valuation of road crossing structures on brook trout passage: Application of continuous passive monitoring to quantify seasonal variation in fish passage and the development of decision support tools for road crossing construction and maintenance projects

Focus Area

Construction and Maintenance Practices


Environmental Process, Natural Resources






2-3 years

Research Idea Scope


It is well established that structures associated with road crossings may have negative impacts on stream fish assemblages. The two primary mechanisms through which road crossings may impact stream fish populations are by (1) increasing sedimentation and (2) obstructing fish passage. Potential impacts due to sedimentation are most often to occur during the construction of road crossing and associated structures; however, any reduction in upstream or downstream movement is a persistent problem that can have population-level impacts. As such, there has been a substantial amount of research devoted to the potential impacts of various road crossing structures on fish passage (e.g., Belford and Gould 1989; Bouska and Paukert 2009; Pépino et al. 2012). This research has focused on a wide-range of species, road crossing structures, and stream types. Despite these research efforts, however, there are still uncertainties regarding what types of structures minimize effects on fish passage. In particular, studies are needed that address seasonal variation in fish movements and provide a continuous assessment of fish passage through these structures. For instance, most of the studies that have examined fish movement through road crossing structures have used mark-recapture techniques. A limitation to using this approach is that it is only effective at detecting fish movement that coincides with recapture sampling (which typically occurs once a month over the summer months). As a result, previous studies using mark-recapture provide only a ‘snap-shot ‘of the effectiveness of various structures in terms of fish passage, which may reduce the ability to assess which structures are effective. In addition, continuous monitoring would facilitate the development of decision-support tools that could be used by managers to predict when (e.g., under what velocity and depth conditions) and where (e.g., streams of different slope) different structures would be effective.

The use of passive integrated transponder (PIT) tag technology is an effective approach that can provide continuous monitoring of fish passage events for a broad range of species. In streams across the northeast, wild brook trout are a species of concern. Continuous passive monitoring of brook trout in its native range would allow for improved assessment of road crossing structures (e.g., commonly used box culverts and open-bottomed arch culverts) with respect to fish passage. This information is particularly needed with the rapid increase in road development associated with natural gas extraction occurring throughout much of the brook trout’s native range and as current road infrastructure is being replaced or repaired. Decision support tools related to brook trout passage at road crossings is relevant for a broad range of companies and state and federal agencies that are involved in road construction and maintenance projects.


The main objectives are to use PIT tag technology to determine 1) the movement of wild eastern brook trout through various road crossing designs, 2) determine if degree of movement differs between structures and seasonally through the use of continuous passive monitoring, 3) develop models describing factors influencing movement and passage dynamics, and 4) make recommendations on culvert design that best allows for brook trout passage that can be used to develop best management practices for future projects.


Key tasks include the development and implementation of a PIT-tag study or brook trout passage across several road crossing structures, with an emphasis on box culverts and open-bottomed arch culverts.

Urgency and Payoff

This proposed research will provide direct information on the design and effectiveness of alternative culvert designs commonly used in road crossings throughout the eastern brook trout’s native range. Management recommendations will be useful to state fisheries management agencies, agencies responsible for permitting road constructions on state and federal lands, and state DOTs. In addition, although this work will focus on brook trout, information collected during this research will likely be applicable to other headwater stream fishes. Cost effective techniques that maximize fish passage are the goal.

Suggested By

Jason Detar, PA Fish & Boat Commission, 814-359-5118

[email protected]