The use of non-invasive sampling to estimate long-term abundance of Hippocampus kuda in the Koh Sdach Archipelago, Cambodia

Abstract

The Koh Sdach Archipelago has been designated as the next location for a marine fisheries management area in Cambodia. As the final phase of the proclamation draws near, it is essential to identify threatened populations of marine species to guide the design of appropriate zones for different forms of management within the archipelago. Despite much of Cambodia’s population being reliant upon the fisheries industry for food security and primary income, there is a paucity of marine research to facilitate effective conservation. We undertook monitoring at five sites in the archipelago between 2014 and 2021 to investigate population trends of Hippocampus kuda (Teleostei: Syngnathidae), a heavily exploited seahorse species which is susceptible to overexploitation due to targeted collection, non-selective fishing gear and habitat loss.

Our findings indicate that overall densities of the species are low (0.0008 ± 0.0001 individuals/m-2) and did not differ significantly between survey sites. Its abundance appeared to be relatively stable with no significant temporal changes noted during the study period. As our study sites comprised a variety of environmental characteristics ranging from bare sand substrate to seagrass meadows, this suggests H. kuda is a highly adaptive habitat generalist capable of utilizing its surroundings or migrating to more preferable areas. This highlights the potential resilience of the population compared to species with more specific requirements. Research on how population densities fluctuate seasonally is required to determine recruitment trends and additional variables such as water quality and holdfast choice must be studied to further understand the habitat preferences of H. kuda within the Koh Sdach Archipelago.

Kalisiak, J., Gray, I., Bruget, R. & M. Correia (2022). The use of non-invasive sampling to estimate long-term abundance of Hippocampus kuda in the Koh Sdach Archipelago, Cambodia. Cambodian Journal of Natural History 1:47-58.