CAPE GIRARDEAU, Mo. (AP) — Low water levels on the Mississippi River are presenting challenges for some fish while benefiting other wildlife, experts say.

The drought has left the middle Mississippi River near record lows, prompting grave concerns about river commerce. The impact on wildlife varies greatly, driving some fish out of normally safe areas but allowing some animals to thrive along sandbars and side channels exposed by the low water level.

Missouri Department of Conservation natural history biologist Bob Gillespie told the Southeast Missourian ( ) that with low water, juvenile fish lack hiding places.

"Organisms that use shallow-water areas will not have as much habitat available to them as they would if the river was at a higher stage," said Gillespie, who works out of Cape Girardeau. Fish, including the pallid sturgeon, use shallow water for spawning and seek refuge there to get out of the current of the deeper water.

On the other hand, birds like the interior least turn benefit because they nest on sandbar islands. With the water so low, they have more nesting areas. When water is high the birds, rare to this region, can be forced to nest inland and become more susceptible to predators.

The Army Corps of Engineers has begun removing rock pinnacles from a six-mile stretch of the river near Thebes, Ill., just a few miles south of Cape Girardeau, as part of an effort to keep commerce flowing during the low-water period. Missouri conservation officials and the U.S. Fish and Wildlife Service are both on hand to monitor the rock removal that is expected to eventually involve the use of explosives. For now, the rocks are being removed through excavation.

Fish within the shock wave of the explosives could be harmed or killed. "When we do end up blasting, we will use the smallest charge necessary to get the job done," corps spokesman Mike Petersen said.

Contractors will employ a loud underwater noise to spook fish out of the blasting area.

"If we have folks downriver who see we get fish coming up to the surface and start to see impacts, we can immediately adjust what we are doing," Petersen said.