Fish Habitat

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Fish Habitat

BY:  President Dave Neuswanger

QLIA members who value good fishing have an opportunity to improve our fisheries by volunteering to help correct a common habitat deficiency (too few trees in shallow water near shore) in Lost Land, Teal, and Ghost lakes. There is no urgency to this, but I have identified three types of projects that would likely improve fishing for species preferred by Quiet Lakes anglers — walleyes, muskellunge, black crappies, and smallmouth bass.  I start, however, with information about a couple popular habitat projects that, if pursued, could waste time and money… and NOT help to achieve our shared vision for the fishery. Prospective volunteers are encouraged to digest this information, decide how you may be able to help, and be prepared to offer your services when we initiate a “Lakeshore Habitat Restoration Project” in 2019 to act on the most promising opportunities.

WHAT WON’T HELP…

Fish Cribs — usually the first thing people think about when considering how to improve fishing.  I call them fish coffins.  Wisconsin fishery biologists (like me in a former life) and lake association volunteers have spent much time and treasure over the past several decades cooperatively installing fish cribs under the misguided belief that fish need them or fisheries are improved by them.  But science eventually catches up with tradition, and we are compelled to rethink our long-held beliefs.

The typical Wisconsin fish crib is an 8’W x 8’W x 6’H log structure filled with brush                              and weighed down with concrete at depths of 15-20 feet.                                  Photo by Engbretson Underwater Photography.

COMMON MYTHS ABOUT FISH CRIBS:

Myth #1:  Cribs increase annual fish production, defined as kilograms per hectare (or pounds per acre for the metrically challeged) per year of added fish biomass in a lake.  Reality: Nope.  Fish like to hang out around cribs, but a heated “attraction/production debate” among fishery scientists ended years ago with a consensus view that the addition of any number of fish cribs does not magically result in more or bigger fish.  Conversely, fish cribs (a.k.a. coffins) make some species of fish (especially crappies) easier for anglers to locate and catch, especially with modern sonar and GPS.  This elevates the risk of over-harvest, as occurred recently in nearby Moose Lake.  We love crappies, but they are not particularly hard to catch once you find them.

Adult crappies are attracted to fish cribs where they rest between bouts of feeding on         zooplankton in open water. Anglers can easily over-harvest fish that congregate near cribs.              Photo by Engbretson Underwater Photography.

Myth #2:  Cribs provide vital fish spawning habitat.  Reality: Uh, no.  Not sure where this came from.  Every species of fish in Lost Lake, Teal, and Ghost lakes spawns near shore in water less than 6 feet deep.  To be legal (and not pose a navigation hazard), the tops of fish cribs must be at least 5 feet below the water surface at the lowest anticipated water level.  A crib 6 feet tall must therefore be placed in water at least 11 feet deep. Most fish cribs are set at depths of 15-20 feet.  None of our fish species are engaged in amorous activity down there.  The water is too cold.  The substrate is too mucky. The honeymoon suite is in shallow, warm water with a firm bed 🙂

Myth #3:  Log cribs and the brush stuffed inside them provide vital substrate for the growth of algae and small invertebrate organisms that graze upon the algae, thereby providing vital food for small fishes.  Reality: This general concept is sound, but it occurs on a scale too small to matter. The food chain of attached organisms also begins on the surfaces of aquatic plants, totally dwarfing the amount of food produced on any imaginable number of log cribs.  And the food chain of attached organisms is dwarfed by the production of unattached algae (phytoplankton) and small invertebrates (zooplankton) in open water — the most significant driver of fish production in most lakes.  Fish in Lost Land, Teal, and Ghost lakes will have access to the same amount of food with or without log cribs.

Myth #4:  Fish cribs provide vital escape cover for small fish to hide from predators.  Reality: I never understood this one either.  Fish cribs attract large predators too, including largemouth bass, walleye, northern pike, and muskellunge.  These predators won’t turn down an easy meal of small, young fish swimming around and between the crib logs.  The aquatic plants in our lakes provide all the escape cover needed by juvenile fish to evade predators.  In fact, I could argue there is too much escape cover in Quiet Lakes weed beds (especially Lost Land), leading to excessive numbers of slow-growing bluegills 4-6 inches long.

Rock Spawning Reefs for Walleye — a commonly employed tactic of fishery managers (with support from citizen volunteers) when reduced reproductive survival (a.k.a. “recruitment”) of juvenile walleyes first became a serious concern in northern Wisconsin lakes in the 1990s.  Biologists suspected that sedimentation and formation of algal scums on rocks (associated with poorly managed shoreland development) might be preventing walleye eggs from surviving during the typical 7- to 10-day incubation period in shallow water near shore. The proposed solution was to place thick blankets of coarse field stone on the ice along select shorelines during mid winter. The rocks would fall through the ice in early spring and create a fresh blanket of clean rock, properly sized to provide shelter to walleye eggs and fry while allowing sufficient flow of water to oxygenate the eggs in the interstitial spaces between the rocks.

Like many past practices, rock spawning reefs (or blankets) sounded like a reasonable thing to try until some follow-up evaluation proved otherwise.  In 2004 I personally collaborated with Dr. Michael Bozek, then Leader of the Cooperative Fishery Research Unit at the University of Wisconsin – Stevens Point, to document the case histories of 20 rock blanket projects initiated in northern Wisconsin, most in the 1990s and early 2000s.  The bottom line?  We found absolutely no evidence that rock spawning reefs increased walleye reproductive survival in those 20 lakes.  Find that hard to believe?  Click on the link below to read the full report.

WDNR Rock Spawning Reef Project Evaluation – 2004

No rock spawning reefs have been built in northern Wisconsin since this report was distributed.  It is now postulated that problems with walleye reproduction are more complex than simply loss of quality spawning habitat along a few hundred yards of shoreline.  Fish community interactions, as influenced by lake basin morphometry and multi-year changes in weather patterns, are now being investigated as more likely causes of decline in walleye recruitment in northern lakes.

WHAT MIGHT HELP

Trees in Shallow Water — The best thing we could do to enhance fish habitat in the Quiet Lakes is to restore a natural amount of coarse woody habitat (dead trees) in shallow water near shore. In August of 2003 the Wisconsin DNR worked with the U.S. Forest Service to create 8 “tree drops” along the northeastern shoreline of Ghost Lake. Neither Teal Lake nor Lost Land Lake have been enhanced in this manner. Near-shore wood in Teal Lake is largely restricted to the state-owned islands, and such habitat is all but absent in Lost Land Lake. But before I can ask QLIA members to volunteer their time and dollars to correct this deficiency, I feel obliged to establish the value of coarse woody habitat in the littoral (near-shore) zone of our lakes. For this purpose, there is no better publication than the following UW-Extension brochure written ~2013 by Dr. Michael Bozek, formerly Leader of the Wisconsin Cooperative Fishery Research Unit in Stevens Point. All members and prospective volunteers are encouraged to read this excellent summary of the history and value of coarse woody structure in the littoral zones of our lakes. (Hint: It is a large document. Give it some time to load.)

A Second Life for Trees in Lakes: As Useful in Water as They Were on Land

For our most inquisitive members and readers, WDNR’s Sawyer County Fisheries Biologist, Max Wolter, has written a technical review of the scientific literature on woody habitat in lakes. This review provides detailed insights into the various factors that may be important when planning fish habitat restoration projects for the Quiet Lakes.

Lakeshore Woody Habitat in Review by Max Wolter ~ 2012

Known primarily as a species that inhabits deep structure and shallow weed bars in the open lake, walleyes will sometimes rest in the shady security of fallen trees near shore, if available.

When members of the Quiet Lakes Association are ready to begin planning projects to restore lakeshore woody habitat, excellent guidance can be found in WDNR’s Best Practices Manual for installing “Fish Sticks” in near-shore areas. These are large woody habitat structures that utilize whole trees cut in off-site locations. The trees are cut in mid winter, then transported and placed singly or in bundles on the ice near shore. The structures are anchored to shore and weighted with concrete to partially or fully submerge them when the ice melts the following spring. Everything we need to know a about planning, permitting, and placement of “Fish Sticks” is covered in this manual.

Fish Sticks – Best Practices Manual by WDNR 2014

Heavy equipment is needed to transport and position “Fish Sticks” along frozen shorelines.

Another option for restoring lakeshore woody habitat involves placement of “Tree Drops” in the near-shore zone. These differ somewhat from “Fish Sticks” projects in that trees of appropriate type and size are cut ON SITE and felled directly into the water, where they are secured. This type of project can be done on a smaller scale at any time of year, and at less cost than a typical “Fish Sticks” project. This may be the best way to initiate the restoration of lakeshore woody habitat on the Quiet Lakes. All such projects require the approval of riparian landowners who are comfortable having one or more trees placed in the water along their frontage. Planning and permitting requirements are described in the following checklist:

WDNR Tree Drop General Permit Application Checklist – Nov 2016

A mature red pine converted from avian habitat to quality fish habitat as a shoreline tree drop.

Finally, a highly targeted type of woody habitat project can be used to increase the number of quality nest-site locations for smallmouth bass. Called “half-logs,” these simple structures provide ideal lateral and overhead cover for spawning adult smallmouth bass, who will build and defend their nests nearby if placed at appropriate depths (2-4 feet) over clean gravel substrate. The Wisconsin DNR and Wisconsin Smallmouth Alliance cooperated in producing the following elegant brochure in order to help lake associations and other volunteer organizations to plan and execute their own half-log projects.

Smallmouth Bass Nesting Cover Brochure by WDNR and WSA 4-25-13

I look forward to finding a Program Leader who could coordinate planning and permitting, and organize a pool of volunteers to help implement a new Shoreline Habitat Restoration project for Lost Land, Teal, and Ghost lakes beginning in 2019. If you are interested in leading this effort, please contact me (Dave Neuswanger) at 715-462-4485 or e-mail at dneuswanger@gmail.com.

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