Thesis
Comparative population biology of native and invasive crayfish in the John Day River, Oregon, USA
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/102250
Abstract
Invasions of crayfish in lakes or rivers often result in decline or extirpation of resident crayfish faunas. Differences in growth rate or life history are one hypothesized mechanism by which non-native crayfish species displace native crayfishes. We evaluated the population biology of the invasive rusty crayfish (Orconectes rusticus) and the native signal crayfish (Pacifastacus leniusculus) in the John Day River, Oregon, where the rusty crayfish has been spreading rapidly and where native crayfish are not found in most invaded stream reaches. Sampling was conducted monthly in 2010 and 2011with D-frame kick nets at both an invasivedominated site and a native-dominated site. Orconectes rusticus young-of-year (YOY) grew faster and overwintered at a larger mean size than YOY P. leniusculus, suggesting O. rusticus has an advantage in size-mediated competitive interactions. Orconectes rusticus showed fewer age classes overall, but more consistently high rates of adult growth. Marked differences in growth between the numerically dominant YOY age classes may do most to drive overall competitive dominance. Juvenile O. rusticus also had largerchelae than P. leniusculus of a similar size, further suggesting competitive dominance. These results will not only inform management of the John Day basin, but should also guide further research into predicting the effects of interspecific life history differences in ongoing and future invasions.
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Details
- Title
- Comparative population biology of native and invasive crayfish in the John Day River, Oregon, USA
- Creators
- Keith Lawrence Sorenson
- Contributors
- Stephen M. Bollens (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525163701842
- Language
- English
- Resource Type
- Thesis