"Wouldn't drawing the pond down concentrate the number of G shad allowing predators to feed on them more effectively? "

Yes. But if there are not enough predators the reduction will be less than needed. Plus the predators still can't eat a 20 inch 2 lb GShad.

"With a greater concentration of G shad wouldn't their natural population control kick in and cause them to stop breeding? "

Possibly but only if the water were down just before and during spawning and only for the time the water is down. When it goes up they will "fill the space". Not sure you want a permanent reduction in pond size.

"If they want the G shad completely gone wouldn't concentrating their numbers and stopping breeding be the best option?"

Removing GShad or continual suppression of them with predation to the point they can't take over the pond are the only ways I have heard of where they don't get to big for predation and fill-up the pond biomass.

Drawing down the pond just before winter (pond low during winter) up north is a good way to create a winter kill of everything including the GShad . Draining the pond would do the same as would rotenone.

Drawing down the pond during spring and concentrating the GShad , finding them with sonar and gill netting them along with increased predation would help.

Last edited by ewest; 10/22/08 08:48 AM.