Flat-faced seahorse
A vulnerable seahorse species traded for medicine and souvenirs.
The flat-faced seahorse, also known as the longnose seahorse, low-crowned seahorse, or three-spot seahorse (Hippocampus trimaculatus), is a species of fish in the family Syngnathidae. It is found in shallow seas across Australia and Asia, including countries such as India, Indonesia, Japan, the Philippines, and Vietnam. This species is notable for its vulnerability due to habitat loss and heavy international trade, leading to suggested restrictions by CITES.
Quick Facts
- Taxon
- Hippocampus trimaculatus
Facts from the source article.
Lore & Background
The flat-faced seahorse is primarily found in shallow seas, typically at depths of 10–100 meters, though juvenile drifting individuals have been observed at less than 0.1 meters in the Malacca Strait, suggesting possible passive long-distance migration. Its diet consists of plankton and small crustaceans, which it sucks in through its snout while anchoring to sea grass to save energy. Appearance varies: it can be golden orange, sandy, black, or have brown and white zebra-like stripes, with a flat body, sharp cheek and eye spines, and a narrow head lacking nose spines. Males are slightly longer on average than females.
Reader's Guide
The flat-faced seahorse is significant due to its vulnerability from habitat loss and heavy exploitation. It is among the millions of seahorses traded internationally each year, frequently caught as bycatch, and used in traditional Chinese medicine, sold as dried souvenirs in the United States, and as pets worldwide. These practices prompted CITES to suggest restrictions on the seahorse trade, including a ban on harvesting individuals under 10 cm. This size restriction is critical because flat-faced seahorses reach sexual maturity before growing to 10 cm, unlike some other seahorse species. Reproduction is size-dependent rather than age-dependent; for example, populations in the South China Sea matured at 3 months old, while those in the North China Sea matured at 5 months old, both at the same size. Gestation lasts 11–20 days, varying with water temperature. Genetically, H. trimaculatus is divided into two lineages across Wallace's Line in Indonesia, with one study finding all sampled trade specimens from the Asiatic lineage, though sample sizes were small. Deep genetic breaks exist among individuals collected 800 km apart, yet identical haplotypes occur up to 10,000 km apart along the Asian continental shelf, indicating extensive gene flow over the last 10,000 years.
Did You Know?
- Juvenile flat-faced seahorses have been observed drifting at depths less than 0.1 meters in the Malacca Strait, possibly the first recorded drifting juveniles of this species.
- Gestation duration varies with water temperature: 19 days at 22.5 °C, 16 days at 24 °C, and 11 days at 28.5 °C.
- All seahorses sampled in one study for Chinese medicine or souvenirs came from the A lineage on the Asiatic side of Wallace's Line.
- Identical genetic haplotypes have been found in specimens collected up to 10,000 km apart along the Asian continental shelf.
Frequently Asked Questions
What is the flat-faced seahorse?
The flat-faced seahorse (Hippocampus trimaculatus) is a Syngnathidae species also called the longnose, low-crowned, or three-spot seahorse. It inhabits shallow coastal waters across Australia, India, Indonesia, Japan, the Philippines, and Vietnam.
Where does the flat-faced seahorse live and at what depth?
Adults typically occupy depths between 10 and 100 meters in shallow seas, though juveniles have been spotted in water less than 0.1 meters deep. Its range stretches across the Indo-Pacific, from the China Sea to Australian coastlines.
How does the flat-faced seahorse reproduce?
Males carry eggs for a gestation period that averages about 16 days, though this shifts with water temperature—ranging from 11 days at 28.5 °C up to 19 days at 22.5 °C. Peak breeding in the China Sea runs from March through May.
Why is the flat-faced seahorse considered vulnerable?
Habitat degradation and heavy international trade for traditional medicine and souvenirs have pushed the species toward a vulnerable status. CITES has suggested restrictions to curb the commercial pressure on wild populations.
How can you tell a flat-faced seahorse apart from other seahorses?
As the name suggests, it has a distinctly flattened facial profile and a relatively long snout, and it typically displays three prominent spots on its body. These features, combined with its Indo-Pacific range, help distinguish it from look-alike species.
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