Exploitation and reproduction of the spotted eagle ray (Aetobatus narinari) in the Los Frailes Archipelago, Venezuela

摘要

We studied a small artisanal fishery for the spotted eagle ray (Aetobatus narinari) off Margarita Island in northeastern Venezuela. We analyzed data from 413 fishingudtrips directed at A. narinari over a 29-month sampling period (August 2005–December 2007). These trips yielded 55.9 metric tons and 1352 individuals from which a subsampleudof 846 females and 321 males was used for biological data. Maximum fishing effort and landings occurred between February and May, and catch per unit of effort was highest between December and February and between July and October with an overall average of 3 individuals and 133 kg per trip. The overall sex ratio was significantly different from 1:1 with a predominance of females. Females ranged in size with disc widths (DW) from 64 to 226 cm. Males ranged in size between 97 and 190 cm DW. There was no statistically significant difference between male and femaleudlength-weight relationships. Mean fecundity was estimated at 3.09 embryos per female, and the largest embryo measured 44.5 cm DW. Females in different maturity stages were found in all months, except November 2007, the month when alludfemales were immature. Postgravid females occurred mainly during the periods of January–May and July–October. Mean length (L50) at maturity was estimated at 129.2 cm DW for males and 134.9 cm DW for females. This study provides muchudneeded information on the biology and life history of A. narinari for the management of an intensive, directed, small-scale fishery for this little known species in northeastern Venezuela.