DOOR COUNTY, WI (WTAQ) - They smell bad and they litter Lake Michigan beaches, but fishery officials say the deaths of thousands of alewives means the big lake is healthy.

Their presence indicates a good food supply for lake trout and salmon.

Experts say fluctuating water temperatures probably killed the small silvery fish.

At Whitefish Dunes State Park in Door County maintenance workers rake the beach every day.

Ten years ago so many alewives died they clogged the cooling systems at power stations.