MINNESOTA DEPARTMENT OF NATURAL RESOURCES
Leech Lake Management Plan - 2011-2015.  Doug Schultz, Large Lake Specialist.  December, 2010

Executive Summary  -  Purpose  -  Update the 2005-2010 Leech Lake Management Plan.

Background & Current Status

Declines in Leech Lake percid populations and their fishery during the early 2000’s prompted the 2005-2010 Leech Lake Management Plan. This plan primarily sought to improve walleye abundance and size structure through the following actions: 

1.      Protect mature female walleye with the current 18-26” protected slot limit and a reduced harvest limit of 4 fish;

2.      Support efforts of the Leech Lake Band’s Division of Resources Management (DRM) to reduce the number of double-crested cormorants on Leech Lake;

3.      Estimate walleye hatch rates by stocking 5 million OTC-marked fry during 2005, 2006, and 2007 and compare estimates to those observed in the Red Lakes as evidence in support of or contrary to the hypothesis of potential reproductive issues in Leech Lake; and,

4.      Continue to protect shore lands sensitive to human disturbance.

Note: The only deviation from this plan consisted of annual walleye fry stockings during 2005-2010 ranging from 7.5 to 22.5 million fry. 

The special walleye harvest regulation was implemented in 2005. Hatch rates of wild walleye were determined during all stocking years and were similar to Red Lake estimates. Approximately 3,000 cormorants were removed from Leech Lake annually during 2005-2009, and nearly 5,000 feet of key shore lands on approximately 300 acres were acquired for protection near or adjacent to sensitive fish spawning and nursery areas. 

Currently Leech Lake boasts one of the best multi-species fisheries in Minnesota. Above-average walleye year classes established during 2005-2008 combined with protection of older fish to produce record catch and harvest rates by walleye anglers during 2008-2009. Estimated walleye hatch rates suggest no chronic issue exists with egg to fry stage survival of wild fish, and the presence of three above-average year classes indicate juvenile walleye survival is not precluding recreational harvest. Yellow perch abundance and harvest have also increased considerably from 2004-2005 estimates. Catch and harvest rates of other species have remained within their relative historical ranges. 

In August 2009 the Commissioner of the Department of Natural Resources (DNR) requested a group of 17 stakeholders with diverse local and statewide interests to work as an advisory committee. The committee was charged with providing DNR with recommendations for Leech Lake management, with particular focus on the walleye population. Most of the objectives and actions proposed and reviewed here, particularly for walleye, are products of that process. 

Sportfish Population Objectives 

·         Walleye: Mature female biomass ranging from 1.5-2.0 lbs/acre.

·         Walleye: Gill net catch rate of 8.5 fish/net or higher.

·         Walleye: Proportion of fish sampled during annual gill net assessment that are shorter than 15 inches ranges between 45-65%.

·         Walleye: Year classes having a measured strength of the long-term average (50th percentile) or higher produced during any 2 out of 4 consecutive years.

·         Walleye: Targeting angler summer harvest rate of 0.25 fish/hour.

·         Walleye: Natural reproduction alone can maintain a healthy, sustainable population.

·         Yellow perch: Maintain gill net catch rate (n/net) above the first quartile.

·         Yellow perch: Maintain population size structure (PSD and RSD-10) above respective first quartiles.

·         Northern pike: Maintain gill net catch rate (n/net) above the first quartile.

·         Northern pike: Maintain population size structure (PSD and RSD-28) above respective first quartiles. 

Management Actions
Assessments 

·         Annual assessments, including gill netting, trawling, electrofishing, seining, and water chemistry.

·         Conduct creel surveys 2 of 6 years. The next scheduled surveys are 2010-2011 and 2016-2017.

·         Formally review the current special walleye regulation during 2010, with any potential changes effective in spring 2011.

·         Continue to improve upon age-0 predictors of potential walleye year class strength.

·         Continue to support the Leech Lake Band of Ojibwe, Division of Resource Management financially and technically with double-crested cormorant control and evaluation efforts on Leech Lake.

·         Complete on-going muskellunge genetic mark-recapture population estimate study as planned. 

Stocking & related activities 

·      Stock Boy River strain walleye fry as follows: 22 million in 2011; 7.5 million in 2012; 7.5 million in 2013; 22 million in 2014; Open in 2015. “Open” includes the potential for a blank (zero fry stocked) to evaluate the capacity for natural reproduction, 7.5 million, or 22 million. Cutfoot strain walleye fry will be used to backfill a shortage from the Boy River run if necessary.

·      Continue to conduct muskellunge spawn take every four years based on statewide needs to maintain genetic diversity in brood stock lakes; return 600 muskellunge fingerlings to Leech Lake during spawn take years. 

Species-specific needs 

·      Consider instituting spring electrofishing assessments for largemouth bass, sunfish, and black crappie conducted on a 3-year rotation to gauge population status. 

Habitat  -  Note: many of these initiatives will only be possible with additional resources (funding and staff) 

·     Continue to partner with and/or provide support to non-government organizations to identify, acquire via conservation easements, to protect shorelands, and to educate resource users on best management practices (BMPs).

·      Continue to aggressively treat aquatic invasive plant species and actively work with local organizations to educate resource users on responsible aquatic invasive species prevention practices.

·      Propose telemetry study to identify additional muskellunge spawning locations to guide future priorities for shoreland protection.

·      Re-inventory walleye spawning habitat in Leech Lake, including use and condition.

·      Monitor aquatic vegetation stands at specific locations on a more frequent (eg. annual) basis to identify potential long-term trends and influences on these trends. 

Other Considerations 

·      DNR will hold annual meetings to update the LLAC and other interested stakeholders with the previous year’s information and status with regards to the management plan.

·      DNR will continue to explore management action thresholds that do not impinge on the population’s potential for self-propagation.

·      The LLAC recommended other sources of information, such as fishing guides, be pursued to compile additional trend information. Walker staff will begin outlining methods to do so with local constituents during winter 2010-2011.

·      Climate effects on walleye populations will continue to be examined. However, due to the high degree of uncertainty surrounding both recruitment and climate trends, current models have limited practical applicability for guiding future management decisions at this time.

·      Habitat initiatives recommended by the LLAC range from additional habitat assessments to protection and enforcement. DNR will continue with those recommendations already included under annual operating budgets. Other recommendations, particularly assessments, will only be accomplished with supplemental funding and collaboration among the many partners interested in ecosystem health and sustainability.

The 2008 creel survey showed approximately 585,371 angler-hours of fishing effort were expended on Leech between May 10 and Sept. 30.  An estimated 67,502 walleye totaling 81,410 pounds were caught at a rate of 0.115 fish per hour across all anglers.  Targeting anglers (those fishing specifically for walleyes) caught walleye at a rate of 0.459 fish per hour.  A total of 136,096 yellow perch (59,149 pounds) were taken at a rate of 0.233 fish per hour for all anglers.  Anglers who targeted perch had an hourly rate of 2.73 fish.  Season totals of catch and harvest rates of walleye, yellow perch and northern pike during recent summer creel surveys on Leech, Mille Lacs, Lake of the Woods (LOW) and Winnibigoshish are presented in the chart, for general comparison.

		Walleye per Hour			Yellow Perch per Hour			Northern Pike per Hour
		Catch	Harvest		Catch	Harvest		Catch	Harvest
All Anglers	Leech, 2008	0.278	0.115		0.766	0.233		0.087	0.029
	Mille Lacs, 2007	0.305	0.101		0.105	0.026		0.009	0.001
	LOTW, 2007	0.544	0.288		0.022	0.009		0.012	0.002
	Winnibigoshish,2007	0.432	0.164		0.657	0.173		0.182	0.037
Targeting Anglers	Leech, 2008	1.064	0.459		6.881	2.730		0.881	0.339
	Mille Lacs,2007	0.391	0.129		5.061	1.184		0.110	0.048
	LOTW, 2007	0.550	0.290		n/a	n/a		0.110	0.040
	Winnibigoshish,2007	0.545	0.229		4.380	1.380		0.451	0.123