Search

A collection of 4770 histological slides collected in NAFO divisions 3LMN in a depth range from 200 to 1500 m and covering a time period between 2001 and 2015, has been reviewed to obtain information on reproductive biology of Macrourus berglax. Especial attention has been paid in atresia because its potential impact on stock productivity. Spatial and temporal variability of size and age at maturity of female roughhead grenadier was analyzed in NAFO divisions 3LMN based on microscopic maturity staging and individual age readings. Spawning capable females are homogeneously distributed nearly year-round, but in scarce numbers what prevent to define a spawning season. This statement united to the high levels of atresia could indicate a reproductive migration. We observed a clear decrease in length at first maturity (L50) of females from 27.8 cm in the period 2005-2011 to 25.6 cm in the last four years. The age at first maturity, A50, varied between 13.1 and 15 years, and there is not an evident trend of change over the years., SI

Since 2003, a stratified random summer bottom trawl survey was conducted by Spain in the NAFO Regulatory Area of Division 3L (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen 1800. Entire series of mean catches, biomass and length distribution for Greenland halibut, American plaice and witch flounder are presented for the period 2003-2015. Greenland halibut biomass and abundance estimates show an increasing trend since 2011, reaching the maximum values in the series in 2008 and 2014. In last years it can be seen a presence of juveniles (around 12-15 cm). American plaice biomass and abundance estimates present an increasing trend since 2010, reaching in 2015 the highest value in the series. Regarding witch flounder, the biomass and abundance increased in 2015, but there is no a clear trend in the whole period 2003-2015., SI

The Spanish Institute of Oceanography carried out in 2016 two bottom trawl surveys in the NAFO Regulatory Area in Division 3NO and 3L during the months of June and August respectively. The results on Northern shrimp (Pandalus borealis) are presented and compared with those from previous surveys from the same series. As recent years in 2016 the shrimp catch (0.385 kg.) and estimated biomass (2.36 t.) in Divisions 3NO remain between the lowest of the series, confirming the decrease of shrimp importance from 2004. Northern shrimp catches in 3L Division have declined from 2009; however, in 2016 a significant increased of the catches was noted (3418 kg.). The biomass estimated in 2016 (20125.2 t.) remain between the lowest values in the historical series., SI

The Spanish Institute of Oceanography carried out in 2014 two bottom trawl surveys in the NAFO Regulatory Area in Division 3NO and 3L during the months of June and August respectively. The results on Northern shrimp (Pandalus borealis) are presented and compared with those from previous surveys from the same series. As recent years in 2014 the shrimp catch (2.75 kg.) and estimated biomass (15.54 t.) in Divisions 3NO remain between the lowest of the series, confirming the decrease of shrimp importance from 2004. In a similar way, northern shrimp indices estimated from 2014 in 3L Division declined 40% with respect to 2013 and confirm the downward trend initiated in 2009. The biomass estimated in 2014 (10846 t.) was the second lowest in the historical series.

This paper shows CPUEs of Loligo gahi and Illex argentinus by Spanish vessels operating in the SW Atlantic from 1988 to 2001. The analysis of the raw data in a haul-by-haul basis indicated that the maximum CPUE for Loligo was obtained on the High Seas in March 2001 (6,372 kg/h), whereas for Illex, it reached 15,000 kg/h also on the High Seas in May 2001 (Division 42º S). Maximum mean monthly CPUE for Loligo almost reached 2,000 kg/h during August and September 2000 to the South of the Falklands (MS), as well as for Illex, a maximum value of around 2,700 kg/h was observed in February 2000 in Division 46º S. Both species are highly influenced by the oceanographic conditions of the area. Shortfin squid (Illex argentinus) performs yearly large migratory movements from the South of Brazil to Falklands, maybe related to its life cycle. Patagonian longfin squid (Loligo gahi) is more confined to a relative small area within Falklands waters, named Loligo-box, but with great explosions of abundance in Autumn (March to May). The seasonality observed in catches may be related to seasonality in fishing behaviour, abundance and/or in recruitments (Portela et al, 2002).

Feeding habits of 7995 individuals of three wolffish species distributed in the north Atlantic were analyzed: 1016 of northern wolffish (Anarhichas denticulatus), 4783 of Atlantic wolffish (A. lupus) and 2196 of spotted wolffish (A. minor). The individuals sampled were taken in the NAFO Area Divisions 3NO in spring in the period 2002-2005, Div. 3L in summer in the period 2003-2004, Div. 3M in summer in the period 1993-2005, and in the ICES Area Div. IIb in autumn in the period 2004-2005. Feeding intensity was higher in the NAFO Area than in the northeast Atlantic (spring-summer vs. autumn), mainly in spotted wolffish in Div. 3M. The importance of each prey taxa was evaluated using the weight percentage. Wolffish species diet showed geographical differences. Ontogenic diet changes and prey variation through the studied period were observed, mainly in Atlantic and spotted wolffishes. This two species preyed primarialy on bottom (echinoderms, gastropods and bivalves) and benthopelagic (northern shrimp and redfish) organisms on Flemish Cap and Grand Bank. However fish and northern shrimp predation were more important on the Flemish Cap, mainly in spotted wolffish, showing periods with higher predation on these prey when the biomass of these prey species increased. This fact might have been the cause of diet overlap between Atlantic and spotted wolffishes in some periods in Div. 3M. Less ontogenic, annual and geographical diet variations were found in northern wolffish in NAFO Area, feeding mainly on ctenophores; however in Svalbard area, this species showed to be highly piscivore. Three species showed cannibalism but only in the Div. 3M.

A review of the species composition, distribution and abundance of sharks in both the Spanish commercial catches (1991-98) and research surveys (1988-98) are carried out. Shark species are by-catches of Greenland halibut fishery. The proportion of shark species in the total catch is small and the main retained species is the black dogfish, whereas the main discard is the boreal shark. Since 1996 the retained proportion of black dogfish increase notably, as well as the proportion of total sharks. In the surveys this shark is the species with the highest biomass index. Black dogfish is found in the deepest waters. The length range of black dogfish is mainly between 50 and 80 cm, with a mode about 62-63 cm. No evident geographic pattern in the length distribution is observed during the studied period.

Length-at-maturity estimates of yellowtail flounder (Limanda ferruginea) based on data collected in the spring Spanish surveys in the NAFO Regulatory Area of Divisions 3NO are presented. Female length at 50% maturity (L50) decreased from 35 cm in 1995 to 23 cm in 1998. IN males, this parameter decreased from 23 cm in 1995 to 19 cm in 1998. The differences in L50 estimates in females were significant between 1997 and the previous years, and between 1998 and both 1996 and 1995, and were not significant between 1997 and 1998. In males, differences were significant between all the years, except between 1997 and 1998. The covariance analysis between the linearized maturity curves was highly significant in both sexes.

This document updates some of the indices for northern shrimp (Pandalus borealis) harvested within NAFO Divisions 3M. The assessment for this resource was completed, within Scientific Council during autumn 2010. Scientific Council recommended that the fishing mortality for 2011 and 2012 be set as close to zero as possible. Now, the low indices of biomass estimated in the 2011 EU summer survey, where the stock size was well below Blim proxy, confirm the depletion of the stock after several years of downward trend, even though the levels of exploitation have been low since 2005 and close to zero in 2011, due to the moratoria initiated in the present year. The catch table (1993-2010) and biomass estimates (EU survey summer 1988-2011) are updated within this report. Data indicate that 1766 t of shrimp was taken in 2010 when the effort was reduced by 50% well below comparing to 5374 t taken in 2009 without reduction on the effort. In the 2011 EU survey the 3M total and female biomass index were 1644 t and 1231 t respectively. These indexes were around 66% lower than last year and the lowest values in the EU survey series. As previous years, the sharp decline of shrimp biomass in Flemish Cap was associated with a strong increase of the cod stock. This unfavorable situation confirms the recommendation carried out within Scientific Council during autumn 2010., Sí