Fishes · Bony fishes · Seahorses

Spotted Seahorse

Hippocampus kuda Bleeker, 1852

syn. Hippocamphus kuda, Hippocampus aterrimus, Hippocampus borboniensis, Hippocampus brachyrhynchus, Hippocampus chinensis, Hippocampus fuscus +14 more

17 - 30 cmCITES IIVulnerable

1602

Hippocampus kuda, commonly referred to as the common seahorse, estuary seahorse, yellow seahorse, or spotted seahorse, is synonymously associated with populations once classified as Hippocampus fuscus, now recognized as H. kuda.

The yellow seahorse is a small marine species reaching lengths of 17–30 cm. It possesses a notably large, elongated body devoid of spines, with rounded bumps. Its head is relatively large in proportion to its body, featuring a short, thick snout. The coronet is modest in size and inclines towards the rear, sometimes displaying filaments of varying lengths. In some adults, a distinctive black line crosses the dorsal fin widthwise. The species’ body color generally presents as dark with a granular texture, although it may also feature yellow, cream, or reddish patterns with numerous small dark spots. The seahorse is equipped with a prehensile tail employed for grasping, enabled by the interplay of body plates and hypoxia muscles facilitating ventral bending.

Hippocampus kuda is distributed across a broad geographic range, inhabiting waters from the 🌊 Persian Gulf to Southeast Asia, extending to 🇦🇺 Australia, 🇯🇵 Japan, select Pacific islands, including Hawaii (🇺🇸 United States), and along the eastern coast of Africa from Tanzania to 🇿🇦 South Africa. The species predominantly frequents the Chinese coast and extends down to 🇦🇺 Australia. Its preferred habitats comprise estuaries, lagoons, harbors, littoral zones, and coastal seagrass beds, thriving in shallow waters up to 55 meters in depth. These habitats may vary from tropical to marine saltwater regions.

The mating system of H. kuda is strictly monogamous, characterized by a distinctive courtship involving the male's color adaptations and a dance around the female, accompanied by a clicking sound produced by the coronet. The mating culminates in the intertwining of tails, facilitating the transfer of eggs via an ovipositor into the male's ventral brood pouch, capable of housing up to 1,000 eggs for a developmental period of 20–28 days. The timing of birth is influenced by monsoon patterns, lunar cycles, and water temperature, with labor occurring predominantly during a full moon. Newly born seahorses measure approximately seven millimeters in length.

H. kuda are omnivorous, utilizing suction feeding to consume microscopic prey including larval fishes and zooplankton, while displaying limited swimming capabilities. Their natural predators include crabs, rays, tuna, sea turtles, and humans.

This species holds significant value within traditional Chinese medicine, purportedly supporting nervous, reproductive, endocrine, and immune systems, resulting in the annual utilization of approximately 25 million seahorses for medicinal purposes. The principal exporters include Vietnam, 🇮🇳 India, the 🇵🇭 Philippines, and 🇹🇭 Thailand.

In aquaculture, H. kuda is popular among enthusiasts who often cultivate brine shrimp and rotifers for feeding, supplementing with daphnia as required. These seahorses require aquarium environments mimicking their need for anchorage to coral reefs and similar structures, favoring quiet tanks free from aggressive fish and strong currents. Compatible tank mates typically include species such as Synchiropus splendidus and other bottom-dwelling fishes.

Despite their continued presence, particularly in regions like 🇮🇩 Indonesia and 🇵🇬 New Guinea, H. kuda is listed as vulnerable by the IUCN due to threats from bycatch in shrimp trawl fisheries, targeted collection for the aquarium and traditional medicine trades, and habitat degradation, compounded by inherent reproductive challenges. The species is also categorized under Appendix II of CITES, necessitating controlled trading to prevent unsustainable utilization. A 30% population decline over recent decades, driven by pollution, habitat destruction, and illegal trade, underscores the need for concerted conservation efforts.

Why it's threatened

Biological resource use

Intentional use: (subsistence/small scale) [harvest] · Unintentional effects: (subsistence/small scale) [harvest] · Unintentional effects: (large scale) [harvest] · Motivation Unknown/Unrecorded

In general, incidental capture in shrimp trawl fisheries and habitat degradation and exploitation are the main threats to this species. H. kuda is susceptible to incidental catch from trawling in many locations throughout its range (Giles et al. 2006, Perry et al. 2010). In China, Cambodia and the Republic of Korea seahorses are caught as bycatch although no information exists on volumes (UNEP-WCMC 2012b). Declines in Thailand of seahorse catches are attributed to overfishing, as well as an increasing number of fishers, trawling, and habitat destruction (Perry et al. 2010).

Hippocampus kuda is caught and traded for traditional medicines, aquaria and curios throughout its range (Perry et al. 2010). Trade in this species is extensive with over 2 million individuals traded per annum (Evanson et al. 2011, UNEP-WCMC 2012a).

Hippocampus kuda is also threatened by damage to its habitats (Vincent et al. 2011) from coastal development and destructive fishing practices. Land-based activities such as coastal construction can diminish seagrass beds and mangroves while leading to increased pollution and siltation in surrounding marine waters. For example, in Malaysia Hippocampus kuda numbers declined due to an extensive port development around the Pulai Estuary that destroyed large tracts of seagrass meadow (Vincent et al. 2011). Fishing methods such as trawling result in substantial damage to seagrass beds globally, and especially in the Indo-Pacific (Short et al. 2011). The decline in and fragmentation of the species’ habitats throughout its range indicates possible declines in populations in addition to those caused by fisheries.

All seahorse species have vital parental care, and many species studied to date have high site fidelity (Perante et al. 2002, Vincent et al. 2005), highly structured social behaviour (Vincent and Sadler 1995), and relatively sparse distributions (Lourie et al. 1999). These life history parameters often make species susceptible to exploitation as has been demonstrated for a number of species, including seahorses (Jennings et al. 1998, Foster and Vincent 2004). Although seahorses also have some traits, such as small body size, fast growth and high fecundity, that may confer resilience to exploitation pressures (Morgan 2007),

Due to the mode of spawning exhibited by Hippocampus kuda (ovoviviparous brood pouch male parental care), fecundityis comparatively low compared to non-brood pouch spawning fishes and therefore its capacity for population growth is more limited than other species (Brown et al. 2008). As a result of the lack of broadcast spawning of pelagic eggs, dispersal of potential recruits is limited. Additionally, given the limited swimming abilities of seahorses, it is highly unlikely that rescue effects would occur from adjacent populations.

Threat classification from the IUCN Red List.