Stimulation by gutweed to increase the abundance of insect larvae as food for shrimp aquaculture in Thailand

Abstract

Naturally occurring insect larvae are a good dietary source of protein for shrimps. The role of gutweed (Ulva intestinalis) to stimulate the occurrence of insect larvae to support the growth of juvenile shrimps has been evaluated in water tank experiments. Larvae of chironomid and mosquito occurred and increased in raked tanks in which different amounts (0, 28, and 56 g/m2) of gutweed were planted but no shrimps were present. Most chironomid larvae (90%) were associated with the gutweed planted. The number of chiromonid larvae showed a higher correlation to the gutweed biomass than did mosquito larvae. When post-larvae (initial weight 0.013 g/individual) of black tiger shrimp (Penaeus monodon) were cultured for 5 weeks with commercial pellets, with neither pellets nor gutweed, or without pellets but with gutweed (56 g/m2) planted, there was no significant difference in shrimp growth between tanks with pellets and those without pellets but with gutweed planted. Gutweed stimulated the abundance of insect larvae, in particular the abundance of chironomid larvae. Planting gutweed in shrimp ponds is an efficient way to support the growth of juvenile shrimps and will reduce the amount of pellet feed that needs to be given in shrimp aquaculture.