Differential Movement of Stream Cyprinids in Urban and Rural Watersheds

Collection of fish using electrofishing techniques.Urbanization is a common problem influencing stream degradation in the United States. Urban stream ecosystems are impacted by habitat degradation and associated loss of species richness. Streams found in watersheds covered with high percentages of urban land use (ULU) and impervious surfaces are subject to high stormflow and low baseflow, loss of riparian buffers, changes to instream habitat quality and channel characteristics, and water quality. In this project, we wanted to determine whether differences in fish movement were related to differences in stream habitat quality in urban vs. rural streams.

We studied the movement of two pollution tolerant minnow species, blacknose dace (Rhinichthys atratulus) and the creek chub (Semotilus atromaculatus), in small first-order streams in Maryland’s eastern Piedmont. Fish were collected and marked with visible implant elastomers. They were recaptured monthly to determine whether they had stayed in their original capture pool or had moved.

Stayers: Individuals that rarely move from a habitat patch; defined where capture pool = home pool.

Movers: Individuals that often move between different habitat patches; defined where capture pool does not = home pool.

We compared stayers (shown in yellow) to movers (shown in green) upon recapture at urban and rural streams. Rural stream populations were found to display a greater “stayer” component than “mover”.

Research Conclusions:

  • The proportion of movers and stayers differ between urban and rural fish populations. Urban fish are more likely to move throughout the stream reach and travel farther over the summer months than fish in rural streams.

  • Differential movement patterns are likely due to instream habitat degradation and altered hydrology associated with urbanization impacts.

This figure represents total distance moved by blacknose dace and creek chub in rural and urban streams from the home pool. Fish found in their home pool are represented in the “0” column. The average distance moved by both fish species in rural streams was 14+/- 2.5 m and 31 +/-3.8 m in urban streams. Fish in urban streams moved farther away from their home pool than rural fish, thus less urban fish were found in their home pool (urban, n = 95; rural, n = 92).To Learn More:

Morgan, R.P. and S.F. Cushman. 2005. Urbanization effects on stream fish assemblages in Maryland, USA. Journal of the North American Benthological Society 24(3): 643-655. (nutshell page)

Project PI's:

Dr. Raymond P. Morgan II

Dr. Susan Flanders Cushman