DNR Hooking Mortality Study 2010 -2015
"Cooler By The Lake"
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Background on tagging. About 7 of us local fishermen are participating in a Michigan DNR Lake Trout Hooking-Mortality 5-year study starting in 2010. It is being conducted in Marquette (Lake Superior) and Alpena (Lake Huron). The only other study of this type was done in 1980 and showed 15% of the Lakers died when released. However, that study had very limited deep water data, which this study covers. Its purpose is to determine the survival rate of Lake Trout caught and released to help DNR biologists evaluate whether establishing certain size catch limits are having the desired management outcome. This information will be useful where slot limits are applied as it's counterproductive to release Lakers if their survival rate is too low. The study's plan is to for anglers to collectively tag and release 600 Lake Trout each year for 3 years and there will be 2 additional years to collect data on recaptured Lake Trout. Concurrently, DNR will tag and release 600 Lakers each year from trap nets to serve as a control group. Anyone who turns in a tag will receive a $10 reward from the DNR and receive a letter telling where and when the fish was tagged. Recaptured Lake Trout tags can come from anglers, trap nets, or gill nets.
How we do it. Once I decide to tag a Laker (it’s my choice whether to keep or tag fish but that must be done before I see the fish), I start a timer when the fish is first hooked to record play time. Once netted, the first timer is stopped and a second timer is started. I then tag the Laker with a green spaghetti tag under the dorsal fin and take a digital picture of the fish to show the tag number and fish length. Once released, the second timer is stopped and the condition of the fish on release is noted. I then log data for each Laker which includes playing time, and handling time, depth of fish when hooked, whether it’s a lean or fat, observed lamprey marks, whether the fish is bloated, how it was caught (e.g., downrigger, steel line, etc), where hooked (usually lip), location on Lake, and whether blood was present, and seagulls in the area. For this I get paid $5 per tagged fish.
Equipment we use. The cradle shown here lacks numbers as it's an early version. It's used for placing the Lake Trout while being tagged and taking a picture. I found it difficult to use and made several modifications shown in the next picture. The timer, and digital camera, and needle for tagging are provided to us, as well as a 3-ring notebook containing log sheets and tags. Click on the pictures to enlarge, and use your back arrow to return here.
The picture below is the fish we thought wouldn't survive but then obviously did and found its way approximately 210 miles to the Apostle Islands some 44 days later. You can see the lamprey scars on its side. Note my modifications to the cradle, including the Plexiglas top, hinged end for easy release, and rubber snubbers to keep the Laker from jumping out. I still wasn't completely satisfied with it and went to a completely different system, which works much better but I don't show here.
2010 Season Overall Results
2010 "Cooler By The Lake" Season Results
2011 Season Overall Results per DNR
2011 "Cooler By The Lake" Season Results
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