Unfortunately, there´s a huge human appetite for these animals and they are sold as souvenirs, and sometimes even snacks, round the world. They are used mainly for medicinal purposes in China, Japan and Korea, as they are believed to treat asthma, sexual dysfunctions, pain, and other ailments. Although there is no scientic proof of the effectiveness of such treatment, the demand for seahorses has exploded in the past few decades, mirroring China´s economic growth.
Fisheries all over the world supply this demand, with seahorses that are either targeted directly, or captured unintentionally (as bycatch) in bottom-trawl fisheries. By 2001, at least 25 million seahorses were traded by 77 countries – more than 70 tonnes!
Seahorses are also popular in aquariums (selling for €100 – 500 each). Thankfully they are now being successfully bred in captivity by the leading authority in Spain – Miquel Planas, University of Santiago de Compostela - who has spent a decade of the research to achieve a 90% success (survival) rate.
The Convention on the International Trade of Endangered Species (CITES) lists all seahorse species on its Appendix II, recognising that they may become threatened with extinction unless trade is closely controlled. In order to trade seahorses internationally, countries who have signed the CITES agreement must control and monitor exports, granting export permits only where it is clear that trade does not threaten wild seahorse populations. Nevertheless, illegal harvesting and trade occurs, and several countries have opted out of the CITES agreement.
In January 2010, 25,000 seahorses were seized from a warehouse in Peru, which belonged to a Chinese citizen who had planned to export them to Japan via Hong Kong. Only a month later in Panama, 20,000 seahorses were discovered hidden inside the stomach of a fish from Peru. In Hong Kong seahorses sell for 550 USD/lb.
Recent research comparing seahorse numbers in no-take fishing zones and adjacent areas suggests that such measures do not benefit seahorses. In fact the population of seahorses was found to be lower in the no-take zones correlated with a higher number of seahorse predators. A better way to protect seahorses is via preserving their habitats.
They commonly live in seagrass beds, mangroves, and coral reefs in coastal shallow waters, which are all highly sensitive to pollution, climate change and other human impacts. For example, the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 destroyed seagrass beds, driving down populations of an already-threatened pygmy seahorse species that inhabits the area. In the Med the seagrass Posidonia oceanica is listed as a protected species but is still declining due to human impacts.
Current research, combined with customs and trade records, shows that seahorse populations have undergone rapid declines. The Ria Formosa lagoon in Portugal was an area that became famous for its European seahorse population. However, after several years of study, these seahorses almost totally disappeared and no-one is sure exactly why (although illegal fishing is suspected).
There are still many unanswered questions, as seahorses are very difficult to study in the wild. They are listed in the IUCN Red List as Data Deficient and organisations such as iSeahorse and the Seahorse Trust encourage divers to report their sightings to their databases.
During the Seahorse Project 2014 research season, 28 individuals were found, about half of these were spotted regularly, others only a few times. A photo base has been built up (without using flash photography so as not to stress these sensitive creatures) in order to recognise individuals and be able to monitor their movements from year to year.