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Special Interest > Habitat and Conservation

Sooties in the Mary - what prospects for Mary River Cod Recovery...?

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I have been coming across increasing numbers of references to the Mary River's apparently increasing Sooty Grunter population including some else where linked videos of some nice kayak based action involving some real thumpers!
I first came across Sooties in the Mary back in 2007 while doing baseline survey work as part of the Traveston Dam studies. At the time we assumed they were simply 'farm dam escapees' as DPI supported farm dam fish stocking programs back in the early 90's allowed Sooties to be stocked into dams under the translocation policies (or lack of) of the day.
Some of the else where and Utube threads associated with Sooty photos and vids from the Mary suggest that their numbers have increased since 2011 following the big floods. One assumes that this is associated with increased releases of fish from dams or breeding recruitment events or both.  Some of the contributors to the threads that obviously have been aware of the Mary's Sooty population were critical of guys who had advertised their presence as they felt that this would now lead to increased pressure on their 'secret' fishery and undermine the efforts they had gone to, to support the development of the fishery!?  What the latter means in terms of what has gone on I'm not sure, maybe some midnight stocking brigade activity into the river itself (cf. farm dams) or maybe some guys having a lend of themselves.
To me it is a real shame. Don't get me wrong next time I kayak the Mary I'm sure to enjoy the slugging hand to hand combat that only sooties can provide. But they just aint meant to be in the Mary River and what really concerns me is that the population of Mary River cod that has slowly been recovering in the Mary main channel - primarily through stocking efforts and perhaps a bit of natural recruitment is now going to be undermined.
Teraponids (Grunters) are a very aggressive family of fish. Anyone that has kept a spangled perch in a tank knows that they don't rate as a community fish. Sooties sit at the top of the Grunter aggression list, it’s part of what makes them such great sport fish.  Percichthids (bass and cod) may have pugnacious, aggressive adults but their juveniles are relative pussies compared to grunters. If you look at the historical distribution of fish in Australia grunters tend to be tropical and basses – cod subtropical and temperate – there was very little overlap between the two (Silver perch are one grunter that went all the way south) – and that is no accident, through evolutionary time it seems anywhere the grunters got to the Percichthids don’t do so well. There is one Percichthid that occurs in tropical north Queensland the Bloomfield Cod – which survives above a major fish passage barrier waterfall free from competition with any grunters – Yellow belly also occurred naturally in the Fitzroy on the boundary of the tropics.
The point of all this is that if Sooties are becoming established in the Mary (which it seems they are) it may be the death knell for Mary River cod ever establishing natural breeding based recruitment. One of the existing issues identified for Mary Cod in the system is the large population of fork-tailed catties that inhabit the lower reaches from around Tiaro up to the mid catchment. Historically these same reaches held good populations of large cod which would have kept catties in check. Now small cod have to make it through the ‘predation bottleneck’ presented by the catfish. Small cod are like jelly beans to catties. It’s no accident that the success of cod stocking in terms of established populations has been greater in the upper reaches where lower temperatures limit catfish numbers than in the lower reaches where catfish abound. Sooties now represent a tightening of this predation bottle neck for the survival of young cod.
I would love to have seen cod recover in the Mary main channel. The numbers have been increasing and fish can be encountered while chasing bass and other species – but now it may be they’ll just become a ghost species dependent upon stocking to keep them there – a poor substitute for a naturally breeding, recruiting, evolving population. The importance of looking after populations in sub catchments separated from the Mary main channel (Coondoo, Tinana) will be even more important now.
I don’t know how established the Sooty population is something we should be asking our fishery agencies to check out (DAFF Sweetwater members?) – but if they are breeding my general belief with exotic/translocated fish is that money is wasted trying to control  them once they’re established – only effective policy is to stop them getting there in the first place. That’s why we have translocation policies governing what species should be allowed to be stocked where.
I know a lot of rec fishers don’t like such constraints. Those less concerned about ecological impacts all want to have their favourite sportfish available in their piece of water…”how cool would it be if we could catch such and such in our creek, dam etc..” – next time you hear such ravings please pull them up – there are real costs to putting the wrong fish in the wrong place. Part of the beauty of having regionally distinct fish communities is that you can travel to different places and experience different species – if we just spread everything everywhere we’ll just end up with a common blancmange of the hardiest most aggressive species everywhere and a loss of some real cool native species in the process. 
Here’s to the recovery of the Mary River Cod  I know it is what I’d most like to encounter in the River – for sooties keep driving another 5 hours north – but if you do catch some Mary River Sooties – wack them in alfoil and throw them in the coals – eaten fresh out of the water – sooties are one of the best sweetwater eating species going! :youbeauty

I saw a Farcebook link yesterday to some video and the tool was abusing people for making it public.  Same fool had pics of MRC on his page during the closed season.  There is a group that was actively, illegally stocking Sooties up near Imbil from what I've heard.  Where do you draw the line at translocation though.

Its a good question Dale, back in my days on Freshwater Mac the approach used was a combination of natural basin range of species, existing fish community integrity of river basin concerned and threats posed by the biology / natural recruitment capacity of the stocked species.

Brad H:
Sooties in the Mary  :OMG definately time to get a yak and go fishing for ferals  :Hunting)

Lets have a 'sack a sooty' comp  :Clap)

Thanks for starting this thread Jim an excellent summary of what is a very concerning situation.
On a brighter note did not encounter any in the range of upper reaches that I covered through late summer and autumn this year nor did anyone else in any key habitat.


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