Lordy / Fitzy,
Agree mullet are a good idea (have made the same recommendation in a report to DNRM) myself - just laughed about Lordy's good environmental measure throw in a few mullet etc..
I don’t have to provide explanations for past stocking or translocation policies - I didn't support them or practice them!
Barra are WAY MORE EXOTIC to the upper Brisbane than Mary River Cod - Mary Cod, Brisbane Cod, Albert Cod, Logan Cod, Cooma Cod - even bloody Clarence Cod are all part of the same EASTERN COD species complex - genetic work has shown Mary Cod to be the closest living relative of Eastern Cod (Clarence Cod) PM me if you want the reference - so Brisbane Cod would be even more closer - probably just about genetically indistinct and definitely ecologically indistinct. Cod are the NATIVE top order predator of the upper freshwater reaches of the Brisbane catchment.
Rivers are not too cool all year round for barra to go walkabout especially when you get a fresh in summer - I know the species well enough.
Brisbane Cod went into an extinction spiral because of low numbers and poor habitat quality coupled with ongoing high fishing pressure and active catchment degradation until the day they checked out (and perhaps not all of them did - there are still recent records of large fish from the upper Stanley) - today catchment degradation has been halted/stabilised (there is more riparian vegetation cover now on many tributary streams than there was in the 50's, 60's) and can be rehabilitated (landcare revegetation etc) and fishing pressure can be managed through prohibition on taking and ultimately bag limits once populations re-established
The dams may not ever be fully suitable for breeding (artificial substrates could help - water authority red tape can be overcome) but many of the tributary streams are - I already mentioned that in my previous post - some including tribs of Big W have clear water, rocky substrates and perennial pools (PM me) - however dams are suitable deep water habitat to maintain a viable large populations of the species which can access tributary streams
Why am I not working in rehabilitating the Brisbane catchment - well I don't live there for starters - but I have worked there - some of my contributions are in a report to DNRM&E ‘Stanley River and Tributaries River Habitat & Processes Study –Condition and Trend Report (2003) – get a copy FYI and secondly I’m busy in working on rehabilitating Eastern Cod habitat in the catchment where I do live which is the Richmond
Yes, I do support stocking for recreational fishing in dams – species native to the catchment i.e. bass (&cod) are fine. Could even be convinced that barra and some principally estuarine species i.e., jack’s, trevally etc would be Ok in some smaller coastal dams if it could be demonstrated that there were no vulnerable natives. JPs which I love (I provided some of the first brood stock to Dilger’s hatchery for trials) also could also be Ok in a basin where they historically were – but in a basin where they were not – they’d be a drama as they can scale just about shear waterfalls to get to upper catchment areas and would slay unsuspecting frog and macroinvertebrate populations not used to such predation.
What to do about exotic species?? – stop putting new ones in – that is about the best you can do – strong translocation policies are part of it, better controls on the aquarium trade and outdoor ponds would also help. Barra may control but will not eradicate – catfish, banded grunter, tilapia – so it is BS to promote them as a solution to ‘noxious’ species – studies in Townsville Reservoirs showed Tilapia to be one of the things stocked barra would eat least in preference to dwindling populations of natives – bony bream etc
Yes I agree it does not need to be an either / or situation – be happy with your bass fishery in SE Qld, do the hard yards (politically and physically) to get Cod established again (another species online) and do some real ecological risk assessment to work out what artificial water bodies in SE Qld could be stocked with some of the more exotic species coming on line without causing impacts. – And I am a supporter of the hard work and conservation messages that the stocking groups do and promote.