Brook trout (Salvelinus fontinalis) are also called brook char and belong to the char group. They have been termed the white rat of aquatic science because more experimental work has been done on this species than any other. Since they live naturally under cool water conditions that are clean, pure, and aesthetically appealing, much of the knowledge gained from these studies help form a basis for understanding the requirements of all salmonids.

General description: Brook trout are distinguished from most trout and salmon by a lack of any black spots on their body. In Alaska, brook trout have a dark green, worm-like marbling on their back and dorsal fin and bluish halos around some of the reddish spots on their sides. Otherwise, they resemble Dolly Varden which lack the marbling and blue halos.

Range and habitat: In Alaska, as in the western states, the brook trout is an introduced species. Between 1917 and 1950, many rivers, streams, and lakes were stocked in Southeast Alaska. As far as is known, none of the fish survived in any of the rivers and streams, and few survived in any of the lakes with access to the sea. However, the brook trout did survive in a few lakes where they now provide good sport fishing. In general, the fish seem to have done best in the barren subalpine lakes with relatively low food supply, marginal spawning, and year-round low water temperatures. They seem to be well adapted to these marginal conditions and probably are better suited for these waters than any other species.

Brook trout are found in Rustabach Lake near Haines; Upper and Lower Dewey lakes near Skagway; Salmon Creek Reservoir near Juneau; Green, Heart, Thimbleberry, and Long lakes near Sitka; Crystal Lake near Petersburg; Grace, Ketchikan, Shelocum, and Perseverance lakes in the Ketchikan area; and Emerald Lake (Texas Lake) near Hyder.

Life history: The brook trout populations in several Southeast Alaska lakes have been evaluated in recent years. Maximum age of fish sampled is 9 years. The majority of individuals are younger, with numbers of fish declining rapidly after age 5. Maximum length of fish sampled and corresponding ages for lakes surveyed are as follows: Green Lake, 14.9 inches, age 7; Long Lake, 7.5 inches, age 6; Lower Dewey Lake, 10. 5 inches, age 9; Rustabach Lake, 6.5 inches, age 9; Salmon Creek Reservoir, I 1. 8 inches, age 9; Thimbleberry Lake, 9 inches, age 5; Upper Dewey Lake, 15 inches, age 8. Populations of brook trout are relatively low in lakes studied, ranging from estimates of 500 catchable fish in Thimbleberry Lake (10 acres) to about 1,500 fish in Salmon Creek Reservoir (192 acres). The larger reservoirs had 6.4 to 8.4 fish per acre. Stomach content analysis of brook trout indicates they eat everything available, including aquatic and terrestrial insects, zooplankton, snails, and leeches.

Brook trout spawn in autumn when temperatures and day length are decreasing. Peak spawning activity in Green Lake was observed in mid-October, with spawning completed by early November. The eggs are deposited in a redd prepared by the female in gravel or other substrate and fertilized, usually by a single male. Most brook trout spawn annually after reaching maturity. They can successfully spawn over a variety of substrates in lakes. This ability makes them especially valuable as a sport fish in lakes with marginal or nonexistent stream habitat for spawning. Most other salmonids in Alaska require streams for successful spawning.

Sport fishing: The annual take of brook trout in Alaska by fishers is small, seldom numbering more than 2,000 fish. This low harvest is due to the small number of lakes containing the fish and that most of these lakes are accessible only by trail or airplane.

Those who pursue the brook trout and know how to fish for them are well rewarded for their efforts. The fish typically travel about the lakes in schools, and once they find your bait, fishing can be fast and furious for a few minutes until the next school comes by. In summer, small spinning lures cast over the shoreline shallows work well. Flyfishing with a size 6 white bucktail on a sinking line is probably how most Alaska fishers do best with these fish. Fresh shrimp meat or salmon eggs on a small hook are a favored method of bait fishing. Brook trout are excellent eating and savored by those who pursue them.