Eastern Freshwater Cod - Conservation

Conservation

Early records reveal eastern freshwater cod were extremely abundant in the Clarence River system as the time of European settlement. These records reveal eastern freshwater cod were so abundant they were caught "on demand" for diners at a riverside hotel, and were sometimes used as pig feed, the latter being quite shocking treatment and waste of a strikingly beautiful and valuable fish.

A number of factors have led to the endangerment of eastern freshwater cod. One factor is gross overfishing, including with lines, nets, explosives and spears. As a very slow growing, top predator with low fecundity ("fertility") eastern freshwater cod are even more vulnerable to overfishing than their relative Murray cod. Another factor was severe whole-of-catchment scale bushfires in the 1930s which caused very large, widespread ash-induced fish kills. Gross habitat degradation and siltation by poor farming practices (such as clearing riverbank vegetation and allowing stock to trample river banks) is another factor that has destroyed many eastern freshwater cod habitats, and unfortunately some of these poor farming practices continue unchecked today. Finally, serious cyanide pollution from mining caused serious fish kills in the late 19th century/early 20th century (Anon, 2004).

All of these factors have reduced the once abundant eastern freshwater cod to an endangered species with a limited distribution in the Clarence River System.

The same factors have led to the extinction of Richmond and Brisbane River cod and the endangerment of Mary River cod as well.

Eastern freshwater cod were recognised as a potentially separate and endangered species of cod in 1984, and were declared a protected species in that year. Subsequent research confirmed they are indeed a separate and endangered species of cod; they remain a protected species. Disturbing levels of illegal poaching are taking place however and are not being tackled.

A restocking programme was undertaken by the government of New South Wales from 1984 to 1989. The government-run stocking programme was ill-advisedly closed after 1989 and contracted to a private operation, which produced and stocked fingerlings until the late 1990s. The eastern freshwater cod stocking programme was then suspended after genetic research indicated the fingerlings being produced had very low levels of genetic diversity.

No eastern freshwater cod are currently being bred or stocked.

The NSW fisheries department has allowed the private operation that produced eastern freshwater cod fingerlings to retain broodfish and produce captive-reared eastern freshwater cod for the table fish market.

Concern has been expressed over the future of all eastern freshwater cod stocks in the Clarence River system after the NSW Fisheries department allowed a stocking of Australian bass fingerlings from a completely different bio-region to proceed (Rowland, 2001). The fingerlings were contaminated with and introduced the banded grunter, Amniataba percoides, to the lower reaches of the river. The banded grunter is an extremely aggressive small native fish species. It is feared banded grunter may yet invade the main freshwater reaches of the Clarence River system with devastating impacts on eastern freshwater cod.