Forecasting Aquatic Invasions in Rivers: Using Riverscapes Genetics to Inform Invasive Fish Species Management at Regional Scales

Invasive species have significant, negative effects on ecosystem structure and function, and predicting and limiting the spread of invasive organisms a priority for environmental managers. Invasive species management is particularly challenging in aquatic habitats, where higher invasion velocities and stronger interactions with native biota result in more significant disruptions to ecosystem structure and function. In particular, through competition, predation, and disruption to nutrient and energy flows, invasive species often lead to a reduction and/or loss of native populations and can decrease ecosystem resiliency to disturbance. In collaboration with state fisheries management agencies and Penn State University, we will apply a novel quantitative framework for riverscape genetics to better understand and predict the invasion potential of invasive flathead catfish in the Susquehanna River Basin. This research will identify management scenarios that can be used to limit future invasion and we will develop a web viewer to communicate the efficacy of different management scenarios to stakeholders and managers.

​Funding: U.S. Geological Survey

Changes in stream fish distribution and occurrence in seven National Park Service units of the Eastern Rivers and Mountains Network

The National Park Service (NPS) mission to preserve, protect, and maintain the integrity of park ecosystems for the enjoyment of future generations relies upon access to science-based information regarding the status and trends of ecosystem condition. The Eastern Rivers and Mountains Network (ERMN) includes nine parks located in four states: New York, New Jersey, Pennsylvania, and West Virginia ranging in size from approximately 66 to 30,000 hectares with over 690 km of rivers and streams. The ERMN documents long-term change in the ecological integrity of one of the most abundant surface water ecosystems types in the network (high gradient, wadeable streams) by monitoring stream fish communities. Assessment of changes in fish community composition, occupancy and abundance is necessary in order to ensure the NPS mission is achieved. The project is a collaboration of researchers from USGS, NPS, and Pennsylvania State University. The statistical models developed during this project will inform decision making processes for the management of park ecosystems.

​Funding: National Park Service

​Determining the consequences of land management actions on fish population dynamics and distributions

Better understanding the drivers and stressors affecting fish health, fish habitat and aquatic conditions remains a significant management need in cool and warmwater rivers. Quantifying the effects of land management activities on aquatic ecosystems plays an important role in environmental management and decision-making. This research will address stakeholder needs related to understanding the effects of land management actions on stream and river habitat conditions – habitat that is critical for supporting socioeconomically and ecologically important fish communities throughout the Chesapeake Bay Watershed. The project is a collaboration of researchers across multiple agencies and includes the USGS and state fisheries management agencies across the Chesapeake Bay Watershed. Through the development of several modeling frameworks, this research will focus on quantifying the effects of land management actions on population-level outcomes that are relevant to managers, including effects on community composition, abundance, recruitment, the number of spawners, and size structure.

​Funding provided by the U.S. Geological Survey

​Watershed conditions and biotic interactions in structuring Pennsylvania stream fish communities


Understanding and predicting fish community interactions and their response to environmental stressors is of utmost importance for fisheries and water resource management. For example, state agencies and other water resource agencies rely on knowledge of stream and river fish communities for assessment programs, many of which have regulatory ramifications and implications for water and fisheries management and aquatic resource use activities. However, traditional fish community studies fail to accommodate potential interactions that exist among the entire fish assemblage and thus represent an overly simplistic view of community dynamics. This is important because treating species independently when quantifying and predicting their responses to changing watershed conditions ignores potential dependencies between species due to biotic interactions and can lead to erroneous predictions. Therefore, the overarching goal of this research is to help inform fisheries and water resource management and conservation by improving our understanding of the relative roles of fish species interactions, environmental factors, and how species traits influence a species’ response to changing watershed conditions in Pennsylvania streams and rivers.

The project is in collaboration with the Pennsylvania Fish and Boat Commission, the Pennsylvania Department of Environmental Protection, the Susquehanna River Basin Commission, and Penn State University. 
​
Funding provided by Pennsylvania Sea Grant.

​Diet composition of invasive Flathead Catfish in the Susquehanna River Basin: quantifying impacts on native and migratory fishes and recreational fisheries

​Flathead Catfish are an indiscriminate predator of other fish and an expanding invader to large river systems outside of its native range, including the Susquehanna River Basin in Pennsylvania. Research efforts are beginning to provide insight on the distribution of this invader in the Susquehanna River Basin, however, there is considerable uncertainty about the potential ecological impacts of Flathead Catfish. In particular, there are concerns about their impacts on native and migratory fish species and on economically important recreational fisheries. To begin understanding the ecological effects of Flathead Catfish invasion, we propose a comprehensive diet study on Flathead Catfish in the Susquehanna River Basin. We will quantify Flathead Catfish diet composition using morphology and molecular identification of ingested prey items. Our study will help inform future fisheries management in the Susquehanna River Basin by increasing our understanding about the predatory effects and potential ecological consequences of invasive Flathead Catfish.
 
The project is in collaboration with the Pennsylvania Fish and Boat Commission and Penn State University.

​Funding provided by Pennsylvania Sea Grant.

​Fish habitat restoration to promote adaptation: resilience of sport fish in lakes of the Upper Midwest

​Climate change is influencing fish communities in lakes throughout the upper Midwest. Popular sport fish such as walleye are declining in many lakes, while warmwater species such as largemouth bass are increasing. However, not all lakes or fish species respond in the same way, even when they experience the same conditions. In some cases, local management actions such as restoration or protection of lake habitat can slow down or mitigate the negative effects of climate change on economically and ecologically important fish species. This project aims to understand how multiple fish species (walleye, yellow perch, northern pike, largemouth and smallmouth bass, and cisco) with different temperature preferences respond to climate change, and how their responses are affected by lake habitat conditions. Researchers will develop models to predict responses to climate change in tens of thousands of lakes in the upper Midwest. By identifying habitat factors that make certain lakes more or less vulnerable to climate change, this research will enable lake and watershed managers to prioritize management actions aimed at reducing the negative effects of climate change. At the same time, lakes where certain species are unlikely to exist under future conditions will also be identified, which will enable managers and citizens to prepare for shifts in fish community composition. Project results will be communicated to managers and the public using online data visualization and communication tools to demonstrate how lakes in the Midwest are affected by climate change and identify lakes where local actions may be effective in preserving cold- and coolwater fish species as the climate warms.
 
The project is a collaboration of researchers across multiple agencies and includes the University of Minnesota, University of Missouri, USGS, Wisconsin DNR, Minnesota DNR, Midwest Glacial Lakes Partnership, and Michigan DNR.

Funding provided by the USGS National Climate Adaptation Science Center.

​Establishing a strategy for assessing the risk of endocrine-disrupting compounds to aquatic and terrestrial organisms

​Endocrine disruption is a national and global concern that affects fish, wildlife and human populations. Through interactions with neural, endocrine, and immune systems, endocrine disrupting compounds (EDCs) can influence growth, development, reproduction, disease, and mortality, with adverse outcomes for populations, communities, and ecosystems. Within the Chesapeake Bay, understanding the effects of EDCs on fish and wildlife populations has been identified as a priority to help inform natural resource management. Specifically, there is a need for assessing the risk of EDCs to fish and wildlife populations. We are currently working to integrate our understanding of the (1) population dynamics of smallmouth bass (Micropterus dolomieu; our case-study organisms), (2) mechanisms through which EDCs interact with individuals, and (3) exposure pathways between sources of EDCs - including hydrological conditions and land use practices - and fish and wildlife populations. This research will help identify short and long-term impacts of compounds or classes of chemicals of concern, potential environmental conditions and stressors that may mediate the effects of EDCs, and how land use management practices may help reduce exposure to EDCs.

Funded provided by the U.S. Geological Survey.

​An investigation into the role of groundwater as a point source of emerging contaminants to smallmouth bass in the Susquehanna River Basin

There is currently a paucity of information on the role of groundwater discharge into surface waters as point sources of contaminants from polluted aquifers. This is critical to understand because groundwater seeps are important ecologically, as they are used by many species, including smallmouth bass. Previous work has shown smallmouth bass (Micropterus dolomieu) utilizing areas of groundwater upwelling for spawning in the Susquehanna River Basin. Exposure to EDCs during this critical life-stage of egg development could have detrimental short- and long-term consequences on immune function and fish health. Therefore, the objective of this research are to (1) identify relationships between contaminants found in samples of groundwater upwelling into streams to the concentrations found in the stream surface water samples, (2) explain the contaminants present in groundwater samples within the context of surrounding land use, and (3) calculate ​an approximate groundwater flux into streams at select upwelling locations to begin to understand the relative importance of groundwater as a pathway for EDCs.

​Funding provided by the U.S. Geological Survey and grants from the RK Mellon Freshwater Research Initiative at Susquehanna University.