Evaluation of Modification of the Upper Batavia Dam on the Fox River, Illinois

Progress Report, Federal Aid Project F-136-R Segment 6Report issued on: August 2004Submitted to Office of Water Resources, Illinois Department of Natural Resource

Selective Predation by Three Esocids: The Role of Prey Behavior and Morphology

We documented differential vulnerability of fathead minnows Pimephales promelas, gizzard shad Dorosoma cepedianum. and bluegills Lepomis macrochirus to predation by muskellunge Esox masquinongy. northern pike E. lucius. and tiger muskellunge E. masquinongy x E. lucius in a 700-L tank. Individual esocids (150-225 mm in total length) were combined with single species groups (N = 15) of optimal-sized prey (25-30% of predator length for bluegills, 37-43% for fathead minnows, and 30-36% for gizzard shad). Capture ability did not differ among esocids; however, mean captures per strike were higher for fathead minnow (0.67) and gizzard shad (0.78) than for bluegill (0.14). Morphology and antipredatory behavior, unique to each prey species, contributed to this differential vulnerability. In the field, we introduced equal numbers and similar sizes of these esocids into two systems, one with centrarchid prey and one with both centrarchid and gizzard shad prey. As predicted from laboratory work, esocids ate fewer prey and grew more slowly when centrarchids were the only prey than they did when gizzard were available. In a third reservoir, containing bluegills and gizzard shad, esocids strongly preferred gizzard shad over bluegills. To maximize growth and survival, esocids should be stocked in systems with soft-rayed or fusiform prey, such as cyprinids or shad, rather than in centrarchid-dominated systems.This study was supported in part by funds from the Federal Aid in Fish Restoration Act under project F-57-R

Factors Influencing Largemouth Bass Recruitment: Implications for the Illinois Management and Stocking Program

Annual Progress Report issued August 2002; NOTE: Two different reports numbered 02/06 were issued from the CAE.Report issued on: August 2002INHS Technical Report prepared for Division of Fisheries Illinois Department of Natural Resource

Energetics, Predation, and Ration Affect Size-dependent Growth and Mortality of Fish during Winter

Winter temperatures may reduce energy costs for ectotherms. However, variable mid-temperate and low-latitude winters may interact with scaling of size, metabolism, and energy reserves to cause energy deficits and require trade-offs between foraging and predation. A dynamic optimization model explored how ration, fall fat, and both non- and size-selective predation influenced foraging (i.e., fast or forage) and energy allocation (i.e., length or fat) decisions that maximize winter survival of age-0 largemouth bass (Micropterus salmoides). During a mid-latitude (38° N) winter, a pond experiment in which age-0 fish occurred with or without adult conspecific predators tested a subset of the model. In the model without predators, winter foraging occurred, with small size only reducing survival when low ration and low fall fat caused small fish to exhaust reserves. With predation, all sizes foraged to maintain mass and fat reserves when ration was sufficiently high, with small fish also growing in length. When modeled predation was nonselective, size-dependent mortality varied in complex ways. In contrast, size-selective predators consistently reduced survival of small fish. Generally consistent with the model, fish in ponds without predators gained mass and energy content, while those with predators only maintained these parameters. All small individuals grew more than large counterparts in length. Mortality in ponds never depended on size but was ~20% higher with predators. Energy deficits often demand active foraging during mid-temperate winters, with predation rather than energy depletion influencing size-dependent survival

Evaluation of Muskellunge and Tiger Muskellunge Stocking Program, July 1, 1993 through June 30, 1994

unpublishednot peer reviewedOpe

Relative Survival of Three Sizes of Walleyes Stocked into Illinois Lakes

The ability to differentially batch-mark several size-groups of fish stocked concurrently in lakes or rivers makes it possible to compare survival within a single year. We evaluated stocking of walleyes Stizostedion vitreum in Illinois during 1991–1996. Ten lakes were stocked with combinations of two or three sizes of walleyes, including fry and small (50-mm) and large (100-mm) fingerlings. This permitted a total of 73 lake-year comparisons: fry versus large fingerlings (23 lake-years), fry versus small fingerlings (29 lake-years), and small versus large fingerlings (21 lake-years). Stocked fish were differentially marked with oxytetracycline or fin clips. Electrofishing catch per effort, relative survival, and population estimates were used in conjunction with production costs to compare size-based contributions and survival. Survival generally favored fingerlings over fry (70% of lake-years for small fingerlings, 67% for large fingerlings) and small fingerlings over large fingerlings (72% of lake-years). In some lake-years, fry and large fingerlings had the highest survival. Fish stocked as fry and small fingerlings were larger than large fingerlings beginning their third year of growth. Based on our results, stocking small fingerlings will generally be more cost-effective than stocking fry or large fingerlings. However, if fry or large fingerlings are available, stocking assessment on specific lakes may allow biologists to determine particular lakes where alternative sizes could be economically feasible

Evaluation of Newbury weirs (rock riffles) for improving habitat quality and biotic diversity in Illinois streams

Illinois Department of Natural Resources, Wildlife Preservation Fund Grant/Contract No: 2005-026Wunpublishednot peer reviewedOpe