The Global Search for Seahorses in Bycatch

Charismatic symbols of the coastal marine habitats they call home, seahorses are flagship species for a wide range of marine conservation issues—but particularly for the indis-criminate capture of marine life by the world’s nonselective fisheries. Seahorses are found in shallow tropical and tem-perate oceans around the world and are bycatch in a great diversity of gear types and countries—from cast nets thrown from a Senegalese beach, to gill nets set in Thailand, to large trawl nets dragged along the ocean floor in Malaysia. Individual fishers or boats catch very few seahorses each day, but these low bycatch rates—when multiplied by the huge global fishing effort—may still pose a problem for sea-horse populations. This study set out to determine how these small seahorse bycatch rates scaled up after accounting for the size of national fishing fleets. The daily bycatch rate of just one seahorse per boat, across five gear types, summed to an estimated 37 million seahorses caught each year. The true number of seahorses in bycatch is certainly much higher, be-cause information was only available for a handful of coun-tries and a small number of gear types within those countries. These large catches are a concern, because seahorses have life history traits that make them more vulnerable to overfishing than other smaller-bodied fishes—for example, male seahorses get pregnant and many seahorse species are monogamous. Indeed, almost all fishers surveyed reported declines in their seahorse catch volumes over time, indi-cating that current catch rates may not be sustainable. For seahorses, as for many of the forgotten species at the bot-tom of world’s fishing nets, mitigation will only come from reductions in the fishing footprint through protected areas and exclusion zones where nonselective gears are banned. Additional mitigation will come from community-based ap-proaches to management, focused on creating incentives for fishers to avoid catching vulnerable species in bycatch.These images showcase some of the fishers, gears, and, of course, seahorses, that our researchers encountered during the global search for seahorses in bycatch.Bright blue, medium-sized trawl vessels on the west coast of peninsular Malaysia. Trawl nets were found to catch the most seahorses each year, although far more information was available for trawl nets than for other gear types. Photo credit: Julia M. Lawson/Project Seahorse.