Size at first sexual maturity of the sting rays Dasyatis guttata and Dasyatis americana , off Ceará State

Abstract

The stingrays  Dasyatis guttata and  Dasyatis americana arespecies are important resources in small­scale  fisheries off Ceará State, Brazil. The main objective of this paper was to estimate the mean length at the female’s first  sexual maturity of those species, which should be enventually used in fishery management action. Sampling for size was  carried out in Fortaleza, Caucaia and Aquiraz counties, Ceará State, Brazil, as by-catch material by the trawlnet and  gillnet fisheries and landings from the hook-and-line fishery and harpooning fisheries, in years 1997, 1999, 2001 and  2003-2005. The data analysis produced the following results: (a) the onset of physiological reproduction is attained at  length classes 50­60 cm DW and and 60­70 cm DW (male), and 60­70 cm DW e 80­90 cm DW (female), for  D. guttata and  D. americana , respectively; (b) and the mean length of the claspers was estimated as 11.2 cm ( D. guttata ) and e 11.8 cm  ( D. americana ), with roughly equal proportions in both species, values which are supposed to define the mean size at first  functional maturity.