Reproductive biology of the sea cucumber Holothuria arguinensis (Echinodermata: Holothuroidea) and its relationship with the environment in the coastal waters of Morocco

Abstract

This study investigates the reproductive biology of Holothuria arguinensis over one year (December 2016 to December 2017) from two locations on the Atlantic coast of Morocco: Skhirat (North Atlantic) and Souiria K'dima (Central Atlantic), including the sex ratio, size at sexual maturity, and reproductive cycle. Monthly sampling was carried out, along with the collection of environmental and biometric data at each site. The sex ratio did not differ significantly from 1:1 at either study site. The gonadosomatic index (GSI) reached its peak during spring (April and May) for both sexes, and the spawning period was observed from summer to autumn (June-October) at both locations, suggest annual spawning. GSI was correlated with increasing or high chlorophyll-a concentrations, salinity, and spawning with rainfall periods. The estimated size at sexual maturity was 15.9 cm body length, 189.1 g total body weight, and 92.5 g gutted body weight. The minimum mean oocyte diameter was recorded during the recovery stage (31 ± 11 m (mean ± SD) at Skhirat and 34 ± 23 m (mean ± SD) at Souiria K'dima), while the highest values were observed in the partial spawning stage (112 ± 27 m (mean ± SD) at Skhirat and 104 ± 19 m (mean ± SD) at Souiria K'dima). This study highlights the need for further research to expand our knowledge of the biological and ecological characteristics of H. arguinensis populations, to facilitate the cultivation of juveniles in captivity, and to develop fishing regulations based on scientific findings. As a fishery management strategy, we suggest a closed season from April to October to protect the reproductive period of H. arguinensis on the Moroccan coast.