A researcher doing measurement on a sighted seahorse. Copyright Ocean Park Conservation Foundation.
Ocean Park Conservation Foundation, Hong Kong (OPCFHK) recently showcased its leadership in seahorse conservation by reporting the results of a seahorse survey in local waters, where six seahorses of one species were found. The Foundation also revealed significant new milestones slated to be achieved in 2013, including expanding the scope of the survey to include embarking on a seahorse tagging initiative, the first-ever in Hong Kong. The tagging technique, already widely adopted internationally, will take the study of local seahorse populations to a more systematic level, thereby enabling researchers to better track changes to particular populations and gain a better understanding of their long-term sustainability as well as the threats they face. The ultimate goal is to formulate more effective conservation management plans to protect the local seahorse populations and their habitats.
OPCFHK sponsored a seahorse survey in 2010 and found five seahorses in Hong Kong’s eastern waters, including areas around Sai Kung and Tung Ping Chau. Species found in the 2010 survey were: yellow seahorse (Hippocampus kuda) and three-spot seahorse (Hippocampus trimaculatus); whilst an additional species, namely great seahorse (Hippocampus kelloggi) has also been previously sighted in Hong Kong. According to data reported ten years ago, yellow seahorses were moderately abundant in Hong Kong waters down to a depth of seven metres. However, different factors threaten the survival of seahorses, with 11 out of 54 species of seahorse being listed as Vulnerable or Endangered in the IUCN (International Union for Conservation of Nature) Red List of Threatened Species. They are typically threatened by overexploitation for uses in traditional Chinese medicine, loss or degradation of natural habitats and bycatch in trawling fisheries as a result of the lack of comprehensive and effective fishery management plans. In order to further understand the current status of seahorses in the area, OPCFHK conducted the first systematic seahorse survey in Hong Kong, covering 31 sites in local waters from September 2011 to October 2012.
A researcher taking photos of a sighted seahorse. Copyright Ocean Park Conservation Foundation.
Ms. Shadow Sin, senior scientific officer of OPCFHK said, “For each sighting, the species and sex were identified, whilst body measurements, exact GPS location and the substrate at which it was found were recorded. A total of six individual seahorses, comprising one male and five females belonging to one species, yellow seahorse (Hippocampus kuda), were observed at two diving sites in Sai Kung waters during the survey. Their overall height (from “crown” to tip of the tail) ranged from 40-to-154mm. During the course of our survey, we also found three fish species, including flagfin prawn goby (Mahidolia mystacina), humpnose big-eye bream (Monotaxis grandoculis) and emperor angelfish (Pomacanthus imperator) that have never been sighted in Hong Kong before.”
OPCFHK will extend the field survey to include more sites in Hong Kong and monitor known seahorse sites for in-depth studies of site fidelity, long-term survivorship and growth within Hong Kong waters through tagging and follow-up monitoring. A non-invasive external tagging technique involving collar tags has been chosen, whereby a small green oval PVC disc (3X5mm) with a three-digit number on one side will be attached to each individual seahorse found during the survey using a soft vinyl cord. This tagging method has been applied on various seahorse species worldwide, including the spiny seahorse and the yellow seahorse. The results of the survey will help inform strategies for the conservation of seahorses within Hong Kong waters.
Suzanne Gendron, director of OPCFHK, said, “All seahorses are listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and seahorses in Hong Kong are only protected under Protection of Endangered Species of Animals and Plants Ordinance to restrict their trade. They are currently not entirely protected by law in Hong Kong waters, so it is critically important for us to learn more about its local population to work with the Government and strengthen the preservation of this precious species. Since Hong Kong is a major regional hub for the seahorse trade with over 2.2 million seahorses imported each year, OPCFHK, as Hong Kong’s leading conservation advocate, has an important role to play in seahorse conservation. The seahorse survey we conducted, and our planned tagging initiative, will generate valuable data to share with the government, other conservation groups and the general public to help make effective conservation management decisions. We also recommend the government to document the sites with a record of seahorse sighting so that an ecological survey for the species would be taken into consideration in relation to any future development at those sites.”
Over the years, the Foundation has funded over HK$500,000 in support of four seahorse-related conservation initiatives in Asia, including arranging for local university students to gain fieldwork experience in seahorse conservation. As the number of seahorses found in the previous round of seahorse survey was very low, OPCFHK will continue the survey in 2013 to cover more sites within the eastern waters of Hong Kong. More surveys and participation by the public will also be needed for sites with previous seahorse sightings to verify their presence.
