Impact of toxic algae on fish

[kickingfrog]

http://www.nugget.ca/2013/01/19/impact-of-toxic-algae-on-fish

 

 

NORTH BAY - Understanding how fish warn each other of predators could shed light on what causes Lake Nipissing's toxic blue-green algae blooms.

 

Northern communities and international agencies charged with protecting fish populations are watching.

“If you want to have effective management, you have to understand what's going on inside the lake itself,” said Reehan Mirza, an aquatic behaviour ecologist at Nipissing University's biology department studying how fish release chemical alarm cues to help their species avoid predators.

 

Research has found some aquatic species produce a chemical within their skin that releases into the water when the skin is broken to warn others of a predator. Mirza said it's unknown what that chemical is, although it's as easy to release as holding a fish and having the scales rub off. “It's a very good system because any kind of mechanical damage from any predator is going to cause a release of that chemical,” Mirza said.

 

Organizations, mainly fishery agencies, from around the world have contacted him about the research. The common way of dealing with fish populations is by stocking, and Mirza said survival rates improve if fish are trained to identify a predator by using these chemical alarm cues. Pollutants in the water could impair the ability of fish to sense these cues, including the toxin released from blue-green algae that may influence behaviour and hurt the ability of fish to find food, mates, habitat and recognize their own species.

“Anything that's altering their ability to sense their environment is going to effect the overall health of the lake,” Mirza said, adding he's also looking at the accumulation of this algae toxin in fish tissue.

In the last couple of years, the North Bay Parry Sound District Health Unit has issued advisories about toxic blue-green algae in Lake Nipissing at the Goose Islands, Callander Bay and the West Arm west of Highway 64. It was thought warmer temperatures contributed to the blooms, although research found that might not be one of the main factors, with temperatures during these occurrences being lower than expected, Mirza said.

 

Septic tanks, cattle operations, detergents and other activities could be contributing to phosphorus and other nutrients entering the lake. “The nutrient load is happening. Where that nutrient load is coming from, that's what we're working on,” Mirza said, adding there could be something happening naturally within the lake bed to be causing the blooms. He's a couple of years into that research which could take another three to five years to draw conclusions.

 

 

The Lake Nipissing Summit last year brought together researchers, municipal and provincial governments, tourism, First Nations and conservation groups which is critical to share information about the lake, Mirza said. Plans are underway to hold the next summit in April. Even the smallest changes to the environment can cause large-scale changes, he said, referring to the decline in the walleye population in Lake Nipissing that led to a reduction in daily catch limits in hopes of rebuilding the fishery. Mirza was among the faculty in 2012 to earn a Nipissing University Research Achievement Award for his work in aquatic behaviour.

Collaboration at the university between biology, geography and environmental history helped create Nipissing's masters program in environmental science and environmental studies, with 19 students in its first year -- double than what was expected, Mirza said.

 

He plans to continue his research, including work with toxic naphthenic acids which are the main source of toxins in Alberta's oil sands tailings. A larger goal is involving the public more in science and raising awareness about issues that protect the health of the environment, he said. Representatives from communities around Lake Nipissing have already contacted the university to learn more about the research and what can be done to protect the popular recreational lake.

 

Mirza can be reached at [email protected].