An assessment of NAFO roughhead grenadier Subarea 2 and 3 stock.

Abstract

The aim of this paper is to present the status of NAFO roughhead grenadier Subarea 2 and 3 stock. Different assessment methods have been applied based on the available data: XSA, ASPIC and a qualitative assessment based on survey and fishery information. The fit of the data to the XSA and ASPIC has been very poor mainly due to lack of contrast and conflicting information from the surveys data. Therefore the results are not considered representative of the stock situation. There are not available surveys indices covering the total distribution, in depth and area, of this stock. Biomass indices from the surveys with depth coverage till 1400 meters are considered as the best survey information available to monitor trends in resource status because they cover the depth distribution of roughhead grenadier fairly well. Surveys biomass indices present a general increasing trend in the period 1995-2004. In the period 2005-2012 all available indices show a clear downward trend except the Canadian Fall (2J+3K) index. In the most recent period (2013-2015) the information of the different indices is contradictory, the Canadian 2J3K and the EU 3L show an increase while EU-FC and EU 3NO continue to decline. With regard to fishing mortality, the trends of the different estimations of F were very similar. F presents a decreasing trend since 1998 till 2006 and since then is more or less stable at very low levels. The recruitment indices analysed (Surveys length and age distributions) show at least three good cohorts: 1993, 2001 and 2012 year classes. To confirm the strength of the last good year class (2012) it would need to have more information about it.