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Exploring non-lethal sampling methods for fish populations

Published: September 14, 2016

BY JENNIFER PARSONS

Part two in our series on the ELA as it opens its doors to the public

The Experimental Lakes Area (ELA) is a unique research station encompassing over 50 fresh water lakes in Northwestern Ontario. Run by the International Institute for Sustainable Development, those at the facility have a mandate to investigate aquatic effects of a variety of ecological stressors from the long-term effects of climate change to the impact of man-made chemicals on fish populations.

During a visit to the facilities last month Biologist Lee Hrenchuk noted to effectively track the progress of contaminants through the ecosystem a team of four spends much of their time studying and tagging the fish that reside among the lakes.

“We go out in the spring and fall to sample all of the fish in [reference] lakes. We have a suite of about six lakes where we have nets for sampling all of the time. They are our reference lakes and we look at a natural fish population and how it is progressing.”

Hrenchuk says the other half the fish program involves studying the fish that are involved in the experiments that are conducted which means taking tissue and mucus samples.

Contaminants expert Vince Palace says with the amount of sampling that is done within the facility the biologists are continually working to find additional non-lethal sampling techniques.

He says in 2016 the team is working with the University of Saskatchewan to explore the use of ultrasound technology that has the potential to protect fish populations in areas where mining and milling is happening.

“Metal mines and pulp and paper mills are regulated and they have to collect a certain number of fish every year… you capture 20 females and 20 males downstream from your affluent and upstream at a reference location. You cut them open to see how big the liver is, how big the gonad is and that tells you whether or not there is an impact on the mine or the pulp and paper operation.”

Palace says use of the technology would allow researchers to measure the organ size without having to kill the fish but would also allow biologists the opportunity to chart the subject’s recovery process from contaminants.

Hrenchuk adds finding non-invasive ways to sample the lake’s fish population is important. “We have really small fish populations because we have really small lakes and we are sampling them all the time so we are really big on non-lethal sampling methods.

Examples of the experiments conducted at the ELA include the introduction of stable isotopes of mercury to Lake 658 from 2001 to 2007 and synthetic estrogen to Lake 260 from 2001 to 2003.

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