Population structure of Dipturus chilensis (Chondrichthyes, Rajidae) in the South western Atlantic 34º30'-39º30'S

Abstract

A total of 2,782 individuals of Dipturus chilensis captured by the Uruguayan industrial fleet, whose target species is the hake (Merlucius hubbsi), that operated between 50 and 400 m of depth during the years 2005, 2006 and 2007 in the Argentinean-Uruguayan Common Fishing zone were analyzed. Females showed a higher mean and median size than males and the highest proportion in the catches. The relationships between the total length and width of the disc and between total length and total weight did not differ significantly between sexes. For the three years analyzed, no significant decrease was found for mean length and median length. The length at which 50% of individuals were retained by the trawl net was smaller than the 50% mature estimated total lengths. Higher catches of immature individuals demonstrate that the fishing operation targeting hake affect the reproductive potential of a species categorized as vulnerable for IUCN.