The Southern Ocean and South Pacific Region

The Region comprises three sub-regions (FAO Statistical Areas) with very different characteristics. The South Pacific includes the vast and virtually unpopulated Southern Ocean surrounding the Antarctic. It has the world’s largest fisheries off Peru and Chile and some of the world’s best managed fisheries in Australia and New Zealand. The Region has over 27% of the world’s ocean area and over 98% of the Region’s total area of 91 million km2 is ‘open ocean’. The Region contains less than 5% of the global continental shelf area and only a fraction of this area is covered by three large marine ecosystems (the New Zealand Shelf, the Humboldt Current and the Antarctic large marine ecosystems (LMEs). The Humboldt Current System (HCS) is the world’s largest upwelling which provides nutrients for the world’s largest fisheries. The Region also has a high number of seamounts. The marine capture fisheries of the Region produce over 13 million tons annually and an expanding aquaculture industry produces over 1.5 million tons. Peru’s anchoveta fishery provides about half the world’s supply of fish meal and oil, key ingredients of animal and fish feeds. El Niño Southern Oscillations (ENSOs), known more generally as El Niños, can substantially change the species composition of the key small pelagic catches (anchovy, sardine, horse mackerel and jack mackerel) causing production to fluctuate from about 4-8 million tons. Partly due to the lack of upwelling and shelf areas, fisheries production in the Southern Ocean and Area 81 is relatively small but supports economically important commercial and recreational fisheries and aquaculture in New Zealand and in New South Wales (Australia). Krill remains a major underexploited resource, but is also a keystone species in the Antarctic food web. The Region is home to numerous endangered species of whales, seals and seabirds and has a high number of seamounts, vulnerable ecosystems fished for high-value species such as orange roughy.

Construcción de índices de biomasa para los recursos anchoveta (Engraulis ringens) y jurel (Trachurus murphyi) del Ecosistema de afloramiento peruano usando modelos empíricos basados en información acústica

Los principales recursos pesqueros pelágicos de interés económico en el Perú son anchoveta (Engraulis ringens), jurel (Trachurus murphyi) y caballa (Scomber japonicus) [3]. Para su evaluación, se lleva a cabo cruceros de evaluación acústica en los que se integra información de ecoabundancia y proporción de tallas por especie para obtener valores de biomasa y abundancia. Sin embargo, para especies no objetivo (como jurel), dichos valores resultan poco confiables por la lejanía entre los puntos de muestreo biométrico y acústico. Para resolver este inconveniente, el presente trabajo propuso utilizar modelos empíricos (de tipo GAM y GLM) integrando variables ambientales y de seguimiento de desembarques con la finalidad de generar índices relativos y absolutos para anchoveta y jurel en el período de 1996-2013 dentro del área de las 200 mn frente a la costa peruana. Los resultados obtenidos realzaron la importancia de los lances de comprobación para la obtención de estimaciones robustas de biomasa. Así mismo, se observó que, para anchoveta, los modelos empíricos sí produjeron un buen índice relativo y absoluto, mejorando la utilización de la ecoabundancia por sí sola. Para jurel, sin embargo, el modelo final calibrado resultó en la obtención de un mejor índice relativo. Se recomienda además, la obtención de información de tallas y pesos medios de desembarques para jurel con la finalidad de mejorar las estimaciones de biomasa y abundancia.

Contribuição para a avaliação da dieta do golfinho-comum (Delphinus delphis) na costa continental portuguesa

O golfinho-comum (Delphinus delphis) é uma das espécies de cetáceos mais abundantes e mais amplamente distribuídas em todo o planeta, sendo a espécie mais abundante ao longo da costa continental portuguesa. Algumas das suas principais presas apresentam um elevado interesse comercial estando por isso, muitas vezes, associado a capturas acidentais em artes de pesca. Contudo, estudos mais recentes sobre os hábitos alimentares desta espécie na costa portuguesa são escassos. Assim, este estudo visa contribuir para a avaliação da ecologia alimentar deste cetáceo na costa portuguesa através de índices de importância numérica, ocorrência e do peso estimado, permitindo descrever a dieta não só em termos qualitativos, mas também em termos quantitativos. Foram examinados os conteúdos estomacais de 55 golfinhoscomuns arrojados na costa continental portuguesa (norte e centro) entre 2004 e 2015. De um total de 6699 presas identificadas, 66% pertenciam à classe dos peixes, 32% eram cefalópodes e 3% eram crustáceos. As espécies-presa de peixes mais importantes em termos de importância numérica foram os góbios (Gobiidae) e o carapau (Trachurus sp.). Em relação à ocorrência foram o góbio (Gobiidae) e a sardinha (Sardina pilchardus), seguidas de carapau, as espécies predominantes. Relativamente ao peso, a sardinha foi a espécie-presa predominante, seguida de faneca (Trisopterus luscus) e carapau. Quanto aos cefalópodes, a lula-bicuda (Alloteuthis sp.) foi a espécie mais importante, tanto em termos de importância numérica como em termos de ocorrência. A lula-comum (Loligo sp.) foi a mais importante em termos de peso total estimado. As espécies demersais dominaram a dieta do golfinho-comum, com uma percentagem numérica de 40%. Foram detetadas diferenças entre machos e fêmeas na composição da dieta relativamente à sardinha. Foram detetadas diferenças entre indivíduos maturos e imaturos na composição da dieta relativamente à lula-bicuda. A diversidade de presas observada nos conteúdos estomacais do golfinho-comum sugere um comportamento oportunista, consumindo as presas mais abundantes, localmente. As interações com as artes de pesca podem levar a uma elevada mortalidade destes mamíferos marinhos. Deste modo, a realização de estudos sobre os hábitos alimentares de cetáceos permitem uma melhor compreensão das possíveis interações com a pesca, e a melhoria de estratégias de conservação para evitar a morte destes animais.

Report of the Stock Identification Methods Working Group (SIMWG) 2016

The Stock Identification Methods Working Group (SIMWG) worked by correspondence in 2016. The working group was chaired by Lisa Kerr (USA). The work plan for SIMWG in 2016 comprised four Terms of Reference (ToR), some of which are continuing goals for SIMWG: a ) Review recent advances in stock identification methods; b ) Build a reference database with updated information on known biological stocks for species of ICES interest; c ) Provide technical reviews and expert opinions on matters of stock identifica-tion, as requested by specific Working Groups and SCICOM; d ) Review and report on advances in mixed stock analysis, and assess their po-tential role in improving precision of stock assessment. ToR a) is an ongoing task of SIMWG in which we provide a comprehensive update on recent applications of stock identification techniques to ICES species of interest, summa-rize new approaches in stock identification, and novel combinations of existing applica-tions. ToR b) is a multi-annual ToR in which SIMWG has taking steps to build a reference data-base consisting of SIMWG reviews of issues of stock identity for ICES species. ToR c) is a key ongoing task by SIMWG in which we addresses specific requests by ICES working groups for technical advice on issues of stock identity. This year we provided advice on mackerel in the Northeast Atlantic as requested by WGWIDE. ToR d) is a multi-annual ToR that is focused on tracking developments in the application of mixed stock analysis and the integration of this information into assessment and management.

Diet of the blue marlin, Makaira nigricans, off the south coast of Portugal

The blue marlin, Makaira nigricans (Istiophoridae), is a large, top predator with a worldwide distribution whose feeding ecology is still unknown in the northeast Atlantic. The stomach contents of 24 Atlantic blue marlin, caught by the Big Game fishing fleet (between 2007 and 2010) off the south coast of Portugal, were studied. All marlin fed exclusively on pelagic fish, with a total of 180 prey items recorded, belonging to 6 identified species. The most important family in the blue marlin diet was Scombridae, representing 70% of the total prey items. Among the Scombridae, the chub mackerel, Scomber colias, was the most important prey species (47.9% by weight, 51.1% by number, 58.3% by frequency of occurrence). The length of prey found in the stomachs ranged from 136 to 727 mm in length, and a significant positive correlation was found between prey and blue marlin size. Our results suggest that in this geographical area (NE Atlantic) marlin feed on a small spectrum of species, with a preference for foraging on seamounts.

Size selectivity of diamond and square mesh cod ends for four by-catch species in the crustacean fishery off the Portuguese south coast

The effects of an increase in cod end mesh size from 55 to 60 and 70 mm and a change of mesh configuration from 55 mm diamond to 55 turn square mesh on the size selectivity of four by-catch species (the red shrimp Aristeus antennatus, the European hake Merluccius merluccius, the horse mackerel Trachurus trachurus and the blue whiting Micromesistius poutassou) commonly captured in the crustacean fishery off the Portuguese south coast, were evaluated. Selectivity parameters for blue whiting, the most abundant species in the catches, were estimated taking into account between-haul variation, while for the remaining species, captured in much lower quantities, the selectivity estimates were based on pooled data by length class for all hauls within the same cod end. Length at 50% retention, L-50, was found to increase with mesh size and with the change in mesh configuration for all the studied species. For blue whiting trawling depth and cod end catch were found to play a role in between-haul variation by increasing L-50 as well. The results suggest that an increase in the current minimum mesh size of 55-70 mm would be advisable to be compatible with the minimum landing sizes (MLSs) of 29 mm carapace length and 27 cm total length for red shrimp and hake, respectively, while it would greatly reduce the amount of discards, particularly those for blue whiting, that accounted for approximately 50% of the total catch weight. Horse mackerel was the only species for which the use of a larger mesh size would result in a significant escapement of individuals above the MLS of 15 cm. (C) 2002 Elsevier Science B.V. All rights reserved.

Environmental influence on commercial fishery landings of small pelagic fish in Portugal

Small pelagic fishes are particularly abundant in areas with high environmental variability (zones of coastal upwelling and areas of tidal mixing and river discharge), and because of this, their abundance suffers large inter-annual and inter-decadal fluctuations. In Portugal, the most important species in terms of landings are European sardine, Atlantic horse mackerel and Atlantic chub mackerel. Small pelagic fish landings account for 62.8 % of the total fish biomass and represent 32.7 % of the economical value of all catches. We have investigated trends in landings of these small pelagic fishes and detected the effects of environmental factors in this fishery. In order to explain the variability of landings of small pelagic fishes, we have used official landings (1965-2012) for trawling and purse seine fisheries and applied generalized linear models, using the North Atlantic Oscillation index (NAO) (annual and winter NAO index), sea surface temperature (SST), wind data (strength and North-South and East-West wind components) and rainfall, as explanatory variables. Regression analysis was used to describe the relationship between landings and SST. The models explained between 50.16 and 51.07 % of the variability of the LPUE, with the most important factors being winter NAO index, SST and wind strength. The LPUE of European sardine and Atlantic horse mackerel was negatively correlated with SST, and LPUE of Atlantic chub mackerel was positively correlated with SST. The use of landings of three important species of small pelagic fishes allowed the detection of variations in landings associated with changes in sea water temperature and NAO index.

Effects of hook and bait on targeted and bycatch fishes in an equatorial atlantic pelagic longline fishery

We examined the effects of different hook style and bait type combinations on the catches of targeted, bycatch, and discarded fishes in equatorial Atlantic waters. In total, 221 longline sets (>305,000 hooks) were deployed from Portuguese pelagic longline vessels (SELECT -PAL Project) during the February–October fishing season. Three different hook styles and two bait types were tested: the traditional J-hook was compared to two circle hooks (one non-offset and one with 10° offset), and squid bait was compared to mackerel. Catch per unit effort (CPU Es) were calculated and compared between the different hook style and bait type combinations, which indicated that the effects of hook style and bait on the CPU Es were species-specific. For example, swordfish CPU Es were higher with J-hooks baited with squid, while for targeted tunas and blue shark only the bait effect was significant, but with opposite effect (i.e., higher catches of tuna with squid bait and higher catches of blue shark with mackerel bait). For the discarded species, at-haulback mortality was also species-specific. Proportions of alive vs dead specimens at time of fishing gear retrieval did not vary significantly by hook style or bait type combinations. The total retained catch was analyzed in value per unit effort (VPU E), and indicated losses in fishery revenue when mackerel was used instead of squid, but not when circle hooks were used instead of J-hooks.