Search

It is imperative to develop aquaculture methods for the tropical sea cucumber, Stichopus fusiformiossa as it is an essential component for the pharmaceutical and traditional medicine industry in Malaysia. With sea cucumber stocks harvested freely, conservation efforts should be in place to overcome future depletion or loss of populations in the wild. This study represents the first report to induce spawning of S. fusiformiossa using conventional methods (thermal shock, desiccation, microalgae stimulation) and neurotransmitter injections (serotonin, 1-methyladenine, epinephrine, norepinephrine) in an indoor based aquaculture system. Post induction, the sea cucumbers were observed for 8 hours. They displayed classic sea cucumber pre-spawning behaviours, namely, raising their head, swaying the anterior (side to side, back and forth, head spinning/circling) and prominent visibility of the gonopore. All neurotransmitters used successfully triggered the pre-spawning behaviours, with the group induced with 1-methyladenine remaining active throughout the observation period. During the first 10 minutes (0 hr) of neurotransmitter injection, 1-methyladenine induced group had more than 50 % of the animals with visible gonopores. Generally, body-raising behaviour was observed across all treatments at 0 hr. On the other hand, swaying behaviour was displayed more frequently in all neurotransmitter induced groups, although it remained below 40 % in each case. No swaying action was revealed in the group with raised temperature and microalgae stimulation treated group. While all treatments showed varying degrees of promising pre-spawning behaviour, none spawned during the observation duration. Histology of male and female gonad development stages were also examined randomly. This study describes challenges faced during spawning induction and general maintenance of stichopodid sea cucumbers which potentially undergo autolysis or melting of their external body wall due to physical stress. Utilization of neurotransmitters was unsuccessful; however, the findings from this study paves way for further avenues of research to elucidate the spawning induction techniques of S. fusiformiossa.

Mantis shrimps are stomatopod crustaceans yet to be successfully cultured on a commercial scale due to several impediments, namely their aggressive behaviour in a communal setting and a lack of understanding on their feeding regime during different life stages in captivity. Local adult mantis shrimp, Miyakella nepa (Latreille, 1828), were observed in laboratory conditions to obtain baseline data of feeding preference behaviour. M. nepa were kept individually, with tube shelter provided, either with or without sand substrate, to understand their burrowing behaviour (n = 16). Most of the stomatopods remained within the tube (>90% of observation time) during pre-feeding but ventured out of the shelter (47–60% of observation time) when feed was provided. They were presented with one or two types of natural feed to identify affinity towards specific food. During the 15-minute observation, mantis shrimps (n = 20) were placed in a testing arena and presented with natural feed. The fastest time for mantis shrimps to approach feed, indicating attractiveness, is fish, clam, shrimp, squid and then polychaetes. About 57% made an approach towards the squid, but none of them managed to consume it. Subsequent feeding preference observation included a combination of two diets presented at the same time: fish-shrimp, fish-clam, fish-polychaete, shrimp-clam, shrimp-polychaete, and clam-polychaete. Observations of M. nepa feeding preference in captivity revealed that they can consume several types of feed. It is recommended to provide fish as they were preferred to all other types of diets comparatively when presented without other food choice, and/or clams as they indicated high attractiveness due to short approach time when presented with choice. Mantis shrimps are considered opportunistic predators in the wild and M. nepa do not show a clear pattern with significant difference of preference towards any single type of natural feed presented in the laboratory setting.