Growth and Survival of the Tiger Tail Seahorse, Hippocampus comes

Abstract

Keeping fish in home aquaria is one of the most popular hobbies globally. The United States is the largest single market for aquarium fish (Walton 1994; Wood 2001). An estimated 11% of all U.S. households with pets keep fish (Tlusty 2002), a level similar to that in Australia, the UK, and probably in many other developed countries. Approximately 10% of all aquaria are believed to be marine, and primarily house tropical coral reef fish species (Sugiyama et al. 2004). Marine aquarium hobbyists, in particular, tend to be passionate about their aquaria, well informed, and interested in marine conservation (e.g., http://www.ems.org/marine_ aquarium_trade/aquarists_profile.html). It is ironic that well-intentioned hobbyists drive a large industry that may threaten wild populations of some coral reef fish species (Wood 2001). Up to 24 million coral reef fishes of over 1000 species are traded annually, and over 98% of these marine ornamentals are wild caught (Wabnitz et al. 2003). This is in stark contrast to the freshwater aquarium hobby in which less than 2% of fishes traded are wild caught (Sugiyama et al. 2004). While the freshwater aquarium hobby trade has made significant strides over the past few decades in the development of breeding techniques for most fishes in the trade, the marine aquarium hobby trade has lagged behind. Seahorses (family Syngnathidae) are a popular group of marine aquarium fishes. In the wild, they are found worldwide in a diverse range of marine habitats, including sea grass beds, coral reefs, mangroves, and estuaries (Lourie et al. 1999). The conservation status of wild seahorse populations is of concern as populations have declined precipitously in some places (Vincent 1996; http://www.iucn.org). One reason for the observed declines in wild populations is overexploitation: the global trade in seahorses was estimated to consume at least 20 million animals annually in 1996 (Vincent 1996). In addition to the aquarium trade, seahorses are also exploited for the traditional medicines and curios trades. Early evidence suggests that the supply of seahorses to the international marine aquarium trade has been affected by their recent listing on Appendix II of the Convention on the International Trade in Endangered Species (CITES) (Job, personal observation). This decision, which came into effect in 2004, requires 169 countries to withhold export permits unless extraction of the seahorses can be shown to be sustainable. As a result, the global demand for seahorses is currently high, and prices have risen. Average wholesale prices for tropical seahorses in Australia, for example, have more than doubled over the past year (Job, personal observation). Approximately five tropical seahorse species are currently cultured on a commercial scale, primarily in the United States, Australia, 1 Corresponding author: Broome Aquaculture Centre, Kimberley College of TAFE, P.O. Box 1380, Broome, WA 6725, Australia. 2 Present address: Project Seahorse, Fisheries Centre, University of British Columbia, 2204 Main Mall, Vancouver, V6T 1Z4 Canada. JOURNAL OF THE WORLD AQUACULTURE SOCIETY Vol. 37, No. 3 September, 2006