Reproductive Biology of Actinopyga echinites and Other Sea Cucumbers from La Réunion (Western Indian Ocean): Implications for Fishery Management

Abstract

Abstract—The sea cucumber fishery is important in several countries of the Western Indian Ocean (WIO) but is generally not adequately managed. A regional MASMA programme (Marine Science for Management) granted by WIOMSA (Western Indian Ocean Marine Sciences Association) is providing data on the reproduction of some commercial species. In La Réunion, the two target species are Actinopyga echinites and Holothuria leucospilota. These sea cucumbers are very abundant on the fringing reefs and were sampled monthly during 2005-2006. Data on the population structure and on the reproductive cycle of A. echinites are presented here. The main results are: 1) eviscerated weight (EW) distribution of individuals within the population of Planch’Alizés site is plurimodal with a main mode at 85-95g, 2) sex-ratio is skewed toward females, 3) anatomy of gonads is described in five maturity stages, 4) a seasonal reproductive cycle with a major spawning event in December-January and a minor spawning event in April, 5) size at first sexual maturity EW50 equal to 45g is determined from another site (a sea grass bed with juveniles). These results are integrated with data from other holothurian species such as H. leucospilota, H. atra and Stichopus chloronotus previously studied in La Réunion and will be useful for research on the reproductive biology of sea cucumbers conducted in the other countries of WIO. ‘Seasonal closure’ using results
on the spawning season during the warm waters period and ‘minimum size’ using size at first sexual maturity are tools for enhancing sustainable management of the fisheries.

Keywords: Sea cucumber, Actinopyga echinites, Aspidochirotid holothurians, reproductive season, first sexual maturity, fishery management, La Réunion, Western Indian Ocean