[PAST EVENT] Impacts of hypoxia and pH on fish growth and behavior

November 7, 2014
VIMS - Watermen's Hall, Watermen's Lobby
1375 Greate Road
Gloucester Point, VA 23062Map this location
Presenter: Dr. Tim Targett, University of Delaware

Reception at 3:00 p.m. in the lobby of Watermen's Hall

Seminar from 3:30 p.m. to 4:30 p.m. in McHugh Auditorium

"Impacts of hypoxia and pH levels in estuarine tributaries on fish growth and behavior: a field and laboratory journey"

Estuaries, coastal bays, and their tributaries constitute important nursery habitats during the larval and juvenile stages of many estuary-dependent fishes. The functional value of these habitats as nurseries is attributed primarily to physicochemical regimes that are physiologically suitable or optimal, abundant prey resources, and low predation risk; conditions that promote rapid growth and enhance survival of young fishes. Chronic and diel-cycling hypoxia has the potential to diminish growth and survival of these young fishes, and thus negatively impact nursery ground function. This seminar will describe the progression of field and laboratory studies that we have undertaken to investigate hypoxia dynamics in estuarine tributaries and the impacts of hypoxia (and most recently pH) on fish growth, behavior, and survival. We have developed a set of computer controlled aquarium systems in which treatment levels and cycles of dissolved oxygen (DO) are monitored, controlled, and recorded. In the field, there is spatiotemporally extensive diel-cycling hypoxia in Delaware waters, growth limitation in free-ranging fishes, and hypoxia avoidance behaviors. In the lab, there are: negative effects of hypoxia on growth rates of several species; interactive effects of hypoxia and temperature on growth rates of several species; behavioral avoidance of hypoxia at DO levels above those which cause growth detriments; growth rate acclimation in mummichogs over several weeks of hypoxia; growth rate compensation in juvenile summer flounder upon return to normoxia; no statistically significant effect of diel-cycling pH (6.8-8.1) on growth rates and no significant interaction with diel-cycling DO. There is the suggestion of an independent influence of low pH on growth of mummichogs at high temperature.

Dr. Targett earned his Ph.D. in Zoology from the University of Maine in 1979, an M.S. degree in Marine Biology from the University of Miami, and a B.S. in Biology from the University of Maine. His research involves controlled laboratory experiments and field studies on the impacts of physical and biological factors on growth and survival of young fishes in estuarine and coastal marine nursery grounds. Most recently the work in his laboratory has focused on effects of hypoxia on early growth and behavior. He has conducted research in estuaries and coastal marine waters along the east coast of the US, the Pacific Northwest, the Caribbean, Bermuda, Japan, the Irish Sea, Scotland, and Antarctica.

[[seitz, Rochelle Seitz]] at 804-684-7698