The largest algae bloom currently on record is growing off of the coast of California. It stretches from Alaska down to central California and measures approximately 40 miles wide, and in some areas, up to 650 feet deep. According to the National Oceanic and Atmospheric Administration (NOAA), this bloom has significantly diminished the populations of many marine organisms living in aquatic ecosystems along the Pacific coastline. 

"Large algae blooms are linked to high concentrations of domoic acid."

The effects of algal blooms on marine ecosystems

Marine algae blooms are normal during the spring, but the large algae bloom in question is producing high concentrations of the toxin known as domoic acid. This biotoxin is being eaten by sardines, anchovies and other small fish that feed on the algae as well as phytoplankton and various microorganisms. These events have the potential to create devastating effects in the marine food chain. For instance, aggressive algal growth can poison birds, sea lions as well as humans that feed on native fish. This process, also referred as biomagnification, is the same issue that almost sent the bald eagle population into extinction when DDT was a widely used pesticide across the U.S.

According to Northwest Fisheries Science Center (NWFSC) in Seattle, "This is unprecedented in terms of the extent and magnitude of this harmful algal bloom and the warm water conditions we're seeing offshore."

Officials in California have warned the general public that consuming recreationally harvested mussels and clams, commercially or recreationally caught anchovy or sardines, and commercially or recreationally caught crab from Monterey and Santa Cruz counties can lead to unsafe levels of the toxin.

Domoic acid is a neurotoxin that interferes with nerve signal transmission in humans and can be very dangerous. In fact, if consumed in large quantities it can be fatal. In smaller doses, domoic acid can cause permanent brain damage and memory loss.

Economic effects

The Northwest Fisheries Science Center closed both large and small shellfish fisheries in Washington, Oregon and California in June 2015. In early June 2015, due to the elevated toxin, local shellfish managers closed the southern Washington coast to dungeness crab fishing. This was the largest closure ever in Washington's multimillion dollar crab fishing industry. The NWFSC is still unsure how this will affect the overall economy for the state of Washington, however they believe the impact will be significant at the end of the fiscal year.

This summer, Oregon officials stopped all shellfish harvesting from the Columbia River and closed the entire coastline to razor clamming. Washington also closed its coastline to razor clamming due to the high levels of domoic biotoxins at an estimated loss of over $9 million in revenue for the coastal communities during June 2015. 

Is there a link between global warming and algae blooms?

Research on past toxic algae blooms has found "hot spots" of toxin-producing micro-organisms along the West Coast. The Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Research Program is completing a study on such a hot spot in California's Monterey Bay. The researchers are trying to determine if there is a link between the warm waters and harmful toxic algae blooms.

Currently, the temperature in California's Monterey Bay is 5 to 6 degrees Fahrenheit warmer than the historic average for early autumn. In 1983 and 1997, which were both strong El Nino years, temporary increases in water temperature resulted in algal growth of this nature, but researchers know this is not the case this time. These warm waters have been present over the last year and seem likely to stay. The results collected by the ECOHAB will hopefully be able to determine what is causing the increase in water temperature, which could help foster better predictions about the future of the coastline. 

What to expect

As the western U.S. coastline continues to be plagued by large algae blooms, it's important for stakeholders in Alaska, Washington, Oregon and Northern and Central California to conduct continuous biomonitoring to determine if the ecosystems are not dangerous to both large marine mammals and locals. By fully understanding the changes taking place in this region's aquatic ecology, experts can then come up with ideas on how to correct these issues.