IT COOL Brook trout are creatures of cool, well oxygenated streams and lakes. They may be found in our smallest streams and largest rivers, from beaver ponds to extensive lakes and from the rapids of a woodland brook to the salt tang of a river estuary. Springs in a headwater stream are best of all. Older trout usually move into larger streams or lakes, with the highest populations being found in moderately sized streams with abundant pools, ample cover and plenty of riffle areas. In some rivers and streams many trout move down to the salt water estuaries where abundant food and favourable temperatures result in faster growth.
Fish are usually two years of age or older before they spawn.
The males take on their breeding coloration as well as a hooked lower jaw, while the females retain a somewhat more subdued appearance. Meanwhile, the male keeps busy driving away intruders and occasionally nudging the female. Once everything is prepared and the redd is 10 to 15 centimetres deep, the two settle into the depression. Then, vibrating intensely with mouths agape they simultaneously discharge eggs and milt. For a short time the 4 to 5 millimetre eggs are adhesive, which prevents those not lodged in the gravel from washing out.