How The Study is Carried Out
Anglers (from the NSSA) and Ontario Ministry of Natural Resources and Forestry (OMNRF) fisheries specialists work in partnership to collect and biologically sample adult steelhead during the spring spawning migration. Each day, over a six-week period (mid-April to the end of May), one or two anglers and an OMNRF specialist catch steelhead using normal angling practices. Each live-captured fish is biologically sampled (length, sex, scale specimen). In addition, a numbered colour-coded plastic Floy disc tag is sewn on the front part of the dorsal fin. In order to take into account possible tag loss, a unique fin clip also is applied each year. On completion of the biological sampling process, all steelhead are released at the location of capture.
Life history information (stream and lake years, age at maturity, total age and number of spawning events) is obtained by analyzing scale samples. Population size is calculated using a Petersen Population Estimate. Fish are marked (tag and fin clip) in one year, and based on the proportion of tagged fish captured the following spring, population size can be estimated. This technique is also used to determine steelhead growth rates, validate ages, document movement patterns and provide stray rates.
Portage Creek's water temperatures are recorded throughout the open water season using automated temperature loggers.
