Understanding Lake Sturgeon Biology and Restoring Their Populations
posted 17 June 2011

The unique and once-abundant lake sturgeon of the Great Lakes and Hudson Bay drainage basins are listed as threatened in Canada and the U.S.  Their life-history characteristics, such as slow-growth rate and late-age-to-sexual-maturity add to the challenges we face in trying to save this vulnerable and culturally iconic species.


Gary Anderson, in the Department of Biological Sciences, is part of a multi-disciplinary team including students, University professors and the Department of Fisheries and Oceans (DFO) researchers studying the biology of the lake sturgeon.  This research is important so that we can make better informed decisions on how to sustain existing populations of this valuable animal.  His research on lake sturgeon examines a number of factors including:  reproduction, calcium regulation, environmental stress, swimming performance, and the adverse effects of chemicals and natural pathogens. 

The Hormonal Regulation of Reproduction

To increase lake sturgeon populations, scientists collect and fertilize the eggs with milt (sperm) from sexually mature adults caught in the wild. In order to maximize the number of eggs from gravid (pregnant) females, a commonly used practice is to promote the final stages of egg maturation and development by stimulating the hormones involved in reproduction. Anderson is currently examining the short and longer term effect of these techniques on adult male and female lake sturgeon. The results of this research are of interest to industry, provincial and local communities that are all involved in intense conservation efforts for lake sturgeon in Northern Manitoba. 

The Sturgeons’ Response to Changing Levels of Calcium

Lake sturgeon have survived for millions of years in calcium-poor freshwater environments.  However, now more than ever, environments are changing at an accelerated pace.  Water chemistry is one important aspect and declining levels of calcium in Canadian Shield aquatic habitats are significantly impacting the flora and fauna of this environment.  Lake sturgeon have very low concentrations of calcium in their blood.  In fact, they are cartilaginous:  which means they don’t have internal bones, and consequently, they don’t have an internal supply of calcium upon which to draw.  As a result, they are 100% reliant on environmental calcium and may be particularly at risk to declining levels of calcium in their environment.  Research in Anderson’s lab is documenting how changes in environmental calcium impact the development of lake sturgeon and their ability to adapt to changing environmental calcium.

The Importance of Environmental Stress, and the Adverse Effects of Chemicals and Disease

The natural environment is an inherently stressful place, and the impacts of pollutants and impoundments, like dams and rapids, may enhance an already highly stressful situation.  From a biological standpoint, a stress response can be either beneficial or detrimental to an organism.  Anderson’s research examines the stress response in lake sturgeon and determines how the environment might influence this response that is present in all animals. 


For example, Anderson’s group discovered that the environment in which sturgeons are raised from egg to juvenile directly influences the development of the stress response in the juveniles.  Those sturgeon raised in an environment more akin to their natural environment respond very differently to those raised in an unnatural aquaculture-type environment. 


More recently Anderson has collaborated with Vince Palace from the DFO, and together they are examining:  the influence of agricultural pesticides on the development of lake sturgeon larvae, and the impact the pesticides may have on the animal’s stress response.  Furthermore, a recent collaboration with Sharon Clouthier at DFO is examining the existence of natural pathogens (infectious agents like viruses and bacteria) in the environment and how these may impact existing stocks of lake sturgeon.

Swimming Performance

The swimming ability of larval lake sturgeon is relevant to a changing environment.  Construction and operation of dams influences the hydrology of a river and will, therefore, influence available and preferred habitat for larval lake sturgeon.  A recent collaboration with Eva Enders at the DFO is examining a variety of aspects of larval and juvenile lake sturgeon swimming.  For example, how soon in lake sturgeons’ life do they have the capacity to swim against a current, and how much energy do they need to, or are they willing to, consume when swimming?


Ultimately, the findings from the research, conducted and driven by the graduate students and post-doctoral scientists, will provide a better understanding of the influence of the environmental changes faced by lake sturgeon:  be they natural, such as pathogens and river flow, or anthropogenic (caused by humans), such as changing calcium levels or introducing pesticides into our waterways.


RELATED LINKS


Dr. Anderson's Website 

Saving Sturgeon from the Brink


Dr. Anderson checking sturgeon larvae


With sturgeon larvae


In his lab


photos by Maureen Paisley