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.
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.
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.
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.