SOLDOTNA - All-terrain vehicles are being blamed for tearing up some backcountry wetlands and for driving through streambeds near the headwaters of the Anchor River and Deep Creek.
That's a fish-rich area on the southern Kenai Peninsula where salmon, steelhead and other species spawn and grow.
Biologists said they discovered the damage almost by accident, while they were conducting fish counts around the area.
``We've only looked at a very small portion of these watersheds,'' said Mike Weidmer, a biologist with the Alaska Department of Fish and Game.
In those short stretches, biologists counted 45 ATV crossings - more than one per mile in Deep Creek and about one every two miles on the Anchor River.
Three of the crossings were within a Critical Habitat Area.
On the south fork of Deep Creek, where an ATV trail merges with the stream, biologists found a rare site: juvenile Dolly Varden with severe injuries.
The fish apparently had been run over.
In other places, erosion along the bank from ATV crossings has caused the stream to become so wide and shallow that spawning fish no longer can pass.
Weidmer said his biggest concern is that the ATVs could be stirring up sediment so badly that it's smothering the juvenile salmon and the insects that the young fish eat.
Overall, fish in the southern Peninsula's streams are doing well. Populations of kings, steelhead and Dolly Varden appear to be stable, said Bob Clark, a Fish and Game research biologist.
Still, the effects of this kind of habitat damage may not show up for a decade, Weidmer said.