Climate change may bring yet another scourge: longer, more frequently occurring toxic algal blooms along the Pacific coast of Canada.

This was suggested by a new study on the presence of algae toxins in marine animals along the coastline of Alaska, which holds a warning for Canada’s British Columbia. Study author and National Oceanic and Atmospheric Administration biologist Kathi Lefebvre said that sharing a coastline puts the region at risk the say way Alaska and Washington were.

The team investigated the carcasses of more than 900 Alaskan marine mammals, looking for signs of two common and possibly fatal toxins from algae: domoic acid and saxitoxin. These toxins had been previously detected in Canadian territory.

A sea lion suffering from domoic acid toxicity, for instance, had never been known north of California, until in 2015 when a case was documented in Washington. Lefebvre said there was a major bloom of domoic acid that year.

"The concern is that it was correlated with the warmer waters. Is this what the future holds? If we have continued warming water, will there be more toxic blooms? Will they be moving North?" she says.

It appears that the toxic blooms have already shifted North, with low domoic acid levels found in all 13 Alaskan mammal species in the study, and saxitoxin found in 10 species. Both were unexpected to be seen in all the studied animals everywhere, Lefebvre warned.

She added that while toxic concentrations that can lead to health impacts remain largely undetermined, increasing algae blooms pose risks as waters continue to warm. Alaskan water temperature has shot up by nearly three degrees in the past decade.

These algae blooms, while not considered a marine mammal killer, are another stressor in the environment, it also has major economic consequences. Record bloom in the Pacific Northwest of the U.S. in 2015, for example, prompted the closure of fisheries, including those cultivating Dungeness crabs.

Last November, California health officials urged people to avoid consuming Dungeness and Rock crabs after dangerous neurotoxin levels were detected and linked to a major algae bloom found off the West Coast.

In December, Mississippi state authorities ordered the closure of oyster reefs and beaches because of a dangerous red tide breakout. The preemptive closure covered all beaches on the Mississippi Gulf Coast, amid algae blooms being unusual given the location and time of the year.

Scientists are seeking to know how these toxins move through the food system and how they connect to climate change and extreme weather. According to Lefebvre, "it could become a bigger issue" unless it is given due attention.

Photo: Diana House | Flickr

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