The Chinese bahaba is one of the largest of all croakers (Sciaenidae) and has a limited geographical distribution. It can attain 2 m and exceed 100 kg (Lin 1939, Chu et al. 1963, Anderson 1972, Trewavas 1977). Based on catch information, the fish are reported from mouths of major estuaries along its distribution that it enters seasonally to spawn in large aggregations. Greatest catches were taken in the weeks prior to full and new moons with up to 300 fish taken in a season in Hong Kong in the past; now only the occasional small fish is taken.

The fish feed on shrimp, crab and other crustaceans. Feeding habit has been suggested to be seasonal, with mainly shrimp from December to May, mudskipper from June to August and lizard fish from September to November (Lu and Ye 2002). Sexual maturation occurs at about 13 kg and 35–40 cm total length (Chu et al. 1963, Wu 1991). Seasonally, the ovary develops from early December with <0.5% body weight, through late December (0– 5%), and become ripe in April (3–11%) when spawning takes place (Lu and Ye 2002). After spawning, adults move out to deeper waters and juveniles may be found in estuarine and coastal areas.

In the Pearl River estuary, the Chinese bahaba is suggested to still spawn around Xiqiyang, Dongguan (Lu and Ye 2002). This view is based on the perception of the fishermen, the high rate of spawned individuals and the believed suitable environment around the area (Le and Ye 2002).

Red List Category

Red List Criteria

Version

2006

Ng Wai Chuen (University of Hong Kong) & Cheung, W. (University of British Columbia)

Sadovy, Y. (University of Hong Kong) & Hilton-Taylor, C. (Red List Programme Office)

The species was first described in western science in the 1930s and now, throughout its narrow range along part of the southern coast of China, it is rare; any large fish caught generally merit a newspaper article. From the sporadic information started in 1930s, the fishing activities targeted on the species became very intensive in 1950s and 60s principally because of the value of its swim bladder for medicinal purposes. Different gear types were employed, including special nets (Ting Ji) designed to target this species (Sadovy and Cheung 2003). Landings of the species decreased with the heavy fishing pressure, from about 50 tonnes in 1930s to 10 tonnes in 50s and 60s (Hong Kong data). In recent years, only small fish (<30 kg) are taken sporadically, catches of large individuals are considered to be significant events, widely known to people locally or reported in local newspapers (Sadovy and Cheung 2003).

The swimbladder (maw) of this species is highly appreciated for its medicinal properties and as a general tonic for health (Lin 1939). Swimbladders price depends on its age and shape, sex and size of fish, and even on the place and season of capture. Its market value (per kg) has increased from little more than a few US$ in the late 1930s, to anywhere between US$ 20,000–64,000 in 2000–2001 (Lin 1939, Chu and Wu 1985, Sadovy and Cheung 2003).

The large body size (to 2m) of the species, its apparent similarities to the Totoaba (Totoaba macdonaldi) listed on Appendix I of CITES in 1975, the declines that have occurred and the general vulnerability of large marine fishes, in general, suggest that this species may be close to extinction. Spawning populations are no longer known (fishing was targeted on spawning aggregations in estuaries in the past) and, given the heavy fishing pressure in the region, there are likely to be few or no refuges remaining for recovery. Although the species is protected in mainland China, it is not protected in Hong Kong, and is still caught and landed in mainland China (Lu and Ye 2002). In addition, the estuaries in which this species spawns are degraded which may also have affected populations. It is not clear whether spawning aggregations of the species still occur, although some evidence suggests they might close to Dongguan, Pearl River.

No abundance, population or official catch data are available or collected.

Catches were highly seasonal, during summer and autumn to north, and November-April to the south in Guangdong Province especially around rocky islands (Chu et al. 1963). In Hong Kong, estimated annual landing was 50 tonnes in late 1930s. The catch dropped dramatically to approximately 10 tonnes by the 1950s and 1960s, with most fish relatively small (12 to 40 kg) and rare large individuals (>80 kg) were found (Lin 1939). By the 1990s, only small fish (<30 kg) were taken sporadically, and large individuals (>50 kg) had become rare (Sadovy and Cheung 2003).

In waters around Dongguan at the Pearl River delta, landings in 1950–1960s were estimated around 180–210 tons [note - this appears to be very high compared to other estimates and trends] (Lu and Ye 2002). In the 1980s, there is no estimate of landing data available. A trawl fishing survey, however, was conducted in 1981–1982. The Chinese bahaba represented 9% weight of the total catch, and 0.7% in terms of abundance. Size of the catch ranged from 55 to 617 mm (TL), mean 187 mm, showed that the smaller individuals dominated the catch. While in 2000s, the catch was estimated to be around 2.5 tons, based on the survey on illegal fishing and trading.

Similar patterns were noted in other parts of its geographic distribution after the 1960s; prior to 1980s, total PRC (mainland China) landings (not including Hong Kong) did not exceed 10–20 tonnes annually (Hui 1987), with 5–6 tonnes in Zhejiang Province (Wu 2001) in 1950s and 1960s. Early catch data for Min River were not available but 80 large fish a year were not uncommon (Sadovy and Cheung 2003): this information comes from a review of the Chinese literature and interviews with fishermen.

Decreasing

The species was threatened by heavy fishing pressure due to its vulnerable biological characters, large size, restricted geographic range and aggregating behaviour in and around estuaries often involving sound production that makes individuals particularly easy to find. It was also heavily targeted due to its high value which increased as it became rarer.

Although listed under Grade II State Protection, the Chinese bahaba is caught and sold illegally. It is estimated that there are about 30 fleets operating around the Pearl River estuary targeting on the species (Lu and Ye 2002), annual catch is over 2,500 kg. Because of the high value of a single fish, fishing continues even though population numbers are very low.

There are no known regulations for this species.

This species was listed as a Grade II State Protected Species in the Peoples Republic of China since 1989. Thus it is protected and its exploitation should be limited and regulated by Chinese authorities under the legislations in China. In 2005, the Chinese government designated a protected area in the Pearl River estuary to help protect this species.