2009-Present A.D. and Annye L. Morgan Professor of Sciences College of Sciences Old Dominion University
2004-Present Eminent Scholar & Professor Department of Ocean, Earth & Atmospheric Sciences Old Dominion University
2003-2004 Eminent Scholar Department of Biological Sciences Old Dominion University
1998-2004 Professor Department of Biological Sciences Old Dominion University
1998-Present Director Center for Quantitative Fisheries Ecology Old Dominion University
1993-1998 Associate Professor Department of Biological Sciences Old Dominion University
1988-2001 Associate Director Applied Marine Research Laboratory Old Dominion University
1988-1993 Research Assistant  Professor Department of Biological Sciences Old Dominion University
1986-1988 Assistant Professor Department of Oceanography Old Dominion University
1986-1988 Adjunct Assistant Professor Virginia Institute of Marine Science College of William and Mary 
1984-1985 Post-Doctoral Associate Department of Natural Resources Cornell University
1984-1985 Project Leader New York Lake Ontario-Lake Erie Creel Survey  
1984-1985 Co-principal Investigator Larval striped bass research project Hudson River Foundation
1982-1983 Consultant  Analysis of pollution impacts on George’s Bank fisheries and modeling of effects of early life history mortality with a Leslie Matrix Model. Applied Science Associates, Wakefield, R.I
1982-1983 Statistical Programmer Statistical applications programming and data base management for medical assessment of community intervention to prevent cardiac disease. Pawtucket Heart Health Program, Pawtucket, R.I.
1980-1982 Graduate Research Associate Research in estimation of larval fish mortality. Data base manager, Bureau of Land Management Outer Continental Shelf Project. This research assessed the impact of oil spills on the ecosystem, with emphasis on the larval fish community. University of Rhode Island.
1978-1980 Fisheries Biologist Analysis of change in community structure of zooplankton and larval fish on George’s Bank. Statistical analysis and programming of NMFS MARMAP data base. National Marine Fisheries Service
1977-1978 Graduate Research Assistant Larval lobster population dynamics research. University of Rhode Island
1976-1977 Oceanographer Biological Coordinator for1976 Atlantic Environmental Group Summary Report. Coauthored and edited biological chapters. Hydrographic data analysis. National Marine Fisheries Service
1974-1975 Project Director Supervised Gibbs Refinery, Portland, Maine biological impact analysis. Planned and budgeted projects and analyzed field data. Normandeau Associates, Bedford, N.H.
1970-1973 Graduate Research Associate Conducted experiments to determine toxicity of chlorinated hydrocarbons to shellfish. University of Rhode Island
1968-1969 Graduate Research Assistant Aquaculture of commercially important shellfish. Masters’ thesis research on metabolic adaptation in crabs. University of Rhode Island