Wednesday, June 15, 2016

MRS Walleye Tagging Study Continues in North Dakota

North Dakota Game and Fish Department fisheries biologists are on the final leg of a four-year walleye tagging study on the Missouri River and Lake Oahe.

South central district fisheries biologist Paul Bailey said this spring's goal in North Dakota is to tag 4,000 adult walleye, which would bring the four-year total covering the entire reach to more than 36,000 fish.

The study area extends from the Garrison Dam in central North Dakota downstream to Oahe Dam in South Dakota, and involves a major collaboration of biologists and researchers from North Dakota Game and Fish, South Dakota Game, Fish and Parks, and South Dakota State University.

“The study is designed to assess walleye movements, mortality and what proportion of the walleye population is harvested annually by anglers,” Bailey said.

The study targets adult walleye, each fitted with a metal jaw tag stamped with a unique number to identify the fish, and a phone number to report the tag. Anglers can either keep or release the fish. Anglers practicing catch-and-release can write the tag number down and report it, leaving the tag on the fish when released.

Bailey said the study has provided biologists with some valuable information. “The angling mortality rate that we’ve seen in the first three years of the study has been about 17-27 percent, depending on the region of Lake Oahe and the Missouri River that we are in,” Bailey said. “Those are all acceptably low rates of mortality that basically says that anglers are not having a negative impact on the fishery at the present time.”

In addition, Bailey believes a lot of anglers assume there is a walleye migration that occurs every spring, similar to a spawning run. “The information that we are getting suggests that this really isn’t the case,” he added. “What anglers are seeing is really an illusion, based on water temperatures.”

Movement patterns suggest over half of the tagged walleye that were reported by anglers were caught within 10 miles of where they were tagged and released. However, Bailey said the pattern shows fish tagged in North Dakota moved greater distances than those tagged farther downstream, and North Dakota fish moved both upstream and downstream after tagging.

While the tagging portion of the project will be completed this year, anglers will be able to report tagged fish as they are caught in the future.

Anglers can report tags by calling the phone number found on tags, which, anglers should note, is a South Dakota phone number. Tag information can also be reported on the Game and Fish Department’s website, gf.nd.gov, or by calling 701-328-6300.

Anglers should record the date and location of the catch, whether the fish was kept or released, tag number and length and weight (if the fish was measured). Anglers who report tagged fish can keep the tag, and will receive a letter providing some history on the fish.

A small portion of the tags offer a reward to anglers to encourage returns, Bailey said, with these tags clearly marked “Reward.”

Reward tags must be physically turned in to Game and Fish offices in Riverdale or Bismarck, or to a Game, Fish and Parks office in South Dakota.