Quantifying the best handling practices for trout
– Dr. Steven Cooke, Carleton University
The Fish Ecology and Conservation Physiology (FECP) Laboratory at Carleton University is committed to ensuring that recreational fisheries are sustainable and to that end they work with a variety of partners to improve the science and practice of catch-and-release. Core to the Kenauk brand is providing clients with a true “wilderness” experience – private access to entire lakes in a pristine setting where the fish are plentiful. Beyond limiting fishing effort on lakes (i.e., clients “book” a specific lake and associated cottage and boat for a period of time), much of the Kenauk reserve is managed under a catch-and-release framework (i.e., fish are released after capture). Nonetheless, Kenauk must engage in extensive and costly stocking efforts to maintain fishing quality which implies that there is some level of post-release fishing mortality. Assuming that catch-and-release mortality occurs (at some unknown level) it is necessary to quantify that mortality to inform stocking practices and to identify opportunities for reducing catch-and-release mortality such that the need for costly stocking could be reduced.
With funding support from NSERC (NSERC Engage Grant funded in May 2015) we will generate the necessary biological knowledge for the industry partner to ensure long-term viability of their recreational fisheries using defensible research methods. The project will involve the capture of trout between spring and early fall to understand how water temperature (which changes seasonally) and fish condition (which also changes seasonally) influence catch-and-release outcomes. Fish would be captured using common gear used by clients including lures (spinners/spoons) and flies with either barbed or barbless hooks. Fish will be fought and handled for various periods of time to reflect a diversity of angler expertise. Details on species, water temperature, gear type, fish size, hook location, bleeding, and fish vitality (assessed with a reflex impairment technique) will be recorded and fish will be temporarily marked (with an external tag) and held for 48 hrs in lake net pens to evaluate mortality rate. Data will be incorporated into a model to identify the factors that influence mortality and reflex impairment which will identify opportunities for reducing mortality and sublethal impacts. We will also identify seasonal thresholds for air exposure which are necessary to share with anglers. The mortality estimate will inform models that will determine the extent to which stocking is needed to maintain fishing quality.
Stay tuned for results