The second ecological form is the short-living predaceous anadromous populations which are found in northern lakes and coastal rivers from Long Island to Hudson Bay, which are referred to as salters.

[7] The brook trout is characterized by its distinctive olive-green body with yellow and blue-rimmed red spots, white and black edged orange fins, and dorsal vermiculation.

[8] The diet of the brook trout is restrictive to the season and location of the fish, but will typically consist of terrestrial and aquatic insects, fry, crustaceans, zooplankton, and worms.

[12] Since the 19th century, isolated native eastern brook trout populations have faced extirpation due to stream pollution, habitat destruction, invasive species, and waterway damming.

[13] Although facing these pressures, the brook trout is not listed as an endangered species by the International Union for Conservation of Nature, but native population decline has been observed.

[17][16] The specific epithet "fontinalis" comes from the Latin for "of a spring or fountain", in reference to the clear, cold streams and ponds in its native habitat.

[3] A potamodromous population of brook trout native to lacustrine regions, which migrate into tributary rivers to spawn, are called "coasters".

[29] Many coaster populations have been severely reduced by overfishing and habitat loss by the construction of hydroelectric power dams on Lake Superior tributaries.

Salters are a short-lived form of brook trout that inhabit smaller bodies of water and exhibit less predacious behavior than coasters.

During this time they won't stray more than a few miles from the river mouth, but then return to freshwater tributaries to spawn in the late summer or autumn.

[32] The brook trout has a dark green to brown color, with a distinctive marbled pattern (called vermiculation) of lighter shades across the flanks and back and extending at least to the dorsal fin, and often to the tail.

[33] Brook trout are native to a wide area of Eastern North America, but are increasingly confined to higher elevations southward in the Appalachian Mountains to northern Georgia and northwest South Carolina, Canada from the Hudson Bay basin east, the Great Lakes–Saint Lawrence system, the Canadian maritime provinces, and the upper Mississippi River drainage as far west as eastern Iowa.

[35] Their southern historic native range has been drastically reduced, with fish being restricted to higher-elevation, remote streams due to habitat loss and introductions of brown and rainbow trout.

The brook trout was eventually introduced into suitable habitats throughout the western U.S. during the late 19th and early 20th centuries at the behest of the American Acclimatization Society and by private, state, and federal fisheries authorities.

The brook trout inhabits large and small lakes, rivers, streams, creeks, and spring ponds in cold temperate climates with mild precipitation.

[39] Clear spring water with adequate cover and moderate flow rates is indicative of strong habitability for brook trout.

In the ensuing stage of their life cycle, the fry will seek cover from predatory species in rock crevices and inlets.

[44] During this period of hiding, the trout will begin to mature into fingerlings by summer and start expressing parr marks to aid in camouflage.

[8] These fully developed adult brook trout will express a vibrant olive-green back, cherry red underbelly, black accented fins, and wavy dorsal patterns.

Revenues derived from the sale of fishing licenses have been used to restore many sections of creeks and streams to brook trout habitat.

[9] Artificial propagation in fish is the process by which eggs are inseminated, hatched, and grown in a controlled environment that minimizes unfavorable environmental pressures.

[58][59] This process was introduced as a way to counteract the effects of overfishing and aquatic habitat loss and to reinforce brook trout populations across the Northeastern United States.

[60] Hatchery rearing was also introduced to raise brook trout in large numbers for food production and sale for human consumption.

[60] Arguments against artificial propagation of brook trout claim that it can cause a degradation of the overall genetic pool due to the possibility of inbreeding among individuals.

[9][60] As early as the late 19th century, native brook trout in North America became extirpated from many watercourses as land development, forest clear-cutting, and industrialization took hold.

In the U.S., acid rain caused by air pollution has resulted in pH levels too low to sustain brook trout in all but the highest headwaters of some Appalachian streams and creeks.