Growth Analysis of the Sea Cucumber Holothuria (Halodeima) atra (Holothuroidea Aspidochirotida) in Seagrass and Seaweed Habitats.

The sea cucumber Holothuria atra is an ecologically and economically important benthic animal. However, biological and ecological data on growth of H. atra in Thai waters are non-existent. Therefore, the present study aimed to obtain and compare growth parameters from length-frequency data of H. atra collected from two habitats. Specimens were collected above ground on intertidal seagrass and seaweed beds along the Andaman coast of Thailand in Satun Province. Theoretical von Bertalanffy growth parameters were analyzed using the ELEFAN I program in the FiSAT II software package. Asymptotic length was smaller and growth coefficient was higher in the seagrass habitat than in the seaweed habitat (L∞ = 32 cm; K = 0.65 year^-1 and L∞ = 40 cm; K = 0.55 year^-1, respectively). It might be that sea cucumbers in the seagrass habitat survived in the less favorable environment by reaching asymptotic length more rapidly. The more complex structure of the seaweed habitat provides protection and shelter from water movement and low tide stresses. These conditions might be more suitable for growth. The theoretical age at length zero was -0.24 year in the seagrass habitat and -0.27 year in the seaweed habitat. In both habitats, length at birth was around 5 cm. Growth was rapid from age 0-2 years, but slow thereafter, until asymptotic length was reached at around 4 years in the seagrass habitat and 5 years in the seaweed habitat. These findings suggest that different habitats influence the growth of H. atra. [ABSTRACT FROM AUTHOR]