By-catch and discards have received a great deal
of scientific attention, their minimisation being a goal
of marine fisheries management (Powers, 2006). The
Nordic workshop (Nordic Council of Ministers, 2003)
defined by-catch as “the proportion of the catch which
is taken on the board, or brought to the surface by
the vessel and which is subsequently thrown back to
sea, dead or dying or likely to die”. Most of the earlier
studies deal with optimisation of fishing efficiency and
minimisation of fishing impact, but by-catch and
discards data have rarely been used to learn about
the distribution, abundance and biology of the incidental
species being caught, although several recent studies
have indicated the informative value of by-catch
concerning food habits (Koen Alonso et al., 2001),
feeding ecology (Rheeder and Sauer, 1998) and
recruitment indices (Payne et al., 2005)
