Ichthyologists place the brook trout in the family Salmonidae and usually refer to it as one of the chars. The term char is one of convenience. It has no zoological significance other than its reference to a closely related group of trout inhabiting northern waters. A recognized Canadian authority on the chars lists at least six different species of chars in eastern North America: the eastern brook trout (Salvelinus fontinalis); the Sunapee trout (Salvelinus aureolus); the arctic char (Salvelinus alpinus); the Dolly Varden (Salvelinus malma spectabilis); the blueback trout (Salvelinus oquassa); and the lake trout (Cristivomer namaycush). These trout are closely related and under certain conditions it occasionally may be difficult to positively identify individual fish.
It is possible to cross the trout, too. Maine fisheries biologists have taken a few zebras, which have been identified as brown trout-brook trout hybrids. The splake, a lake trout-brook trout cross (SI, July 11, 1955), is another.
Nevertheless, the eastern brook trout is usually recognizable. In 1815 a New York scientist named Mitchill identified this fish as a new species of char (Salvelinus) and called it fontinalis, which means "living in springs."
The official name listed by the American Fisheries Society Committee on Scientific and Common Names is eastern brook trout, but fishermen locally have attached a number of other names to the eastern brookie. They call it a speckled char, cedar tree trout, snow-shoe trout, native trout, mountain trout, red-spotted trout and Salter (sea-run) trout, among others. The term brook trout is misleading. There are literally thousands of rivers, lakes, ponds, thoroughfares and bogs in Maine and Canada which contain the eastern brook trout. In many of these waters the lake trout (called a togue in Maine) is also found. To distinguish between them, nomenclature identifies Salvelinus fontinalis in Maine as a squaretail trout and in Canada as a speckled trout.
The color of the back and sides of a brook trout is dark olive. The back is marbled or barred (see painting on pages 74-75). There are numerous spots on the sides, usually red but sometimes running into orange or yellow. The belly is light, but frequently it is the same color as the spots on the sides and may be gold or fiery red in the spawning season. The lower fins are dusky. Often they are orange with a line of black and in the fall a conspicuous edge of white. In the spawning season the male has a hooked lower jaw.
There are color variations not only on brookies in different waters but even on the same fish, according to the season. The richness of color in the fall spawning time is unbelievable, particularly on the male.
Though the skin shines when a trout is taken from the water, it is not particularly slippery and there is a healthy firmness to the flesh.
The growth rings on scales of Salvelinus fontinalis (see page 77) suggest that the species may expect to live but two or three years, on the average. Because they believe that some brook trout in streams may mature and die without ever reaching a length of six inches, certain states are reducing legal length limits for fishing on the species. A brook trout which lives as long as six years is considered by fishery experts to be quite old.
Growth rate, further research shows, may be rapid where food conditions are ideal in lakes and ponds. A three- or four-pound brook trout still may be a comparatively young fish.
In the middle 1800s this kind of information was not available. A certain Professor Agassiz, widely known in the Rangeley, Maine area, was asked the probable age of eight brook trout, weighing from 5� to 8 pounds, caught by a George Shepard Page of New York City. "They might be 10 or 200 years old," he is said to have replied.