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

Data for Roughhead grenadier (Macrourus berglax), Thorny skate (Amblyraja radiata) and White hake (Urophycis tenuis) from Spanish Spring survey are presented. The abundance and biomass were estimated for the period 1997-2008 for Roughhead grenadier and Thorny skate, and 2001-2008 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 years 2004-2006, mainly in 2004. In 2007 and 2008 the biomass are on the level of 2003 value. Thorny skate indices decreased since 2001 until 2003, increased for 2004-2006 and decreased again in 2007 and 2008. 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, 2007 and mainly in 2008. In 2004 we can see a good presence of individuals between 16 and 26 cm