Preliminary success in closing the life cycle of exploited seahorse species, Hippocampus spp., in captivity

The trade in seahorses for aquarium fishes is contributing to the depletion of many wild populations of these animals. Many seahorses are sold to replace those that have died in captivity as a result of husbandry problems. It can be particularly difficult to rear the young seahorses, because of their need for varied live food and their vulnerability to disease. We here report a pilot study on rearing broods from males of three species (H. fuscus, H. barbouri, and H. kuda) that had mated in the wild and gave birth in captivity. The new-born seahorses were fed an initial diet of enriched Artemia until 7 days, after which copepods were added to the diet. From 5 weeks, frozen mysids were gradually phased in to replace both other food items. Scrupulous hygiene was maintained. We achieved 100% survival of the partial broods we reared for all three species and achieved life cycle closure in two of these during the experimental period. Of the three species, H. kuda grew to be largest and longest, and H. barbouri grew least. However, H. kuda were the slowest to mature and reproduce while H. fuscus (intermediate in growth) were the fastest. Techniques used in this work should be more generally applicable, both for aquarium husbandry and for small-scale aquaculture to help provide alternative incomes for small-scale fishers who are otherwise dependent on catching wild seahorses.