Great Seahorse

Hippocampus kelloggi is a large-bodied seahorse, among the biggest in its genus, reaching lengths of up to around 30 centimeters. Like other syngnathids, it has a bony, ring-plated exoskeleton, a tubular snout used for suction-feeding on small crustaceans, and a prehensile tail for anchoring to holdfasts. Males carry fertilized eggs in a brood pouch until juveniles emerge fully formed.

Adults are typically slow-moving, sedentary ambush predators, feeding on tiny crustaceans and other zooplankton, and they contribute to the trophic structure of coastal marine communities.

The species occupies marine neritic waters across a broad Indo-Pacific range, with records from China, Japan, India, Pakistan, Oman, Tanzania, Australia, and Vanuatu. It is typically found in shallow coastal habitats, including seagrass beds, coral reef margins, and soft-bottom areas offering vegetation or structure for attachment.

The primary threat to the Great Seahorse is direct fishing and harvesting, both as bycatch in trawl and net fisheries and through targeted collection for use in traditional medicine markets and the aquarium trade. Its limited mobility and reliance on specific coastal habitats make it particularly vulnerable to sustained extraction pressure.

Conservation measures include the species' listing on CITES Appendix II, which regulates international trade, along with some national fishing and export restrictions in range states. Marine protected areas overlapping seagrass and reef habitats offer partial refuge, though enforcement varies across its range.

The population is assessed as decreasing, and the species is classified as Vulnerable. Continued demand for seahorse products and ongoing habitat-adjacent fishing pressure suggest the downward trend is likely to persist without stronger enforcement of existing trade and habitat protections.