Jeffrey M. Kampa

Factors Affecting Growth of Northern Pike in Small Northern Wisconsin Lakes

Abstract Fish assemblages that include northern pike Esox lucius as a dominant predator were sampled in 19 small (<120 ha) northern Wisconsin lakes. The purpose of this sampling was to describe northern pike population characteristics and identify factors affecting growth rates. Fish assemblages in these lakes were dominated by centrarchids, primarily bluegill Lepomis macrochirus, and small fusiform species such as yellow perch Perca flavescens. Northern pike population size structures were typically truncated at around 53 cm. Average density of northern pike (≥35 cm) was 16.1 fish/ha and ranged 2.8–38.0 fish/ha. Growth of northern pike decreased, in comparison with a growth standard, as early as age 4. Most northern pike were less than age 6, and few fish were older than age 8. Diet of northern pike generally indicated opportunistic feeding strategies with some preference for fusiform prey. Multiple factors were identified as potentially limiting northern pike growth and size structure. Northern pike gro...

Changes in Bluegill, Black Crappie, and Yellow Perch Populations in Wisconsin during 1967–1991

Abstract A common perception among fisheries managers is that the mean size and number of fish within populations has decreased over time. We examined changes in size of bluegills Lepomis macrochirus, black crappies Pomoxis nigromaculatus and yellow perch Perca flavescens in fyke net samples during 1967–1991 to determine changes in size of fish and in creel surveys during 1980–1991 to determine changes in size of fish harvested and total angler catch and harvest. Mean size and proportion of large bluegills and yellow perch in fyke net samples decreased throughout the sample period. Total catch and harvest of bluegills, black crappies, and yellow perch decreased significantly during 1980–1991. Although mean size of bluegills and yellow perch harvested did not change during 1980–1991, the proportion of large bluegills harvested decreased and the proportion of large black crappies harvested increased. We conclude there was a small, but significant reduction in the size of bluegills and yellow perch in the po...

Survival, Growth, and Tag Retention in Age-0 Muskellunge Implanted with Passive Integrated Transponders

Abstract Mark–recapture studies are an important component of fisheries research and management. Underlying assumptions of such studies include minimal tag loss and negligible effects on the behavior, fitness, and survival of tagged individuals. Passive integrated transponder (PIT) tags are becoming increasingly commonplace, largely because of their small size, ease of implantation, longevity, and reportedly high rates of retention. We evaluated tag retention and survival and growth effects on age-0 muskellunge Esox masquinongy marked with PIT tags at two implantation sites, the peritoneal cavity and the dorsal musculature, during overwinter trials in Illinois and Wisconsin. For both trials, no significant differences in survival (88.0–89.8%), relative daily growth (0.0006–0.00062 mm·mm−1·d−1), or tag retention (99.5–99.8%) were observed among the two implantation groups and a control group. Survival and tag retention were also similar between trials. Our findings suggest that PIT tags implanted either in...

A Comparison of Fish and Aquatic Plant Assemblages to Assess Ecological Health of Small Wisconsin Lakes

ABSTRACT Biological monitoring uses assemblage structure to assess condition of ecological systems. Taxa that effectively integrate impacts within the system of interest are useful for biological monitoring, whereas taxa that do not demonstrate predictable responses can provide ambiguous or misleading indicators. We compared the effectiveness of aquatic plant and fish assemblages for biological monitoring in 16 small lakes (< 80 ha). The lakes were limnologically similar but differed in extent of lakeshore development and type of watershed land-cover. Linear regression analysis revealed that the quality of the aquatic plant community declined with increasing lakeshore development (number of dwellings per km of shoreline), which is the primary source of impacts within this group of northern Wisconsin lakes. As lakeshore development increased, we observed a decrease in the Floristic Quality Index (FQI) of a lake, number of plant species per lake, number of highly intolerant plant species per lake, and the species richness and frequency of occurrence of floating vegetation. Conversely, fish species richness, centrarchid species richness, number of small benthic fish species, intolerant fish species richness and the proportion of the total catch of intolerant and vegetative-dwelling fish were not related to lakeshore development. These results indicate that, within the range of conditions observed, aquatic plant communities are more sensitive to lakeshore development than fish communities. Neither aquatic plant species composition nor fish assemblage variables were correlated with watershed land cover types; however all the watersheds were relatively small and undisturbed. In small lakes with few fish species, aquatic plants can be used as biological indicators for monitoring ecological conditions.

Implementation of Genetic Conservation Practices in a Muskellunge Propagation and Stocking Program

Conservation of genetic resources is a challenging issue for agencies managing popular sport fishes. To address the ongoing potential for genetic risks, we developed a comprehensive set of recommendations to conserve genetic diversity of muskellunge (Esox masquinongy) in Wisconsin, and evaluated the extent to which the recommendations can be implemented. Although some details are specific to Wisconsins muskellunge propagation program, many of the practical issues affecting implementation are applicable to other species and production systems. We developed guidelines to restrict future broodstock collection operations to lakes with natural reproduction and to develop a set of brood lakes to use on a rotational basis within regional stock boundaries, but implementation will require considering lakes with variable stocking histories. Maintaining an effective population size sufficient to minimize the risk of losing alleles requires limiting broodstock collection to large lakes. Recommendations to better app...

Evaluation of Supplemental Walleye Stocking in Northern Wisconsin Lakes

Abstract Supplemental stocking of walleye Sander vitreus is an important component of fishery management programs in North America. We conducted an experimental study in 23 northern Wisconsin lakes over a 4-year period to assess differences in year-class strength with and without supplemental stocking. These study lakes all hosted walleye fisheries targeting mixed-recruitment populations (i.e., ones with both natural reproduction and supplemental stocking). We tested for differences in catch per effort (CPE) between stocked and nonstocked years using a general linear mixed model. Catch per effort of age-0 walleyes was 2.3 greater per shoreline mile when lakes were stocked, suggesting that stocking increases year-class strength by about 0.13 age-0 walleyes/ acre. Catch per effort values approximated a Poisson distribution, most lakes showing low CPE of age-0 walleyes whether or not they were stocked. Stocked fingerlings were marked with oxytetracycline as fry to determine the percent contribution of stocke...

One-Year Retention of Passive Integrated Transponders in Adult Muskellunge, and Applications to Broodstock Management

Abstract Muskellunge Esox masquinongy are long-lived fish that typically occur at low densities. Tracking the history of individuals used as broodstock allows accurate determination of the effective population size and is essential to meeting genetic objectives for management-oriented hatchery propagation programs. We tested the utility of passive integrated transponder (PIT) tags for tracking individual muskellunge. We placed PIT tags in the cheeks of 291 adult muskellunge netted during the spring spawning season in two Wisconsin lakes. Partial fin clips were used as a secondary mark. The lakes were sampled during the following year, and 73 fish with fin clips were recovered in a sample of 271 fish. The one-year tag retention rate was 90.4% in the two lakes. Six fish without functional tags were examined for the presence of broken or malfunctioning tags, and all were missing tags. The use of PIT tags is feasible for adult muskellunge and is useful for maintaining individually based broodstock records.

Spring Capture Site Fidelity of Adult Muskellunge in Inland Lakes

Abstract Behaviors that affect the distribution of fish within aquatic systems are important considerations in the design of sampling programs. Although movements consistent with reproductive homing have been documented for muskellunge Esox masquinongy in relatively large, complex systems, quantitative data describing their distribution at the restricted spatial scale relevant to small lake fisheries are lacking. We sampled muskellunge by means of fyke netting over 2 years in each of four Wisconsin lakes with surface areas between 110 and 588 ha. Individual capture locations were recorded. Each muskellunge sampled during the first year was injected with a passive integrated transponder to allow identification of the individuals recaptured during the second year. The number of recaptures with functional transponders during the second year ranged from 15 to 43 per lake. Capture site fidelity, defined as the percentage of recaptured fish being found in the same spawning area in two consecutive years, varied ...

Survival and Growth of Walleye Fingerlings Stocked at Two Sizes in 24 Wisconsin Lakes

Abstract We compared the performance of walleye Sander vitreus fingerlings of two different sizes that were stocked into Wisconsin lakes during 2004–2007. Small fingerlings were stocked in June at a total length of 1.0–2.0 in. Large fingerlings were stocked in September at a length of 7.0–8.0 in. The study lakes ranged from 120 to 515 acres in surface area and were dispersed north and south across the state. We electrofished the entire shoreline of each study lake with a boomshocker and two dippers during the spring after stocking. The mean age-1 catch per effort (CPE) was significantly higher for large fingerlings (11.2/mi) than for small fingerlings (2.8/mi). Location in the state was not significantly related to age-1 CPE. Stocked year-classes were detected for 11 of 12 large-fingerling stocking events but only 7 of 12 small-fingerling stocking events. The total length of age-1 walleyes was not significantly related to size at stocking but varied significantly among locations. Stocking large walleye fi...