Dam Level's

[Fitzy]

Quick update dams are not allowed to run dry as it plays up with the main dam wall! I spoke with DPI and they said that dams are stocked for"high water quality purposes"and NOT just for fishing.

Hi Wizard,
While your statement isn't entirely correct, one good effect from stocking fish into lakes is that their presence can potentially be of a benefit to water quality. It all depends upon the food web of any particular lake & how densely it is stocked with predatory fish. In the case of over stocking, it can have the opposite effect. I think the species stocked would also have a bearing.
In short it is theoretically possible (although not entirely proven in Oz) that stocking of predatory fish can manipulate the food webs to control algal blooms. It is proven in overseas situations & is reguarly used as a management tool. We just use that info as ammo to gain further support for stocking here & fisheries folk do the same. Helps keep them in a job after all.

Cheers,

Fitzy..

[Fitzy]

Pardon my ignorance, but isn't that exactly why the dams are there in #the first place? #

Hi Rev,
Partly yes. Other major reasons include flood mitigation, urban water storage (water for humans), industrial use & for entirely political reasons.
One thing that tends to get forgotten is that almost every dam around has been built by, or funded by taxpayers money. Therefore the everyday joe deserves to be allowed to utilise these dams & not just irrigators & multi-million dollars cotton plantations whom get thier water at a highly subsidised rate.
We should also remember that once any barrier is put across any river/stream etc, the endemic fish poluations are virtually doomed as most need to migrate to spawn. It also affects the recreational fishing opportunities for us. It is written into Qld law (don't know about other states) that any barrier across a water course must compensate the fishery that its presence has disrupted. That means supporting/funding the stocking if a fishway of some manner isnt possible.
Now before any fish are stocked into any crown waters, the managers of these lakes need to approve. By their approval they carry a duty of care to maintain enough water for the stocked fish to survive. If they dont, they risk public, private & taxpayers money being wasted. Since the start of the Recreational Fishing Enhancement Program in Qld some 15 years ago, we haven't seen any stocked lake totally drained, but we've come close a few times. The fallout if this ever happens could be significant.
While I support the stocking of our lakes/dams/weirs, I would prefer to see none built at all, but they are necessary. The artificial breeding & stocking of fish is an absolute last resort for fish preservation & should always be seen this way.
Nobody is suggesting that any dam be built just for fishing, that is quite absurd. (I'm still writting protest letters about this bloody Paradise Dam getting built on the Burnett R) But why not utilise them for maximum recreational fishing benefit once they are built.

I sometimes sympathise with irrigators when they don't get their "allocation" of water for the season. I am however very dirty over the fact that in some cases, Sunwater have over allocated the available water by upto 20 fold. That way if they get a big wet season, they can sell ALL of the water & not just the average years rainfall. (They commonly appear to work on the absolute best case scenario) . How rediculous.

Cheers,

Fitzy..

[PG]

The question..At what level should we stop fishing dams?
My 2 cents worth says when ya can't float your boat.
When water levels get low the food for the stocked predatory fish are starting to become scarce and therefore the fish are taken more easily. If those fish are not taken out I would imagine the primary consumers and primary predators (shrimps, small fish, plankton, dragonfly larvae, small fish) begin to disappear as they are eaten. What this would mean is an imbalance in the whole food chain. Top and bottom heavy as it were, where we have a larger population of predators and algae etc and not enough of the 'in between'. Not only does this make the health of the predators compromised but it also means that the animals that graze on algae, blue-green algae and bacteria are not in sufficient numbers to control them and therefore the water quality drops. I don't have an answer for how many fish per megalitre, or when we should stop pulling out fish but to me it would seem smart to keep the population of consumers of algae and bacteria to a level where they can control the blooms of such organisms as the water quality drops (which would result from an increase in nutrient levels due to nutrient concentration from evaporation, use and temperature increase).
I suppose, what I'm trying to say is that predatory fish eat the animals that eat the animals that eat shit. If you reduce the middle bit(by allowing the predators to eat them) you're left with predators and shit !
Predators < shrimp/fish< algae/plankton < algae < fish shit/nutrients.
This water is to be used for irrigation, human consumption, stock water and I don't know what else. If I was one of those people I'd like to have reasonably healthy water for any one of these purposes.

PG.

[wizard]

[quote author=Fitzy link=board=Freshwater;num=1062081580;start=10#10 date=09/02/03 at 00:54:04]I think dams should be fished at all levels. Mainly because of the fact that 99% of the target fish are stocked & are there for the sole purpose to BE caught.

Hi Fitzy
This is what I told the DPI officer and he stated 3 or 4 reasons for fish being stocked in dams. You used the word "sole"-"being the only one"

Wizard

[Justme]

Geez Fitzy
You sure sound like a towny to me.
Your going to deny people a livelyhood and let pigs die of thirst just so you can go fishing.
You have no idea of the hardships the pig industry & other intensive animal industries are in at the moment because of rising feed prices due to drought. They're not making squillions as you are indicating.
You'd better stay in town with thoughts on primary industries like yours or someone might take offence.
LBJ