A boldly patterned, small fish, the jarbua terapon (Terapon jarbua) is characterised by the curved, dark brown bands that run along the length of its body, which provide excellent camouflage on the sandy sea bed where shadows are cast by ripples on the water’s surface (3). Silver-grey on the upperside and silver-white on the underside, with an iridescent sheen on the head, body and fins (2)(3), the jarbua terapon may also be identified by the blotches of black on the first, deeply-notched dorsal fin and the tail fin, which has black-tipped and black-barred lobes (3)(4)(5). Like other members of the grunter family of fish (Terapontidae), the jarbua terapon has a rather compressed, oblong body with a strong, powerful spine on each gill cover, and a slightly downward-pointing mouth armed with numerous small, sharp teeth (4).
An omnivorous predator, the jarbua terapon has a varied diet of fish, algae and invertebrates, which are all taken near the sea bed (2). It also displays another, slightly more unusual feeding strategy by consuming the scales of other live fish. It does this by initially settling in a slight depression in the sand and waiting for an unsuspecting victim to swim past. It then vigorously sweeps its tail so as to create a dense cloud of sand and thereby prevent its prey from spotting it as chunks of scales are taken from the prey’s body (4). This stealthy predator, however, may also fall prey to other fish, but when captured it often assumes a characteristic U-shaped posture, with the body bent almost double, by contracting the muscles along one side of the body. This makes the fins and spines around the gills erect so that the jarbua terapon becomes very difficult to swallow and is subsequently released by its captor (5). The jarbua terapon spawns in the sea, which takes place in spring off the South African coast (4).
Wide-ranging across the Indian and Pacific Oceans, the jarbua terapon is distributed from the Red Sea and east African coast through Southeast Asia to the Samoan Islands, southern Japan and Australia. It also occurs around a number of oceanic islands, including the Seychelles, Maldives and Mauritius (2)(3)(6).
The jarbua terapon is primarily a coastal species found in tropical and warm temperate brackish waters over shallow sand bottoms, often in the vicinity of river mouths. It also occurs in mangroves and may even enter freshwater. Juvenile jarbua terapons commonly use sandy intertidal areas as nurseries and are often found in tidal pools (2)(3)(4)(7).
While the current extent of the threats to the jarbua terapon is currently unclear, it is captured in fisheries across its range. In many places it is considered unpalatable and is mainly caught as bycatch in fisheries targeting other species, with up to five tonnes of grunters landed by New South Wales fisheries alone each year (8). In the Far East, however, this species is captured as a food fish (2)(4).
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