Baltimore Ecosystem Study Institute of Ecosystem Studies

2013 BES Annual Meeting Presentation and Poster Abstracts

Habitat requirements of River chub (Nocomis micropogon), an urbanization sensitive keystone fish species: Relation to functional restoration of urbanized waterways
Kemp, Stanley
Co-Authors: Stanley J. Kemp, University of Baltimore

Urbanization poses a growing threat to the integrity of aquatic ecosystems and has been shown to severely impact ecosystem function and services. Recent reviews have indicated that attempts to restore biodiversity in urbanized waterways have frequently been unsuccessful. One possible impediment to successful restoration of ecosystem function is that mechanisms through which urbanization impacts specific organisms remain incompletely known. Lacking this information, restoration practitioners are hampered in designing and implementing successful restoration plans. This paper focuses on determining specific nesting habitat requirements for River chub (Nocomis micropogon), a species which has largely disappeared from Baltimore’s urbanized waterways. Males construct large pebble mound nests which are critically used by a number of other species as ideal nesting habitat. Local streams which continue to harbor River chub populations (Little Gunpowder Falls, Winters Run) as well as those which do not have River chub (Gwynns Falls, Jones Falls) were surveyed focusing on nesting habitat. Streams with extant populations were surveyed for nesting activity during 2012- 2013. Nest dimensions, substrate availability, stream velocity and flow rate, water depth, and erosion rates were measured for natural nests. An experiment using artificial nests was conducted (2013) to compare nest survival rates between urbanized streams and areas with extant populations. River chub are highly selective in nest site selection and composition. Results indicate presence of suitable substrate and conditions in urbanized streams, but reduced nest survival due to flashy hydrology. Future research will focus on linking specific habitat requirements with population persistence and impacts of restoration efforts.