Ecological and reproductive characteristics of holothuroids Isostichopus badionotus and Isostichopus sp. in Colombia

Abstract

Isostichopus badionotus and Isostichopus sp. are two holothuroids exploited in the Caribbean region of Colombia. Until recently, they were considered a single species. During one year, 222 individuals of Isostichopus sp. and 114 of I. badionotus were collected in two bays of the Santa Marta region to study their reproductive biology and collect information on their size, weight and habitat. Both sea cucumber morphotypes showed an annual reproductive cycle, with a reproductive season from September to November, closely related to the increase in water temperature and rainfall. In both sea cucumbers the population structure exhibited a unimodal distribution composed of mature individuals and a sex ratio of 1:1. Isostichopus sp. had an average size and weight (193 ± 52 mm and 178 ± 69 g) and size and weight at first maturity (175 mm and 155 g) that was much lower than I. badionotus (respectively, 324 ± 70 mm and 628 ± 179 g; 220 mm and 348 g). While 98% of Isostichopus sp. individuals were collected in the upper 2.5 m, on rocky bottoms between cracks, 73% of I. badionotus individuals were found between 3 and 7.8 m depth, exposed on sandy bottoms. These differences imply that management measures (e.g. minimum catch size) should not be the same for both sea cucumbers morphotypes.