The red tide is here

red tide in la jollaI was one of thousands devastated by the declaration in November 2015 that the dungeness crab season would be indefinitely delayed due to the accumulation of toxic levels of demoic acid in their crabby bodies. Sure, they’re just crabs, but dungeness season is one of my favorite food holidays on the calendar. There would be no crab cake benedict, no crab boil with friends, no dungeness tacos to stuff myself with.

Turns out there are more serious consequences of a poisoned crabbing season in California than just my unfed crab-tooth. Although the California Department of Public Health re-opened all areas south of Point Reyes to recreational dungeness and rock crab fishing last week, the  Dungeness Crab Task Force decided yesterday not to begin commercial fishing at this time for fear of sickening consumers and doing long term damage to the industry’s image. Governor Jerry Brown, concerned that the crab industry may remain shuttered through the season, has asked the U.S. Secretary of Commerce to declare a disaster and commercial fishery failure for the state’s full $90 million industry.

The vulnerability of an, admittedly, luxury, food source is disconcerting. More frightening is what turned the Pacific Coast’s normally innocuous crabs in to toxin carrying, nausea, dizziness and seizure inducing, death machines. Marine biologists have termed it a Red Tide, the rapid proliferation of phytoplankton in huge numbers that results in a bloom of algae with high levels of toxins. The consumption of the algae in these blooms can be deadly and result in “dead zones” (hypoxia) where fish and other life can’t survive. Scientists link the high numbers of dead sea lions and sea birds washing up along the California coast in 2015 to a 40 mile wide, 650 foot deep (at some points) Red Tide  stretching from Southern California to Alaska (and possibly all the way to the Aleutian Islands). This is the largest, most dense algae bloom ever seen in this region.

Red Tides are not new. An algae bloom on the Pacific Coast of the United States in 1988, for example, stretched from San Diego to Washington state. Scientists are concerned, however, that climate change may lead to better conditions for algae blooms including salinity fluctuation, warmer water temperatures, greater concentrations of atmospheric carbon dioxide and more rainfall resulting in the increased runoff of industrial chemicals into bodies of water. These conditions may further increase the prevalence of toxic strains of bacteria produced in Red Tides. A paper published in 2012 in the Polish Journal of Environmental Studies called algae blooms “one of the most serious risks to human health in the 20th century.”

Harmful algae bloom. Lake Erie. July 22, 2011. Credit: NOAA.

Harmful algae bloom. Lake Erie. July 22, 2011. Credit: NOAA.

And if you aren’t already cowering in fear from the relatively minor risk to humans posed by the 2015 U.S. Pacific Coast bloom, or China’s 2013 Red Tide which spread over an area larger than Connecticut in the Yellow Sea, consider this: freshwater lakes are also vulnerable to toxic algae blooms. And where does a significant portion of U.S. drinking water come from? You guessed it, freshwater lakes. 400,000 citizens of Ohio and Michigan were left without safe drinking water in August 2014 when an algae bloom in Lake Erie released unsafe levels of mycrocystin in to the Toledo water system, sending 70 people to the hospital for such possible health effects as abdominal pain, vomiting and diarrhea, liver inflammation and hemmoraghing, pneumonia, dermatitis and the promotion of tumor growth. Lake Erie was declared a safe source of drinking water again within just a weekend but officials believe that increased phosphorous in water runoff entering the lake from agricultural and residential fertilizers were a major factor in the bloom.

With our marine mammal and fish populations already under stress from pollution and overfishing and our access to safe, clean water diminishing day by day, algae blooms are just one more drop in the bucket of human-induced destructive environmental change.


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