CANADIAN CONFERENCE FOR FISHERIES RESEARCH (CCFFR)
THE J.C. STEVENSON MEMORIAL LECTURE

This is a prestigious lectureship instituted in memory of Cam Stevenson, the long-time Editor of the Canadian Journal of Fisheries and Aquatic Sciences (CJFAS), published by NRC Press and is conferred upon a young, energetic and creative researcher at the cutting edge of an aquatic discipline. Each year a Lecturer is selected by the Journal's Editorial Board. In the Spring of each year a call for nominations is sent to the Chairs of Zoology and Biology departments across Canada, as well as to the research directors of the federal Departments of Fisheries and Oceans and Environment Canada and the National Research Council. The list of nominees is then sent to the CJFAS Editorial Board, who provide recommendations and justification for their selections. The Lecturer delivers a stimulating presentation of their work as the keynote address in the opening session of the Annual CCFFR meeting. A written version of the presentation is normally published as the lead article in the January issue of CJFAS or sometime soon thereafter.

The 2006 Stevenson Lecturer is:

Dr. Colin Brauner
Department of Zoology
University of British Columbia

brauner@zoology.ubc.ca

The use of sub-lethal physiological indicators in fish for environmental management; from the Salton Sea, California, to Lake Qinghai, China.

Abstract:

The Salton Sea is the largest lake in California (1000 km^2). It is below sea level, has no outflow, and high evaporative water loss. The salinity is currently 43 g/L, and increasing at a rate of 0.3 g/L per year. This hypersaline lake supports a recreational fishery, consisting of several marine fish species and the California Mozambique tilapia (Oreochromis mossambicus x O. urolepsis hornorum ), which is the most abundant fish species. Lake Qinghai is the largest lake in China (4000 km^2) and resides on the Tibetan plateau at 3200 m. This lake also has no outflow and high evaporative water loss, and significant inflow is diverted away from the lake for agricultural purposes. The lake salinity is presently 9 g/L, but increasing as the lake water levels continue to fall. Lake Qinghai is home to the lake Qinghai scale-less carp (Gymnocypris przewalskii), a Tibetan cultural icon and the species that historically supported a commercial fishery that has since collapsed. In both systems, lake salinity is progressively increasing, largely due to anthropogenic factors, and will eventually surpass salinity tolerance of resident fish species. We are conducting experiments to investigate the physiological mechanism(s) and threshold(s) of salinity tolerance (based upon changes in gill Na+,K+ ATPase activity, gill morphology, drinking rate, plasma ion levels and osmolality, metabolic rate, and growth, among other parameters) of these fish to gain insight into their ability to acclimate to increasing salinity. In each system, tilapia and carp appear to be on the edge of their salinity tolerance, necessitating large changes to water use and water management strategies, if these species are to persist.