The biology of anadromous Salvelinus fontinalis (Mitchill, 1815) and Salmo trutta Linnaeus, 1758 in river systems flowing into Placentia Bay and St. Mary's Bay, Newfoundland

• Main Author: O'Connell, M. F. (Michael Francis)
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1982
• Subjects: North Harbour; Newfoundland
• Online Access: https://research.library.mun.ca/4191/; https://research.library.mun.ca/4191/1/OConnell_MichealFrancis.pdf; https://research.library.mun.ca/4191/3/OConnell_MichealFrancis.pdf

The biology of anadromous brook trout (indigenous) and brown trout (introduced) was studied for several river systems flowing into Placentia and St. Mary's Bays, Newfoundland. Outward movements of brook trout were observed from April to June; inward movements occurred in July-August. Movements between fresh and salt water in Northeast and Southeast Arms, Placentia appear to occur throughout the year. Outward movements of brown trout occurred concurrently with brook trout (North Harbour River, S.M.B.) while inward movements were observed from July through September. Smolt age of brook trout ranged from 1.⁺ to 7.⁺ years and that of brown trout from 1.⁺ to 8.⁺ years. Modal smolt age of brook trout ranged from 2.⁺ to 4.⁺ while for brown trout it was 2.⁺ to 3.⁺. The great majority of all samples for both species were comprised of smolt/post-smolt. It is possible that specimens of brown trout with a history of sea life leave North Harbour River, S.M.B. in a discrete run prior to the one observed in April-May which was comprised almost exclusively of smolt. There was some indication that homing occurs to Southeast River and its tributary Beaver River for brook trout. -- Growth in freshwater was slower than previously reported for the freshwater form of each species in lakes on the Avalon Peninsula. Growth in freshwater and salt water was slower than that reported for anadromous populations elsewhere in North America (brook trout) and in Europe (brown trout). The slow growth of brown trout in salt water could partially result from the relatively small portion of the yearly increment attained during the winter with temperature being the dominant determining factor. Newfoundland populations overwintering in estuarine and coastal areas likely experience temperatures of 0°C and less compared with 5-6°C for certain European populations. There was a dramatic increase in growth rate in salt water compared with freshwater for both species; also there was a tendency towards attainment of a greater ultimate size the younger the ...