Brook Trout in Chester County

Executive Summary

Brook trout are under significant pressure in Chester County, PA due to habitat loss and degradation that started with deforestation and agricultural development in the 1700s, and increased with more recent suburban development. One key problem this application addresses is the lack of updated brook trout distribution information for Chester County.

Our overarching goals are to preserve current brook trout habitat where populations currently occur in Chester County, and to reestablish brook trout where conditions are appropriate. The specific goals include:

  1. Update wild brook trout survey data by revisiting sites known to support wild brook trout in the 1980s and 90s, and characterize the physicochemical and ecological conditions at sites that still support wild brook (or brown) trout.
  2. Survey nearby streams with similar physicochemical and ecological conditions to confirm the presence or absence of trout in these streams. 
  3. Use this information to make a plan to preserve current brook trout populations, and to reestablish brook trout where habitat currently appears suitable, but brook trout are not found.

Methods include utilizing environmental DNA (eDNA) to identify/confirm existing brook trout streams. We will also record temperature, dissolved oxygen, pH, and conductivity, and use macroinvertebrates for additional information on overall stream health. Land cover will come from the NLCD 2016 database. Streamside habitat will be assessed using PA DEP protocol.

These data will be used to characterize the conditions that still support wild brook trout, and to set long-term priorities for brook trout conservation and restoration in Chester County, PA. Stroud Water Research Center will oversee technical aspects of eDNA protocol development, water sample collection and analysis, and GIS mapping.

Background to the Project

This project is an important contribution to the Valley Forge Chapter’s long-term efforts to conserve and restore trout in S.E. Pennsylvania, with particular focus on brook trout (Salvelinus fontinalis) in Chester County. Chester County is located in SE, Pennsylvania and is situated less than 1 hour from Philadelphia, PA and still a key population center in the U.S.

Brook trout streams under consideration are situated proximal to numerous sites of national historical significance including Valley Forge National Historic Park, the Brandywine Battlefield, and Hopewell Furnace National Historic Site. After more than 300 years of intensive land and water use, brook trout populations in this region are highly fragmented due to habitat loss and degradation. A key problem that this application rectifies is the lack of recent brook trout survey data in Chester County, PA.

Most data date back to the 1980s and 90s, reflecting invaluable efforts by Chapter member Joe Armstrong, with more recent observations by PA Fish and Boat and Chapter members from a limited number of sites.

This study would address brook trout conservation priorities as outlined in the Pennsylvania Wildlife Action Plan as a species of greatest conservation need. Additionally, this project would be in alignment with the Eastern Brook Trout Joint Venture which has goals to increase the average size of brook trout patches, restore wild brook trout to catchments where they were extirpated, maintain the number of wild brook trout patches and increase connectivity within and among brook trout catchments.

Brook trout presence in streams is indicative of high water quality and habitat. When brook trout are not present, it is an indication of habitat loss and degradation that started with deforestation and agricultural development in the 1700s, and increased with intensive suburban development where open space was developed at a rate of an acre per hour in the 1990s and early 2000s.

Deforestation, agricultural practices, and suburbanization increased stream temperature, buried stream beds with eroded sediments, and elevated nutrient and toxic loads. Historical data indicates that there are approximately 20 brook trout patches in Chester County, PA. The fact that these data have not been updated in several decades calls into question the current status of brook trout health and sustainability in Chester County, PA.

A key aspect of this application will be to assess through brook trout environmental DNA(eDNA) testing the brook trout sites that have been previously identified, in order to determine if there have been any changes to their status. Historically, eDNA technology has not been available for such research investigations. Electrofishing has been the standard in terms of assessing fish population heterogeneity, numbers and sizes. Although electrofishing has the advantage of providing a quantitative assessment of fish population species, numbers and size, there is the potential for substantial morbidity associated with the electro-fishing process, especially in smaller tributaries with much less surface area. In addition, the cost of undertaking electrofishing studies across several watersheds in Chester County would be prohibitive. For example, a one site electrofishing study could cost up to $3000 per site for a 100m section, whereas an eDNA assessment of the same site would cost approximately $67.

Although, eDNA technology has not currently been validated to measure abundance of either brown or brook trout, we believe that eDNA testing represents a good screening tool that can direct selective electrofishing assessments if quantitative data are needed.

As brook trout patches are identified through eDNA testing, we can better identify and understand the conditions under which brook trout are currently residing by recording temperature with remote sensors, and dissolved oxygen, pH, and conductivity with hand meters, and collecting macroinvertebrates for addition information on overall stream health. Watershed and streamside land cover will come from the NLCD 2016 database. Streamside habitat will be assessed using the PA DEP protocol. As a part of this evaluation, the genetic presence of brown trout (Salmo trutta) will also be assessed, which will give us insight into the overall suitability of stream habitat for trout, and the brook trout/brown trout presence and their potential interaction. Our partners will include the University of Maine for eDNA testing and Stroud Water Research Center for eDNA protocol development, water sample collection, mapping and data analysis. Land access will be accomplished through partnerships with Natural Lands and French and Pickering Conservation Trust. Valley Forge TU members will oversee data collection for temperature, dissolved oxygen, pH, conductivity, macroinvertebrates, and habitat assessments.

By assessing current brook trout habitat status in Chester County, we hope to gain an understanding of the physicochemical and biological conditions that brook trout are currently experiencing in the face of climate change and future development inevitibilities. In addition, we hope to utilize this information to inform the conservation and restoration efforts in brook trout streams that are under threat, as well as repopulate streams with Brook Trout where appropriate habitat exists.

Our goal would be to share this newly generated data with PA Fish and Boat Commission and the EBTJV, in order to better optimize and prioritize brook trout conservation and restoration efforts in S.E. Pennsylvania. In addition, we will be sharing these data with PA DEP where trout and macroinvertebrate data suggest that current Designated Uses are not protective of Existing Uses (i.e., we will contribute to upgrade petitions to better protect brook trout habitat).

With an updated data set, we hope to have the opportunity to work with the PA Fish and Boat Commission when appropriate brook trout habitat is identified and to obtain their assistance in transferring brook trout from existing local brook trout streams to those that can support brook trout, but where none have been identified.

In summary, our objective is to update brook trout physical and biological survey data to current day standards and to further the science and understanding of brook trout habitat in S.E. Pennsylvania with the ultimate goal of preserving the species and water that they inhabit for future generations.

Project Objectives

  1. Survey 30 streams identified as having wild Brook Trout in SE Pennsylvania, Chester County, utilizing eDNA to confirm the presence or absence of brook trout.
  2. Upon confirmation that Brook Trout are present, a select number of these streams will be surveyed for macroinvertebrate and land use assessments
  3. Survey select number of Pickering Creek headwater streams for Brook Trout using eDNA. The Pickering Creek headwaters are currently unassessed based on the Eastern Brook Trout Joint Venture identifier map and the PA Fish and Boat Commission.
  4. Informed by eDNA results, survey select Brook Trout streams for macro-invertebrate populations as well as complete an assessment of dissolved oxygen, temperature, conductivity and pH.
  5. Recommend/prioritize next steps for brook trout preservation, restoration and repopulation.