Hippolyte varians (provisionally named the “variegated seagrass shrimp”) belongs to the family Hippolytidae and genus Hippolyte. It is a small shrimp species that primarily inhabits seagrass beds, reaching a maximum body length of nearly 3 cm. It is commonly found in shallow seagrass meadows and occasionally in rocky reef areas with abundant algae, feeding mainly on epiphytic algae and organic detritus. Recently, during a routine intertidal biological survey at the seagrass bed near the lagoon mouth on the western coast of Dongsha Island, contracted researcher Liao Chen-heng of the Marine National Park Headquarters (MNPH) unexpectedly collected numerous specimens of H. varians, confirming the presence of a stable population within Dongsha Atoll National Park.
Specimen of H. varians collected from Dongsha Island displaying a brilliant emerald-green coloration (ovigerous female). (Photo by Liao Chen-heng)
H. varians is named for its highly variable body coloration, which may range in shades of yellow, brown, blue, or green. Its coloration is closely associated with the surrounding environment. Around Dongsha Island, possibly due to the extensive and pristine seagrass beds, individuals are often observed displaying a striking emerald-green hue, translucent and jewel-like, leaving researchers fortunate enough to observe them in awe. As global seagrass habitats continue to decline, populations of H. varians have diminished significantly. The International Union for Conservation of Nature (IUCN) has assessed its conservation status as Vulnerable under criterion B1ab(iii), indicating fragmented distribution and severe reduction in global habitat area. The presence of H. varians often reflects eutrophic conditions in local waters. Within Dongsha Island’s lagoon, limited water exchange and relatively abundant decomposing seagrass create nutrient-rich conditions, while the extensive seagrass beds at the lagoon mouth provide an ideal habitat and breeding ground for this species.
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H. varians mottled morph. (Image source: http://www.aphotomarine.com) |
H. varians brown morph. (Image source: http://www.aphotomarine.com) |
The occurrence of H. varians in the waters of Dongsha Atoll National Park shows clear seasonality. Its breeding season typically extends from November each year to around July of the following year, during which population densities may reach up to 15 individuals per cubic meter. Researchers at MNPH have attempted artificial propagation and restoration through captive breeding. Although larvae were successfully produced, the techniques for providing suitable larval feed remain under development, and early-stage artificial breeding efforts were ultimately unsuccessful. Dongsha Atoll National Park boasts world-class seagrass ecosystems that nurture remarkably rich biodiversity. Viewing this environment from a microscopic perspective allows one to more deeply appreciate the intricate beauty of its marine ecology. (Text by Liao Chen-heng)
The extensive seagrass beds at the lagoon mouth on the western coast of Dongsha Island serve as the primary habitat of H. varians. (Photo by Liao Chen-heng)