Sand star, Astropecten indicus Döderlein, 1888, as an alternative live diet for captive harlequin shrimp, Hymenocera picta Dana, 1852

Harlequin shrimp, Hymenocera picta, are commonly maintained on a diet of comet seastars, Linckia multifora, however, difficulties in sourcing a ready supply throughout the year, represent limitations to their sole use within commercial scale production. In a two-step approach, to address their limited availability, firstly the acceptability of several alternative prey items (i.e. Astropecten indicus, Luidia maculata, Culcita novaeguineae and Holothuria leucospilota) were assessed and then secondly, in-depth studies were conducted with the most acceptable species identified from the first step. In the first trial, the feeding responses, i.e. time taken to attack prey, by 120-day old, pre-starved shrimp were assessed. Shrimp quickly overturned specimens of A. indicus and began feeding within 5min, while specimens of L. maculata and L. multifora were carefully assessed before a limb was selected and excised. As the seasonal availability of Linckia is limited, the performance of shrimp fed less frequently was explored. The second trial, therefore, investigated the growth, survival and reproductive capacity of shrimp fed different regimes of live L. multifora over a 5-month period compared to shrimp fed a favourable alternative prey identified from the first experiment, i.e. A. indicus. Shrimp were fed either: 1) live L. multifora daily (LMD); 2) live L. multifora every alternate week (LMW); 3) live A. indicus daily (AID); or, 4) live A. indicus every alternate week (AIW). There was 100% survival of those fed the LMD and LMW diets but 67% in those groups fed AID and AIW respectively; females displayed better growth than males but there were no significant differences (p<0.05) in the growth performance of shrimp fed the different diets. Shrimp fed LMD, LMW and AID all spawned; AIW failed to spawn. There was a statistical difference in the time to first spawning between harlequin shrimp fed LMD (shrimp first spawned at 206±12.78days) and those fed LMW (shrimp first spawned at 236±5.20days); there were no other statistical differences. The study concludes that A. indicus appears to represent a favourable alternative live feed to the use of L. multifora that can be readily maintained within aquaria. During periods when the availability of live L. multifora is limited, a regime of either LMW or AID are appropriate for the maintenance of shrimp, however, minimising the time interval between feeding L. multifora would result in better performance.“Evaluating alternative live diets for harlequin shrimp”.The study assesses locally available alternative live feeds for the potential commercial-scale aquaculture of harlequin shrimp in Thailand, focusing on the use of Astropecten indicus as an appropriate live feed that can be supplemented when Linckia multifora is not available.