Educational Video October 1, 2015
How We Do Things at IISD-ELA is a series of videos that highlight research conducted by scientists at the IISD Experimental Lakes Area (IISD-ELA), a unique freshwater science research facility in northwest Ontario, Canada.
Ever since the incidence of mercury toxicity in Minamata, Japan, high levels of mercury in fish has been a topic of global concern. Mercury gets into lakes either from the atmosphere or from point sources of pollution, and from there it accumulates in the organisms that live in the lake. Through a process called biomagnification, animals at the top of the aquatic food web, including fish, accumulate the most mercury. If these concentrations are high enough, the fish can be unsafe for people to eat.
By examining mercury accumulation in fish at IISD-Experimental Lakes Area (IISD-ELA), we can help scientists and governments better understand how this process works, and how long it takes for mercury levels to decrease after pollution stops. The lakes at IISD-ELA are small and have low numbers of fish, so we developed a method of determining mercury levels without killing the fish. This method, called a biopsy, allows us to track mercury concentrations in individual fish over time and is a great alternative to the lethal sampling used in many mercury studies. The biopsies we have collected from fish at IISD-ELA have increased our understanding of how fish mercury concentrations change over time and give us insight into the recovery of mercury-contaminated fisheries in lakes around the world.
For more information about this procedure, please refer to the following paper or contact IISD-ELA Biologist Lee Hrenchuk.
Baker, R.F., Blanchfield, P.J., Paterson, M.J., Flett, R.J., and Wesson, L. (2004). Evaluation of nonlethal methods for the analysis of mercury in fish tissue. Transactions of the American Fisheries Society, 133, 568-576.