Growth and life-history parameters of the high-value sea cucumber, Holothuria fuscogilva

Growth rates and life-history parameters of marine animals underpin conservation planning and fishery harvest strategies yet are unknown for most sea cucumbers. The white teatfish Holothuria (Microthele) fuscogilva, a high-value species, is widely harvested and listed on CITES Appendix II. We used a photographic mark−recapture method to measure growth of wild white teatfish in New Caledonia. Ex situ measurements of the animals weakly corresponded with their in situ measurements. Bidimensional metrics of body size using ex situ measures provided the most reliable predictions of body weight. Length−weight relationships for H. fuscogilva varied greatly among data from New Caledonia, French Polynesia, Torres Strait (Australia) and the Coral Sea. Of 67 animals photographically marked, seven were recaptured 13 months later. Growth averaged 220 g (total whole weight) or 1.4 cm (total length) per individual. We modelled growth using the Electronic Length Frequency Analysis (ELEFAN) routine using data of all captured animals. The growth coefficient (K) was estimated at 0.082 y⁻¹ and natural mortality rate (M) was approximated at 0.19 y⁻¹. Age-at-first-sexual-maturity was estimated at 15−23 years and longevity at 57 years. While the modelling deserves caution, the data overall suggest that H. fuscogilva is a slow-growing species with a considerable lifespan. Management and conservation measures for teatfish sea cucumbers (subgenus Microthele) should be highly conservative in light of their vulnerable life-history traits.