Q-n-A: The Susquehanna River

By Steve Midway

Welcome to another Fisheries Blog Q-n-A!  This segment is designed to showcase the knowledge and specialty of someone in the fisheries world who flat out knows their stuff.  For this Q-n-A, we are featuring Megan Kepler, a PhD student at the Pennsylvania State University who is conducting dissertation research on fish in the Susquehanna River basin. Megan has grown up in the Susquehanna watershed and has turned her passion for the outdoors into a promising career. And with Susquehanna smallmouth bass recently in the news, I figured it was time for Megan to weigh in…


1. This past week intersex fish were reported in the Susquehanna. What are ‘intersex’ fish and how does intersex happen?
Intersex in fish is the presence of both male and female reproductive characteristics in a single individual.  As reported by Dr. Vicki Blazer and colleagues in a recently published paper, male smallmouth bass in the Susquehanna, Ohio, and Delaware Rivers in Pennsylvania had immature eggs found in their testes as well as the presence of vitellogenin in their blood plasma, which is the substance that results in yolk formation.   The cause of intersex in fish is actively being studied with various estrogenic compounds being found where intersex is occurring.


Susquehanna River at Harrisburg
Susquehanna River at Harrisburg. The Susquehanna basin covers three states and is the longest river on the Atlantic slope. (Source)


2. Other than intersex, what additional negative fisheries outcomes are you seeing in the Susquehanna basin? Any idea what might be causing the problems?
In addition to intersex, there are concerns for the presence of disease and mortality of fish species in the Susquehanna River basin. Specifically, my dissertation research involves studying the presence of disease in smallmouth bass, which in adult fish include melanistic spots, abnormal/missing eyes, lesions,  and various infections, to name a few.  In addition to concerns with disease in adult smallmouth bass, mortality of young-of-the-year has also been present.  Since the onset of disease, a wide range of potential disease causing agents have been and are being studied, including parasites, bacteria, viruses, water quality (i.e., DO, temperature, pH, nutrients), and contaminants.  Collaborations with various agencies continue to try to understand the role many of these factors of concern may play in onset of disease and mortality.


3. Unfortunately the Susquehanna basin has frequently been in the news the past several years. Can you give us a brief overview of what the basin and fishery was like 20 years ago? 10 years ago? And currently?
This is a very interesting question and at the same time differs across the Susquehanna basin.  In the past the Susquehanna River basin was revered for its game fishery, especially smallmouth bass throughout the main-stem reaches.  In the West Branch of the Susquehanna River, a different story was the case.  Due to impacts from acid mine drainage very few fish were found in the upper reaches (near Lock Haven, PA).  In the present day, due to reclamation efforts, fish populations are present throughout the West Branch and I am even conducting a telemetry research project in the Lock Haven area of the West Branch Susquehanna and two of its tributaries where smallmouth bass populations are present.  The Susquehanna River is still regarded for its fishery, but now there is much concern about the population status of various fish species and overall health of the fishery.


Susquehanna Smallmouth
Diseased smallmouth bass from the Susquehanna River. (Source)


4. Obviously, tackling problems in a big river basin presents challenges (compared to a small, isolated watershed). However, it would seem that there might be more interested parties and more stakeholders willing to work toward a solution. Is this the case in the Susquehanna basin, and if so, has this collaboration been productive?
I am very new to the various environmental concerns in the Susquehanna River basin, but in the past year that I have been involved I can say that collaboration between agencies has been key to research being completed.  I have worked with various agencies including USGS, PA Department of Environmental Protection, and PA Fish and Boat Commission as well as other interest groups and have found the relationship excellent.  Everyone brings a different skill set to the table and being able to work together is allowing research groups to evaluate a wide range of characteristics in this system.


5. In your opinion—as someone who has spent their life working and recreating in the Susquehanna basin—what do you think the main stem Susquehanna and all its tributaries will be like in another 10 or 20 years? 

This is a question that does concern me as a young scientist and also someone who is an avid outdoorswoman.  I think the future of various water systems including the Susquehanna depends on many factors including various anthropogenic impacts and environmental factors.  I am concerned about the many emerging chemical constituents and the future effects on the ecosystem.  Factors affecting land use including urbanization and deforestation could have altering effects on composition and quality of the water systems. Then there’s potential impacts from climate change, including changes in water temperature. I could go on and on listing future and current concerns, but through all of this management, policy, and research will be important in shaping decisions regarding the river system.  I am hopeful that we can better understand the current system and use that to protect the fishery in the future.


Susquehanna Runoff
Draining an immense area, of which much is agricultural, this image captures the runoff capable of being produced in the Susquehanna River. This image is from the late summer 2011, when flows were are record levels. (Source)


6. While the Susquehanna is a very large watershed that feeds the Chesapeake, there will still be many readers who don’t live or work in the Susquehanna basin. Why might the problems and lessons learned here be of interest to fisheries and resource managers elsewhere?
The Susquehanna River basin is not the only system to have concerns with fish disease and mortality.  Comparisons of various characteristics of systems can help researchers investigate similarities and differences, which has implications for future management.  Identifying potential disease causing agents will help better understand disease dynamics and can be used for guidelines elsewhere.


Megan Kepler
Megan Kepler (left).


Megan Kepler is a PhD candidate in the Intercollege Degree Program in Ecology at Penn State University.  Her dissertation research focuses on disease dynamics in smallmouth bass in the Susquehanna River basin.  She is working under Dr. Vicki Blazer at the USGS Leetown Science Center and Dr. Tyler Wagner at Pennsylvania State University in Pennsylvania Cooperative Fish and Wildlife Research Unit. Check out this recent piece on her!



Alvarez, D.A., W.L. Cranor, S.D. Perkins, V.L. Shroeder, L.R. Iwanowics, R.C. Clark, C.P. Guy, A. E. Pinkney, V.S. Blazer, and J.E. Mullican.  2009. Reproductive health of bass in the Potomac, USA, drainage: Part 2. Seasonal occurrence of persistent and emerging organic contaminants. Environmental Toxicology and Chemistry. 28(5):1084–1095.

Blazer, V., D.D. Iwanowicz, H.L. Walsch, A.J. Sperry, L.R. Iwanowicz, D.A. Alvarez, R.A. Brightbill, G. Smith, W.T Foreman, and R. Manning. 2014. Reproductive health indicators of fishes from Pennsylvania watersheds: association with chemicals of emerging concern [online serial]. DOI 10.1007/s10661-014-3868-5.

Blazer, V.S., L.R. Iwanowicz, H. Henderson, P.M. Mazik, J.A. Jenkins, D.A. Alvarez, and J.A. Young. 2012.Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects. Environmental Monitoring and Assessment. 184:4309–4334.

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