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 provides 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 2007 Stevenson Lecturer is:

Dr. Karen Kidd

Canadian Rivers Institute and Department of Biology

University of New Brunswick, Saint John, New Brunswick


Responses of a freshwater food web to whole-lake additions of a potent estrogen


Considerable evidence now exists that fish are being adversely impacted by estrogens and their mimics in municipal wastewater treatment plant (MWTP) effluents.  However, it is not known whether the responses observed at the organism level, such as the production of egg protein precursors (vitellogenin) in male fish downstream of MWTPs, are indicative of problems at the population level.  To investigate this unknown and assess the effects of an estrogen on lower-trophic-level biota, an estrogen-addition experiment was conducted at the Experimental Lakes Area (ELA) in northwestern Ontario from 1999-2006.  This study examined the effects of whole-lake additions of the synthetic estrogen 17a-ethynylestradiol (EE2) used in birth control pills on fish, amphibian, zooplankton, benthic-invertebrate, algal, and microbial communities.  In the summers of 2001—2003, EE2 was added continuously to the epilimnetic waters of one lake to achieve constant and environmentally-relevant concentrations of this estrogen.  In the study and reference systems, population-level data were collected for all trophic levels, and several tissue- and biochemical-level endpoints were examined in lake trout, white sucker, pearl dace and fathead minnow.  The experiment was successful at reproducing (no pun intended) the organism-level impacts observed in wild fish downstream of MWTPs; we also observed a population collapse of the shortest-lived fish species in the lake, the fathead minnow, after the second summer of EE2 additions.  Results from this study are being used to understand the magnitude of the impacts that hormone mimics have on aquatic organisms, and the risks that environmental estrogens pose to freshwater food webs.