Goldstriped Seabream

Rhabdosargus sarba, commonly referred to as the goldlined seabream, silver bream, tarwhine, or yellowfin bream, is a notable species within the family Sparidae, comprising seabreams and porgies. This species is widely distributed across the Indo-Pacific region.

The species was initially described as Sparus sarba in 1789 by the German zoologist Johann Friedrich Gmelin, based on observations by Peter Forsskål. The designated type locality for this species is Jeddah. In 1855, Wilhelm Peters described a new species, Sargus auriventris, from 🇲🇿 Mozambique. In 1933, Henry Weed Fowler reclassified S. auriventris into the new monospecific genus Rhabdosargus, naming it the type species. However, S. auriventris is considered a junior synonym of Gmelin's Sparus sarba. The genus Rhabdosargus is categorized within the family Sparidae and the order Spariformes, as outlined in the 5th edition of Fishes of the World. While some authorities propose a classification within the subfamily Sparinae, this edition does not recognize such subfamilies within the Sparidae.

The genus name, Rhabdosargus, combines "rhabdos," meaning "stick" or "rod," referencing the yellow abdominal band of Sargus auriventris, with "Sargos," a term used for Sparid fish in ancient Greek, specifically relating to Sargus as a synonym for Diplodus. The specific epithet, sarba, derives from the Arabic name for this species in 🇸🇦 Saudi Arabia's 🌊 Red Sea region.

Rhabdosargus sarba exhibits a deep, compressed body with a depth that fits into its standard length 2 to 2.3 times, and features a convex dorsal profile, most pronounced between the snout and the dorsal fin origin. The eyes are moderate in size, diminishing relative to the head with age. The dorsal fin comprises 11 spines and 12 or 13 soft rays, whereas the anal fin is supported by 3 spines and 11 soft rays. The largest molar-like teeth are those at the rear of the third outer row. The species displays a greyish color with a silvery-gold hue and yellowish to golden horizontal stripes along the flanks. The pelvic and anal fins show a yellowish to brownish tint. Rhabdosargus sarba reaches a maximum recorded total length of 80 cm (31 in), typically around 45 cm (18 in), and a maximum recorded weight of 12 kg (26 lb).

Geographically, Rhabdosargus sarba spans the Indo-Pacific from the 🌊 Red Sea and eastern Africa's coastlines, extending to southern 🇿🇦 South Africa, through the 🌊 Indian Ocean, and into the Pacific as far as the South China Sea and 🇯🇵 Japan, reaching 🇦🇺 Australia's coasts. In 🇦🇺 Australia, it is noted along the Western Australian coast from Bremer Bay to Exmouth and on the east coast from Townsville, Queensland, to Mallacoota, Victoria. There is an isolated record from the Mediterranean off Syria, likely indicating a Lessepsian migration from the 🌊 Red Sea via the Suez Canal (🇪🇬 Egypt). The tarwhine inhabits depths between 0 and 60 meters, with juveniles residing in estuaries and adults migrating to deeper coastal waters.

This species primarily preys on benthic invertebrates, particularly molluscs. The goldlined seabream is identified as a protandrous hermaphrodite in regions such as 🇿🇦 South Africa, 🇭🇰 Hong Kong, and the 🌊 Persian Gulf. However, research from Western and Eastern 🇦🇺 Australia suggests its classification as a rudimentary hermaphrodite, indicating potential species differentiation within the R. sarba complex. In 🇿🇦 South Africa, sexual maturity is achieved at approximately 26 cm (10 in) in total length, whereas, in Western Australia, it ranges between 15 and 21 cm (5.9 and 8.3 in) in fork length. Spawning occurs from July to November near large estuaries and river mouths in KwaZulu-Natal (🇿🇦 South Africa) and similarly timed in Western Australia, where the species spawns in batches. Sexual maturation averages at 1.8 years in KwaZulu-Natal (🇿🇦 South Africa), with sex change from male to female occurring between 1 and 2.5 years. They are observed moving to offshore locations for spawning purposes.

Rhabdosargus sarba holds significance as a recreational angling species in 🇦🇺 Australia, though it maintains minor importance commercially in southundefined. In 🇿🇦 South Africa and 🇲🇿 Mozambique, it is targeted by both artisanal and recreational fisheries. Overfishing in the 🌊 Persian Gulf has led the International Union for Conservation of Nature to classify R. sarba as Near Threatened in that area, although it remains categorized as Least Concern globally.