Thursday
February 20, 2003
4:30-5:30 pm
102 Fishery Sciences
(auditorium)
Social follows talk
David PhilippsSenior Scientist, Illinois Natural History SurveySupplemental Fish Stocking—Demographic Benefit or Genetic Disaster |
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Evolutionary theory predicts that differential selection pressures coupled with a restriction in gene flow among populations occupying distant habitats or isolated areas will result in the divergence of those populations and ultimately in the generation of discreet gene pools (or stocks) that are adapted to their local environments. Based on this theory, we can make two fundamental predictions concerning the outcome of a stock transfer (i.e., the introduction of fish from one or more non-native stocks into the habitat of a divergent, but native, stock). First, because of local adaptation, we predict that the introduced, non-native stock will be less reproductively fit than the native stock in that environment (Stock Transfer Prediction 1). Second, in cases where some portion of the transferred stock survives to maturity and hybridizes with the native stock, we further predict that this new interstock hybrid will have reduced fitness compared to the original, native stock (Stock Transfer Prediction 2). Such a loss in fitness is termed Outbreeding Depression. To test these two basic predictions empirically, we used genetically-tagged stocks of largemouth bass Micropterus salmoides from Wisconsin, Illinois, and Texas, as well as a stock of Florida bass M. floridanus from Florida in a series of "common garden" experiments in different geographic regions within the United States (Minnesota, Illinois, Texas, and Florida). In each of the four geographic regions, the native stock had not only superior rates of survival and growth, but also, and more importantly, superior rates of reproductive success. These results are highly consistent with our first prediction. Moreover, the absence of fully assortative mating resulted in extensive interbreeding among stocks in the experimental ponds. We tested the effect of this interbreeding on the fitness of the recipient, local Illinois stock. Here, interbreeding of the native Illinois stock with the transferred stocks led to a hybrid population with more than a 50% reduction in reproductive fitness relative to the original, local Illinois stock, an outcome consistent with the second prediction. Recent experiments with known interstock crosses have provided insight on the potential mechanisms driving the observed outbreeding depression.
Senior Scientist
Center for Aquatic Ecology
Illinois Natural History Survey
philipp@uiuc.edu
Education
BS Chemistry 1970 - Lafayette College
MS Biochemistry 1973 - University of Massachusetts
PhD Biochemistry 1976 - University of Massachusetts
Professional Experience
2001- Illinois Natural History Survey Senior Scientist
1990-98 Illinois Natural History Survey Director, Center for Aquatic
Ecology
1987-01 Illinois Natural History Survey Professional Scientist
1982-87 Illinois Natural History Survey Associate Professional Scientist
1977-82 Illinois Natural History Survey Assistant Professional Scientist
1975-77 University of Illinois (Dept of Gen & Dev) Postdoc Res
Associate
Affiliate Position at the University of Illinois
Professor, Department of Natural Resources and Environmental Science
Professor, Department of Animal Biology
Professor, Department of Animal Sciences
Current Research Interests
Natural resource conservation genetics; factors controlling reproductive
success in fishes; evolution of reproductive behaviors in fishes; evolution
of gene regulatory mechanisms; developmental and biochemical genetics of
fishes.
Major Activities
1986-88. Served as first President of the Fish Genetics Section, American
Fisheries Society
1988-92. Served on the Steering Committee for the First World Fisheries
Congress, Athens, Greece.
1993-94. Served as President of the North Central Division,American
Fisheries Society
1989-92. Served on the Northwest Power Planning Council's Columbia
River Basin Fish Genetics Management Plan Review Committee.
1990-00. Served on Review Panel for the USFWS Comprehensive Colorado
River Gila study.
1997-02. Served as Co-organizer and Editor for the Black Bass 2000 Symposium,
a four day event held in St. Louis, MO, August 20-24, 2000.
1999- Serving on the Independent Scientific Advisory Board for the
Northwest Power Planning Council and the National Marine Fisheries Service
– a ten member board that oversees the implementation of the fish and wildlife
management plan for the Columbia River Basin.
1. Bisson et al (the ISAB on which I serve). 2002. Hatchery surpluses in the Pacific Northwest. Fisheries 27(12): 16-27.