The love for seahorses is a big reason we are here today.
After years of front-line conservation and research, we have also gained the attention of the international media. To date, we have identified and documented six seahorse species. You can find out more in our published reports.
What is a seahorse?
Although seahorse has a horse-like head, bony-plated body and prehensile tail, it is actually a fish.
Seahorses are from the genus Hippocampus, and belong to the family Syngnathidae. Their close relatives include the pipefish, pipehorses and seadragons.
Out of the 32 known seahorse species around the world, we have identified 6 species in our study areas, namely H. Spinosissimus, H. Kuda, H. Histrix, H. Trimaculatus, H. Kelloggi and H. Comes.
In addition, we also suspect the presence of two additional species, H. Barbouri and H. Monhikei.
Lab and aquarium observations have shown that small seahorse species have a lifespan of about 1 year, while larger species live to 3-5 years.
Here in Cambodia, our seahorses reside in coastal waters between the depth of 1-30m. They favor sheltered environments such as seagrass beds, rocky reefs, mangroves, sandy bottoms and coral reefs.
Seahorses have an equine appearance.
Its head is at right angles to the body. They also have a fully prehensile tail, and their eyes can swivel independently of each other.
Like other fish, they breathe through gills, extracting oxygen from the water that passes over them. However, their gills are small and compacted, almost like a grape in structure.
Another unique feature that is different from other fish species is the lack of scales. Instead, they have a thin layer of skin stretching over a series of bony plates, appearing as rings around the trunk.
Some species also have bony bumps or skin filaments protruding from the rings. These rings are very useful in species identification.
Besides the rings, we can also identify the species with their coronet, which is a crown-like group of spines on the top of the head.
Certain seahorse species even have special cheek spines, which are yet another identifying feature.
Seahorses are most common in sheltered environments where the water current is weak.
One of the reasons is that they are poor swimmers, and they only swim when necessary. They swim using the propulsive force of a quickly oscillating dorsal fin, and use the pectoral fins on either side of the body for steering and stability.
Most of the time, they use their prehensile tail to fasten themselves to seagrass stems, corals, sticks, or any other suitable natural or artificial object.
They also rely on camouflage – with changing colors and growing skin filaments – to blend in with their surroundings. This helps avoid detection from predators.
Seahorses are predators,
but they have no stomach or teeth. They feed by sucking in prey through a tubular snout, and then pass it through an inefficient digestive system.
Their feed on fish fry, amphipods, and other invertebrates that are small enough to fit into their snout.
They will sit and wait at the same spot, while either of their eyes move independently to search for prey. Once the prey comes close enough, the seahorse will suck them in rapidly using their long snout.
Seahorses have an unusual mode of reproduction: the male is the one that gets pregnant. This is one of the most extreme forms of parental care by the male.
Once a male reaches sexual maturity, he develops a brood pouch and is able to become pregnant anytime during the breeding season. The timing of the breeding season is probably dependent on water temperature, monsoon and the lunar cycle. In most seahorse species, the male and female are pair-bonded (i.e., monogamy) during the entire breeding season.
When a pair is ready to reproduce, the female deposits her eggs into the male’s brood pouch with the help of her ovipositor. The male then fertilizes the eggs, embeds them in the pouch wall, and envelopes them with tissues.
From this moment, the pouch functions like the womb of a female mammal. The fluid in the pouch is similar to placental fluid, where it bathes the eggs, provides oxygen and nutrients, and helps remove waste products. In short, the pouch helps reduce the stress of the offspring at birth.
The pregnancy can last between 2-4 weeks, with shorter duration under higher temperatures. During this period, the female would come and “greet” the male daily. The pair would change color, promenade, and pirouette together for several minutes. After the daily greeting, they then go on their separate ways for the rest of the day.
At the end of gestation period, the male will finally go into labor, which is usually at night. He will pump and thrust for hours to release all his brood. Each brood has about 100-200 individuals, but can be as low as 5 or up to 1,500 depending on the species. The newborns usually range between 7-12mm, and look just like the miniature version of the adult seahorses. From this point, the newborns receive no further parental care and have to survive on their own.
A mere few hours after the male has given birth, he is ready to become pregnant again. The pair will engage in courtship behavior – which looks like a extended version of their daily greetings – for up to nine hours.
Since we first started studying the seahorses in 2006, we have noticed increasing threats to these animals in Sihanoukville, Kampot, and Cambodian coastal waters in general. We stopped seeing certain species that were once present in the area, suggesting the possibility of local extinction. We also see a dramatic decrease in the rest of seahorse populations.
The threats to seahorses are two-fold.
The first part is about the biology of seahorses. Because seahorses are usually holding on to substrates instead of free-swimming, they have a small home range and high habitat fidelity. This makes them very sensitive to habitat destruction. The fact that they are monogamous and pouch-brooding also limits their reproduction rate. This means that it takes time for them to recover their population.
Globally, many of the Syngnathids (a.k.a., seahorses, pipefish, pipehorses and seadragons) are listed as vulnerable or endangered by the IUCN Red List. The Cambodian list of endangered and protected species also currently includes the seahorses, although the list is not fully implemented yet.
Seahorses are not only valuable as aquarium pets and curios, but for centuries, people also believe them to hold magical and medicinal properties. In traditional Chinese medicine, for example, people believe that seahorses can treat asthma, impotence, sexual dysfunction, lethargy, pain and other conditions. This is also the reason why China, Hong Kong and Taiwan are the biggest net importers of seahorses.
As for the supply, the majority of seahorses come from a handful of Asian countries, such as Thailand, Vietnam, India and the Philippines. Unfortunately, Cambodia is also one of the exporting countries. In fact, dried seahorses are transported illegally to Vietnam for 500 USD/kg through the black market right here in Kep.
By-catch and habitat loss
Many of the fishing practices in Cambodia are destructive and unsustainable. Bottom trawling, for example, can uproot the entire seagrass bed along with seahorses and every single organism. The unwanted catch or accidental catch is called by-catch.
On the other hand, coastal development, land reclamation and other human activities degrade and destroy important mangrove forests and seagrass beds. This causes habitat fragmentation and habitat loss, which are detrimental to not only seahorse but many other organisms.
Seahorse Research and Conservation
MCC has been protecting the seahorses and their key habitats since 2007. We believe that learning about their population dynamics, biology, and behaviors can help us set up a comprehensive conservation program for seahorses. We also conserve the seahorses via the following approaches:
1. Community-patrolled areas
Teaming up with the local authorities, the fisheries administration, and the community in Koh Rong Samloem and Kep, we can manage fish stocks and protect vulnerable habitats inside the community-patrolled areas.
2. Active patrols
Law enforcement is key. Active patrols around the islands of Koh Rong, Koh Rong Samloem and Kep help us put a stop to illegal and destructive fishing practices once and for all.
3. Fishery management protocols
New management protocols and models can help communities realize the ecological and economic impacts of fisheries.
4. Education and training
Through education and training, we help the local fishing communities who make use of non-selective fishing gears reduce by-catch rate.
5. Habitat restoration
We work to restore and reforest the degraded seagrass beds, which are an important seahorse habitat. We have also secured two of the main breeding grounds against human exploitation.
6. Economic Alternatives
By developing alternative livelihoods that are both ecologically and financially sustainable, we can reduce the pressure on the wild seahorse populations.