Why it matters

Seahorses are unique fishes. Unlike most other fishes, they swim upright, with their horse-like head at the top and monkey-like tail at the bottom. Even more astonishingly, it is the male seahorse that gets pregnant. Really! Males and females generally form faithful pair-bonds and meet daily to greet each other with a kind of dance. When they are ready to mate, the female inserts her eggs into a brood pouch located under the male seahorse’s torso. The eggs are fertilized within the pouch and the male seahorse carries them around and provides them with nutrients until the baby seahorses hatch inside the pouch. The male then undergoes contractions to propel the baby seahorses out of a small opening in the pouch.

Seahorses are also excellent at hiding. They can change their colour and grow filaments and appendages to blend in with their environment. This helps them avoid their predators, because they are not strong swimmers. It also helps them surprise their own prey. They wait unnoticed until their favourite food (a tiny shrimp or copepod) swims by at close range and then simply suck them into their mouth. Seahorses have fused jaws, so their snout is similar to a vacuum tube.

There are many different species of seahorse. Indonesia is home to 13 different kinds – that is more than a quarter of all the seahorse species that exist worldwide!

Unfortunately, many of the features that make seahorses special also make them vulnerable to over-exploitation by fisheries. As poor swimmers, they have no chance escaping from fishing gears such as trawls, bottom-contact seine nets, or push nets that actively sweep the sea bottom habitats where seahorses live. Similarly, they are easily caught by passive fishing gears, such as set gillnets, fish and crab pots, and other traps, because they like to hold on to ropes, mesh and other thin structures with their tail. This means seahorses are caught incidentally as bycatch by many different types of fishing gear. When one seahorse is caught, it’s partner may not find a new mate for a long time, because of the faithful pair-bond. Moreover, compared to other fishes, seahorses have relatively few young.

It is important, therefore, to understand where seahorses live, what pressures they face there (from fishing but also other changes to their environment) and how these pressures are affecting their abundance. If seahorse numbers decline, they cannot effectively play their role in the ecosystem. Their disappearance can also have important socio-economic consequences. Seahorses are attractive fishes for divers and therefore represent opportunities for tourism. Seahorses are also valued by some for use in traditional medicine. In addition, live seahorses are sometimes used as aquarium pets.

In Indonesia, the collection and trade of seahorses requires a government permit. Understanding where the different seahorse species live and how their populations are doing can help the government determine how many permits to issue to make sure any utilization and trade is sustainable.

Improved recognition of the different seahorse species and regular monitoring of seahorse populations, seahorse catch and seahorse trade can help assure ecological sustainability. In turn, healthy seahorse populations in healthy coastal ecosystems help maintain coastal livelihoods and associated cultural traditions. Good management of seahorse fisheries and trade is part of properly taking care of marine resources for the benefit of nature and people. 

[Updated 20 August 2026]