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

Abstract

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 1995-2016, for redfish (Sebastes spp.) for the period 1997- 2016 and for witch flounder (Glyptocephalus cynoglossus) for the period 2002-2016. Detailed índices are presented from 2012. 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 2014-2016. Redfish indices oscillate greatly over time, probably because the gear does not simple adequately aggregating pelagic species. There was a sharp increase in 2009 and since then until 2015, biomass fluctuated maintaining higher values than before 2009. In 2016 biomass dropped. The 3N division comprises around the 90% of the total biomass in the last years. Good year classes have not been registered recently. Witch flounder is very scarce and its indices fluctuated throughout the series reaching the minimum value in 2014 and increasing in the last two years. Recruitment was quite good at the beginning of the series but poor in recent years.