg: 509-1010 µg kg(-1)). The ratios of MeHg to tHg in the different fish species ranged from 0.46 to 0.99.

SUMMARY: This paper estimates the age and growth of the alfonsino Beryx splendens in the waters around the Izu Islands off the Pacific side of Japan. The samples consist of 250 fish of the landings of the offshore longliners from December 1995 to November 1996 and 10 fish of the coastal longliners in February of 1995. By the surface method using a microscope, a reader counted the number of hyaline and opaque zones on the sagittal otoliths, judged whether the edge was hyaline, and measured the radii from the focus to the outer edge of each hyaline zone. In order to estimate the parameters of the von Bertalanffy’s growth equation representing the overall ages, the age and fork length data and the mean length at 1 year old. In a previous study were used for the maximum likelihood approach. From the results, the rate of readability of the otolith from the offshore samples was 97.6% and that from the coastal samples was 100%. The monthly changes in the frequency of the opaque edge showed that the hyaline and opaque zones were laid down once a year. The hyaline zone began to form from May to July (peaking in August). The ages of the offshore samples for both the sexes ranged from 2 to 23 years, and those of the coastal samples 2 to 5, respectively. The estimated growth curves were expressed by l(t) = 44.4[1–exp{–0.132(t + 3.45)}] for males and l(t) = 45.0[1–exp{–0.150(t + 2.08)}] for females, where l(t) and t denote the fork length (cm) and the age in years, respectively. The issues to be resolved in the future were discussed.

The reproductive biology of the alfonsino Beryx splendens was studied by histological examinations, gonadosomatic index and macroscopic scales of maturation of a large sample of gonads. Alfonsino is a gonochoric species. The size-frequency distribution of the sex ratio was bimodal and considered to be due to size dimorphism. In New Caledonia, the breeding period of this species occurs during the southern summer, with a peak in December to January. The spawning stage is attained at a minimum fork length of 28 cm for females and 33 cm for males. The size at which 50% of the population attain sexual maturity (FL50) is 33.2 cm for females and 34.5 cm for males. Maximum potential fecundity is estimated to lie between 270 000 to 675 000 eggs for fish between 34 and 40 cm in fork length. It was possible to differentiate vegetative zones, in which juvenile alfonsino grow until they reach maturity, from reproductive zones (fishing grounds) which are inhabited by mature individuals. The larvae and juveniles could be carried from the reproductive zone to the vegetative zone by currents in an oceanic eddy system.

Age and growth of the alfonsino Beryx splendens from New Caledonia seamounts were determined by examination of whole and sectioned otoliths. One growth-ring (annulus) in the otoliths appears to be laid down each year. It consists of one opaque (summer, fast-growing) zone and one hyaline (winter, slowgrowing) zone. Thin-sections of otoliths revealed daily rings which allowed us to estimate that the formation of the nucleus takes ∼10 mo. The first annulus following the nucleus is incomplete. Females have a higher growth rate than males. Sexual maturity is reached at the age of 7 to 8 yr for males and 6 yr for females. Maximum age attained would be ∼20 yr for alfonsino >50 cm in fork length. the results are compared with those from the few other studies on the growth of alfonsino.

This paper deals with the influence of temperature on the growth of alfonsino, Beryx splendens , caught in New Caledonia at 23–25°S and 165–171°E. The mean temperature of the 0–500 m water layer was cross-correlated with the Southern Oscillation Index after the seasonal cycles were removed. It is shown that the interannual fluctuations of temperature are influenced by ENSO (El Nino-Southern Oscillations) events with a time-lag of several months. The growth study is based on the reading of annuli on sagittal otoliths. In order to show fluctuations in otolith growth, an index of increase variation I va was defined. Superposition of the I va series on temperature series suggests the growth of alfonsino to be strongly related to temperature fluctuations in intermediate-depth water masses and consequently by ENSO events which appear further north at low latitudes in the equatorial Pacific. “El Nino” events would increase growth rate whilst “La Nina” events would reduce it.

The main aim of this work is to provide a detailed analysis of the reproductive cycle of Beryx splendens in the Juan Fernandez Archipelago. The gonadosomatic index (I(G)) and maturity ogives in both sexes were estimated using an extensive database collected by onboard scientific observers between January 2006 and October 2009. A histological analysis of maturation was also completed for females collected between May and December 2001. Variations in both I(G) and proportion of mature individuals were observed in fish with a fork length (L(F)) >37 cm for females and >33 cm for males. The main reproductive season was in the austral winter and spring (June to November). Fork length at 50% maturity (L(50)) was estimated as 39·67 cm for females (95% c.i. =39·34, 40·02 cm) and 36·88 cm for males (95% c.i. =36·45, 37·36 cm) using macroscopic analysis of gonads. Estimates for females using histological data varied slightly with an estimated L(50) of 43·67 cm (95% c.i. =42·82, 44·91 cm). Changes in I(G) and maturity were modelled as a function of month and L(F) within a generalized additive model framework. A high porportion of immature individuals were found throughout the year. The results of this study are compared with reproductive traits reported for B. splendens in other areas of its distribution and are discussed with reference to exploitation, vulnerability and conservation of the B. splendens stock in Juan Fernandez Archipelago.

Mitochondrial control region sequences of 141 alfonsino Beryx decadactylus sampled off the coast of South Carolina were compared with 164 sequences from B. decadactylus collected in the Azores for inferring population structure and demographic history of this deep-water teleost in the North Atlantic Ocean. Analysis of molecular variance showed that 100% of the genetic variation was found within populations, indicating an absence of population structure (Φ(ST) = -0· 003). Neutrality tests and mismatch distribution analyses of pooled sequences suggested that B. decadactylus in the North Atlantic Ocean have undergone population expansion. These results may indicate that transatlantic gene flow occurs, possibly through passive drift of larvae or adult migration. The potential of a shared stock between the eastern and western North Atlantic Ocean will need to be considered if a directed fishery for B. decadactylus were to develop in the U.S.A.

The diet of the alfonsino Beryx splendens was determined from examination of stomach contents of 287 specimens of 17 to 48 cm fork length (L(F)) sampled by bottom trawl on the Chatham Rise to the east of New Zealand. Prey items were predominantly crustaceans and mesopelagic fishes. The most important prey species by mass was Sergestes spp. prawns, followed by the myctophid Lampanyctodes hectoris, and then Pasiphaea spp. prawns. Multivariate analyses indicated that small crustaceans (euphausiids and amphipods) were most important in the diet of smaller B. splendens (100-424 g, 17-26.5 cm), with larger prawn species and mesopelagic fishes most important for larger fish (425-2070 g, 27-46 cm). Moon phase and bottom temperature also explained some of the variability in diet, but the moon phase effect was difficult to explain, and the bottom temperature effect may have been confounded, to some extent, with L(F). The results indicated that B. splendens were moderately selective feeders that foraged primarily in the mesopelagic layers. The diet of New Zealand B. splendens is generally similar to those reported from other areas, i.e. dominated by mesopelagic crustaceans and fishes, and with a transition from small crustaceans to fishes with increasing predator size.

Commercial landings of alfonsino (Beryx splendens Lowe, 1834) from the Palliser Bank, Tuaheni High, and Paoanui Ridge were sampled to describe growth and determine the age composition of catches. The study indicated that one opaque and one hyaline zone were formed annually in sagittal otoliths, the hyaline zone being deposited in late autumn. Fish were probably about 10 months old when the otolith nucleus was fully formed. The length‐weight equations for males and females differed and both changed throughout the year in parallel with the spawning cycle. Size‐selective mortality did not occur on the Palliser Bank. Females were significantly larger at any given age than males on all grounds examined, but growth of males and females appeared consistent between grounds. Growth was slower than in Japanese waters and the Atlantic. Age structure varied between grounds, but was reasonably constant over time on the Palliser Bank. Full recruitment to the commercial fishery occurred at age 5 on the Palliser...

The alfonsino Beryx splendens Lowe, 1834 is a species typical of elevations and promontories of the ocean bottom, which has been widely studied in its distribution areas, although characterization of its populations lacks detailed comparative analyses regarding many important aspects of its biology. The present paper studies age and growth of alfonsino from the Gulf of Guinea seamounts, based on whole otolith readings. Ages of the fish studied ranged from 1 to 21 years (14.1-46.4 cm fork length). The Von Bertalanffy growth parameters for males were L∞ = 42.9 cm, K = 0.135 per year, and t0 = -2.11 years, and for females, L∞ = 52.6 cm, K = 0.077 per year and t0 = -3.82 years. For both sexes combined, the Von Bertalanffy growth parameters were L∞ = 48.0 cm, K = 0.097 per year, and t0 = -3.09 years. Statistical differences in growth between males and females were found in one of the tests applied, although it is inconclusive whether there are effective differences in the growth pattern between sexes. A new perspective regarding the study of this species's growth has made it possible to compare population patterns in different oceans, and to conclude that the the growth parameters of the alfonsino from the Gulf of Guinea seamounts differed significantly from those of the Indian Ocean. Several factors are indicated that are probably responsible for these differences. El alfonsiño Beryx splendens Lowe, 1834 es una especie distintiva de elevaciones y prominencias de los fondos oceánicos ampliamente estudiada en las zonas donde se distribuye, aunque la caracterización de sus poblaciones carece de análisis comparativos detallados relativos a muchos aspectos importantes de su biología. Se estudian aquí la edad y el crecimiento del alfonsiño de las montañas submarinas del golfo de Guinea a partir de la lectura de otolitos enteros. Las edades de los individuos analizados estaban comprendidas entre 1 y 21 años y sus tallas entre 14,1 y 46,4 cm de longitud a la furca. Los parámetros de la ecuación de crecimiento de Von Bertalanffy, obtenidos a partir de pares de valores de talla-edad, fueron, por sexos, L∞ = 42,9 cm, K = 0,135 por año y t0=-2,11 años para machos y L∞ = 52,6 cm, K = 0,077 por año y t0=-3,82 años para hembras; para ambos sexos en conjunto fueron L∞ = 48,0 cm, K = 0,097 por año y t0=-3,09 años. Aunque en uno de los test realizados se observaron diferencias significativas de crecimiento entre machos y hembras, no se ha podido concluir la existencia de diferencias reales entre los patrones de un sexo y otro. Una perspectiva nueva en el estudio del crecimiento de la especie ha permitido la comparación entre patrones de poblaciones de océanos distintos, y concluir que los parámetros de crecimiento del alfonsiño del golfo de Guinea difieren significativamente de los del océano índico, señalándose los factores probablemente responsables de estas diferencias. Instituto Español de Oceanografía

The feeding habits of Beryx splendens and B. decadactylus were determined from stomach contents obtained on a monthly basis during commercial fishing off the Canary Islands in 1996–1997. Changes in diets were studied in relation to predator size and seasonal variation in the food composition. The diet of both species has much in common with regard to its main components of small fishes, crustaceans and cephalopods. More important differences were found in the fish prey of B. decadactylus. A variation in the diet of B. splendens was observed according to its length. Seasonal variations in feeding habits were associated with either variations in the abundance of prey or variations in the depth distribution of predator and prey.

La pesca exploratoria con espineles se efectuó en torno a la isla Robinson Crusoe del archipiélago de Juan Fernández, entre noviembre de 1996 y marzo de 1997. Esta experiencia fue desarrollada mediante el calado de espineles horizontales y verticales en estaciones posicionadas sobre 4 transectas orientadas radialmente a las islas, entre 50 y 1000 m de profundidad. En dicha experiencia se trabajó principalmente con anzuelos desbalanceados números 5, 6, 7 y 9. Los principales recursos capturados en estas actividades correspondieron a: anguila de profundidad (Bassanago nielseni), breca (Cheilodactylus gayi), cabrilla de Juan Fernández (Scorpaena fernandeziana), chancharro (Helicolenus lengerichi), corvina de Juan Fernández (Umbrina reedi), jurel de Juan Fernández (Pseudocaranx chilensis), morena (Gymnotorax porphyreus), ribaldo (Mora moro), tollo de Juan Fernández (Squalus mitsukurii), pez mariposa (Pterygotrigla picta) y alfonsino (Beryx splendens). Si bien las capturas obtenidas con estos aparejos no fueron especialmente abundantes, permitieron determinar la fauna íctica de aguas profundas en torno a estas islas. Las especies que presentaron los rendimientos más altos fueron la breca y tollo de Juan Fernández, entre 50 y 200 m, y el ribaldo, entre 400 y 600 m. Entre 600 y 1000 m no se registró captura de peces

The oils from the edible flesh, frame, head, skin and viscera of seven deep-sea fish namely, alfonsino (Beryx splendens), cardinal fish (Epigonus sp.) javelin fish (Lepidorphynchus denticulatus), lookdown dory (Cyttus traversi), rattail (Coelorynchus sp.), ribaldo (Mora pacifica) and sea perch (Helicolenus papillosus) were examined. The fatty acids analysed are present as glycerol-based lipids and no marine wax esters were detected. The distribution of the major fatty acid moieties, i.e. 16:0, 18:1 and 22:6 resembled the pattern common to established commercial fish oils.

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