Comparative study of the Genus Isurus (Rafinesque, 1810), and description of a form (Marrajo Criollo) apparently endemic to the Azores

Abstract

Numerous captures of mako sharks (Isurus sp.) are made annually by the Spanish longline fishing fleet in the north-eastern Atlantic Ocean and the western Mediterranean Sea. Sampling of catches allowed us to compare the morphology of two species of Isurus (I. Oxyrinchus and I. Paucus) and to document the variations due to size or sex observed in populations exploited by the different fisheries.

The distinctive features of a form apparently endemic to the Azores ('marrajo criollo') are defined, and the form's taxonomic identity is discussed. This form is possibly a distinct population of shortfin mako (I. Oxyrinchus).

The presence of longfin mako (I. Paucus) is confirmed in waters off north-western Morocco, and this species is recorded for the first time off the Iberian peninsula.