Post
by Truedogz » Tue Mar 07, 2017 2:01 pm
Deathray
Cod have crossed the Great Divide on a number of occasions in the past to evolve into different species or subspecies. These include the Clarence, Richmond, Albert, Logan, Brisbane, Mary and Burnett systems. Similarly the ancestors of Macquarie perch were in the Shoalhaven system and crossed the divide into Murray-Darling Basin. In human history on this continent aboriginal people shifted fish around too. Their most lasting impact is the presence today of river blackfish in streams upstream of waterfalls.
I agree with peoples sentiments about developing the Yarra as a better fishery - save for the fact that care has to be taken as The Macca population is the best one in the country. The problem is the idealogues in some agencies believe that it should only have its originals fish species - a sentiment with some merit but totally impractical. All of the original large fish species in the Yarra, bar blackfish, were dependent on migration to the sea and some were totally dependent on the conditions which existed in the original Yarra estuary, which no longer exist.
The experts say bass don't come west of Wilsons Prom based on a 1986 survey. But old anglers who knew maintained there were pockets further west and I have seen absolute proof of this in the form of old pics of bass from the Tarwin and other systems. It leaves no doubt that bass were present but in lower densities than found in east Gippsland. In recent years bass have turned up in the Yarra and Maribyrnong and there is a fair population in the upper Glenelg. Anglers have been blamed for illegally stocking them but I suspect that it might be natural.
It appears from early accounts that estuary perch were present in numbers in the Yarra and Maribyrnong rivers, with bass in lesser numbers. There are accounts for example of 'Gippsland perch' being caught at Warrandyte during the goldrush, also near Sunbury, Keilor Plains etc. However, but by the 1870s the lower Yarra was trashed with the destruction of the rockbars, diversion of the river, filling in of wetlands and pollution from abattoirs. This led to their almost total disappearance though in recent decades they have recovered to be present in small numbers. The problem, until recent years, is that anglers didn't realise they were there or knew how to target them.
Based on the results elsewhere the estuary perch stockings will succeed. The areas being stocked are in fact freshwater so anglers will have to adapt their techniques to suit. Its a pity some don't get stocked upstream of Dights Falls.
Best Wishes
Truedogz