SEXUAL MATURITY, FECUNDITY, AND EMBRYO LOSS IN THE PONTONIINE SHRIMP CUAPETES AMERICANUS (KINGSLEY, 1878) (DECAPODA: PALAEMONIDAE) IN BAHIA DE LA ASCENSION, QUINTANA ROO, MEXICO

Cuapetes americanus (Kingsley, 1878) is distributed along the Atlantic coast of the Americas, from North Carolina and Bermuda to Sao Paulo, Brazil and the West Indies. The present goal was to conduct a comparative study of reproductive aspects of C. americanus: size at sexual maturity, fecundity, and embryo loss. Specimens were obtained from Bahia de la Ascension, Quintana Roo, Mexico in November 2000 (n = 345) and November 2001 (n = 156). Samples were collected with a marsh net on Thalassia testudinum-meadows. The average size of the specimens was significantly different between the two dates, with larger females in 2001 (2.46 +/- 0.47 mm CL) than in 2000 (2.20 +/- 0.23 mm CL). The size at which females reached sexual maturity was 2.01 +/- 0.24 mm CL in 2000, and 2.39 +/- 0.51 mm CL in 2001. The embryos were categorized in three embryonic stages. Average fecundity at the first stage of development was higher in specimens collected in 2001 (74 +/- 57) than in 2000 (47 +/- 21). On both sampling dates, fecundity increased with female size but also varied among females of the same size group. Embryos were significantly larger in 2000 than in 2001 (0.034 mm(3) and 0.028 mm(3), respectively). The maximum increase of embryo volume (78.5%) and brood loss (27.5%) with developmental stage was seen in 2001. The differences between the sampling dates and from others populations of this species from different localities suggested an apparent plasticity of the reproductive traits of C. americanus.