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Fish consumption is considered the main route of exposure to mercury for the human population. In this sense, this study analysed the total and organic mercury content present in the muscle tissue of 38 fish species caught in different geographical areas of the North Atlantic Ocean (included in FAO fishing areas 27 and 31). The potential risk to human health through fish consumption was assessed using the maximum limit for mercury intake of 1.3 μg methylmercury Kg body weight−1 week−1. The results show that carnivorous species presented higher mercury content (range 0.03–0.88 μg g−1) when compared to omnivorous (range 0.003–0.19 μg g−1) in all sampling sites. Furthermore, demersal fish exhibited higher mercury levels (range 0.01–0.88 μg g−1) than the pelagic species (range 0.003–0.38 μg g−1) did. From the 38 species analysed only Zeus faber presented mercury levels (0.68 ± 0.07 μg g−1) above the maximum limit (0.5 μg g−1) established for human consumption. On the other hand, mercury intake can be higher than the recommended due to the consumption of 13 species from fishing area 27 (Azores archipelago and Northwest Portuguese coast) and one species (Cynoscion nebulosus) from fishing area 31 (Southeast Mexican coast). However, only the consumption of Zeus faber and Aphanopus carbo from the fishing area 27 is discouraged. Thus, the fish consumption per capita in a specific area can exceed the limits of mercury ingestion, even when the mercury content in the fish is below the recommended for consumption.

Several artisanal fisheries target deepwater species. These stocks are highly sensitive to overfishing because of their slow growth and late maturation. This vulnerability is higher if species concentrate during spawning season in coastal areas, as occur with scabbardfish (Aphanopus spp.). In this paper, we explore if two Aphanopus species (A. carbo and A. intermedius) that coexist show migration patterns to coastal areas during spawning. We analysed specimens of both species throughout 4 years (2014–2017) in a weekly basis and compare morphological parameters with the distance of the coast (coastal (12 n.m.)). Both species showed coastal patterns of migration during the spawning season (October–December), with 65.90% of total specimens of A. carbo and 51.60% of A. intermedius being caught at

Aphanopus arigato Parin, 1994. Pacific Black Scabbardfish. To 120 cm (47.2 in) TL (Nakabo 2002). Japan, Kuril Islands (Nakamura and Parin 1993), and south-eastern Kamchatka (Sheiko and Fedorov 2000); British Columbia southward to near Punta Eugenia (27��33���N, 115��53W) (Personal communication: Scripps Institution of Oceanography Fish Collection, La Jolla, California), southern Baja California. Records from northern Chile (Nakamura and Parin 1993), Peru, and Islas Gal��pagos (McCosker et al. 1997) are likely Aphanopus capricornis Parin, 1994. Benthopelagic; depth: adults mostly at 800���1,350 m (2,624 ���4,428 ft) (Nakamura and Parin 1993), at least one at about 498 m (1,620 ft) (Fitch and Gotshall 1972); juveniles mesopelagic, at 300���1,000 m (984��� 3,280 ft) (Nakamura and Parin 1993); also reported at surface (Orlov and Tokranov 2019). North Pacific records of Aphanopus carbo Lowe, 1839, are now considered to belong to A. arigato, while A. carbo is recognized as an Atlantic Ocean taxon. Sometimes referred to as Aphanopus intermedius Parin, 1983, now considered to be an eastern Atlantic species (Fricke et al. 2020)., Published as part of Love, Milton S., Bizzarro, Joseph J., Cornthwaite, Maria, Frable, Benjamin W. & Maslenikov, Katherine P., 2021, Checklist of marine and estuarine fishes from the Alaska-Yukon Border, Beaufort Sea, to Cabo San Lucas, Mexico, pp. 1-285 in Zootaxa 5053 (1) on page 210, DOI: 10.11646/zootaxa.5053.1.1, http://zenodo.org/record/5578008, {"references":["Nakabo, T. (Ed.). (2002) Fishes of Japan with Pictorial Keys to the Species. Tokai University Press, Tokyo.","Nakamura, I. & Parin, N. V. (1993) FAO species catalogue. Volume 15. Snake mackerels and cutlassfishes of the world. FAO Fisheries Synopsis, No. 125, Volume 15. FAO, Rome.","Sheiko, B. A. & Fedorov, V. V. (2000) Chapter 1. Class Cephalaspidomorphi - Lampreys. Class Chondrichthyes - Cartilaginous fishes. Class Holocephali - Chimaeras. Class Osteichthyes - Bony fishes. In: Catalog of Vertebrates of Kamchatka and Adjacent Waters. Kamchatsky Pechatny Dvor, Petropavlovsk-Kamchatsky, Russia, pp. 7 - 69 [In Russian.]","McCosker, J. E., Merlin, G., Long, D. S., Gilmore, R. G. & Villon, C. (1997) Deep slope fishes collected during the 1995 eruption of Isla Fernandina, Galapagos. Noticias de Galapagos, No. 58, 22 - 26.","Fitch, J. E. & Gotshall, D. W. (1972) First record of the black scabbardfish, Aphanopus carbo, from the Pacific Ocean with notes on other California trichiurid fishes. Bulletin of the Southern California Academy of Sciences, 71, 12 - 18.","Orlov, A. M. & Tokranov, A. M. (2019) Checklist of deep-sea fishes of the Russian northwestern Pacific Ocean found at depths below 1000 m. Progress in Oceanography, 176, https: // doi. org / 10.1016 / j. pocean. 2019.102143","Fricke, R., Eschmeyer, W. N. & van der Laan, R. (Eds). 2020. Eschmeyer's Catalog of Fishes: Genera, Species, Reference. Available from: http: // researcharchive. calacademy. org / research / ichthyology / catalog / fishcatmain. asp (accessed 17 April 2021)."]}

© The Author(s)., [Background]: The presence of Anisakis larvae in fish represents a major public health concern. Effective risk management procedures should be applied to prevent heavily infected products from reaching the market. The aim of the study is to provide preliminary data on parasite exposure and risk classification in frozen fish products by applying a risk categorization scheme (site, abundance, density and epidemiology – SADE) and Fish Parasite Rating (FPR) method. Fish and cephalopods samples (N = 771) from 5 different FAO Atlantic areas were examined and categorized after an accurate visual inspection and a chloro-peptic digestion., [Results]: In 25 out of 33 fish species parasite larvae were found. 10897 anisakids larvae were collected and identified to genus level. Molva dypterygia, Conger conger, Zeus faber and Aphanopus carbo were shown to be the most highly infected species. SADE and FPR scores were 1 and poor, respectively, for the referred species, because of the disseminated Anisakis infection and commercial rejection., [Conclusion]: SADE/FPR method showed high specificity and accuracy. The information provided in this work could be used in early warning systems for the detection of parasites in fishery products and might help fishing industries in establishing management strategies for infected stocks in terms of cost saving decisions., This work has been partially supported by the Istituto Zooprofilattico Sperimentale della Sicilia – granted project "Indagine epidemiologica sulla prevalenza di allergie da Anisakis nella Regione Sicilia”.

Black scabbardfish, Aphanopus carbo, is a commercially important species that takes distant migrations throughout its life cycle. Sex steroids were measured by radioimmunoassay in the blood plasma of specimens caught off the Madeira Archipelago and mainland Portugal to link this species migratory path with its reproductive cycle. Furthermore, a pilot study using Mozambique tilapia (Oreochromis mossambicus) was designed to evaluate the effect of sample freshness on steroid levels because black scabbardfish blood was collected at separate times after specimens were caught. The changes in T and 11-KT concentrations between the time of blood extraction and the time after preservation did not statistically differ among the different methods applied. Therefore, measured black scabbardfish steroid concentrations were directly used in the subsequent data analyses. In females, E2 and in T concentrations peaked at a late stage of vitellogenesis. E2 concentration was significantly different between females caught off each area. Clustering E2 and T concentrations from all developing females resulted in the separation of two distinct groups, independently of their geographical area. In males, T and 11-KT were not significantly different between maturity stages. The hepatosomatic index of males caught off mainland Portugal was relatively high. This may reflect a mechanism for storing energy that will later be consumed during migration to the spawning grounds. The trend of sex steroids concentrations throughout the sexual maturation of the species is consistent with the morphological indicators and shows evidence of the reproductive and migratory pattern hypothesised for the black scabbardfish in NE Atlantic., This work was supported by the Portuguese Foundation for Science and Technology (FCT – Fundação para a Ciência e Tecnologia) under the PhD Grant SFRH/BD/64434/2009 to I. Fa. and the project UID/Multi/04326/2013 to A.V.M.C.; the Portuguese Government Development Investments and Expenses Program (PIDDAC – Programa de Investimentos e Despesas de Desenvolvimento da Administração Central) under the EU/DG Fisheries' Data Collection Framework (DCF); the Portuguese Fisheries Operational Program (2007–2013) (PROMAR – Programa Operacional Pescas), co-financed by the European Fisheries Fund (EFF) (2007–2013), under project CERTIFICA (2011–2015), MSC Certification in Portugal - Acquiring the knowledge and studying the viability for its application to coastal and artisanal fisheries.

The deep sea fishery targeting the black and intermediate scabbardfishes (Aphanopus spp.) off the Madeira archipelago represents one of the world long standing exploitations of meso- and bathypelagic fishes. The intensive fishing of the target species caused an overall decrease of more than (51%) in their yields. Fishing vessels had to go further away of the usual fishing grounds, leading to a progressive geographical expansion of the fishery reaching as far as the Southern Azores Seamount Chain and the Canaries Economic Exclusive Zone. Changes in the fishing pattern of the Madeira fleet were also registered along the last decades. Trends of the spatial distribution of the fishing sets and of the fishing pattern exerted by the Madeira fishing fleet in the North-central eastern Atlantic are presented herein and its implications for the conservation of the resource and fishery management are discussed, along with the emergence of new fisheries upon this resource at regional level. Changes in the conservation and management strategies followed so far is urgent and should integrate all fisheries acting upon the resource and take in account the phase of the life cycle it fishes otherwise the sustainability of the exploitation may soon be in danger. Authors propose a prohibition of bottom trawling bellow 200 m deep and a temporary closure of the fishery in some areas.

In this paper, we revisit the state of deep-water fisheries to the west of the British Isles and aim to provide an overview on the key drivers behind community changes along continental margins. The deep-water fisheries to the west of the British Isles that extend from the shelf-slope break down to the lower slope and along banks and seamounts of the Rockall Basin, mainly target blue ling Molva dypterygia, roundnose grenadier Coryphaenoides rupestris, orange roughy Hoplostethus atlanticus, with by-catches of black scabbardfish Aphanopus carbo and tusk Brosme brosme. These fishing grounds experienced a long period of exhaustive exploitation until the early 2000s, but subsequently the implementation of management strategies has helped to relieve excessive fishing pressure. It is widely accepted that a better understanding of the long-term implications of disturbance is needed to understand patterns in deep-water communities and what sustainable use and exploitation of resources might look like in this context.

The influence of different culinary practices (boiling, frying, grilling) and seasoning (salt, lemon, combined) on the Hg levels (total and organic) found in three marine fish species (Scomber scombrus, Dicentrarchus labrax, Aphanopus carbo) was evaluated. Cooking affected the Hg levels in a species-dependent manner. With the exception of D. labrax, T-Hg decreased in grilling and frying, while O-Hg decreased in all culinary practices. For all species, some Hg was also found in the boiling water. Since O-Hg is the major portion of Hg in fish muscle and all culinary practices removed O-Hg, setting consumption thresholds in terms of T-Hg in raw tissue seems protective and adequate. S. scombrus and D. labrax emerge as healthier and safer choices, while moderate consumption of A. carbo is recommended. These findings reinforce the need to maintain FAO/WHO's recommendation that vulnerable groups should eat less than 100 g of predatory species per week.

Scabbardfishes are a group of deep-water fishes from the family Trichiuridae that form the basis of an important longline fishery in the Madeira archipelago, in the southern part of the Northeast Atlantic. Two closely related and morphologically similar species occur in this area: the black scabbardfish, Aphanopus carbo, and the intermediate scabbardfish, A. intermedius. In this study, 112 scabbardfish specimens captured in Madeira, Canary Islands, and nearby seamounts were examined for the presence of anisakid nematodes. Infection levels were extremely high in both species. A generalised linear model was applied to anisakid abundance, using fishing location and several host parameters as predictors. Fish length had a strong positive effect, and A. carbo was more heavily infected than A. intermedius, whereas fishing location had no effect. The microhabitat distribution of anisakid larvae within the fish followed a gradient from the stomach to other visceral organs; however, infection levels in the muscle were not negligible, which raises safety issues for consumers. It is strongly recommended that scabbardfish should never be eaten raw or undercooked, unless frozen prior to consumption.

This study reports on the first record of the intermediate scabbardfish Aphanopus intermedius in the western South Atlantic Ocean, based on a single specimen 725 mm standard length collected between 0 and 610 m depth around Rocas Atoll off north-eastern Brazil. Measurements and counts are provided and compared with those available in the literature.

Novel statistical tools were tested with the muscle and liver of anglerfish species ( Lophius piscatorius and Lophius budegassa ) and black scabbard fish ( Aphanopus carbo ) and the muscle of blackbelly rosefish ( Helicolenus dactylopterus ) and megrim species ( Lepidorhombus boscii and Lepidorhombus whiffiagonis ). Methylmercury (methyl-Hg) content and selenium (Se) and eicosapentaenoic (EPA) + docosahexaenoic acids (DHA) were analysed. For muscle, it was determined that probabilities of the methyl-Hg intakes exceeding the provisional tolerable weekly intake (PTWI) (weekly meal, from 1:12 in L. boscii to 1:2 in H. dactylopterus ) were always higher than probabilities of the Se and EPA + DHA intakes surpassing the recommended daily allowance (RDA) (weekly meal, never surpassing 1:2,938,713 in L. budegassa ) and intake (weekly meal, never surpassing 1:13,974 in L. whiffiagonis ), respectively. For liver, probabilities of the Se intakes exceeding the RDA (weekly meal, from 1:82 in L. piscatorius to 1:1.2 in A. carbo ) were higher than probabilities of the methyl-Hg intakes exceeding the PTWI (weekly meal, from 1:96 in L. budegassa to 1:4 in A. carbo ). The Se health benefit values calculated for the muscle (from 5.5 in H. dactylopterus to 27.5 in L. budegassa ) and liver (from 165.7 in L. piscatorius to 1041.7 in A. carbo ) were all positive.

Author's version of an article in the journal: Canadian Journal of Fisheries and Aquatic Sciences. Also available from the publisher at: http://dx.doi.org/10.1139/cjfas-2013-0343 As human exploration and harvesting moves to the high seas, ecological understanding of the deep sea has become a priority, especially in those commercially exploited species whose life cycle, habitat use, and demographic structure remain poorly understood. Here we combine otolith trace element and stable isotope analyses with microsatellite data to investigate population structure and connectivity in the migratory deep-sea black scabbardfish (Aphanopus carbo), sampled along a latitudinal gradient spanning much of the known species range in the Northeast Atlantic. In each sampled life stage, otolith trace element and oxygen isotope compositions are similar among fish from different capture locations, but otolith compositions vary greatly between life stages. Oxygen isotope compositions indicate ontogenetic migrations from relatively warm water conditions during larval growth to cooler waters with increasing age. Analysis of microsatellite DNA also suggests lack of genetic structure among the areas sampled. The multidisciplinary approach employed collectively suggests that A. carbo individuals undergo an ocean-scale ontogenetic migration, beginning with spawning in southern, warm-water Macaronesian areas (potentially dominated by Madeira), followed by a large proportion of immature fish moving to and feeding on the continental slope in northern areas. The results lend the first conclusive evidence for defining the life-history circuit of this species and the perception of its stock structure across the North Atlantic.

Fishing is occurring all over the globe, with an increase trend of exploiting deep stocks. Several species are currently targeted from the deep ocean, and some artisanal fisheries developed fishing gears, e.g. long lines, with limited impact to the environment but scarce information is available on biological aspects of these exploited stocks. In the Macaronesian region and specifically in Madeira archipelago, two Aphanopus sympatric species have been extensively exploited for decades but no detailed information is available on the spatial and vertical distribution of both species (Aphanopus carbo and Aphanopus intermedius). Currently, they represent an important percentage of landings from artisanal fishermen of Madeira (27% of the total catches in 2017). We herein observed that they showed a pattern of depth segregation, where adults of both species are more abundant (ca. 80%) at deeper seafloor (> 2500 m). A. intermedius was more numerous in fishing areas with greater seafloor depth (> 4500 m) compared to A. carbo. This pattern may be explained by a food source overlap between both species, and also the vertical segregation within the same species may be considered as a pattern to avoid cannibalism. Also, migration patterns were found in both species being more pronounced for A. intermedius where > 86% of individuals were collected offshore (> 12 n.m.). The present results constitute a step forward to start developing integrative management actions to preserve stocks of both species in the medium and long term in the study region.

The aim of this work was to evaluate the hazards and benefits of the consumption of 6 deep-water fish species from the Portuguese coast. Samples from muscle and liver of Lophius piscatorius and Lophius budegassa and Aphanopus carbo and from muscle of Helicolenus dactylopterus and Lepidorhombus boscii and Lepidorhombus whiffiagonis were analyzed. It was found that a portion size of 160 g significantly contributes to the recommended daily allowance/intake (RDA/RDI) for a balanced human diet, with respect to the essential elements analyzed. Moreover, 49% and 84% of the RDI of 500 mg for main n -3 polyunsaturated fatty acids was achieved through consumption of a 160 g portion of A. carbo and L. whiffiagonis , respectively. Average Cd and Pb contents in all fish muscle samples were consistently below the EU limit. Attending to the tolerable weekly intake/provisional tolerable weekly intake (TWI/PTWI), it appears that studied species muscle does not represent a hazard for human consumption. However, the consumption of liver of the studied fish species must be avoided. A weekly meal of L. whiffiagonis may be advised on the basis of its significant contribution for elemental and n -3 fatty acid requirements and its minimal contamination risks.

Information about the spatial distribution of bycatch species and their spatial overlap with the target species is essential for fisheries management. The present study used fishery-dependent data (vessel monitoring systems, logbooks and official daily landings) to study the spatial distribution and overlap between black scabbardfish Aphanopus carbo and leafscale gulper shark Centrophorus squamosus taken by the longline fishery operating off mainland Portugal. The geostatistical method kriging was applied to estimate the distribution of the leafscale gulper shark in relation to black scabbardfish and thus assess the impact of the fishery on the leafscale gulper shark. Results indicate that in fishing grounds where the black scabbardfish is more abundant, the relative occurrence of deepwater sharks is reduced. These findings have implications for alternative management measures to be adopted in this particular fishery, particularly where it concerns the minimization of deepwater shark bycatch.

The biology, ecology, and dynamics of the deep-sea teleost black scabbardfish in the northeast Atlantic are reviewed. The black scabbardfish is a commercial bathypelagic species found in the NE Atlantic mostly from Iceland to the Canary Islands and Western Sahara, at depths from 800 to 1300 m. The spatial structure of its population is still uncertain, although the existence of one single stock that migrates around the NE Atlantic driven by feeding and reproduction is the most likely hypothesis consistent with available data. This review is based on data from commercial fisheries off the Faroe Islands, Hatton Bank, the west of the British Isles, and Portugal (mainland, Azores, and Madeira) and from Icelandic and Scottish scientific surveys collected between 1988 and 2012. Spawning of black scabbardfish occurs around Madeira and the Canary Archipelagos during the last quarter of the year. According to the migratory hypothesis, eggs, larvae, and possibly juveniles move north to areas from south of Icelandic and Faroe Islands to the west of the British Isles where they remain for some years to feed and grow. Then, they move south to the area off mainland Portugal, where they reach the size of first maturity but do not reproduce, and later move further south to the spawning grounds. Further studies are needed to understand which of the environmental conditions prevailing around Madeira and the Canaries, but not elsewhere, allow this species to mature and subsequently reproduce. This review suggests that a multidisciplinary approach is required to confirm the spatiotemporal migration and habitats used by black scabbardfish populations in the NE Atlantic at different life stages. Otolith contour shape and microchemistry, fatty acids, carbon and nitrogen stable isotopes, as well as steroid hormones are proposed as promising alternative tools for responding to this challenge. © 2013 EDP Sciences, IFREMER, IRD., This work was supported by the DCF – European Commission Fisheries Data Collection Framework, the EU project Management and monitoring of deep-sea fisheries and stocks (DEEPFISHMAN, Grant No. 227390), the Portuguese project Certificação MSC em Portugal: obtenção de conhecimento e estudos de viabilidade para candidaturas de pescarias costeiras e artesanais (CERTIFICA, PROMAR, 2011-2015), and a doctoral fellowship granted to I. Farias by Fundação para a Ciência e Tecnologia (SFRH/BD/64434/2009)

A risk–benefit assessment was performed in two marine resources of great importance in Southern Europe, i.e. black scabbard fish (Aphanopus carbo) and edible crab (Cancer pagurus), by determining the intake of Methyl-Hg, Cd, Se and EPA + DHA through the consumption of these species, as well as the associated probability of exceeding the tolerable weekly intakes (TWI; for Methyl-Hg and Cd) or dietary reference intakes (DRI; for Se and EPA + DHA). Average weekly intakes (AWI) were estimated by combination of the consumption frequencies in the Portuguese population and the concentration of each constituent. To estimate probabilities, two estimators were used: plug-in (PI) for higher probabilities and tail estimation (TE) based on the application of the extreme value theory to intakes distribution curves for lower probabilities. It was found that edible crab's white meat (meat from claws and legs) can be included on a well balanced diet, but black scabbard fish and edible crab's brown meat (mixture of gonads and hepatopancreas) should be consumed parsimoniously by adults and children.

The black scabbardfish is a deep water species of high commercial interest in the NE Atlantic. Specimens were collected from commercial trawls to the west of the British Isles and from longliners operating near Madeira between September 2008 and May 2010. Stomach content analysis was confined to samples from the northern area, because of a high number of empty stomachs from Madeira. Stable isotope analyses identified that black scabbardfish feeds on species with epipelagic and benthopelagic affinities. For the west of British Isles, the δN values were significantly different between seasons suggesting a change in the diet throughout the year. Black scabbardfish have higher δN and δC values compared with other co-occurring benthopelagic feeders and lower nitrogen values than the true benthic predators and/or scavengers. Comparison with stable isotope analysis in samples from Madeira indicated that black scabbardfish feed at a similar trophic level and has the same trophic niche width in both areas, assuming similar baseline isotope compositions. The diet in the northern area comprised fish (68% N), crustaceans (22% N) and cephalopods (15% N) with blue whiting ( Micromesistius poutassou ) constituting 40% of the prey. Seasonal shift in diet was observed, with a predominance of blue whiting (70%) in the first quarter of the year, shifting to a more diverse diet in the remainder of the year. These results indicate that the diet of black scabbardfish is closely linked with the seasonal migration of blue whiting and that they likely select prey in proportion to availability. This study demonstrates that the combined used of both methods can elucidate the trophic ecology of black scabbardfish, in situations where conventional methods alone provide insufficient data.

We develop a spatially and seasonally explicit bioeconomic model with three fleet dynamics processes built in endogenously. The model has been applied to the large French trawlers harvesting a medium-depth demersal stock, North Sea saithe (i.e., pollock, Pollachius virens), and a mix of deepwater species over a 10-year period (1999-2008), and the predictions have been contrasted with observations. The best overall fit was achieved where effort allocation was determined to be 80% by traditions and 20% by economic opportunism and where harvest efficiency increased by 8% a year. With this fleet dynamics parameterization, annual trends in fishing effort and profit were well reproduced by the model over the whole time period. Time series of the observed fishing effort by metier were generally well fitted by the model over the period 1999-2003, but less so over 2004-2008. The model also reasonably reproduced the catches by species over most of the time series, except for black scabbardfish (Aphanopus carbo)., Nous développons un modèle bio-économique spatial et saisonnier dans lequel trois processus caractérisant la dynamique des flottilles sont décrits de manière explicite. Ce modèle a été appliqué aux grands chalutiers français exploitant le lieu noir de mer du Nord (Pollachius virens) et une variété d'espèces profondes au cours d'une période de 10 ans (1999–2008), et les prévisions ont été contrastées avec les observations. Le meilleur ajustement est obtenu lorsque l'allocation de l'effort de pêche est déterminée a` hauteur de 80% par les traditions et 20% par l'opportunisme économique, et lorsque l'augmentation de l'efficacité de pêche est d'environ 8% par an. En paramétrant ainsi le module de dynamique des flottilles, les tendances annuelles de l'effort de pêche et du profit sont bien reproduites par le modèle sur l'ensemble de la période. Les variations temporelles de l'effort de pêche par métier sont généralement bien prises en compte sur la période 1999–2003, mais non sur la période 2004–2008. Le modèle ajuste les captures raisonnablement sur la plus grande partie de la période d'étude, pour toutes les espèces sauf le sabre noir (Aphanopus carbo).

The otolith was used to investigate the variability between Aphanopus carbo and Aphanopus intermedius inhabiting the north-eastern Atlantic Ocean. The results indicate a high degree of morphological affinity between species and areas; a noticeable metabolic change in the otolith shape was noted in the specimens of A. carbo, which may be related to migrations of individuals from shallow water (closer to the continental coast) to deeper water (archipelagos of Madeira and the Canary Islands). The results suggest a single population for both species in the north-eastern Atlantic Ocean, although not conclusively.

The deep-sea sharks associated as by-catch of the Madeiran midwater drifting longline fishery for scabbardfishes (Aphanopus spp.) were investigated by means of an experimental survey at 800-1200 m depth within the Canary Islands Exclusive Economic Zone, whose fishing grounds have been exploited during the past 15 years. Nine species of chondrichthyans were identified, belonging to five families: Pseudotriakidae, Centrophoridae, Etmopteridae, Somniosidae and Chimaeridae. Data on length, weight and sex ratio for the 436 chondrichthyan individuals caught in the March 2009 survey are given. Several voucher specimens of each species caught were deposited in the collections of the Natural History Museum of Funchal.

A total of 32 species were caught in surveys using Madeiran traditional longlines targeting the black scabbardfish (Aphanopus spp.) in the Canarian archipelago (northwest of Africa). Of these species, 15 belonged to the subclass Actinopterygii, 16 species to the Elasmobranchii, and one to the Holocephali. Species of the genus Aphanopus, the target species of this fishery, represented 38.5% of the catch in terms of the number of individuals and 36.4% in relation to the weight of the catch. The bycatch, which are non-target species of commercial interest, comprised only four species: two Teleostei species, Mora mora and Benthodesmus simonyi, which represented approximately 3.2% of the catch in number and 2.4% in weight; and two Elasmobranchii species, Centrophorus granulosus and Centrophorus squamosus, which represented 6.6% of the catch in number and 15.4% by weight. Deep-sea sharks were observed to be the most important component of the incidental catch (discarded species) of the traditional black scabbardfish longline fishery in the Canarian archipelago, representing 35.1% of the catch in number and 38.8% by weight. All of the Actinopterygii species were present in a proportion of less than 1%. The deep-sea shark species that were most frequent in the catches were Zameus squamulosus (44.9%), Deania hystricosa (14.7%), C. squamosus (13.5%), Centroscymnus coelolepis (6.7%) and Etmopterus princeps (5.1%). The ratio between the commercial catch (targeted species and bycatch) and the incidental catch was 1:1 in number of individuals. The ratio between the catch of the target species and the deep-sea sharks was 1:1 in number of individuals and in weight. The proportion of immature sharks constituted 31.7% of the total of all sharks caught.

Machete, M., Morato, T., and Menezes, G. 2011. Experimental fisheries for black scabbardfish (Aphanopus carbo) in the Azores, Northeast Atlantic – ICES Journal of Marine Science, 68: 302–308. In this study, we used fisheries observers' data to analyse and describe the experimental fishing of black scabbardfish in the Azores in terms of type of gear, fishing operation, catch per unit effort (cpue), and fish size compositions. Standardized catch in numbers per 1000 hooks varied from 103 to 210 fish with an overall average of 132 fish per 1000 hooks. Recorded cpue values were similar to those recorded for Madeira and mainland Portugal in early 2000 but were higher than those observed in mainland Portugal for recent years. Bycatch was similar to that observed for other longline fisheries but much lower than in the North Atlantic deep-water trawl fishery. Fish size composition showed differences between locations in the Azores. Fish in Pico and São Jorge/Graciosa were consistently smaller than in other areas sampled and this may reflect the occurrence of an additional species, Aphanopus intermedius, in this area as proposed by gene analyses. Black scabbardfish (of possibly two species) may be considered an alternative resource for Azorean fisheries. Based on experience from other scabbardfish fisheries, however, it is suggested that fishing mortality should be maintained at a low level, traditional fishing methods should be encouraged, and bycatch should be closely monitored. Future studies of biology and distribution, stock assessments, and fisheries management advice should take into account the probable occurrence of two very similar species in the area. This study also highlights the importance of maintaining the fishery monitoring programme for the black scabbardfish fisheries in the Azores.

SUMMARY: The sagittal otolith and eye diameter of two sympatric species of the genus Aphanopus, A. carbo and A. intermedius, from North Atlantic waters were investigated. The study objectives were to find morphometric variables of otoliths to identify the two species and relate ecomorphological characters of otolith and eye diameter to the depth distribution of each species. The otoliths of the two species are very similar, although significant differences in shape, otolith height and weight and the sulcus acusticus area were detected. The ratio between eye diameter and cephalic length (ED:CL ratio) was also significantly different. In both analyses A. carbo obtained higher values, which suggests that A. carbo and A. intermedius live in different spatial niches, and that A. carbo inhabits deeper waters. The ratio between the sulcus and otolith areas (S:O) was low compared to other fish species, which suggests that the hearing capacity of Aphanopus spp. is adapted to low frequency sound. This adaptation may be related to the oceanographic conditions in which these species live, and in particular to the characteristics of sound transmission in the “SOFAR channel”.

Priede, I. G., Godbold, J. A., Niedzielski, T., Collins, M. A., Bailey, D. M., Gordon, J. D. M., and Zuur, A. F. 2011. A review of the spatial extent of fishery effects and species vulnerability of the deep-sea demersal fish assemblage of the Porcupine Seabight, Northeast Atlantic Ocean (ICES Subarea VII). – ICES Journal of Marine Science, 68: 281–289. We review information from scientific trawl surveys carried out between 1977 and 2002 in the Porcupine Seabight and Abyssal Plain area of the Northeast Atlantic (240–4865 m water depth). Since the late 1980s, commercial bottom-trawl fisheries targeting mainly roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo), and orange roughy (Hoplostethus atlanticus) have been operating at depths of 500–1500 m, intersecting the depth ranges of 77 demersal fish species that would therefore be vulnerable to fishery effects. Comparisons of trawls pre-1989 and post-1997 indicate a significant decrease in total abundance of demersal fish down to 2500 m. Detailed analyses of the 15 most-abundant species showed that nine species with depth ranges within the commercial fishing depth have decreased in abundance. Other species were either not affected (Bathypterois dubius) or only affected at the shallow end of their range (Coryphaenoides guentheri). Species with a minimum depth of occurrence >1500 m (Coryphaenoides armatus and Coryphaenoides leptolepis) increased in abundance over part of their depth range. Decreases in abundance are probably caused by commercial fishing activities, an effect that is transmitted downslope by removal of fish at the shallow end of their depth range, resulting in declines at the deeper end of the depth range. The estimated fishery area is ca. 52 000 km2, but the potential impact probably extends to ca. 142 000 km2 and to many non-target species.

The intake of Cd, methyl-Hg, and Pb through consumption of black scabbardfish (BSF) (Aphanopus carbo) in Portugal as well as the associated probability of exceeding the respective provisional tolerable weekly intakes (PTWIs) was estimated. For this purpose, the contamination levels of heavy metals in this fish species were combined with constructed consumption scenarios or with a hypothesized consumption distribution. Whereas Cd and Pb posed no serious risk, the consumption of at least one portion of BSF per month as well as the hypothetical study in the Portuguese population produced nonnegligible probabilities of surpassing the PTWI for Me-Hg. Risk assessment for Portuguese consumers revealed a higher risk regarding Me-Hg, 1.19% and 1.81% with the plug-in (PI) and the tail estimation (TE) estimators, respectively. On the other hand, the risk for Cd and Pb was less than 1 in 100,000. TE was more realistic and accurate for Cd and Pb. Concerning Me-Hg, TE and PI estimators produced similar results. Furthermore, the limitations of a deterministic approach were shown.

The preparation of protein hydrolysates from black scabbardfish (Aphanopus carbo) by-products (BSB) was studied as an alternative for the upgrading of this raw material. Different levels of Protamex™ were used in the hydrolysate preparation and the peptides obtained and the lipids present in each of the four fractions obtained after centrifugation of the hydrolysed material were characterized. The nitrogen solubilization achieved was around 83% and degree of hydrolysis (DH) was about 57%. A high proportion of the peptides had molecular weights lower than 1000 Da. The highest percentage of oil remained in the emulsion (50–65%) and the highest percentage of free oil obtained was ca. 36%. The fatty acid profile of lipids present in the BSB and in the different fractions was similar. The triacylglycerols were dominant in all fractions and the highest percentage of phospholipids was detected in the oil from sludge and hydrolysate, followed by the emulsion but they were not present in the free oil. Cholesterol and cholesterol esters were detected in all fractions at low levels. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and the reducing power of BSB hydrolysates increased with increasing DH. However, the hydroxyl scavenging activity decreased with DH.

Total mercury (THg), cadmium (Cd) and lead (Pb) concentrations were investigated in muscle, liver and gonad tissue of black scabbardfish (Aphanopus carbo) from the southern northeast Atlantic at three Portuguese locations: the mainland and the archipelagos of the Azores and Madeira. Particular emphasis was placed on the comparison of metal levels between geographic locations. Other factors such as size, sex and sexual maturity were also investigated. The median concentrations (mg/kg ww) of THg showed a decreasing trend in the order liver>muscle>gonad. Cadmium levels decreased in the order liver>gonad>muscle and Pb levels decreased in the order gonad>liver>muscle. According to the EU limits, the concentration observed in some specimens, particularly those of THg, raises some food safety concerns. In all the tissues the concentrations of each toxic metal differed between locations. In particular: i) THg concentrations in specimens from Madeira were significantly higher than those from the Azores and the mainland; ii) Cd levels in specimens from the mainland were significantly higher than those from Madeira and the Azores; and iii) for all analysed tissues Pb levels were significantly higher in specimens from the Azores than in those from the mainland. The differences in toxic metal levels between locations were further discussed in relation to aspects of species dynamics and the influence of the main environmental features at each location.

sesimbra (Portugal) was followed for one year. the nutritional quality (proximate chemical composition, amino acid and fatty acid profiles, cholesterol and minerals) of raw, fried and grilled BsF was evaluated in one period of the year. BsF is a semi-fatty species, the protein content was 15-17.5% and the most abundant amino acids were glutamic acid, aspartic acid and lysine. the dominant fatty acids were monounsaturated (66%), followed by saturated (19%) and polyunsaturated (10%) ones. Potassium, phosphorus and sodium were the most abundant minerals. some dehydration occurred in cooked BsF but fat content was the most affected nutrient, particularly in fried fish. these results may suggest that the absorption of frying oil led to important changes in the fatty acid profile, and particularly in the linoleic acid level. the highest protein losses were recorded in fried BsF. in general, the nutritional quality of grilled fish

Though whole otoliths are commonly adopted in age assignment of black scabbardfish, this study showed that sectioned otoliths are more appropriate because growth increments are more evident and ageing of larger specimens is easier. Vertebrae are not the most appropriate structure for ageing but, in the absence of otoliths, this structure may be useful in age assignment of this species. To verify possible differences between age and growth among specimens from the southern NE Atlantic, 1075 sectioned otoliths from specimens from mainland Portugal, 436 from Madeira and 107 from the Azores were analysed and the distribution of length-at-age obtained for each sex and region was determined. Significant differences were obtained in the comparison of the distribution of length-at-age between Madeira, the mainland and the Azores. The von Bertalanffy growth model was applied to back-calculated mean length-at-age data from Madeira (Lt = 1586 [1 – e –0.119(t+2.282) ] females; Lt = 1461 [1 – e –0.146(t+1.441) ] males) and mainland (Lt = 1354 [1 – e –0.170(t+2.040) ] females; Lt = 1240 [1 – e –0.208(t+1.654) ] males), and significant differences in the growth equations were obtained. Furthermore, a regression tree model was used to investigate how growth is conditioned by reproduction. The results showed a clear separation between individuals from the two areas, both females and males from the mainland (non-reproductive individuals) being characterised by a lower gonadosomatic index and a lower age.

Black scabbardfish stock structure is still unknown in European waters where, due to the scarcity of biological information, the ICES considers that there is a single stock unit. This study is the final outcome of a scientific project that applies a holistic approach to research on the population structure of the black scabbardfish and aims to define the most appropriate strategy for the conservation of this resource in southern NE Atlantic waters. The factors studied include life history parameters, otolith shape analysis, parasites, landings-and-effort data and contaminants. Sampling was conducted between 2005 and 2007 in three areas of the southern NE Atlantic: mainland Portugal, Madeira and the Azores. The mainland and the Azores have an established commercial fishery, whereas the Azores has only an exploratory fishery. The majority of results indicated the existence of different stocks of black scabbardfish in the study area. Of the 8 parameters, 6 were in agreement with separate stocks between the mainland and Madeira, 5 were in agreement with separate stocks between the mainland and the Azores, and 4 were in agreement with separate stocks between Madeira and the Azores.

Gonads of the NE Atlantic black scabbardfish were examined to give an insight into the reproductive biology of this species. It was concluded that black scabbardfish had determinate fecundity because: (i) a distinct hiatus in oocyte size was observed between pre-vitellogenic and vitellogenic oocytes; (ii) vitellogenic oocytes increased in size during the spawning season; (iii) the number of vitellogenic oocytes did not increase during the spawning season; and (iv) the intensity of atresia was low in pre-spawning and spawning ovaries. Fecundity estimates ranged from 73 to 373 oocytes g-1 female. Comparison of developing ovaries from mainland Portugal and Madeira revealed that those from Madeira were more advanced in development, with more cortical alveoli stage oocytes and a higher gonadosomatic index. Starting in July, the reproductive development of all females from mainland Portugal was interrupted by a generalised atresia of developing oocytes. Completion of gametogenesis and spawning only occurred for fish from Madeira but some fish from this area also failed to complete oocyte development due to mass follicular atresia of vitellogenic oocytes. The percentage of Madeiran fish that failed to spawn due to follicular atresia ranged from 21.2% in 2006 to 37.4% in 2005.

Aphanopus carbo, black scabbardfish, specimens from 3 Portuguese regions (the mainland, Madeira and the Azores) during four (mainland and Madeira) or two (Azores) seasons of the year were examined for the presence of Anisakis. All the fish examined (n=287) were infected with Anisakis L3 larvae (prevalence = 100%). Significant geographical differences in intensity were found: the Azores showed the lowest mean intensity value (53.7) and Madeira the highest one (253.9). The intensity of infection was positively correlated with the host length in specimens of Sesimbra and Madeira. Significant seasonal differences in intensity were found in the studied regions. The very high values in prevalence and intensity strongly suggest that the consumption of raw or undercooked black scabbard fish is a potential risk for human health.

For several decades, the black scabbardfish ( Aphanopus carbo , Lowe 1839) has been a valuable resource for fishing communities in Madeira and more recently for those in mainland Portugal. The evaluation of the species’ exploitation status was conducted only in the late 20th century and separated for the two areas of the Portuguese Exclusive Economic Zone (EEZ). Nowadays, species stock assessment studies are usually conducted in the framework of scientific working groups from regional fisheries organizations: ICES analyses data from the fishery operating in continental waters, whereas CECAF deals with the data pertaining to the Madeiran fishery. This paper presents the first attempt to combine the information available from the two longline fisheries targeting black scabbardfish in Portuguese waters in one single analysis. A description of the two fleets’ technical characteristics was conducted and a unique model was developed for the standardization of the fishing effort aimed at the species in the Portuguese EEZ. From this model, weekly landings-per-unit-effort time series were estimated by region for the period 2005-2007 and compared using a non-parametric statistical test. Percentages of discarded species, in number and weight, were calculated and reveal consistently low figures. These discards seem to depend on the number of hooks, soaking time and depth.

We studied the use of parasites as biological tags for discriminating fish stocks of Aphanopus carbo (Osteichthyes: Trichiuridae) from Portugal (Sesimbra on the mainland, Madeira and the Azores). Sixteen different metazoan parasites were found (14 from Madeira, 9 from Sesimbra and 7 from the Azores). Some parasites occurred only in fish from Madeira. The prevalence and mean intensity of the infection was recorded for each parasite and locality, and their values were statistically compared between the three sampling localities and related to host length classes. The differences between some of these parameters were statistically significant among the three localities or between two of them. It is suggested that 6 parasites (Tentacularia coryphaenae, Sphyriocephalus tergestinus, Campbelliella heteropoeciloacantha, Anisakis spp., Bolbosoma vasculosum and unidentified Acanthocephala larvae) can be used as biological tags to discriminate Portuguese stocks of Aphanopus carbo. Se estudió el uso de parásitos como marcadores biológicos para discriminar los stocks de Aphanopus carbo (Osteichthyes, Trichiuridae) de Portugal (Sesimbra en el continente, Madeira y Azores Islas). Dieciséis parásitos metazoarios fueron encontrados (14 en Madeira, 9 en Sesimbra y 7 en Azores). Algunos parásitos se presentaron sólo en Madeira. La prevalencia y la intensidad media de las infecciones fueron calculadas para cada parásito y cada región, y sus valores fueron comparados estadísticamente entre los tres lugares de muestreo, y relacionados con la talla del huésped. Se encontraron diferencias estadísticamente significativas entre algunos de estos parámetros de las tres regiones o entre dos de ellas. Se sugiere que 6 parásitos (Tentacularia coryphaenae, Sphyriocephalus tergestinus, Campbelliella heteropoeciloacantha, Anisakis spp., Bolbosoma vasculosum y larvas no identificadas de Acanthocephala) pueden ser usados como marcadores biológicos para discriminación de stocks de Aphanopus carbo de Portugal.

The main biological characteristics for black scabbardfish in the Canary Islands waters were established, focusing on its reproductive behaviour and strategy and its growth pattern. The sex proportion differs significantly from the 1:1 ratio, being clearly unbalanced towards the females. The sex ratio according to depth clearly shows the presence of male and female individuals in all the studied layers, thus sex segregation does not happen according to depth. The Canaries can be considered to be a reproduction site for A. carbo , since samples showing all stages of maturity have been observed. The gonadosomatic index (GSI) showed that the mean values were higher in the third and fourth quarters of the year. The index values clearly allow the differentiation of the individuals in resting or in spent (II and V) stages from individuals in ripe or in ripe and running stages, indicating that index levels higher than 2 are typical of maturation followed by spawning process. Up to twelve marks, assumed to be annuli, were visible in the sampled otoliths. Three to five years old were the dominant age classes and only 7.7% of fish were 7 years old or older. Age estimates ranged between 2 and 8 years for males and between 2 and 12 years for females. Estimated growth parameters were: L ∞ = 1477 ± 18.73 mm; k = 0.200 ± 0.016 year −1 ; and t 0 = −4.58 ± 0.413 year. Biological aspects of the black scabbardfish suggest that this species has a generalist life-history strategy.

The black scabbardfish is a deep-sea teleost species with high commercial interest in the NE Atlantic. While it is caught by large offshore trawlers in the North of Europe, in the south it is captured by artisanal longlines. On the Portuguese continental slope, in the south of ICES Division IXa, a longline fleet has been engaged in the capture of black scabbardfish for more than 20 years. This paper reviews and analyses the features of this fishery from a temporal perspective based on information from different data sources. The fishery is based on the port of Sesimbra, where a family type fishing community strives to keep catches profitable without altering the artisanal features that characterizes the fleet. Although the fleet has experienced some technical improvements through time, the fishing operations and strategy have changed very little. Fishing occurs at particular areas on the slope, where individual vessels have their own fishing grounds. Annual landings surpassed 4,000 tonnes in the early 1990’s, but decreased to nearly 3,000 tonnes and have remained at this level since 2000. The length structure of the landings was stable from 2000 to 2005, with a modal (total length) class of 1,090 mm. Monthly landings per unit effort estimated by a generalized linear model did not present any marked trend for the period 2000–2004. The landings reported in mainland Portugal were compared with the ones from other regions of the ICES area and the different characteristics of the fisheries operating in the north and south of Europe were analysed.

Results of observations from the underwater inhabited device “Sever-2” of the behavior and distribution of fish on seamounts of the Azores region up to a depth of 1200 m are provided. In the natural habitat, 52 species of fish of 46 genera belonging to 36 families were recorded. In the ichthyofauna of the studied region, bottom (37.0%) and near-bottom (29.2%) species dominate; the proportion of off-bottom and off-bottom-pelagic species is 18.0 and 12.4%, respectively, and pelagic species account for only 3.4%. Pelagic species Scomber japonicus and Trachurus picturatus; off-bottom-pelagic Beryx splendens, Lepidopus caudatus, and Aphanopus carbo; and near-bottom species Zenopsis conchifer, Macrorhamphosus scolapax, Antigonia capros, Capros aper, Anthias anthias, and Callanthias ruber dominate by numbers and the amount of biomass.

Aphanopus carbo fishery is economically relevant in Portugal (Madeira Archipelago) since the 19th century and an important diet component of its inhabitants. However, Hg levels in this species are a cause of concern due to the insufficient knowledge of Hg subcellular distribution, accumulation and detoxification mechanisms. Hg concentrations (total and subcellular) and metallothionein-like proteins (MTs) were measured in the gills, muscle and liver of A. carbo of different size (50-150 cm) to assess Hg subcellular distribution and the role of MT in Hg binding. Total Hg concentrations in A. carbo decrease from liver to gills and increase exponentially with fish length in all tissues. Hg subcellular distribution in muscle and liver decreased from insoluble > high molecular weight proteins and heat-treated cytosol where MT occurs highlighting the role of the insoluble fraction in Hg distribution. In the gills, Hg was mainly in the soluble fraction except for 75-100 cm specimens, whose Hg distribution was similar between soluble and insoluble factions. The variation of MT with size is different from that of Hg. MT levels in the gills decrease with size/age and is unrelated with Hg concentrations. In the muscle although decreasing with size/age, MT is inversely proportional to Hg. In the liver, however, MT is directly proportional with size/age and to the Hg accumulated (total and HTC subcellular fraction) highlighting an age related change in these two parameters and the importance of MT in detoxifying Hg in this tissue. Due to Hg concentrations present in the muscle (used for human consumption) and liver (consumed mainly by fisherman) consumption of A. carbo should be taken with caution in a population with such an important seafood weekly intake. info:eu-repo/semantics/publishedVersion

Total mercury, cadmium and lead concentrations were measured in black scabbard fish (Aphanopus carbo), caught off Madeira and the Azores archipelagos (Portugal). The metal contents were expressed in mg kg(-1) wet weight. The mean mercury levels in liver were 4.50 and 2.37 whereas, in skin, such values were 0.59 and 0.36 (Madeira and Azores, respectively). Onaverage, the muscle content was around 0.9 in fish from both areas. Cadmium maximum levels in muscle and skin were found in Azores samples (0.09 and 0.11, respectively). Mean lead contents in all samples were always below than 0.10. In general, the results obtained did not allow the establishment of any relationship between metal accumulation and fish weight or length. According to the permissible WHO and FAO levels, these results, suggest that this species does not represent a risk for human consumption if the liver is excluded and the edible part consumed with moderation. (c) 2006 Elsevier Ltd. All rights reserved.

The deep-sea environment is a sink for a wide variety of contaminants including heavy metals and organic compounds of anthropogenic origin. Life history traits of many deep-water fish species including longevity and high trophic position may predispose them to contaminant exposure and subsequent induction of pathological changes, including tumour formation. The lack of evidence for this hypothesis prompted this investigation in order to provide data on the presence of pathological changes in the liver and gonads of several deep-water fish species. Fish were obtained from the north east region of the Bay of Biscay (north east Atlantic Ocean) by trawling at depths between 700 and 1400 m. Liver and gonad samples were collected on board ship and fixed for histological processing and subsequent examination by light microscopy. Hepatocellular and nuclear pleomorphism and individual cases of ovotestis and foci of cellular alteration (FCA) were detected in black scabbardfish (Aphanopus carbo). Six cases of FCA were observed in orange roughy (Hoplostethus atlanticus) (n = 50) together with a single case of hepatocellular adenoma. A wide variety of inflammatory and degenerative lesions were found in all species examined. Deep-water fish display a range of pathologies similar to those seen in shelf-sea species used for international monitoring programmes including biological effects of contaminants. This study has confirmed the utility of health screening in deep-water fish for detecting evidence of prior exposure to contaminants and has also gained evidence of pathology potentially associated with exposure to algal toxins.

Black scabbardfish (Aphanopus carbo Lowe, 1839) is a widely distributed species across the Atlantic ocean. In Portuguese mainland waters the existing specimens are immature (not able to reproduce). It is admitted that they have migrated from the West of the British Isles and that they remain in the area for some years, until they attain an adequate size or physiological conditions which allow them to migrate and reproduce elsewhere.The present study aims to model the dynamics of the population of black scabbardfish living in the International Council for the Exploration of the Seas Division IXa, for which disaggregated data are available, although within the context of a larger population. With this purpose, a state-space model is used, which enables the estimation of the unknown abundance (latent process) by exploring its dependency relationship with the observational data on the species fishing landings in that area. The population is partitioned into length groups and the population evolution process is subdivided into biological related subprocesses.The estimation is achieved within a Bayesian paradigm, where all the available biological information is incorporated in the prior distributions of the parameters of the subprocesses. Later, short-term trajectories of the population living in IXa are studied, via simulations that are constructed based on different management scenarios.

Black scabbardfish (Aphanopus carbo), a commercially valuable marine fish off Portugal and the Madeira Archipelago, was surveyed for mitochondrial DNA variation of part of the cytochrome b gene. In all, 51 fish from three Northeast Atlantic localities were examined using ten restriction enzymes. Overall nucleon diversity was 0.180. Genetic differentiation (θ=0.25) was significant; the Madeira Archipelago sample was distinguishable from samples from the other two localities. The approach should be useful for a more extensive study of black scabbardfish populations.

Larval stages of Anisakis spp. (Nematoda: Anisakidae) were found encapsulated or free in the viscera and abdominal cavity of the black-scabbard fish, Aphanopus carbo, chub mackerel, Scomber japonicus and oceanic horse mackerel, Trachurus picturatus in Madeiran waters. The prevalence of infection reached 97.2% (n=142) for A. carbo, 69.5% (n=154) for S. japonicus and 62.5% (n=40) for T. picturatus. Considerable differences in parasite intensities between A. carbo and both S. japonicus and T. picturatus were found, with mean intensities up to 69.6 in A. carbo, while in the other two fish hosts the intensity reached only a maximum of 2.6. These differences were probably due to different feeding behaviours of the hosts. Intensities of Anisakis sp. in A. carbo were high irrespective of sex and season. No relationship between host length and prevalence of infection was observed for A. carbo, while for S. japonicus a weak positive significant relationship was found.

Black scabbardfish is a deep-water species, common in the NE Atlantic at depths between 450 and 1300 m, currently exploited by some European countries. Between May 1998 and April 2000, specimens collected at three different locations in the NE Atlantic—NW of Scotland, Sesimbra (mainland Portugal) and Funchal (Madeira)—were analysed. The evolution of maturity of both sexes throughout the year was studied based on the macroscopic and microscopic analysis of the gonads. Specimens with the largest total length were found in Funchal, whereas the smallest size was recorded in the NW of Scotland. Neither spawners nor post-spawners were ever observed in NW of Scotland and Sesimbra. In Sesimbra, only a few individuals attained pre-spawning stage and most of the early developing females exhibited atresia in their ovaries. In Funchal, all the maturity stages were found; spawners occurred from September to December (females) and from August to December (males). Length of first maturity for females was estimated to be around 1000 mm. Two groups of spawners with different sizes were observed during the spawning period off Madeira.

To facilitate intercalibration of the age readings of black scabbardfish, Aphanopus carbo, a collection of otoliths was exchanged among the participating laboratories in Portugal, Scotland, and Spain and a workshop was held to discuss the results. The age precision was significantly improved by the intercalibration exercises but remained relatively low. The indirect validation methods applied showed that the growth increments used for age determination were consistent. However, some discrepancies were found between otoliths from different areas, probably due to the complex spatial distribution of the species and the differing length structure, depending on the area and the method of fishing. Interpretation criteria were defined pending more definitive validation studies.