Reproductive biology of Holothuria fuscocinerea (Echinodermata: Holothuroidea) from Oaxaca, Mexico

Abstract

The sea cucumber Holothuria fuscocinerea is among the most common holothurian species widely distributed in the Tropical Eastern Pacific Region and is becoming a potentially important fishery in Mexico. Nevertheless, there are no studies about its reproductive biology. This study analyzed several reproductive traits of H. fuscocinerea based on monthly time-series samples taken from April 2008 to March 2009 at La Entrega Bay, Oaxaca, in the Mexican tropical Pacific. Sex ratio, gonad development stages (GDS), reproductive cycle, diameter and distribution of oocytes, and fecundity were determined. Reproductive indices (the gonadosomatic index [GSI] and maturity index [MI]) were calculated, and their relationship with some environmental factors (temperature, rainfall, salinity, and pH) was evaluated. H. fuscocinerea is a gonochoric holothuroid, and its annual ratio of males to females was not significantly different from 1:1. Four GDS (i.e. gametogenesis, mature, spawning, post-spawning) as well as one period of gonadal recovery, which is ‘sexually undifferentiated’, were established. Spawning occurred from June to October in females and from April to September in males. Post-spawning of females and males and recovery stages coincided from October to January. Mean fecundity was 2.9 ± 2.8 million oocytes per female, with ovaries exclusively comprised of vitellogenic oocytes from June to September. GSI and MI values showed similar variations in accordance with the reproductive cycle, and GSI showed a relationship with rainfall season. Seasonal rainfall may act as a cause of the seasonal reproductive pattern observed in H. fuscocinerea.