Editing Eastern freshwater cod (section)

===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/>