Biomass and length distribution for Roughhead grenadier, Thorny skate and White hake form the surveys conducted by Spain in NAFO 3NO

• Main Authors: González-Troncoso, D. (Diana), González-Costas, F. (Fernando), Paz, X. (Xabier)
• Format: Report
• Language: English
• Published: Centro Oceanográfico de Vigo 2007
• Subjects: Hake; North Atlantic; Northeast Atlantic
• Online Access: http://hdl.handle.net/10508/611

Data for Roughhead grenadier (Macrourus berglax), Thorny skate (Amblyraja radiata) and White hake (Urophycis tenuis) from Spanish Spring survey are presented. The survey vessel changed in 2001, from the C/V Playa de Menduíña to the R/V Vizconde de Eza, so, in order to maintain the historical series, we transformed the data for Roughhead grenadier and Thorny Skate until that year. 1997-2000 data are transformed data from the C/V Playa de Menduíña and 2002-2006 data are original data from R/V Vizconde de Eza. In 2001, there are data from the two vessels for these two species. The abundance and biomass were estimated for the period 1997-2006 for Roughhead grenadier and Thorny skate, and 2001-2006 for White hake. The length distribution was obtained and presented in numbers per haul stratified mean catches. The indices of Roughhead grenadier present no trend along the years until 2003, with an increase in the last years, mainly in 2004. Thorny skate indices decreased since 2001 until 2003 and increase since then. The 2006 value is the second highest value of the series. For White hake, there were great catches in 2001, and a sharp decrease since then, broken in 2005 for an increase in the indices, but a new decrease in 2006. In 2004 we can see a presence of individuals between 16 and 26 cm.