Comparison of age and growth parameters of flathead catfish in invasive and native populations: a meta-analysis with implications for invasive species management in Pennsylvania
Flathead catfish (Pylodictis olivaris) are a long-live apex predator native to the Mississippi, Mobile and Rio Grande drainages, and the Laurentian Great Lakes region. These fish have been introduced into most of the East Coast and areas of the Western US. Introduced Flathead Catfish populations often have detrimental effects on native fauna. In the Atlantic Slope portions of Pennsylvania the status of flathead catfish has not been adequately documented. Several large to medium-sized river systems in Pennsylvania have yet to be surveyed so the residency status of flathead catfish in those systems remains unknown. The primary objective of the project will be to determine flathead catfish distribution, and estimate abundance and population characteristics for both native and introduced populations in Pennsylvania. Much of the focus of the analysis will include age and growth analysis and modeling to put the current population status in the introduced range in a larger regional context for management purposes moving forward. Several other Atlantic Slope drainage have encountered similar invasions in recent decades so comparison with Pennsylvania populations with those will help to predict what to expect moving forward with existing populations as well as in areas where they have not yet invaded.
Preliminary determination of density and distribution of flathead catfish Pylodictis olivaris in the Susquehanna River and select tributaries
The goal of this project is to estimate the relative abundance and age and growth characteristics of invasive Flathead Catfish (Pylodictis olivaris) in three reaches of the mainstem Susquehanna River with different degrees of population establishment. By examining river reaches with different degrees of population establishment, data collected during this study will serve to help understand current distribution and population characteristics (e.g., size distribution, growth rates). In addition, we will develop models (based on population vital rates and habitat use) to predict future changes in establishing populations as well as to evaluate potential impacts to areas where Flathead Catfish have not yet invaded. These models can be used to help inform management of Flathead Catfish and native species throughout the Susquehanna River Basin.
Can plasticity protect populations from rapid environmental fluctuation?
Rates of population extirpation from habitat loss have reached unprecedented levels and climate change is predicted to be a leading cause of future species extinctions. Accordingly, conservation of emergent properties that promote resistance and resilience to environmental perturbation will be vital to future population persistence. Though it has been demonstrated that phenotypic plasticity increases resilience to habitat loss, the ability for plasticity to promote population persistence under climate change and habitat degradation has not been explored. If plasticity does increase survival, failure to conserve highly plastic genotypes could accelerate species extinction. This research focuses on an economically and socially important species, brook trout (Salvelinus fontinalis), to determine how the interactive effects of genetics and behavior influence differential survival of fish populations under a changing climate.
Linking fish health, contaminants, and population dynamics of smallmouth bass populations in the Susquehanna River, Pennsylvania
Since 2005, diseased smallmouth bass have been observed throughout the Susquehanna River and its tributaries, raising concern regarding the overall health of smallmouth bass and the Susquehanna River. In a collaborative effort with Pennsylvania Fish and Boat Commission, PA Department of Environmental Protection, U.S. Geological Survey, and Penn State University, this project aimed to investigate a wide-range of variables (e.g., fish health analysis, contaminants, population genetics, fish movement ecology) to gain a better understanding of factors that could be contributing to disease in smallmouth bass populations.
Transboundary management and conservation: linking large-scale dynamics to ecological monitoring and management
A central challenge to natural resource management is to understand and predict ecological responses to management and environmental change over large spatial scales. It is recognized, however, that the management and conservation of many important ecological systems and the services they provide must be addressed at spatial scales that transcend jurisdictional and political boundaries. Although transboundary approaches are necessary to understand large-scale phenomenon (e.g., species range), it remains unclear in many cases how best to address the inherent complexities in managing ecosystems at large (e.g., regional, sub-continental) spatial extents. In addition to challenges associated with performing transboundary research, it is often unclear how to link large-scale system dynamics with on-the-ground decision-making processes, which are often done using adaptive management principles. Th overarching objective of this research was to use freshwater stream fish populations as model systems to develop a framework and tools for addressing the inherent challenges in performing trans-boundary research and for linking large-scale dynamics to ecological monitoring and management.
Funding provided by the U.S. Geological Survey.
Characterization of spatial and temporal variability in fishes in response to climate change
The number of fish collected in routine monitoring surveys often varies from year to year, from lake to lake, and from location to location within a lake. Although some variability in fish catches is expected across factors such as location and season, we know less about how large‐scale disturbances like climate change will influence population variability. The Laurentian Great Lakes in North America are the largest group of freshwater lakes in the world, and they have experienced major changes due to fluctuations in pollution and nutrient loadings, exploitation of natural resources, introductions of non‐native species, and shifting climatic patterns. In this project, we analyzed established long‐term data about important fish populations from across the Great Lakes basin, including from Oneida Lake in NY, Lake Michigan, and the Bay of Quinte in Lake Ontario. Our objective was to evaluate spatial and temporal variation in fish catches from large freshwater lakes that have experienced large‐scale changing conditions. We evaluated analytical approaches with the potential to disentangle sources of variability in standardized monitoring data. Specifically, we considered 1) how the decomposition of spatial and temporal variation in fish catches can be used to measure a response to perturbation; 2) how truncation of population age structure can alter population oscillations which may shift how a population is affected by environmental fluctuations; and 3) how the composition of a fish community may respond to a suite of environmental drivers through time. Using long‐term gill‐net data for walleye, we found that average catch and variance structure differed before and after large‐scale perturbations. More generally, our results suggest that fish population responses to changing environments can be complex, but that long‐term monitoring combined with modeling approaches can allow for detection of quantifiable changes.
Fish community assessment in the Eastern Rivers and Mountains Network and integration with existing monitoring data
The National Park Service (NPS) has initiated a long-term ecological monitoring program, known as Vital Signs Monitoring, to provide the minimum infrastructure to allow more than 270 national park system units to identify and implement long-term monitoring of their highest-priority measurements of resource condition. The term "vital signs" refers to a relatively small set of information-rich attributes that are used to track the overall condition of park natural resources and to provide early warning of situations that require intervention. Vital signs are defined as a subset of physical, chemical, and biological elements and processes of park ecosystems that are selected to represent the overall health or condition of park resources, known or hypothesized effects of stressors, or elements that have important human values. The Eastern Rivers and Mountains Network (ERMN) includes nine parks in New York, New Jersey, Pennsylvania, and West Virginia which together encompass nearly 91,000 ha of land area and more than 600 stream and river miles within the parks' authorized boundaries. A primary objective of the ERMN monitoring program is to evaluate status and trends in the condition of tributary watersheds flowing into and through member parks. The objectives of this study were to: (1) Characterize fish communities in selected ERMN stream reaches, and (2) combine fish community data with existing monitoring data (e.g., macroinvertebrates) to provide an integrated measure of stream ecological condition.
Funding provided by the National Park Service.
Evaluation of wild trout resources and restoration efforts in Pennsylvania
The overarching goals of this research was to (1) provide relevant information on wild brook trout Salvelinus fontinalis (a keystone species and indicators of excellent water quality and healthy coldwater ecosystems) and brown trout Salmo trutta (an ecologically and economically important fish species) movement dynamics and habitat use, and (2) help guide fisheries management and restoration efforts in the Commonwealth of Pennsylvania by providing a thorough literature review with respect to methods for assessing instream habitat. The research helped reduce uncertainties with respect to key management questions that are necessary to develop effective management plans (including the planning, implementation, and monitoring stages).
Funding provided by the Pennsylvania Fish & Boat Commission.
Comparative energetics of lake trout morphotypes
The objectives of this research were to: (1) Improve existing bioenergetics models for lake trout by modeling a wider range of temperatures to capture the descending portions of the consumption and respiration functions; (2) Compare the energetics of two morphotypes of lake trout: humper and lean; and (3) Make recommendations for the most suitable morphotype to stock given current and future temperature regimes in various waterbodies.
Funding provided by the U.S. Fish & Wildlife Service.
Habitat use, movement and genetic composition of lake trout in the Niagara River and Niagara Bar
Restoration of lake trout (Salvelinus namaycush) to the Great Lakes has focused on hatchery supplementation to establish naturally reproducing populations. Successful restoration is measured in part by the establishment of naturally reproducing and self-sustaining populations. This project focused on lake trout movement and spawning in the Niagara River and Niagara Bar area of Lake Ontario to: 1) quantify genetic differences between the lake trout hatchery strains stocked into Lake Ontario, 2) assess if there are strain-specific differences in movement patterns during the fall and winter when the lake trout enter the Niagara River and Niagara Bar area to spawn, and 3) assess if there are strain-specific differences in reproduction location and reproductive success within the Niagara River and Niagara Bar area.
Funding provided by the U.S. Fish & Wildlife Service.
Distributions of PCB congeners in Pennsylvania streams and fish: Implications for risk management and fish health
The goal of this project was to provide information related to PCB congener distributions and concentrations in Pennsylvania aquatic systems that could have potentially limited future management and policy decisions with respect to site remediation and health advisories. This research also examine the effects of food deprivation, following PCB exposure, on PCB congener mobilization and biotransformation in relation to lipid depletion and its subsequent effects to fish health. This research had implications for consumption advisories targeting channel catfish (Ictalurus punctatus), a recreationally important warmwater fish species in Pennsylvania.
Funding provided by the Pennsylvania Fish & Boat Commission.
Spatial and temporal components of variation in Great Lake percid populations: implications for conservation and management
The purpose of this project was to provide monitoring recommendations for fishery-independent surveys of percid populations (e.g., yellow perch Perca flavescens and walleye Sander vitreus) in the Great Lakes Basin. Throughout the basin, fishery-independent surveys are the primary means for collecting data on fish populations. These surveys often provide a wealth of information including indices of relative abundance, a description of the size and age composition of the population, and measures of fish condition and sex ratios. This information is then often used to evaluate the success of restoration efforts and improve understanding of the development of percid populations over time. Ultimately, the information derived from such surveys can be used to inform management decisions, such as those related to harvest policies. The specific objectives of the were to:
Determine relative magnitudes of spatial and temporal components of variation in percid relative abundance data and how these variance structures may differ among systems in the Great Lakes Basin.
Determine whether variance structure itself is responsive to large-scale ecological perturbations.
Develop recommendations for the design of monitoring programs and analysis of resulting data to support management of important percid fisheries within the Great Lakes region.
Funding provided by the U.S. Fish and Wildlife Service, Great Lakes Restoration Initiative.