Age, growth, and feeding of boarfish, Capros aper (Linnaeus, 1758) in the Southwest of the Iberian Peninsula

Abstract

ABSTRACT The boarfish (Capros aper) is a pelagic species that appears on numerous occasions as bycatch or discard in trawl fisheries in the Northeast Atlantic and Mediterranean. Existing information on this species and its occurrence as bycatch is incomplete for the Atlantic coasts. The objectives of this work were to study its growth, ageing, and diet in the southwest of the Iberian Peninsula. We found that the length–weight relationship was TW = 0.022*TL2.89 (R2 = 0.94). We observed age classes ranging from 1 to 5 years and that otoliths vary in shape and size according to the age of the individual, becoming more irregular in the lateral areas and increasing the size of the central cleft as the specimens grow older. The parameters of the von Bertalanffy growth equation were L∞ = 11.80 cm; k = 0.21 yr−1; t0 = −1.60 yr. Diet analysis indicated that copepods were the most abundant prey in the stomachs analysed, (IRI index value of 84.24%). This study serves to increase knowledge on the biology of the boarfish, which may be useful for future studies on the species, as well as for other members of the family and fisheries in which it is discarded.