Thousand Islands level year-round, and support at least two living trees. The Thousand Islands archipelago is located at the outlet of Lake Ontario at the head of the Saint Lawrence River. The region is bisected by the Canada–United States border and covers portions of Jefferson and St. Lawrence counties in the U.S. state of New York, in addition to parts of the United Counties of Leeds and Grenville and Frontenac County in the Canadian province of Ontario. Geologically, most of the islands are located where a branch of the Canadian Shield runs south across the river to join with the Adirondacks. The
North American river otter spp.), daces ("Rhinichthys" spp.), shiners ("Notropis" and "Richardsonius" spp.), and squawfishes ("Ptychocheilus" spp.); and Ictaluridae, which consists of bullheads and catfish ("Ictalurus" spp.). Other fish an integral part of the North American river otters' diets are those that are often plentiful and found in large schools: sunfish ("Lepomis" spp.); darters ("Etheostoma" spp.); and perches ("Perca" spp.). Bottom-dwelling species, which have the tendency to remain immobile until a predator is very close, are susceptible to North American river otters. These include mudminnows ("Umbra limi") and sculpins ("Cottus" spp.). Game fish, such as trout (Salmonidae) and pike (Esocidae), are not a significant