The waters are generally turbid and visibility is limited, though water clarity has drastically improved over the past decade as a result of the accidental introduction of the zebra mussel. Ice is present for three to four months and as a result of the shallow depths, the region is completely covered for part of the winter. Because of its small volume, the retention time in Lake Erie is only 2.6 years. The shoreline is generally quite regular and low-lying, dominated by low eroding bluffs. An outcrop of bedrock in the extreme northeast has given rise to a series of headlands separated by sandy beaches that interrupt the straight trend of the coast.
Beaches are rare elsewhere.
The Wildlife Lake Erie had one of the most diverse fish faunas in the Great Lakes, essentially a warm-water one with over 110 native species, including bowfin, northern pike , yellow bullhead, freshwater drum, rainbow smelt, white bass, yellow perch, smallmouth bass, walleye and muskellunge. The lake chubsucker, restricted in Canada to Lake Erie and Lake St. Clair, occurs locally. Pollution and encroachment by introduced species, particularly carp, have resulted in an appreciable reduction in the number of native species. Important populations of amphibian and reptile species inhabit the coastal marshes and waters. Lake Erie sees the greatest diversity of bird species in the Great Lakes, mostly migrants .