Volume 57
A Fecundity Study of Gag, Mycteroperca microlepis (Serranidae, Epinephelinae), from the Campeche Bank, Southern Gulf of Mexico
Authors
Martínez, J.T.; Brulé, T.; Colás-Marrufo, T.E. Download PDF Open PDF in BrowserOther Information
Date: November, 2004
Pages: 401-422
Event: Proceedings of the Fifty Seventh Annual Gulf and Caribbean Fisheries Institute
City: St. Petersburg, Florida
Country: USA
Abstract
The gag grouper, Mycteroperca microlepis, is the third most commercialized serranid species in the southern Gulf of Mexico. However, production volumes and the current fishery status of the Campeche Bank’s stock are uncertain. This study focuses on the fecundity of the specie, a novel contribution towards understanding its reproductive biology and also providing valuable information on the stock for the southern Gulf of Mexico. Females from the 212 analyzed ranged from 45 cm to 111 cm furcal length (FL). Gonads were fixed in Bouin’s liquid for histological examination and Gilson’s liquid for the measurement and quantification of oocytes. Gag is a multiple spawner with an indeterminate fecundity: no hiatus was observed between previtellogenic (20 – 119 µm) and vitellogenic oocytes (75.3 µm – 1015.5 µm) during its maturation and spawning periods. The oocyte size-frequency method determined stage V oocytes (211.7 – 509.3 µm) as the most advanced batch of oocytes. The minimum diameter limit established for stage V oocytes was recorded at 290 µm. Absolute batch fecundity estimates were based on females ranging from 72 to 105 cm FL sampled during April 1996 through August 1999. The maximum absolute batch fecundity estimate obtained was 4,270,250 ova for a female of 97 cm FL, with a minimum of 170,610 ova for a female of 72 cm. The average absolute batch fecundity was 1,649,675 ± 1,145,305 SD oocytes per female, a high variability which has also been observed for other grouper species, for example the red grouper, Epinephelus morio. The best predictor of absolute batch fecundity for M. microlepis from the Campeche Bank was gonad weight.