Red Cliff Hatchery bolsters Lake Superior coaster population - Stocks walleye in local lakes

Transcription

1 Red Cliff Hatchery bolsters Lake Superior coaster population - Stocks walleye in local lakes By Sue Erickson, Staff Writer Red Cliff,Wis_Rehabilitation of the coaster brook trout population in Lake Superior tributaries is one long-term goal of the Red Cliff Hatchery. The tribe's goal includes the restoration of Red Cliff Creek and the re-establishment of a naturally reproducing coaster brook, trout population in the creek in seven to eight years. Currently the hatchery is home to 1800 coaster brook trout used as brood stock to produce and rear "coasters." Sean Charette, Red Cliff Hatchery manager, says another of the hatchery's objectives is to bolster the existing wild strain of coaster brook trout. The effort seems to be working. This year twenty-five coaster brook trout with the hatchery's fin clip have been reported from areas near Grand Portage, Minnesota and east of Marquette, Michigan. Reports also suggest there has been interbreeding with the wild strains of coasters, Charette says. The hatchery staff does not have time to track down stocked coasters, so relies on reports of clipped fish for information. If an individual contacts the hatchery regarding a fin-clipped coaster, the informant will receive a fishing lure and information about the size and weight of the fish when it was stocked. Red Cliff cooperates with the U.S. Geological Survey, the U.S. Fish and Wildlife Service and a trout unlimited task force on coaster brook trout management. The Red Cliff Hatchery is the only source for the Niipigon strain of coasters in the U.S. The brood stock was originally obtained from Lake Niipigon in Canada and selected for its consistent spawning and hatch-out. The federal hatchery at iron River, Wisconsin is the only other hatchery producing coasters, and those are from the Isle Royale strain. Reserving 82,000 fingerlings for local stocking, in 2003 the hatchery shipped out 260,000 fingerlings to agencies and private ventures such as the Marquette Fish Hatchery: an aquatics laboratory in Sault Ste. Marie, Michigan: Brule High School in Wisconsin: Perdue University in Michigan, and the Grand Portage Band in Minnesota. While coaster brook trout rehabilitation is a major focus for hatchery, it also produces and stocks extended growth walleye. Currently, two million walleye fingerlings inhabit the hatchery's three rearing ponds. In early October, they should reach inches and be ready to stock, Charette says. This year both the Red Cliff and Lac Courte Oreilles Hatcheries will be stocking Nelson Lake, Sawyer County, where natural reproduction seems to be failing. Red Cliff will also stock Lake Nebagamon, Bayfield County. The Red Cliff Tribe generally stocks walleye in lakes that have been used during the spring spearing season.

2 In addition to hatching, rearing and stocking coaster brook trout and walleye, the hatchery provides tours to school groups, tourists or other interested persons. Last year 308 people visited the hatchery, and fifteen tours were conducted, Charette says. While most tours are for areas schools, a group of nurses from Chicagowas among the tours hosted last year. Visitors can also fish for trout in a trout pond on the hatchery's premises. The pond was originally established to remove excess nutrients from hatchery waters before entering into the Red Cliff Creek. Visitors can fish and release and also get some education on how the food chain works, according to Charette. Hatchery staff works closely with other tribal programs to enhance and protect the fishery as well as provide public education. For example the hatchery and Red Cliff's Natural Resources Department are collaborating to establish a full-fledged visitor's center, including an aquarium, as a public education tool on the hatchery's grounds. Hatchery staff also works in conjunction with the Red Cliff Fish and Wildlife Department in fishery assessments and inventories. The staff joins Matt Symbal, Red Cliff fish and wildlife biologist, in performing lake trout assessments in Michigan and Wisconsin waters of Lake Superior. Other assessment work in Wisconsin waters of Lake Superior includes juvenile lake trout surveys, comparing spawning in the lake trout refuge vs. Sand Island spawning grounds; tag and release studies of lake trout spawning, and whitefish spawning assessments. Another cooperative venture, this time with Red Cliff's wastewater facility, converted four sewage ponds into walleye and perch ponds for hatchery use. Reprinted with permission from Mazina'gan, Fall, 2003; a publication of the Great Lakes Indian Fish and Wildlife Commission State walleye anglers onmillelacslakestay well within quota so far Mille Lacs Lake, Minn. _Unlike last year, state harvest of walleye in Minnesota's Mille Lacs Lake is well under quota to date. As of July 15, the Minnesota Department of Natural Resources reports a total walleye kill of 56,379 pounds. The figure combines 30,292 pounds of harvested walleye and an estimated mortality of released fish at 26,087 pounds. This compares to last season's July 15 figure of 348,732 pounds of walleye killed. That put the state well over its 300,000-pound quota by mid July in This year, the state and the tribes did not reach consensus on a harvestable surplus level for Mille Lacs Lake. In the absence of consensus, the state unilaterally set its 2003 quota at 450,000

3 pounds before subtracting an 8,000-pound penalty for last year's overage. The state relies on a inch protected slot to help keep the angling harvest figure within quota. Reprinted with permission from Mazina'gan, Fall, 2003; a publication of the Great Lakes Indian Fish and Wildlife Commission The Art of Tag and Recapture - Adapted from "The Challenge of the Unknown", J.C. Crimmins and Co., 1986 In order to estimate the number of walleyes in Mille Lacs Lake or other lakes including Lake Superior, the Great Lakes Indian Fish and Wildlife Commission biologists and technicians use a technique called tag and recapture. This process is often used to count large populations of fish or animals in the wild. Here is how this works. Imagine being given a bag full of Ping-Pong balls and being asked to estimate how many balls are in the bag. One way to guess would be to paint 10 of the balls red, put them back in the bag, shake up the bag and then draw out 10 balls at random. If one of the balls in your second draw is red, that is one out of ten or 10%, you could estimate that the bag contained about 100 balls altogether. Applying this technique to walleyes in Mille Lacs Lake, the GLIFWC team catch, tag and release as large a number of walleyes as possible. After waiting for the walleyes to swim around the lake presumably distributing themselves randomly they then catch a smaller sample of walleyes and record the number of tagged walleyes in the "recapture" sample. The relationship between tagged and untagged fish and subtotal and total populations in the Mille Lacs Lake can be expressed in this formula. T = t N n Where T = number of walleyes tagged; N = total number of walleyes in the lake t= number of tagged walleyes recaptured in second sample; n=total number of walleyes captured Assume that the team tags a total of 400 walleyes. If they recapture 100 walleyes and finds that half of them are tagged, the equation would look like this:

4 400 = 50 N 100 By solving for N, it is estimated that N (the total number of walleyes in the lake) is 800. Show all work in these exercises 1. Write a ratio to represent each of the following statements a. 5 of 30 walleyes in a sample were tagged; b. 1 of 8 walleyes in a sample was tagged; c. every other walleye in a sample of 120 walleyes was tagged. 2. Assuming that a GLIFWC technician tags 500 walleyes in his first sample, what would be your estimate of the total number of walleyes in the lake if he recaptured 50 walleyes in the second sample and 5 of them were tagged? 3. What if he recaptured 300 and 60 were tagged? 4. What if he recaptured 175 and 70 were tagged?

5 5a. Complete the following table (the first entry has been done for you): T = number of tagged walleyes in the first sample. N = Total number of walleyes in the lake. t = Number of tagged walleyes in second (recaptured) sample. n = Total number of walleyes in the second (recaptured) sample. T t n N b. Looking at the last two entries in this table, what can you say about the total number of walleyes in the lake if a recaptured sample of 100 walleyes did not have any tags? 6. A GLIFWC fish technician stocked a fresh-water lake with 300 bass. If 3 out of every 20 bass were tagged, how many were tagged in all? 7. Compare Exercises 2,3 and 4. In which of the three cases are you most confident that your estimate is close to the true total?.