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Brook Trout Salvelinus fontinalis

Soil & Water Conservation Society of Metro Halifax (SWCSMH) Acknowledgements

March 06, 2007

The Province of Nova Scotia declares the Brook Trout as the Provincial Fish: Bill No. 70 (November 23, 2006) .... with salutations to the Legislature of the Province of Nova Scotia and the MLA for Preston, Keith Colwell, a former Minister of Fisheries!

For an extensive treatise on trout, the best reference is:
Stolz, J., and Schnell, J. 1991. (Editors) Trout. The Wildlife Series. Stackpole Books, Harrisburg, PA. 370 pp. ISBN 0-8117-1652-X.

The history

The brook trout is truly a North American species. The North American brook trout, Salvelinus fontinalis, actually is a char, the common English name given to all members of the genus Salvelinus. It was first described taxonomically by Samuel Latham Mitchell in 1814 from specimens collected near New York city (Flick, W.A., in Stolz and Schnell, 1991, Editors).

Range

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Habitat

Of all the members of the char family, brook trout adapt most easily to their environment and will tolerate the widest range of conditions, including extremes in temperature and pH level.

They grow and survive best in temperatures between 13° and 18°C (55° and 65°F). Brook trout, which like other char and trout are a coldwater species, can survive a wide range of temperatures, from near 0°C (32°F) to around 22°C (72°F). However, they have been known to tolerate temperatures above 25.6°C (78°F) for up to a few hours.

Brook trout tolerate acidic conditions particularly well, compared with other species. They have been known to survive at pH 3.5, though only in unusual circumstances. Realistically, the lower limits are around pH 4.8. The presence of aluminum ions or other heavy metals may raise the lowest pH level at which brook trout can survive. Where pH levels are low, brook trout may be the only game fish that can survive. But even this species has suffered because of acid rain, particularly in the northeastern United States and southeastern Canada.

High alkalinity is not a critical factor under natural conditions, and survival has been recorded at pH levels of 9.8!

Lake habitat

Many mistakenly consider deep, coldwater lakes the ideal habitat for brook trout. However, brook trout are not a deep-water species. They can tolerate that environment, but seldom will they use depths greater than 4.6 to 6 meters (15 to 20 feet) unless temperatures in shallower water are too high and no other coldwater refuge areas exist.

In fact, when water temperatures are high, brook trout are more likely to concentrate where a spring seeps, in cold water that may be only a foot deep, than to venture into deeper water of favorable temperature. Such behaviors contrast with those of most other chars, particularly lake trout (Flick, W.A., in Stolz and Schnell, 1991, Editors).

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Studies have shown that maximum growth and standing crops of brook trout occur in shallow ponds and lakes that contain no competing species. In contrast to the stream habitat, the trout do not have feeding stations. Cover in lake habitats is of minor importance!

Brook habitat

Brook trout can be found in even the smallest spring-fed streams, especially where cover is available. Fingerlings prefer shallow water about 41 cm (16 in.) deep, and adults do not need much more than that.

In streams, they prefer areas where the substrate consists of gravel and cobble with diameters of between 2 and 25 cm (0.8 to 10 in.). Stream fish have small home territories, or stations, and may remain by a given rock or log throughout the season, provided it is close to cover. Trout establish hierarchies and exhibit agonistic behavior at feeding stations, but they often will share escape cover.

As stream temperature drops in the fall and winter to the low 40sF, brook trout feed less and move closer to cover.

Spawning

Brook trout spawn in the fall. They prefer to select their spawning sites at places where groundwater wells up, a condition that is more important to them than the size of the substrate. This preference makes them highly successful spawners and enables them to spawn in ponds and lakes as well as in streams; most other salmonids spawn only in streams. Brook trout have an amazing ability to detect even minute amounts of groundwater seepage even when water temperatures in the stream or lake are similar to the upwelling water. If no upwelling groundwater is available, brook trout will use the tails of pools or riffles for spawning. where the gravel is about 0.34 to 5.05 cm (0.13 to 2 in.) in diameter and water velocity is 1 cm (0.39 in.) per second to 92 cm (36 in.) per second. Water temperatures at the time of spawning are usually 4° to 13°C (40° to 55°F). The spawning act is similar to that of other salmonids except lake trout.

Acknowledgements

Brook trout in the WikipediA

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