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today's strib article on C&R


big_fish_guy

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does this number sounf too high? Is it inflated to make people feel good?
What say you...

http://www.startribune.com/stories/767/4771402.html

Catch-and-release walleyes live to be caught again, study finds
Doug Smith, Star Tribune
May 12, 2004DOUG12

More Minnesota walleyes caught by anglers are ending up back in the water instead of a frying pan, partially because many more lakes have special regulations that require anglers to release certain-sized fish.

But what are the odds those walleyes will survive to be caught again?

Pretty good -- depending on how and when the fish was hooked, handled and released.

Preliminary results from a hooking mortality study being done on Lake Mille Lacs by the Department of Natural Resources show that most walleyes survive being hooked and released. Of 848 walleyes caught by volunteer anglers and DNR employees last year, 47 -- or about 5.5 percent -- later died. When adjusted for several factors, officials believe the actual walleye mortality rate on Mille Lacs -- the most popular walleye lake in the state -- was about 3 percent last year.

94% of walleyes survive catch-and-release.Dennis AndersonStar Tribune"Catch-and-release works," said Keith Reeves, a DNR fisheries research biologist who is leading the two-year, $174,000 study -- one of the largest of its kind undertaken anywhere.

The study has implications for anglers, especially on Mille Lacs, because the results could influence fish management decisions.

Several factors affect hooking mortality, Reeves said, including water temperature and the depth of the water where fish were caught. Only 2.3 percent of the walleyes caught and released in May and June -- when waters are cold and fish tend to be in shallow water -- died. The mortality rate in September and October was even lower, 1.3 percent.

But more than 13 percent of the walleyes died in the warm-water period of July and August, when fish were caught in 24 to 33 feet of water.

"It's a combination of factors," Reeves said. In the fall, anglers are using crankbaits, which tend to hook walleyes only in their mouths. In the summer, anglers are using live-bait rigs and more often are deeply hooking walleyes.

"And warm water is more stressful," he said. "It may not be a good idea to catch and release a lot of fish in the summer on live bait."

The size of the fish also was a factor. Although most fish died after suffering damage to internal organs caused by hooks, medium-sized walleyes, 17 to 21 inches long, appeared more resilient to being caught and released than smaller or larger fish, Reeves said.

Smaller fish appeared to be more vulnerable to hook damage, and large walleyes were more vulnerable to stress and exhaustion, he said.

One warning to anglers: Some fish that appeared fine when released later died.

"Most of the fish we cut open had internal injuries . . . damage to heart, kidney or liver," Reeves said. The heart of a walleye is at the base of its throat, so when anglers remove a hook embedded in the gut or throat, they might cause mortal damage.

That's why DNR officials suggest cutting the line on deeply hooked fish rather than trying to remove the hook.

But Reeves said some fish that were bleeding when released did survive, especially when the water was cooler. And although few fish floated to the surface when released, almost half of those that did later died.

"Jigs, despite their ease of removal compared to regular barbed hooks, did not lead to increased survival," Reeves' preliminary report said.

Officials placed 6-foot-by-6-foot net pens in Mille Lacs, then put fish caught by DNR employees and volunteer anglers in the pens for five days, to determine delayed deaths. Handling time, hook location, bleeding and other factors were recorded.

About 120 volunteer anglers agreed to donate their fish to the study, but interest waned as fishing became more difficult last summer, Reeves said.

"It was difficult to get volunteers in the summer because fishing was so slow," he said.

The DNR is hoping to get help again this season from anglers. Officials also will be seeking walleyes on Gull Lake near Brainerd this summer to include in the study. Mille Lacs has few smaller 12-to 17-inch walleyes and Gull Lake has many, and Reeves wants to see how the smaller walleyes fare when caught and released.

Researchers and volunteers also will be catching walleyes on both lakes this summer using barbless hooks to determine if they reduce hooking mortality.

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Three percent mortality seems pretty low but here's the key information:

"Pretty good -- depending on how and when the fish was hooked, handled and released."

I'd say that it's pretty hard to get an accurate number because your survey should be reflective of all the variables. Looks like the reached the point of good enough data when the $174,000 was spent and moved on to the next project.

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Ya I dont think their numbers are to reliable. Lots of stuff they just cant measure accurately if they didnt catch the fish themselves.
Mil Lacs was a poor place to do the study. Unless how many 10' live bait rigs were found ingulfed in a fishes throat was measured.

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We have the full study summary on our website if you care to read the scientific facts. www.MnWalleyeAlliance.com
Keith Reeves, the DNR person in charge of the study, sent it to our club.

We are going to help out the dnr on a portion of the study this year that will study smaller fish from Gull lake so the process is continuing.

ccarlson

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It seems to me that they are making a reasonable effort to try to quantify hooking mortality on ML. For sure this isn't an exact science due to all the variables, but it's a start. At least now they have some better lake-specific data on mortality instead of just assuming an across-the-board 10% (or whatever) mortality. When they figure the safe harvest level for ML they include mortality so if the studies show less mortality than what was previously thought then that should result in an increase in the poundage of fish that can be harvested. Theoretically that is.

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