Whither Maine Char?

No freshwater fish has a more northerly distribution and no salmonid a wider distribution than the Arctic char. Restricted in the north only by perpetual ice and in the south (below about the 45-degree latitude line) by warmth, anadromous and landlocked forms range across North America, Siberia, Europe, Iceland and Greenland.

As the last glacier retreated, streams and lakes of what are now the contiguous United States were invaded from the sea by anadromous fishes such as salmon, smelt and char. As recently as 5,000 years ago, when the ice sheet still lingered in Maine, Arctic char abounded in the Northeast. Today you’d be more likely to encounter an Atlantic walrus or a polar bear in New England than an anadromous Arctic char. But that doesn’t mean the species isn’t present.

At their southernmost range on the planet, 12 or 11 (one is in doubt) relict populations persist in deep, cold lakes in Maine. The last populations in New Hampshire and Vermont were lost in the 20th Century when stocked lake trout preyed on them, competed with them and eventually hybridized them out of existence.

It’s misleading to refer to “the Arctic char” because forms throughout the northern hemisphere and even in Maine (where they’re called blueback trout) are so morphologically divergent—more so, for example, than some of the genetically divergent cutthroat trout we classify as “subspecies.” Few if any fish taxonomies are more complex, clouded or controversial.

While there is no general agreement as to classifications, ichthyologist Robert Behnke argues that North American Arctic char should be divided into three subspecies: Salvelinus alpinus oquassa of Maine and southeastern Quebec, probably representing the first evolutionary line of Arctic char on the continent established before the last glacial epoch; S. a. erythrinus of the high Arctic including wide swaths of Siberia; and S. a. taranetzi of Alaska and the Chukchi and Kamchatka peninsulas.

In Alaska most char live their whole lives in fresh water. In Scandinavia, Iceland and Great Britain multiple forms inhabit the same lakes. Most landlocked char that evolved in New England and southeastern Quebec were reef spawners, but the form native to Maine’s Rangeley Lakes—last seen in 1904—was a stream-spawner. The large char of Floods Pond (the water supply for Bangor, Maine) are piscivorous and grow to more than 20 inches. The invertebrate feeders of Maine’s Green Lake are apparently dwarfs, rarely making it past seven inches. In Maine’s Gardner Lake there’s even a snail-eating char.

Leading an intensive study of America’s last native populations of sub-Alaska Arctic char has been Dr. Michael Kinnison of the University of Maine.

“The thinking was that the fish of Floods Pond were more closely related to those of New Hampshire’s Sunapee Lake [lost in the mid-20th Century],” he told me. “Later genetic evidence indicated that they did not represent distinct ancestral lineage following glaciation. I think that the state misread that and went with the idea that all Arctic char are the same. What we’ve shown is that they’re not. The populations in Maine are about as isolated since the last Ice Age as they could be. Some populations have heavy spotting on their backs, almost like vermiculations. Others have nothing—the classic blue back. Gill-rakers vary. Maine’s Arctic char populations have had ten or fifteen thousand years to diverge, and they’ve become unique evolutionary entities.”