Biomass and length distribution for roughhead grenadier, thorny skate and white hake from the surveys conducted by Spain in NAFO 3NO

Data for roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata) and white hake (Urophycis tenuis) from the Spanish Spring survey are presented. Abundance and biomass were estimated for roughhead grenadier and thorny skate for the period 1997-2014 and for white hake for the period 2001-2014. The length distribution is presented as numbers per haul stratified mean catches for the last five years (2010-2014). The roughhead grenadier indices showed no discernible trend until 2012, reaching a maximum in 2004 - 2006 and afterwards stabilised at levels slightly higher than in the early years. In the last two years a decline was appreciated in the indices, reaching in 2014 one of the lowest values of the entire time-series. Thorny skate indices follow a large oscillating trend, dropping in 2007 and being since then more or less stables at a low level, reaching the minimum of the series in 2014. White hake indices were highest in 2001 and then showed an overall decreasing trend until 2008 with low values. Indices increased since then until 2013 but declined again in 2014. A small recruitment event was detected in 2005 and in 2013, with individuals between 16 - 26 cm

Ecological trend on demersal community in the Southern Grand Banks (NAFO Div. 3NO) from the Spanish Surveys: 2002-2011

Some ecological indices were calculated from the data obtained in the research surveys conducted by Spain in NAFO divisions 3NO between the years 2002 and 2011. These indices were calculated for individual populations (intrinsic population rate of growth and mean length) and for all the community (ABC curves, indices about faunal diversity, proportion of non-commercial species, mean length in community and size spectra). We use the data of twenty five species caught in the survey along the years, included Northern shrimp (Pandalus borealis). The data of Northern shrimp, capelin (Mallotus villosus) and Northern sand lance (Ammodytes dubius) have a great influence in the value of the indices, as their abundance is very high in relation to their contribution to the biomass. The indices present a general stable pattern with a slight improvement in recent years. After two decades of moratorium, yellowtail flounder (Limanda ferruginea) seems to be recovered and other important commercial species as Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) begin to recover in the South of the Grand Banks

Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area

Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the NAFO Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder (Limanda ferruginea) are presented for the period 1995-2014, for redfish (Sebastes spp.) for the period 1997-2014 and for witch flounder (Glyptocephalus cynoglossus) for the period 2002-2014. Detailed indices are presented from 2009. Yellowtail flounder indices do not show a clear trend. Biomass increased from 1997 to 1999 and then remained almost constant throughout all the period, decreasing slightly in 2014. Redfish indices oscillate greatly over time, probably because the gear does not sample adequately aggregating pelagic species. There was a sharp increase in 2009 and since then has maintained higher values than before 2009, comprising the 3N around the 90% of the total biomass in the last years. In 2014 there was a decrease in all the indices in both Divisions. Good year classes have not been registered recently. Witch flounder is very scarce and its indices show a general decreasing trend throughout the period (2002-2014) remaining at very low levels. Recruitment was quite good at the beginning of the series but very poor in recent years

Persistence and Variation on the Groundfish Assemblages on the Southern Grand Banks (NAFO Divisions 3NO): 2002–2011

Data from EU-Spain (Instituto Español de Oceanografía) bottom trawl surveys in the NAFO Regulatory Area (2002–2011) were analyzed to examine patterns on the South of Grand Banks (NAFO Div. 3NO) of groundfish assemblage structure and diversity in relation to depth. The 1160 hauls from the slope surveys spanned between 38 and 1460 m in depth. We focused on the 28 most abundant species, which made up 92.6% of the catch in terms of biomass. Assemblage structure was strongly correlated with depth. For the most part, changes in assemblages seem to be fairly continuous, although there were more abrupt changes at 300 m. Five assemblages were identified. Two shallow assemblages were found in the shelf. Assemblage I (Shallow) comprises the strata with depths lesser than 150 and include yellowtail flounder (Limanda ferruginea), American plaice (Hippoglossoides platessoides), Northern sand lance (Ammodytes dubius), moustache sculpin (Triglops murrayi), capelin (Mallotus villosus) and web sculpin (Hemitripterus americanus). Assemblage II (Shallow) includes the strata with depths between 151 and 300 m and comprises Atlantic cod (Gadus morhua), American angler (Lophius americanus), wolfish (Anarichas lupus) and thorny skate (Amblyraja radiata). Assemblage III (Intermediate) contains the depth strata between 301 and 600 m. Redfish (Sebastes spp.), spotted wolfish (Anarhichas minor), Arctic eelpout (Lycodes reticulatus), Northern wolfish (Anarhichas denticulatus), white hake (Urophycis tenuis), witch flounder (Glyptocephalus cynoglossus) and longfin hake (Phycis chesteri) were included in the intermediate assemblage. Finally, we found two deep clusters: Assemblage IV (Deep) contains the depths between 601 and 1000 m, and Assemblage V (Deep) the depth strata greater than 1001 m. Greenland halibut (Reinhardtius hippoglossoides), marlin-spike (Nezumia bairdii), roughhead grenadier (Macrourus berglax) and spinytail skate (Bathyraja spinicauda) formed Assemblage IV. Snubnosed spiny eel (Notacanthus chemnitzii), blue antimora (Antimora rostrata), Northern cutthroat eel (Syphanobranchus kaupii), roundnose grenadier (Coryphaenoides rupestris), black dogfish (Centroscyllium fabricii), Arctic skate (Amblyraja hyperborean) and longnose chimera (Harriotta raleighana) made up the deepest assemblage. Despite dramatic changes in biomass and abundance of the species in the area, the boundaries and composition of the assemblages seem to be similar to the period before the collapse. Although some changes were evident, the main ones were replacements of the dominant species in several assemblages and bathymetric range extension of distribution of some species. Yellowtail flounder appears to be the dominant species in the shallowest assemblage instead of Atlantic cod and American plaice that were dominant in the period before the collapse in the area; redfish is the dominant species in the second shallow and intermediate assemblages. Diversity appears inversely related to biomass in the different assemblages. Despite the fishing effort in the deep waters of the Grand Banks, the overall pattern of demersal fish assemblages remains similar over time. This pattern is similar in other Atlantic areas; it indicates that changes in the fish populations in Northwest Atlantic have been produced on a large scale and are not limited to specific areas

Persistence and Variation on the Groundfish Assemblages on Flemish Cap (NAFO Divisions 3M): 2004-2013

Data from the EU (Spain-Portugal) bottom trawl surveys in the Division 3M of the NAFO Regulatory Area (2004-2013) were analyzed to examine patterns on this zone of groundfish assemblage structure and diversity in relation to depth. 1699 hauls between 129 and 1460 m in depth were carried out. We focused on the 29 most abundant species, which made up 87.5% of the catch in terms of biomass. Assemblage structure was strongly correlated with depth. For the most part, changes in assemblages seem to be fairly continuous, although there were more abrupt changes at 600 m. Three main assemblages were identified. A shallow assemblage was found in the shelf. Assemblage I (Shallow) comprises the strata with depths lesser than 250 m and include American plaice (Hippoglossoides platessoides), witch flounder (Glyptocephalus cynoglossus) and Atlantic cod (Gadus morhua). Assemblage II (Intermediate) includes the strata with depths between 251 and 600 m and comprises Acadian redfish (Sebastes fasciatus), Arctic eelpout (Lycodes reticulates), thorny skate (Amblyraja radiata), longfin hake (Phycis chesteri), deepwater redfish (Sebastes mentella), spinytail skate (Bathyraja spinicauda) and Northern wolffish (Anarichas denticulatus). Three species are present in the two first assemblages: Atlantic wolffish (Anarichas lupus), golden redfish (Sebastes marinus) and spotted wolffish (Anarichas minor). Assemblage III (Deep) contains the depth strata greater than 601 m. Marlin-spike (Nezumia bairdii), scaly dragonfish (Stomias boa), Greenland halibut (Reinhardtius hippoglossoides), sloane’s viperfish (Chaulonius sloani), black dogfish (Centroscyllium fabricii), Snubnosed spiny eel (Notacanthus chemitzii), roughhead grenadier (Macrourus berglax), roundnose grenadier (Coryphaenoides rupestris), blue antimora (Antimora rostrata), threadfin rockling (Gaidropsarus ensis), bean’s sawtoothed eel (Serrivomer beanii), Northern cutthroat eel (Syphanobranchus kaupii), lanternfish (Lampanyctus sp), vahls’s eelpout (Lycodes vahlii), Arctic skate (Amblyraja hyperborea) and Demon catshark (Apristurus sp) formed Assemblage III. Despite dramatic changes in biomass and abundance of the species in the area, the boundaries and composition of the assemblages seem to be similar to the period before the collapse. Extending depth range to 1460 m, no another boundaries were found. Although some changes were evident, the main ones were replacements of the dominant species in several assemblages and bathymetric range extension of distribution of some species. Acadian redfish and golden redfish appear to be the dominant species in the shallowest assemblage instead of Atlantic cod that were dominant in the period before the collapse in the area; redfish is the dominant species in the second shallow and intermediate assemblages. Diversity appears inversely related to biomass in the different assemblages. Despite the collapse in some species and the permanent fishing activity target to the North Shrimp (Pandalus borealis), redfish (Sebastes spp) and Greenland halibut, the overall pattern of demersal fish assemblages remains similar over time. This pattern is similar in other Atlantic areas; it indicates that changes in the fish populations in Northwest Atlantic have been produced on a large scale and are not limited to specific areas

Results for Greenland halibut, American plaice and Atlantic cod of the Spanish survey in NAFO Div. 3NO for the period 1997-2014

Greenland halibut (Reinhardtius hippoglossoides), American plaice (Hippoglossoides platessoides) and Atlantic cod (Gadus morhua) indices from the bottom trawl survey that Spain carries out in Spring since 1995 in Div. 3NO of the NAFO Regulatory Area are presented. Biomass, stratified mean catches and mean number per tow for the three species are presented since 1997, year in which the survey extended the depth strata. Mean catch per town, length distribution and age distribution are presented for the last five years (2010-2014). Greenland halibut biomass and abundance estimates presented a decreasing trend since 1999, cut in year 2007 with an increase, reaching in 2009 the highest value in the series. In 2011the biomass drops under the 2008 value, being stable since then. In last years it can be seen a presence of juveniles, mainly in 2004, but the greatest lengths have failed, although in 2009 there is a quite good presence of individuals of ages 6-7 and in 2010 between 5-7. In 2011-2014 the presence of all ages is poor. For American plaice we can see an increasing trend along the whole period, reaching a maximum of mean catch and number in 2006. The greatest recruitment in the presented series occurred in 2004 and we can follow their mode along the years. No good recruitments were seen since then. For Atlantic cod it can be seen a general decreasing in the biomass between 2002 and 2005 and an increasing since then, especially in 2006 and, higher, in 2009-2011, decreasing again in 2012-2013 but reaching the maximum in the series in 2014. In 2007-2008 the youngest length classes were much over the rest of the length classes. With the 2006 cohort the series reaches the maximum number of its historical values at five years in 2011. There have been no good recruitments since 2009