Our research projects span a wide variety of species and systems investigating the relationships between sport fish population dynamics and human activities. We explore mechanisms that drive population dynamics and recruitment mechanisms in largemouth bass, a freshwater sport fish common in North America. We also study bonefish and sharks in the eastern Carribbean, where we are interested in understanding how angling these species can affect their survival in the short term, and population demographics in the long term.
Evaluation and Restoration of Sport Fish Populations on the West Branch of the DuPage River
The DuPage County Forest Preserve District, the Illinois Department of Natural Resources (IDNR) and the Sport Fish Ecology Lab at the Illinois Natural History Survey (INHS) have teamed up on a research and monitoring project of sport fish populations on the West Branch of the DuPage River. A large-scale Superfund clean-up and stream bed reconstruction on the West Branch of the DuPage River was recently completed. This area is where our research team will monitor, investigate and assess the recovery of sport fish populations in a restored urban stream, highlighting the potential for a quality urban stream fishery in the Chicago suburbs. As human populations urbanize, identifying and providing angling opportunities in densely populated urban areas has become an important component of fisheries management.
Influence of predator density on brood predation rates during a catch-and-release angling event
The impact of the removal of a nest-guarding male bass during a catch-and-release angling event on the survival of that male’s brood should be determined by three components. First, the length of time that elapses between removal of the parental male and first intrusion of a brood predator determines the onset of brood predation. Second, the number of brood predators feeding on eggs determines the instantaneous rate of consumption. Finally, the length of time the male is gone from the nest determines the extent of the cumulative predation. All three factors combine to determine the total number of eggs consumed during the angling event. Brood loss is an important signal to a returning male bass that impacts the decision by the male to either continue to defend the remaining brood or abandon the nest entirely (Suski and Philipp 2004). This study proposes to examine how brood predator densities near the nest and male parental care behaviors influence when brood predation begins, how the number of brood predators controls the rate of brood predation, as well as how the impact of brood predation affects the male’s decision to continue to provide parental care or to abandon the nest.
Impacts of catch-and-release angling on large mouth bass recruitment
During a catch-and-release angling event, the brood of the angled male is exposed to increased risk of predation by nearby brood predators. A reduced number of eggs or larvae remaining in the nest may trigger abandonment by the parental male, eliminating any contribution to the year class by that male. Even if the male continues to defend a reduced brood, the maximum number of individuals that male may contribute to the upcoming year class may be reduced. Alternatively, compensatory mechanisms may allow surviving young to maintain year class strength. This study examines whether brood reductions across an entire population affects the size of the resulting year class.
Streams and their aquatic communities are directly and indirectly influenced by the past and present activities of humans. Land-use changes in Champaign County over the past 100 years have significantly influenced aquatic communities. More recently, climate change may be rapidly impacting fish assemblages throughout Illinois.
Building on the efforts of Forbes and Richardson (1908), Thompson and Hunt (1930), Larimore and Smith (1963), and Larimore and Bayley (1996), the next iteration of "The Fishes of Champaign County" is being conducted by our lab. The study began in the spring of 2012 and includes sampling of fish populations at pre-determined field sites, assembly and analysis of land-use and stream habitat data, collection and analysis of physio-chemical habitat data, and analysis of the effect of fish community/environmental parameter interactions on distribution and assemblage characteristics. The expansion of sampling beyond Champaign County will enhance the benefits of this work to a broader geographic range and provide a more robust set of data with which to examine the impacts of climate change on fish populations. Understanding the long-term implications of such changing land-use practices on stream fish assemblages is critical to sound environmental management and planning.
Sampling has begun and the initial data is being analyzed.
Influence of hook type and hook retention on angled bonefish
Hooking is an unavoidable consequence of catch-and-release angling, potentially causing tissue damage to fish that have been caught. In many situations, fish are hooked in the lip or corner of the mouth, which can make hook removal prior to release easy and rapid, and therefore minimizing major tissue damage. In some instances, however, hooks are ingested deeply by fish with hooking occurring in the gut or esophagus. Additionally, there are many types of hooks used in sport fishing — barbless, barbed, etc. To date, there have been several studies for a range of marine and freshwater species that have investigated the effects of leaving deeply set hooks in place, as well as the post-release effects of removing deeply set hooks. The objective of this study was to quantify the consequences of hook retention on the survival and feeding performance of bonefish, and to determine if these responses were influenced by hook type, hook size and/or hook location. This study attempted to simulate techniques used in both fly angling and bait fishing.
For a summary of these results, please click here.
Development of Metrics to Evaluate Fishing Quality
It is critical for fisheries managers to understand the interaction between sport fish populations and anglers. Using a wide array of information to make resource management decisions, managers can support and promote healthy fisheries. To ensure success, resource managers need easy access to long-term fisheries data, analytical tools and metrics that offer insight into the quality of a fishery, and an understanding of the factors that influence fish population dynamics.
Toward that end, we're working to develop a wadeable and non-wadeable Fishing Quality Index (FQI) for common Illinois sport fish species. We are looking at individual species of sport fishes and sport fish assemblages for individual lakes, rivers and streams across Illinois. To develop this FQI, we use data collected through standardized field sampling and creel surveys.
The development and implementation of the Fishing Quality Index (FQI) will provide researchers, managers, and the public with a simple method to quickly assess the quality of a particular fishery. The FQI will be periodically updated to provide a tool for tracking changes in fishing quality over time. Changes in FQI can alert managers to changes in population dynamics of a particular fishery, therefore providing a valuable tool for resource managers to identify emergent problems and/or assess recent management actions. Additionally, the FQI will be ideal for describing the quality of a particular fishery to the public in a way that is easily understood by anglers.
April 18, 2012 -- The joint CEI and University of Illinois shark research team just returned from the second of four, 2-week field expeditions to a shallow bank known as "the bridge" that connects the southern tip of Eleuthera to the northern tip of Cat Island. The first expedition went out in November 2011.
This historical project is re-creating a study from a dataset detailing the diversity and abundance of shark populations in The Bahamas that took place over 30 years ago. That study was conducted under the direction of Captain Stephen Connett, who lead shark research from autumn 1979 through to spring 1981, focusing on "the bridge" area. The data resulting from these surveys, representing a snapshot of Bahamian shark abundance and diversity from over 30 years ago, have never been rigorously analyzed or published.
In more detail, this research program recreates these shark surveys to look for historical variation in the diversity, abundance and demographic population structure of apex predator assemblages to provide insight into the effectiveness of potential conservation strategies. By repeating an assessment of shark populations in The Bahamas 30 years after the original assessments by Connett, it will be possible to test the effectiveness of the 1990s longline ban, which halted any commercial exploitation of sharks within Bahamian territorial waters.
In the original Connett dataset, 96 sharks from six species were captured during 25 scientific longline sets. In just 12 sets completed in the current assessment, we have already caught 84 sharks from three species! While the current study has encountered a lower diversity of species, the species dominating the catch remains the same. In the original dataset, tiger sharks represented 54% of the catch, and Caribbean reef sharks represented 33%; however, in the modern surveys, Caribbean reef sharks and tiger sharks appear to have switched places, representing 67% and 31% of the catch, respectively.
These preliminary results are especially interesting in relation to the Bahamian ban on longline fishing instated in the 1990s, as Caribbean reef sharks, which are thought to be less migratory in nature than tiger sharks, might be benefitting from the indirect protection. Conversely, tiger sharks are more migratory in nature, and the benefits of the ban may be more limited. With two more expeditions planned for 2012 and 2013, a much clearer picture should evolve by the end of the project.
Publications pertaining to the widespread declines in shark populations around the world are commonplace in scientific literature. Sharks are both economically and ecologically vital to The Bahamas. The shark tourism industry directly contributes approximately $78 million annually to the GDP of The Bahamas. Furthermore, they provide vital ecosystem services that maintain the overall health of the coral reef ecosystems upon which fisheries and tourism depend. Understanding long-term changes in apex predator assemblages is critical to understanding the impact of over-exploitation of these vulnerable, long-lived species and formulating effective management and conservation initiatives.