Project Descriptions

Factors affecting age-at-maturity in bluegill populations
D. Derek Aday, David H. Wahl, David P. Philipp

We are examining life-history decisions of bluegill in populations of different size structures. Specifically, we are examining factors that influence age-at-maturation in stunted and non-stunted bluegill populations. Previous research (conducted as part of the state-wide bluegill project) has demonstrated that stunted bluegill mature at younger ages and smaller sizes than non-stunted individuals. We are examining several potential mechanisms associated with early maturation in stunted populations, including differences in resource availability (which affects juvenile and adult growth rates), mortality rates, and influences of social interactions between mature and immature male bluegill. This research provides insight into reasons that populations become stunted, which should help fishery managers decide appropriate actions to return stunted populations to a normal size structure.

Factors determining yellow perch year-class strength in Lake Michigan
B. Pientka, J. M. Dettmers, C. E. Cáceres

Ongoing research is exploring some factors that may affect yellow perch year class strength. In particular, we are trying to determine whether larval yellow perch are suffering from severe food limitation and/or vulnerable to predation. To explore these hypotheses, we are sampling larval yellow perch, zooplankton, and alewife (a major predator of larval fish). Age-0 yellow perch were sampled with a bottom trawl to assess survival of larvae to the juvenile stage. Results to date suggest that zooplankton density is positively related to survival of yellow perch during their first year of life. This relationship appears to have changed over the last decade, with similar densities of zooplankton now yielding fewer yellow perch than was the case during the late 1980s. This shift may be due to changes associated with reduced nutrient loading or the recent influx of exotic species like zebra mussel, spiny water flea, and fishhook water flea.

Sport fishing in Lake Michigan
W. Brofka, J. M. Dettmers, D. P. Philipp

A survey of sport fishing in the Illinois portion of Lake Michigan is conducted annually from April 1 to September 30. The survey covered all legal sport fishing during that period excluding fishing from chartered boats and smelt fishing. The intent of the survey was to provide reliable estimates of sport fishing activity, sport fish harvest, expenditures for sport fishing, and the quality and distribution of sport fishing. During 1999, estimated total fishing effort for pedestrians and boaters was 444,000 angler-hours. Estimated total harvest included 57,300 yellow perch, 3,700 brown trout, 5,400 rainbow trout, 2,700 lake trout, 16,400 coho salmon, and 12,700 chinook salmon. Estimated expenditures for boats, motors, trailers, fishing gear, and automobile gas were $5.2 million. The yield value of the sport fishing harvest was approximately $1.14 million.

Species composition of the Lake Michigan egg bank
C.E. Cáceres

When dormant stages remain viable for an extended (longer than one season) period, a reservoir of both genetic and species diversity is maintained in an egg or seed bank. This reservoir of biodiversity can influence population and community dynamics in ways that could not be predicted by examining the active individuals alone. However, in aquatic systems, the ties between the active and dormant stages are rarely considered especially in large, permanent lakes. Ongoing research is addressing the role of zooplankton dormancy in the present, past, and future community interactions of nearshore Lake Michigan. The Laurentian Great Lakes have been heavily impacted by human activity, resulting in numerous changes in the planktonic food web. By examining 6 sediment cores from Lake Michigan, data on the size, age (which is correlated with sediment depth) and species composition of the egg bank are being collected. By comparing the species list from the egg bank to both past and present water-column records, the persistence ability of various species can be assessed. These data will provide insight into the mechanisms permitting the long-term persistence of some species and the elimination from the water column of others.

Diapause termination in freshwater zooplankton
C.E. Cáceres and M. Schwalbach

Many populations of freshwater zooplankton produce long-lived diapausing eggs that accumulate in lake sediments in large numbers. In Oneida Lake, NY, these eggs likely can remain viable for over 125 years. Prior research has demonstrated a difference between the benthic-pelagic link of the two species. Although the two species reach similar population densities in the water column, fewer D. galeata mendotae females switch to the production of the dormant eggs than D. pulicaria. This results in fewer diapausing eggs being produced and stored by D. galeata mendotae, which results in lower emergence rates. Current research focuses on the cues required to terminate dormancy in these two populations.

An experimental investigation of the dispersal ability of freshwater invertebrates
C.E. Cáceres, D.A. Soluk

Experimental studies of dispersal and colonization by zooplankton are rare, making it difficult to assess the relative importance of local vs. regional processes in the structuring of aquatic systems. To test for colonization rates and identify potential dispersal vectors, we are performing a field experiment in which we manipulate access to 150 L mesocosms. Treatments are: 1) closed (covered with plastic), 2) 500 mm netting, 3) 2.5 cm netting, 4) 10 cm netting, and 5) open (no netting). The 25 enclosures are located within our experimental pond facility that has numerous ponds and cattle tanks as potential sources of zooplankton. To date, there has been no significant effect of mesh size on the number of taxa recorded. Of the 26 non-insect taxa found to invade the array, on average only 13.9±0.6 (SE) taxa were recorded from each enclosure. Bdelloid and monogonant rotifers were the first non-insect colonists, beginning in week 3. The cyclopoid copepod Eucyclops agilis colonized all of the enclosures beginning in week 5. The first cladoceran, Chydorus sphaericus, appeared at week 8, but several cladoceran species were not found until the following spring. Diaptomid copepods, although present at the pond site, were never found in the mesocosms. Our results suggest dispersal limitation of some taxa, as well as the importance of local processes in structuring zooplankton assemblages.

Linking life-history traits to community dynamics in freshwater ecosystems
C.E. Cáceres, A. Tessier (Michigan State University)

Ecosystem, community and population processes are mediated by the life history traits of organisms. Hence, a focus on key life history traits of ecologically important species can provide valuable insight into processes occurring at multiple trophic levels. Ongoing research focuses one such life-history trait: dormancy in freshwater zooplankton. We are examining variation in dormancy investment in 14 populations of Daphnia. Large-bodied Daphnia species interact strongly in aquatic systems as a primary grazer of algae and an important prey resource for many fish species. The goal of this research is to not only quantify variation in dormancy investment across populations, but also to link variation in this life-history trait to variation in overall planktonic dynamics.

Zebra Mussel Workshops for Inland Water Users: Prevention and Protection through Education
P. Charlebois, D. Jensen, G. Kreag, M. Klepinger, F. Snyder, C. O'Neill, and C. Kraft

This project provides Great Lakes Sea Grant Network expertise and existing products to a new audience--inland water users. Inland water users need and want information on preventing the spread of the zebra mussel and other exotic species, and on protecting their waterbody and personal property from the impacts of zebra mussels. This project will 1) involve recreational boaters in preventing the introduction and dispersal of exotic species, and 2) provide regional coordination of exotic species information to prevent duplication of effort. Information on the zebra mussel and other exotic species will be provided to inland water users through a series of evening workshops. These workshops will be tailored to the concerns of each audience, and will combine computerized presentations, demonstrations of proper boat-washing techniques, and use of veliger sampling equipment. Workshop participants will receive written materials (e.g., fact sheets) reinforcing the information provided in the presentations.

Factors affecting establishment of aquatic vegetation in Lake Chautauqua
Thad R. Cook and Mark A. Pegg

Submersed aquatic vegetation (SAV) is important to many aquatic organisms and provides such benefits as protection from predators, nursery areas, and is an important food source for migrating waterfowl and shorebirds. Submersed aquatic vegetation was once an abundant component of the Illinois River floodplain ecosystem. However, much of the Illinois River has experienced a marked decline in SAV in recent times. Several hypotheses have been proposed as to why SAV has declined ranging from continued disturbance via barge traffic in the main channel to over-grazing from herbivorous fish and extensive wave action in backwater areas. We are examining the growth and survival of submersed aquatic vegetation in the north cell of Lake Chautauqua, in an attempt to identify causal factors that preclude recovery of SAV to floodplain lakes through a series of enclosure experiments.

Model HACCP-Like Plan to Restrict the Spread of Exotics via the Baitfish/Aquaculture Vector
J. Gunderson, M. Klepinger, P. Charlebois, F. Snyder, D. Jensen, and R. Kinnunen

Hazard Analysis and Critical Control Point (HACCP) is a preventative program designed to insure food safety. We propose that the HACCP approach also has application to reducing the risks from other hazards, like the spread of aquatic nuisance species such as zebra mussels. We do not include species that are intentionally stocked by state management agencies or legally stocked by private fish farmers or species allowed to be harvested from the wild. As recently introduced aquatic nuisance species of fish, plants, and invertebrates continue to spread through the Great Lakes, there is concern that the transport of baitfish, aquacultured fish, or other fish harvested or cultured in infested water may further spread ANS to other watersheds. Several states have already instituted a ban on harvesting bait from infested waters or they require certification that bait or fish for stocking are ANS-free. Other regulations are being considered that would further disrupt economically viable businesses. This project will assess the risk of the spread of ANS through the bait industry, and provide the industry with proactive methods for eliminating this risk.

Research and Outreach to Prevent and Control Aquatic Nuisance Species: Invasions: A National Invasive Aquatic Plant Outreach Initiative
H. Crawford, D. Jensen, S. Kay, S. Grantham, P. Charlebois, B. Doll

Invasive aquatic and wetland plant introductions result in highly significant economic and environmental impacts. Early identification and control of invasive introductions by resource managers and the general public can reduce these impacts. In this project, we will educate consumers and property managers about the negative impacts of selecting invasive aquatic and wetland plant species and therefore reduce the annual number of potential introductions. This will be done through a searchable Website, a high-quality technical field identification guide for professional resource managers, an identification guide for the general public, a pamphlet for water garden hobbyists; and a booklet for developers, commercial landscapers, property associations and other lay audiences. We will also examine the likelihood of spread of invasive aquatic plant species through mail-order and Internet sales and their potential for overwinter survival under ambient conditions. This will allow us to help improve industry grow-out and shipping practices.

Aquatic Nuisance Species Research and Outreach: Biological Control of Purple Loosestrife by 4-H Field Volunteers
J. Schwartz, M. Klepinger, P. Charlebois, R. Wiedenmann, D. Voegtlin, N. Carroll, and D. Jensen

Purple loosestrife (Lythrum salicaria) is a European plant species which is an aggressive invader of North American coastal wetlands. Once established, purple loosestrife forms impenetrable monospecific stands significantly reducing biodiversity and degrading coastal wetland quality. This species is now controllable with natural enemies (beetles), and several Great Lakes states have developed limited control programs. The challenge is to establish viable populations of loosestrife's natural enemies in all Great Lakes wetlands. At present, professional staff resources can manage biocontrol releases on just a handful of sites per year. By training and supporting 4-H groups interested in rearing these natural enemies, it will be possible to greatly multiply the number of beetles reared and release sites impacted.

Aquatic Nuisance Species Research and Outreach: Sustaining Wild Harvest and Aquaculture of Bait Fish in ANS Infested Waters and Reducing Risk of ANS Spread
J. Gunderson, M. Klepinger, R. Kinnunen, P. Charlebois, F. Snyder, D. Jensen, E. Obert, and S. Curcio

This project will provide vital options to an industry vulnerable to policy and regulatory decisions. The times is ripe for this outreach effort because many licensing authorities are considering regulations or changes to existing regulations. If objective research is incorporated into the regulation-making process, then baitfish industry practices that have low risk of spreading ANS can be sustained while protecting aquatic resources from infestations via this potential pathway. Survey results indicate angler concern over the spread of exotic species and a willingness to take action, but a lack of knowledge regarding what to do with unused bait. We address this issue in this project by providing point of sale educational materials. Training, education, and public outreach materials will be used and distributed by wild baitfish harvesters, fish farmers, natural resource management agencies, retail outlets, and anglers.

Trophic Transfer of Pcbs: Zebra Mussels and Round Gobies
M. Berg, J. Janssen, D. Jude, and P. Charlebois

Zebra mussels accumulate a variety of toxic substances and round gobies, especially larger individuals, consume primarily zebra mussels. Because round gobies are prey to many sport fish, it is imperative to determine if there is a potential for bioaccumulation of PCBs that could be transferred to humans. The health risks associated with exposure to PCBs are substantial and well documented. However, the most likely non-occupational exposure for humans is through the consumption of fish. The round goby is rapidly expanding its range in areas of rocky substrate, not only in the Great Lakes, but also inland in Michigan and in Europe. Our objective is to track the flow of toxic substances in three Area of Concern (AOC) ecosystems impacted by the recent invasion of zebra mussels (Dreissena polymorpha) and round gobies (Neogobius melanostomus). We also will provide extensive public outreach directed towards resource managers and public health officials in Illinois, Indiana, and Michigan, and non-English speaking resource users in the three AOC ecosystems.

Long Term Resource Monitoring Program, Pool 26
John H. Chick

In 1986, the United States Congress recognized the national significance of the Upper Mississippi River System as both an ecosystem and a commercial navigation system. Balancing the often conflicting demands of navigation and natural resource users is a great challenge to river managers. The Water Resources and Development Act of 1986 authorized the Long Term Resource Monitoring Program (LTRMP) as part of the Army Corps of Engineers' Environmental Management Program. The goal of the LTRMP is to provide river managers with the ecological information needed to make sound management decisions for this ecosystem. The Great Rivers Field Station is one of six field stations conducting monitoring activities for the LTRMP. Since 1989, the Great Rivers Field Station has monitored fish populations, aquatic vegetation, aquatic invertebrate composition, turtle abundance, and water quality in navigation Pool 26 just north of St. Louis, MO. These data will be used to assess changes in ecosystem features associated with anthropogenic activities and natural biotic and abiotic processes.

Long Term Resource Monitoring Program: Out-of-Pool Analysis
John H. Chick, Mark A. Pegg

The fisheries component of the Long Term Resource Monitoring Program (LTRMP) was designed to provide scientists, resource managers, decision makers and user groups, with information needed to maintain fisheries resources in the Upper Mississippi River System (UMRS). The ability to detect trends in the abundance and community composition of fishes and to evaluate factors influencing these trends are central to the LTRMP mission. For ten to twelve years, fish monitoring has been conducted at six study areas in the UMRS (Mississippi River: Pools 4, 8, 13, 26, Open River reach; Illinois River: La Grange reach). If these data are to be used to make inferences to the entire UMRS, it is critical to assess how well these six study areas represent the range of ecological conditions found throughout this system. We will analyze out-of-pool fisheries data collected during the 2000 monitoring season to evaluate how well the composition and abundance patterns of fishes within the six study areas of the LTRMP can be used for inferences to the UMRS as a whole. Specifically, we will attempt to: 1) classify UMRS pools based on the species composition and abundance patterns of fishes; 2) determine which species have the greatest influence on pool classifications; and 3) determine whether species composition and abundance patterns relate to the habitat characteristics and latitude of pools.

Locomotory dynamics as indicators of stress in fish – remote measures utilizing activity transmitters.
S.J. Cooke, J.F. Schreer, D.H. Wahl, and D.P. Philipp.

Stress related physiological disturbances can result in either locomotory impairments or hyperactivity. These behavior-altering disturbances, however, are difficult to quantify. Devices capable of remotely monitoring and quantifying the locomotory activity of free-swimming fish have been developed and have been applied widely within fisheries science, particularly for the determination of activity patterns and the calibration of bioenergetics models. The application of these devices to the measurement of environmental or anthropogenic stressors provides the opportunity to link behavior and physiology in an effort to understand the influences of these stressors from both an energetic and ecological framework. We are currently using activity transmitters in the areas of aquaculture production research, thermal effluent monitoring, and handling and angling related disturbances. The approach of coupling behavior and physiology provides detailed information on how stress manifests itself at the organismal level.

Seasonal energetics and physiological ecology of syntopic centrarchid fishes across a paternal care gradient
S.J. Cooke, J.F. Schreer, D. Wahl, and D.P. Philipp

One of the best studied groups of organisms providing paternal care is the temperate freshwater sunfishes of the family Centrarchidae. Despite the importance and extreme energetic costs of this life-history strategy, little is known about the comparative physiological energetic capabilities of the different centrarchid species. With a large degree of variation in parental care, it is likely that physiological differences exist that underlie the behavioral differences observed. We will undertake a series of physiological energetics assessments among various centrarchid taxa to compare and contrast behavioral variations in parental care with cardiac performance and metabolic rates. Specifically we will determine basal cardiac output values, the relative contributions of heart rate and stroke volume, differences in cardiac performance, critical swimming speeds, swimming speed at which anaerobic muscle is recruited, spontaneous activity and oxygen consumption. Those data will be assessed across a gradient of parental care that exists within the centrarchid family as determined from a literature meta-analysis. Experimental studies are being conducted at the Queens University Biology Station in Ontario, on Lake Opinicon.

Exploring Artificial Reef Dynamics
J. M. Dettmers

In November 1999, an artificial reef was constructed approximately 2 km offshore in Lake Michigan to increase angling success for smallmouth bass. To identify the role of the artificial reef in nearshore food web dynamics we are sampling larval and adult fish, zooplankton, invertebrates, and water temperatures at the reef and a nearby reference site during 1999-2001; Preliminary results indicate that both sites were similar in biotic and abiotic characteristics prior to construction. As a result of these similarities, the reference site will be used as a model of the environment before reef construction. Since construction, we sampled round gobies, smallmouth bass, and rock bass in greater numbers at the artificial reef than at the reference site. Additional data collection and analysis will allow for suitable comparison between the reef and reference sites, lending insight into the impact of an artificial reef on nearshore food web dynamics.

Spatial Variability in Nearshore Fish Recruitment
J. M. Dettmers

Recruitment success of fishes in large systems may depend on favorable conditions at local or regional scales. To explore possible variation in conditions, we are sampling larval fish, zooplankton, invertebrates, and water temperatures at four locations along a 100 km stretch of southwestern Lake Michigan during May-July 1999-2001. Water temperatures increased faster, reached greater peaks, and were more stable at two southern sites. Densities of larval fish and zooplankton began increasing 1-2 weeks earlier at the two southern sites. Furthermore, the composition of both zooplankton and larval fishes differed between northern and southern sites. More zebra mussel veligers and larval fish taxa associated with warm water were present at the southern sites. These patterns suggest that mechanisms influencing recruitment may operate at regional scales (i.e. <100 km) in large systems.

Potential importance of the main channel to fishes in the Mississippi and Illinois rivers
J. M. Dettmers, D. A. Soluk, D. H. Wahl

The main channel is a largely overlooked habitat when considering the function of large floodplain rivers. Our research with collaborators at the USGS-BRD Upper Mississippi Environmental Science Center has sampled the main channel for fishes during the late 1990s. Research results to date reveal that a diverse assemblage of larval, juvenile, and adult fishes use the main channel, with eight larval taxa and 24 species of larger fish collected during 1996. Furthermore, the main channel supports large numbers of benthic invertebrates and zooplankton. These results suggest that a food web develops in the main channel, but that the ultimate sources of the energy supplying this food web is not yet clear.

Mechanisms affecting recruitment of yellow perch in Lake Michigan
J. M. Dettmers, J. Janssen (UW-Milwaukee), D. J. Jude (U of Michigan), D. M. Mason (NOAA-GLERL), and A. S. McNaught (Central Michigan U)

Yellow perch have suffered poor recruitment in Lake Michigan since 1989, although the mechanism(s) determining recruitment success have not yet been identified. Two prominent hypotheses are that food availability limits recruitment success and that larval fish predators consume most larvae of yellow perch. A third complementary hypothesis suggests that offshore transport of larval yellow perch spawned nearshore may affect recruitment success. We seek to evaluate these three hypotheses through extensive lake-wide sampling of larval yellow perch and zooplankton, estimating spatial overlap of alewife predators with larval perch prey using acoustic techniques, and sampling along nearshore to offshore gradients to determine offshore movement rates of larval yellow perch and correlate them with wind events during 2000-2002.

Angler attitudes towards the imposition of regulations
T. W. Edison, D. H. Wahl, D. P. Phillip, and D. J. Austen

An important and underutilized tool in fisheries management are angler surveys toward regulation changes. Using regulations to improve size structure of bluegill populations is one possibility to please anglers and improve fisheries. Currently there exist few harvest restrictions on
bluegill populations throughout Illinois. Through the use of an angler attitude survey I will categorize anglers attitudes between lakes that contain stunted bluegill populations and those lakes which contain quality bluegill populations. Some potential regulations that anglers were asked about are those of size limits, creel limits, closed seasons, and closed portions of the lake. Preliminary results indicate differences between stunted and quality lakes with anglers at stunted lakes being more supportive of regulations.

Sex Ratios, Foraging and Mating Behaviors of the Hine's Emerald Dragonfly, Somatochlora hineana in Different Habitats
S. E. Foster and D. A. Soluk

Sex ratio may vary both temporally and spatially due to differences in male and female reproductive constraints. Females may optimize foraging in order to improve egg quality and/or quantity. By occupying territories or patrolling large areas in the breeding habitat males may increase their opportunity of encountering receptive females. If foraging and breeding are optimized in different habitats for the sexes, males and females may use different habitats. This study examines patterns of habitat use, foraging and mating behavior in an endangered species of dragonfly, the Hine's Emerald Dragonfly, Somatochlora hineana. The emphasis of this study will be on how sex ratios vary temporally and spatially.

Individual-based model for walleye
T. Galarowicz, D. Wahl, and R. Herendeen

Size-dependent mechanisms and physical factors influence fish growth and population dynamics. Individual-based models, which follow individuals of a species rather than an "average" individual, provide additional insight into these relationships. By modeling foraging, daily growth and mortality using an individual based approach we hope to predict growth and survival of young-of-year walleye. Parameters for the model are based on extensive field data and laboratory foraging experiments.

Maintaining diversity in aquatic systems: the causes and consequences of pigment variation
G. Gerrish and C. E. Cáceres

Daphnia play a major role in most freshwater systems as the main grazer of algae and as a main resource for many species of fish. In many systems, Daphnia produce dormant eggs as of means of surviving harsh environmental conditions. These dormant eggs are encased in a protective coating known as an ephippium. There is considerable variation in the pigmentation of the ephippia, ranging from nearly transparent to completely opaque. Ongoing research addresses several potential causes of this variation as well as the potential consequences of pigment variation to dormant egg survival and hatching.

Growth and Survival of Larval Yellow Perch
B. Graeb, J. Dettmers, and D.H. Wahl

Yellow perch recruitment has declined dramatically during the last decade in Lake Michigan. Concurrent with this decline, zooplankton (an important prey item of larval yellow perch) density has decreased and the zooplankton taxonomic composition has shifted. This suggests that food availability may be a factor shaping yellow perch recruitment. By conducting experiments that quantify the relationship between zooplankton species and size on the growth and survival of larval yellow perch we hope to determine how food availability affects recruitment of larval yellow perch. We will also quantify aspects of feeding behavior (search time, capture success, handling time, etc) to more explicitly understand why food availability affects recruitment.

Dynamic Trophic Interactions in Ecosystems
Robert Herendeen

Trophic cascade and top-down:bottom-up hypotheses are used to describe and
predict how perturbing one organism affects the others in an ecosystem. I
previously developed a quantitative general theory that predicts all
features of trophic cascades and top-down:bottom up effects, and covers
intermediate cases as well. Specific quantitative predictions agreed with
known results from the Lotka-Volterra theory of predator-prey
relations. This method, however, is based on comparison of systems at
steady state, yet most experimental and real ecosystems are in continual
dynamic change. I have now extended the theory to include dynamic systems,
and am testing against recently available data.

Ecological Accounting of Community Agricultural Systems
Robert Herendeen, David Onstad, Edmond Zaborski, and Alex Winter-Nelson

Project is comparing energy, nutrient, and resource budgets:
1. at the farm level for conventional and organic farms in Illinois,
2. at the community level for the town of Matfield Green, Chase County, KS.
Accounting will be framed by three types of indicators:
1. dependence on external inputs and external pollution sinks,
2. disturbance of natural cycles of mature pre-settlement ecosystems,
3. depletion of non-renewable resources.
The indicators will be applied to three interconnected types of
sustainability: environmental, social, and economic. Comparisons will draw
from energy analysis, mass-balance analysis, and economics.

Stable Isotope Analysis of Large River Food Webs
B. R. Herwig, D. A. Soluk, D. H. Wahl, J. M. Dettmers

To more fully understand the trophic basis of production in large rivers (e.g., Mississippi and Illinois River) we are examining how resource use changes both seasonally and in relation to the amount of intact floodplain area within a river reach. To determine the sources of organic matter assimilated by consumers in large river food webs we are determining naturally occurring stable isotope ratios (del 13C and del 15N ratios) of resources and consumers (invertebrates and fish). Determining the sources of organic matter assimilated by consumers is critical for understanding resource-consumer dynamics, trophic relationships among consumers, and the inter-relationship of the lotic, lentic, and terrestrial habitats that comprise large floodplain river ecosystems.

Largemouth bass diet and growth in bluegill and gizzard shad dominated reservoirs
Jay Y. Hodgson and David H. Wahl

Two somewhat different approaches to the study of growth rates have emerged: (1) growth rate is independent from spawning, in that growth rates are primarily controlled by the timing and availability of size-structured prey communities, and (2) the earlier a piscivore spawns in relation to its prey fish communities, the sooner it can switch to piscivory and maximize growth. Both approaches are underlain with the assumption that piscivores are gape-limited predators and pass through distinct ontogenetic diet shifts. We are evaluating the importance of largemouth bass spawning date and ontogenetic niche shifts on their growth and recruitment and comparing these processes in reservoirs that are dominated by either bluegill or gizzard shad.

Evaluation of largemouth bass stocking program
J. Hoxmeier, K. Ostrand, D.H. Wahl, and D.P. Philipp

Although largemouth bass are stocked extensively in Illinois, little is known about the long-term contribution of hatchery fish to the natural population. Factors that influence stocking success include prey availability and predation or abiotic factors such as water temperature and water level. Prey availability and predation are dependent on the size of stocked largemouth bass. As a result, the current study is examining lakes and reservoirs throughout Illinois to determine factors affecting growth and survival of stocked largemouth bass. Evaluations are being made of small and large fingerling bass to determine appropriate stocking size. In addition, we are evaluating the contribution of stocked fish to future reproductive success and harvest. These results will be used to develop management strategies that optimize use of these >important stocked sportfish.

Bluegill and largemouth bass populations in the Chicago area forest preserves
J. Hoxmeier and D. Wahl

Chicago area forest preserve lakes provide many angling opportunities for local residents, however, factors effecting growth and survival of fish in urban settings have recieved little attention. The effects of angling can be dramatic in this area given the unusually high fishing pressure. We are currently studying bluegill size structure along with largemouth bass recruitment and stocking strategies in several Chicago area forest preserve lakes. We will eventually develop and test several management strategies to improve bluegill size structure. The results from this study should give us a better understanding of factors effecting growth and survival of largemouth bass and bluegill, and how to manage for quality fisheries in metro areas.

Factors effecting bluegill population size structure
J. Hoxmeier, J. Claussen, D. Aday, D. Philipp, and D.H. Wahl

Stunted bluegill populations are viewed as a major problem by many Illinois anglers. Factors that control bluegill population size structure include growth rate, life span, and age at maturation. Stunted bluegill populations can result from overharvest, density dependent growth limitations, large portions of the population maturing at early ages, or from an overabundance of cuckolders. We categorized Illinois bluegill populations based on adult size structure using existing creel surveys and standardized sampling to determine which factors are controlling size structures in each of these populations. We then developed an adaptive management experiment to assess the ability of several management alternatives (regulations, predator manipulations) in altering bluegill size structure. The management experiment is divided into four treatments across 32 lakes in Illinois. The four treatments consist of a control, an 8-inch minimum bluegill size limit, largemouth bass stocking, and a combination of the latter. We plan to use the results from this experiment to improve stunted bluegill populations by implementing appropriate management strategies.

Evaluation of walleye stocking program
J. Hoxmeier and D.H. Wahl

Success of walleye stocking is highly variable, and reasons for successes are not well understood. Factors influencing stocking success may include prey availability, predation, or abiotic factors such as water temperature. Prey availability and predation are highly dependent on the size of the walleye. The current study is examining eleven lakes across Illinois to understand factors causing differences in growth and survival among stocked walleye fry as well as small and large fingerlings. These results will be used to develop management strategies that optimize stocking of these important sportfish.

Long-term monitoring in Lake Shelbyville
J. Hoxmeier and D.H. Wahl

Long-term data collection is important for detecting large scale temporal trends. In addition, these samples can be valuable for use as pre-data in evaluating the effects of a disturbance. We have been collecting data from Lake Shelbyville since the 1980's and are currently using this data set for answering and developing new research questions. All of the data is collected at fixed sites throughout the lake at regular time intervals. Variables that are being sampled include adult and juvenile fish assemblages, zooplankton, invertebrates, water level, and nutrients. In the future we will continue to develop this long-term data set in order to gain a better understanding of the interactions among measured variables and the factors determining community structure in this important reservoir system.

Stream habitat assessment using sonar
R. Illyes, S. Kohler, P. Bayley
Assessment of instream physical habitat is often used in conjunction with fish and invertebrate surveys to identify mechanisms responsible for changes in biotic integrity. Such assessments are frequently time-consuming and are difficult to perform in many habitats (e.g., deep or highly turbid areas). Researchers are attempting to develop a sonar-based device that will allow rapid and effective quantification of major stream-bottom features under a wide range of physical conditions. Data collected by the device will be downloaded to a computer for storage and analysis.

Effects of abiotic and biotic factors on gizzard shad growth
K. G. Ostrand, J. M. Dettmers, D. H. Wahl, J. Kalas, and C. L. Pierce

Gizzard shad (Dorosoma cepedianum) are important forage fish for game species; however, variable growth rates limit many management options. Many factors, operating independently or concurrently can effect growth rates of forage fish species. These factors include (1) environmental conditions, (2) food availability during the early life stages and throughout the growing season, (3) predation and competition for food, (4) availability of adequate habitat, and (5) timing of predator and prey spawning. We are quantifying the variation in growth rates of gizzard shad in the midwest and southern U.S. and exploring the relationship with important biotic and abiotic factors. Development of a model to predict shad growth will help guide future management efforts.

The effects of water quality in live wells on initial and delayed largemouth bass mortality during tournaments
K. G. Ostrand, S. Cook, D. H. Wahl, and G. R. Wilde

Black Basses (Micropterus spp.) captured in competitive fishing events suffer high rates of mortality. Public and management agency concerns for possible fishery impacts associated with tournament angling have led to the widespread adoption of live-release practices by tournament sponsors. Nevertheless, about 30% of black bass captured in tournaments do not survive despite these practices. Therefore, we are examining the effects of live well conditions on largemouth bass mortality. These results will be useful in reducing the initial and delayed mortality associated with fishing tournaments.

Effects of fish diversity on ecosystem structure and function
K. G. Ostrand, D. H. Wahl, S. R. Chipps, S. Callahan

Diversity of any community is in part a function of productivity. Increased productivity of an ecosystem, commonly associated with nutrient availability and primary productivity, may determine sustainable population sizes and increased diversity. On a regional scale maximum diversity is attained at intermediate levels of productivity. Few studies have examined these issues in freshwater systems or examined the alternative potential role of species diversity on system productivity and functioning. Current freshwater fish management promotes single-species strategies with little concern for fish diversity. Therefore we are examining the relationships between species diversity and productivity in ponds with varying numbers of fish species.

Largemouth bass recruitment in Illinois
J. Parkos, J. Hoxmeier, D.H. Wahl, and D.P. Philipp

Recruitment of largemouth bass in Illinois is highly variable and most likely depends upon a variety of biotic (e.g., food availability, predation, population structure, etc.) and/or abiotic factors (e.g., spring water levels and temperature, spawning habitat, angling pressure, etc.). This research will examine recruitment dynamics among reservoirs representing a gradient of conditions in Illinois in order to evaluate which factors are most consistently important in determining year-class strength in largemouth bass. An understanding of largemouth bass recruitment mechanisms will help to guide management decisions, such as supplemental stocking, designed to enhance the largemouth bass fishery in Illinois.

Long Term Resource Monitoring on LaGrange Reach, Illinois River
Mark A. Pegg

Multiple use, human demands (e.g., navigation, hydropower, water supply, and recreation) on large river systems are complex and can have far reaching effects. Many of these uses directly or indirectly conflict with the needs of aquatic organisms. The Upper Mississippi River System (UMRS) accentuates this conflict, through being declared both a nationally significant ecosystem and a nationally significant commercial navigation system. However, in an attempt to maintain a sustainable ecosystem in conjunction with human demands, five states of the UMRS and the federal government formed a partnership through the Environmental Management Program to monitor, maintain, and restore the natural resources of the Upper Mississippi River and its navigable tributaries, including the Illinois River and a portion of the Kaskaskia River. The goal of this project is to provide decision makers with the biological information needed to maintain the multiple use aspect of this ecosystem. Since 1989, the Illinois Natural History Survey has operated a field station that monitors water quality, aquatic vegetation, fish, and macro invertebrate populations along the LaGrange Reach of the Illinois River. Current research focuses on population trends over the past decade in relation to abiotic factors.

Long Term Illinois Fish Population Monitoring on the Illinois River
Mark A. Pegg and Michael A. McClelland

Long-term riverine fish population data sets are rare but valuable because they allow assessment of community responses to biotic and abiotic phenomena in these dynamic systems. Fortunately, such a data set does exist for the Illinois River through an existing fish population study that began in 1957. Since that time, fishes have been collected annually at 27 fixed sites throughout the Illinois River and at one fixed site in Pool 26 of the Mississippi River using a boat-mounted AC electrofishing unit. This gear configuration and standardized sampling protocol has not changed over the life of the project thus creating a nearly unprecedented long-term fisheries data set. The Illinois River was historically a considerable source of fish production through the early to mid 1900s. However, human disturbance in the form of levees and dams over the last 100 years has changed the river and its biological community. Despite these problems, the Illinois River was recently identified as one of three large, floodplain ecosystems with enough integrity to possibly recover from these changes. Therefore, as restoration efforts begin, the importance of this long-term data set is further emphasized to provide insight into how best to manage the river. Current research focuses on longitudinal species richness and temporal shifts in fish community structure.

Crayfish burrows as refuge for the federally listed, endangered Hine's Emerald Dragonfly, Somatochlora hineana
Lauren M. Pintor and Daniel A. Soluk

Aquatic invertebrates that occupy small intermittent stream use various life history and behavioral tactics to avoid or tolerate desiccation or temperature extremes. One potential refuge that has a high likelihood of retaining non-frozen standing water is a crayfish burrow. The federally listed, endangered Hine's Emerald Dragonfly, Somatochlora hineana, inhabits small, flowing wetland habitats that experience seasonal drying that can last for several months. Results of a 7-month sampling have shown that S. hineana larvae inhabit crayfish burrows not only during periods of drought, but also while the streams have flowing water. Trends showed that once drought conditions began, S. hineana larval densities in the stream channel showed a dramatic decline, whereas densities in the burrow only showed a slight decline. This suggests that the burrows provide a better refuge for larvae to survive through periods of drought. Further investigation is being conducted to understand the costs and benefits of living in crayfish burrows.

Understanding the interaction of crayfish and the Hine's Emerald dragonfly larvae coexisting in crayfish burrows
Lauren M. Pintor and Daniel A. Soluk

The Hine's Emerald Dragonfly, Somatochlora hineana, inhabits small, ephemeral streamlets that experience seasonal drying; a situation intolerable for many larval Odonates. Field studies indicate that larvae use active crayfish burrows to survive through periods of drought. Crayfish are predators of dragonfly larvae, which raises the question of how these organisms coexist in burrows. To resist predation, S. hineana larvae may simply be distasteful or crayfish may fail to recognize them as prey. Lab experiments were conducted to establish whether a direct predator-prey relationship exists between S. hineana larvae and the crayfish, Cambarus diogenes. Results show that C. diogenes readily consume S. hineana and other dragonfly larvae, and are only limited by the size of the larvae relative to it's own size. To further investigate predation by crayfish inside burrows and whether larvae avoid active burrows, we conducted a field exclusion experiment manipulating the presence of crayfish in burrows. Preliminary results of a repeated-measures analysis shows no significant difference between treatments (p =0.87), indicating that the presence of crayfish has no effect on S. hineana larval densities within burrows. This suggests either that larvae may not be able to discriminate between burrows with crayfish present/absent, or that the cost may not be high, relative to the benefits attained by inhabiting the burrow. S. hineana larvae probably exhibit unique behaviors that allow them to avoid predation by crayfish within burrows. Further investigation is being conducted to uncover more information on the interaction between the S. hineana and crayfish. Understanding the relationship between these two organisms helps us to further understand the ecology of this endangered dragonfly which will hopefully contribute to the conservation and recovery of the Hine's Emerald Dragonfly.

Exploring Artificial Reef Dynamics
M. J. Raffenberg, J. M. Dettmers

In November 1999, an artificial reef was constructed approximately 2 km offshore in Lake Michigan to increase angling success for smallmouth bass. To identify the role of the artificial reef in nearshore food web dynamics we sampled larval and adult fish, zooplankton, invertebrates, and water temperatures at the reef and a nearby reference site during May-July 1999; Preliminary results indicate that both sites were similar in biotic and abiotic characteristics prior to construction. As a result of these similarities, the reference site will be used as a model of the environment before reef construction. Additional data collection in 2000 and 2001 will allow for suitable comparison between the reef and reference sites, lending insight into the impact of an artificial reef on nearshore food web dynamics.

Spatial Variability in Nearshore Fish Recruitment
M. J. Raffenberg, J. M. Dettmers

Recruitment success of fishes in large systems may depend on favorable conditions at local or regional scales. To explore possible variation in conditions, we sampled larval fish, zooplankton, invertebrates, and water temperatures at four locations along a 100 km stretch of southwestern Lake Michigan during May-July 1999. Water temperatures increased faster, reached greater peaks, and were more stable at two southern sites. Densities of larval fish and zooplankton began increasing 1-2 weeks earlier at the two southern sites. Furthermore, the composition of both zooplankton and larval fishes differed between northern and southern sites. More zebra mussel veligers and larval fish taxa associated with warm water were present at the southern sites. These patterns suggest that mechanisms influencing recruitment may operate at localized scales (i.e. <100 km) in large systems.

The role of avian predators in structuring stream populations and communities
J. Steinmetz, D.A. Soluk, and S.L. Kohler

Birds are common and widespread, yet understudied, predators on aquatic organisms. We are examining their role in structuring fish populations and community structure in streams. Our work is taking place in two streams (Jackson Creek and Prairie Creek) at Midewin National Tallgrass Prairie, south of Joliet, Illinois. Great blue herons and belted kingfishers are the main avian predators on these streams. A pilot study indicated that birds are showing size selective predation on medium sized minnows. This summer we will conduct a large-scale exclosure experiment in conjunction with a smaller scale caging experiment to further examine the effects of the birds on both the minnow population and the invertebrate stream community. One of the main mechanisms of avoiding avian predators is by shifting to deeper water. A potential cost of this strategy may be increased predation risk from aquatic piscivores, such as smallmouth bass. The caging experiment will also look at the trade-offs associated with trying to avoid both avian and aquatic piscivores.

Population viability of mottled sculpin in Black Partridge Creek
J. Steinmetz and D.A. Soluk

Black Partridge Creek contains a unique fauna for an Illinois stream. The mottled sculpin, for example, is found in only two locations in the Des Plaines River drainage. Sculpin are more typically found in higher gradient cold water streams. Its occurrence in Black Partridge Creek is most likely due to the unique stream characteristics found within the Black Partridge Forest Preserve: high gradient and spring-fed water create a cool, clear, high gradient stream. The Illinois Department of Transportation is concerned that a planned road extension may impact the sculpin population in Black Partridge Creek. The construction of roadways has the potential to increase run-off into streams, which could increase sedimentation and water temperature. Both of these effects could potentially harm the sculpin population. However, extensive development in the Black Partridge drainage basin may already have imposed these and other potentially negative effects on the population. IDOT has commissioned us to examine the current status of the sculpin population.

Fish Production and Escapement from Lake Chautauqua
James A. Stoeckel, Kevin S. Irons, A. Maria Lemke, Mark A. Pegg

Lake Chautauqua, an Illinois River floodplain lake, is managed by the U.S. Fish and Wildlife Service as a moist soil unit to provide food and refuge for migrating waterfowl and shorebirds. Floodplain lakes managed for these purposes are annually flooded with river water from fall to early summer and subsequently dewatered during the summer. Additional interest pertaining to the suitability of Lake Chautauqua as habitat for young-of-year fish has prompted a study to investigate the production and subsequent release of larval and juvenile fish into the Illinois River. A major consideration for managed floodplain lakes is how the timing of dewatering events affect young-of-year survival when released into the river. Also, because zooplankton production is typically lower in rivers than in lakes, survival of fish produced in Lake Chautauqua may be lower when moved into the river system if they have not shifted their reliance from zooplankton to fish and/or macro invertebrates as a principal food source. Our primary objectives are to: 1) compare diet compositions among several fish taxa in order to gain insight on diet overlap, and possible interspecific competition, at the larval and juvenile stages and 2) determine the size ranges at which piscivorus species shift their diet from zooplankton to macro invertebrates and fish.

Illinois Chorus Frog Wetland Mitigation Impact
John K. Tucker

The purpose of this research is to track responses of the Illinois chorus frog (Pseudacris streckeri illinoensis) to a wetland/sand prairie restoration project. Currently the project is in its second year of data collection. Work at the site includes mark and recapture study of the chorus frog along with other reptiles and amphibians occurring at the site. I am also collecting data on food habits for other members of the herpetological fauna. A number of short notes have already been published on various observations made here during this project and the pre-restoration phase of the project (1993-1998).

Dredge Material Deposition and the Illinois Chorus Frog.
John K. Tucker

The purpose of this research is to track the impact of dredge spoil deposition on the Illinois chorus frog (Pseudacris streckeri illinoensis) at a US Army Corps of Engineers dredge deposition site at Beardstown, Illinois. The project was initiated in 2001 and could last up to four years. The main goal is to find out if the frog will use sand dredged during channel maintenance for non-breeding habitat.

Spunky Bottoms Herpetological Survey
John K. Tucker

The purpose of this research is to survey the reptiles and amphibians of Spunky Bottoms, an area being restored to river wetlands by the Nature Conservancy. I am making periodic visits in order to set-up pre-project transects and establish trapping sites. At present data collection began in 2000 and will conclude in 2001.

Facilitation between predators: Do dragonfly larvae benefit bass or do bass benefit dragonfly larvae?
H.D. Vance and D.A. Soluk

Interactions among multiple predator species generate unexpected complexity in aquatic communities. This complexity is sometimes impossible to detect in short-term experiments. We are running a series of cattletank and pond enclosure experiments comparing growth of largemouth bass (Micropterus salmoides) and dragonfly larvae (Tramea and Erythemis) when they are separate and when they are in each other's presence for a three week period. Experiments have dragonfly and bass densities set to natural levels and the dragonflies are too large to be eaten by the bass. Preliminary results indicate that both dragonfly head width growth and bass total length growth are significantly increased by the presence of the other species. Possible mechanisms for this facilitation include behavioral responses by the prey to the presence of the two predator species that make them more susceptible to predation, or changes in prey community composition among the treatments.

Differences in foraging behavior among multiple predator species: Implications for prey communities
H.D. Vance and D.A. Soluk

The effect of single predator species on prey populations has been studied extensively for decades. However, in nature most prey are not isolated with a single predator species but are confronted with the presence of multiple predator species. In this situation, a prey's risk of predation may equal the sum of the risks of predation from each predator species in isolation (additivity) or the level of risk may be increased (risk enhancement) or decreased (risk reduction) relative to the outcome expected from additivity. The degree of similarity in the foraging behavior among a suite of predator species may influence the likelihood that the prey's risk of predation will be increased or decreased. When two predator species are present that use similar foraging methods (both active or both sit-and-wait), an individual prey can use an antipredator defense that is effective against both predator species simultaneously. The two similar foraging predator species may also interfere with each other, resulting in a decreased risk of predation (below expected) for the prey. In contrast, if two predators use differing foraging methods (one active and one sit-and-wait), the antipredator defense that the prey use against one predator species may actually put it at a higher risk of predation from the other predator species. This situation may result in an increased risk of predation for the prey (above expected). Using a series of lab and field approaches, we are testing whether differences in foraging behavior between predator species leads to these hypothesized differences in a prey species' risk of predation.

The Illinois Pilot Watershed Program: effects of best management practices on stream quality
D. Wahl, H. Dodd, J. Hoxmeier, G. McIssac (University of Illinois), D. Roseboom (Illinois State Water Survey)

Many lotic systems in Illinois remain in a degraded condition as a result of nonpoint sources of pollution. Best Management Practices (BMPs), which include both on-field and off-field techniques, can be used to improve stream quality. The Pilot Watershed Program is designed to examine the effects of BMPs on physical/chemical water quality and stream biota. Four Illinois stream basins were selected for this study with each basin containing a "pilot" watershed, which will have extensive BMP implementation, and a nearby reference watershed without extensive BMPs. During this ten year study, we will be monitoring changes in habitat/water quality, macroinvertebrate, and fish assemblages before and after BMP implementation.

Evaluation of Woody Debris as a Habitat Restoration Tool for Stream Biota: Assessment of Macroinvertebrate Communities.
J. Weidner, H. Dodd, and D. H. Wahl

Illinois streams experience flash floods which drastically change the appearance of the stream. As the streams recede back into their banks, deposition of new woody debris takes place, forming complex logjams and snags which are utilized by a number of stream biota. In streams with little or no woody debris, introduced woody structures have been placed into the stream to create habitat for fish and macroinvertebrates. In our study, we are examining macroinvertebrate colonization of introduced woody debris seasonally and comparing this to naturally deposited woody debris. We are also examining the effects of temperature and stream geomorphology on colonization by comparing colonization in four streams in the northern portion of Illinois and four in the southern portion. As part of the Pilot Watershed Program, this study will aide in the evaluation of restoration practices to improve Illinois streams.

The effect of common carp on aquatic ecosystems
M. Wolfe, J. Parkos, V. Santucci, Jr., and D.H. Wahl

The common carp is an excellent example of how an exotic species can invade and dominate aquatic systems. Since its introduction into North America during the early 1800's, the common carp has invaded and adapted to almost every type of freshwater habitat. Most of the methods used in attempts to eliminate these fish from aquatic systems are either very costly or ineffective. Even though this large benthivore is prevalent, little research has quantified the effect of common carp on aquatic ecosystems. In association with the Max McGraw Wildlife Foundation, we have been assessing the effects of carp on the trophic ecology of lentic freshwater systems and compared these impacts of those of other large benthivores. Current studies are examining the effects that the common carp have on growth, survival, and reproduction of largemouth bass and bluegill in pond experiments.

Other Projects

Biodiversity

An experimental investigation of the dispersal ability of freshwater invertebrates C. Caceres, D. Soluk

Ecology of the federally listed, endangered Hines Emerald dragonfly, Somatachlora hineana D. Soluk, L. Pintor, S. Foster

Foraging mode and the prediction of the impact of multiple predators on prey populations.H. Vance, D. Soluk

Solar radiation, growth dilution, and metal accumulation by autotrophic biofilms W. Hill, I. Larsen

Factors inducing and terminating dormancy in zooplankton C. Caceres, A. Rachubinski, A. Andreou

Conservation ecology and genetics of black rat snakes G. Blouin-Demers, P.J. Weatherhead, H. L. Gibbs

Reproductive ecology of northern water snakes K.J. Kissner, P.J. Weatherhead

Relationship between fish biodiversity and ecosystem structure and function K. Ostrand, D. Wahl

Ecosystem Management and Restoration Ecology

Evaluating the effects of reducing water levels in backwater habitats of large rivers during midsummer D. Wahl, J. Dettmers, B. Herwig

Sewage Treatment as Ecosystem Management D. Schneider

Use of stable isotopes to examine food webs in the Illinois and Mississippi rivers B. Herwig, D. Soluk, D. Wahl, J. Dettmers

Maintaining diversity in aquatic ecosystems: the causes and consequences of pigment variation G. Gerrish, C. Caceres

Linking life-history traits to community dynamics in freshwater ecosystems C. Caceres, A. Tessier (Michigan State University)

Analysis of aquatic resources in habitats out-of-the-pool in the Mississippi and Illinois rivers. J. Chick

Long Term Resource Monitoring Program: out-of-pool analysis
J. Chick, M. Pegg

Lake Chautauqua Habitat Rehabilitation and Enhancement Project (HREP) J. Stoeckel, K. Irons, T. Cook

Long-term Illinois River Fish Population Monitoring Program
M. McClelland, M. Pegg

Watershed-scale effects of best management practices on stream fish and invertebrate populations in the Illinois Pilot Watershed Restoration Program D. Wahl, H. Dodd

Fish and Wildlife Research

Sportfishing creel survey of the Illinois portion of Lake Michigan J. Dettmers, D. Philipp

Growth and survival of nearshore fishes in Lake Michigan J. Dettmers

Mechanisms affecting recruitment of yellow perch in Lake Michigan J. Dettmers, B. Pientka, C. Caceres

Effects of food availability on recruitment of yellow perch in Lake Michigan B. Graeb, J. Dettmers

Population viability of mottled sculpin in Black Partridge Creek J. Steinmetz, D. Soluk

Reproductive ecology and impacts of catch-and-release angling in bass
D. Philipp, J. Claussen, D. Wahl, C. Suski, T. Kassler, J. Parkos

Creel Surveys on Illinois impoundments D. Benjamin, B. Carroll, L. Miller-Ishmael, D. Philipp

Physiological ecology of centrarchid fishes including energetics of parental care S. Cooke, J. Schreer, D. Wahl, D. Philipp, P.J. Weatherhead

Phylogenetic relationships among the black bass and assessment of local adaptation T. Kassler, J. Koppelman, J. Levengood, J. Claussen, D. Philipp

Illinois chorus frog: wetland mitigation impact and dredge material deposition J. Tucker

Spunky Bottoms Herpetological Survey J. Tucker

Importance of flood plain lakes as fish nurseries in the Lower Kaskaskia
D. Wahl, D. Thomas

Quality management of bluegill: reproductive strategies factors affecting population size structure D. Wahl, D. Philipp, J. Hoxmeier, J. Claussen, D. Aday

Factors influencing largemouth bass recruitment D. Wahl, D. Philipp, J. Hoxmeier, J. Parkos

Individual-based modelling of walleye and gizzard shad populations in Illinois impoundments T.L. Galarowicz (UIUC), R. Herendeen, D. Wahl

Invasive Species

Reducing risk of aquatic nuisance species spread via baitfish P. Charlebois

Trophic transfer of PCBs: zebra mussels and round gobies P. Charlebois

Invasive aquatic plant outreach including biological control of purple loosestrife by 4-H field volunteers P. Charlebois, , R. Wiedenmann, D. Voegtlin

Zebra mussel metapopulation dynamics D. Schneider, R. Sparks, K. Blodgett, J. Stoeckel, C. Rehmann, D. Padilla

Carp, culture, and a century of exotic species introductions: an environmental history D. Schneider, G. Sandiford

Exotic zooplankton in the upper Mississippi River J. Stoeckel

Implications of the introduction of D. lumholtzi on fish and zooplankton assemblages D. Wahl and C. Kolar

Effects of common carp on aquatic communities D. Wahl, V. Santucci, J. Parkos, M. Wolfe