A Review of the Fishery and the Investigations of Roughhead Grenadier (Macrourus berglax) in Flemish Cap and Flemish Pass

Abstract

We review the fishery and biological investigations carried out in the Flemish Cap and Flemish Pass area during the 25 years of NAFO history. In particular, we examine the information available on the biology and population structure of roughhead grenadier recorded in the following 7 research surveys carried out in the Flemish Cap and Flemish Pass area (NAFO Div. 3LMN): Russian bottom trawl research survey (1974–86), Russian longline research survey (1982), Canadian deepwater bottom trawl research survey (1991, 1994 and 1995), European Union longline research survey (1996), European Union Flemish Cap bottom trawl research survey (1988–2004), Canadian autumn bottom trawl research survey (1978–2004) and Spanish 3NO bottom trawl research survey (1995–2004). In addition, biological data collected aboard Spanish commercial fishery vessels were analysed from 1997 to 2004. Indices of biomass from various surveys suggest stability during recent years. Most surveys indicated catch rates as well as average fish size increased with depth. Growth studies by sex demonstrated both sexes grew similarly up to 9–10 years, but the male growth was slower thereafter. Estimates of size and age at 50% maturity and fecundity were very similar for the different data sets studied, showing a late maturity and low fecundity. All the studies examined found that the roughhead grenadier show a very wide feeding spectrum.