Results on Blue Whiting Spanish Discard Sampling Programme

Abstract

Quarterly discards per ICES Divisions estimates for the Spanish bottom otter trawl fleet fishing in the Northeast Atlantic ICES Subareas VI, VII, VIII and IX are presented for blue whiting (Micromesistius poutassou). Information was obtained by observers on board under DCF discard sampling program carried out by the Spanish research institute IEO. Raising based on effort (number of trips) was used to estimate total quarterly discards in weight and number for the most important fleets of Bottom Otter Trawlers. Discards age distributions are also presented. Discards are highly variable throughout the series, both in weight and in number ranging from 680 to 6 800 tonnes per quarter and from 1 to 68 million fish. 100% catches are discarded in Sub-areas VI-VII. The highest discards weights are in Divisions VIIj and VIIIc. There is no clear seasonal pattern of discard, but there are generally higher discard in the second quarter, although there are years with high values in others periods. Age distributions of blue whiting discards in Divisions VIIIc and IXaN show that most of the individuals are juveniles (ages 0 to 3), however older than are also discarded.