Editing Eastern freshwater cod (section)

==Conservation status==
Following heavy declines in numbers and distribution, the eastern freshwater cod is currently classified as [[endangered species|endangered]] by the [[IUCN]].<ref name="iucn status 19 November 2021" />

===Population decline===
Early records show that eastern freshwater cod were extremely abundant in the all parts of the Clarence River system at the time of European settlement.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2009/>  They were so abundant that they were caught "on demand" for diners at one riverside hotel,<ref name=prokop/> and were reportedly even used as pig feed, as were the related [[Mary River Cod]].<ref name=rowland_1993/><ref name=pusey/>

A number of factors have led to the decline of eastern freshwater cod. One factor was decades of pronounced [[overfishing]], including with lines, nets, explosives, and spears. As a very slow-growing top predator with low fecundity, eastern freshwater cod are even more vulnerable to overfishing than Murray cod.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2010/><ref name=butler_2011/>

Another factor were several huge bushfires (on the scale of the entire catchment) in the 1920s and 1930s, but particularly a bushfire in late 1936. These caused severe and widespread ash-induced fish kills in the first rainfall events post-fire.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2010/><ref name=trove/>

Habitat degradation and siltation brought on by poor farming practices (such as clearing riverbank vegetation and allowing stock to trample river banks) has also destroyed many eastern freshwater cod habitats. Some of these practices leading to [[land degradation]] are still continuing.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2009/>

===Mining pollution===
[[Tin mining]] and dredging/sluicing for tin caused serious and widespread pollution of the Clarence River system in the late 19th century/early 20th century, with dozens of newspaper reports suggesting it reached its worst extent in the mid-late 1930s.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2009/> These reports detail numerous pollution events characterised by milk-coloured stinking water, stained river rocks, cattle refusing to drink river water, and hundreds or thousands of dead fish per event. An article in [[The Daily Examiner]] from 11 October 1935 states that pollution was "causing alarm amongst fishermen, stockowners and people interested in preserving the Clarence and its tributaries as tourist attractions", and that farmers had trouble in getting their stock to drink from the polluted water. It includes statements from fishermen who describe fish "dead in thousands".<ref name=examiner/>

This [[tin mining]] pollution caused many severe fish kills and was probably a key factor in the extirpation of eastern freshwater cod from large tracts of the Clarence River system in the 1930s.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2009/>

===Conservation actions===
The above factors, which have in the past led to the extinction of the [[Richmond River cod]] and the [[Brisbane River cod]] and the endangerment of the [[Mary River cod]],<ref name=pusey/> have reduced the eastern freshwater cod from an abundant fish found in all parts of the Clarence River system to an endangered fish absent from most parts of it. It survives only in limited, remote parts of the Nymboida/Mann and Guy Fawkes/Sara sections.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=nock_2009/> The latter population is now at risk of severe [[inbreeding depression]] and is in need of "genetic rescue" via translocation of genetically differing fish from the former, more diverse population.<ref name=nock_2010/><ref name=nock_2009/> Currently there are no management plans to undertake such translocations.

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 this finding. While a high level of poaching is still taking place, legal protection has played a large role in finally allowing the species to commence a limited natural recovery.<ref name=Anon_2004/><ref name=rowland_1993/><ref name=butler_2009/>

A restocking programme was undertaken by the government of New South Wales in 1984-1989, but was then closed and contracted to a private operation, which produced and stocked fingerlings until the late 1990s. The eastern freshwater cod stocking programme was suspended after genetic research indicated the fingerlings being produced had lower than desirable levels of genetic diversity.<ref name=nock_2009/> No eastern freshwater cod are currently being bred or stocked.

Concern has been expressed over the future of 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 bioregion to proceed. The fingerlings were contaminated with and introduced the [[banded grunter]] (''Amniataba percoides''), an aggressive small native fish, to the lower reaches of the river. It is feared that banded grunter may yet invade the main freshwater reaches of the Clarence River system, with possibly devastating impacts on eastern freshwater cod.<ref name=rowland_2001/>