Results for Greenland halibut, American plaice and Atlantic cod of the Spanish survey in NAFO Div. 3NO for the period 1997-2015

Abstract

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 (2011-2015). 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 2011 the biomass drops under the 2008 value, being stable since then with a slight increase in 2015. 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 2011-2015 the presence of all ages is poor, although in 2015 an increase in the range of the length can be seen with regards to last years. 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, but a discrete occurrence of individuals of 12-20 cm appears in 2015. 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 2015 the biomass is in the level of the 2012 biomass but the mean number is almost the same as 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, although in 2015 a discrete presence of individuals of age 1 can be seen. MaterialPostprint0,000