Marine Ornamental Shrimp: Biology, Aquaculture and Conservation

Abstract

The research and development of marine ornamental shrimp aquaculture have focused on species of Lysmata and Stenopus. The sexual system of several species of Lysmata has recently been described as protandric simultaneous hermaphrodite (PSH) with out-crossing, a unique (and puzzling) system within the decapod and other Malacostaca crustaceans (Bauer 2000), including peppermint shrimp L. wurdemanni (Bauer and Holt 1998), white banded cleaner shrimp L. amboinensis (Fiedler 1998), Mediterranean cleaner shrimp L. seticaudata, Tiger cleaner shrimp L. nilita (d'Acoz 2003), Scarlet cleaner shrimp L. grabhami, and Kukenthal's cleaner shrimp L. kukenthali (Rhyne and Lin, unpublished data). A shrimp first matures as a male, then may change to a simultaneous hermaphrodite as size increases. In L. wurdemanni, all shrimp change to simultaneous hermaphrodites if raised individually; however, when raised in a group, a percentage of the shrimp remains male (Lin and Zhang 2001b). The characterstic of PSH may be widespread among the Lysmata species. Cincinnuli (coupling hooks) on the first pleopods occur in male-phase (MP) shrimp but are absent in euhermaphrodite-phase (EP) individuals, and appendices masculinae are well developed in the second pleopods of MP shrimp, but absent in EP individuals (Bauer and Holt 1998; Zhang and Lin, in press). The presence of two long setae with many long, tangled hairs is a reliable additional criterion to distinguish the sexual phases (Zhang and Lin, in press). The United States is the largest market for ornamental fish in the world. About 75% and 14% of saltwater ornamental fish were imported from Southeast Asia and South America, respectively (Chapman et al. 1997). The great increase in the popularity of saltwater aquaria has dramatically stimulated the worldwide fishery for small, colorful coral reef fishes and invertebrates. People involved in this fishery utilize a variety of techniques, ranging from hand-operated nets to extremely damaging application of toxins (e.g., cyanide and bleach, Jones et al. 1999) and explosives to stun fishes so survivors can be easily caught. All of these techniques can have deleterious effects on the reef ecosystems. Coral reefs are the most diverse of marine ecosystems in the world. This biodiversity is most pronounced in the western Pacific and Indian Oceans (e.g., Bellwood and Hughes 2001). Assessments performed in late 2000 indicated that 27% of the world's coral reefs have been effectively lost (Wilkinson 2000). Global warming, coral bleaching, and overfishing are among the most serious threats to coral reef biodiversity. The ornamental live fish industry, heavily dominated by freshwater species, is the fastest growing segment of the U.S. aquaculture industry. The freshwater ornamental fish industry is now entirely driven by aquaculture. In contrast, the vast majority of the marine species are collected from the wild. There is an urgent need to develop the technologies for culturing more species. Despite apparent environmental and economic benefits, if the ornamental species are cultured in the west, there are significant social and economic implications for the countries that supply the animals. Developing and transferring the culture technology to the developing countries with a favorable climate and low production costs would be an effective way of coral reef conservation while promoting the economy of the countries involved (Fletcher et al. 1999).