Preliminary observation of spawning behaviour in sea cucumber, Stichopus horrens, induced by physical stressors in captivity

In Malaysia, Stichopus horrens (Phylum Echinodermata; Class Holothuroidea; Family Stichopodidae) is known as gamat. It is a premium commercial species in Malaysia, where it is used as a primary ingredient in traditional medicine, nutraceuticals, and food products. Induced spawning in sea cucumber is challenging, as achieving healthy and mature gamete from the broodstock is critical in aquaculture for ensuring a continuous seed production and larviculture throughout the year. Therefore, the aim of this study is to develop artificial spawning protocol in S. horrens culture. This study investigated the effects of physical stress on the sea cucumber, Stichopus horrens, in order to better understand their behaviour and responses to different types of conditions. These trials used four different physical stress treatments: heat shock, cold shock, desiccation, and phytoplankton stimulation. After being stressed, the behaviour of S. horrens was observed in the observation arena for eight hours. An ethogram was created to represent the general qualitative behaviours observed during the experiment periods. Each treatment was tested in triplicate at ۱-month intervals in May, Jun, and July ۲۰۲۲. Sixty sea cucumbers with a mean weight of ۱۶۸.۷± ۲.۸g were used in this study for spawning induction trials. This finding demonstrated no physical parameters in these trials could induce spawning in this species. However, there were some common spawning behaviours showed by S. horrens such as raising the anterior, raising posterior, swaying side by side, swaying back and forth, swaying both directions, body shaking, bulging gonopore, and deflated gonopore. Among the four physical stress treatment tested, desiccation showed the most promise in terms of displaying spawning behaviour and should be further investigated to achieve successful spawning. However, no sea cucumbers spawned despite showing potential behaviours related to spawning. Phytoplankton stimulation showed some potential to induce spawning in S. horrens, whereas heat shock and cold shock showed the least effectiveness to induce spawning in this species. Therefore, more trials are required to produce a consistent result and to demonstrate its potential as an artificial spawning inducer for S. horrens.

کلیدواژه ها:

Spawning ، Stichopus horrens ، Aquaculture ، Sea cucumber