In the Pacific Northwest massive blooms of the single-celled alga, Heterosigma akashiwo, can secrete toxins that destroy fish gills, causing suffocation of both wild and farmed fish such as the economically important salmon. To understand what causes spikes in the population and toxicity of Heterosigma, NOAA scientist Vera Trainer is leading an investigation as part of a Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) project funded by the National Centers for Coastal Ocean Science.
Interestingly, Heterosigma is not always toxic. One theory is that it secretes toxins into the water as a way to kill competitors for nutrients needed for growth and reproduction. Fish kills would be an undesirable side effect.
The ECOHAB project research team hopes to develop a convenient test that will immediately tell whether a bloom is hazardous and alert fishery and hatchery managers. This information, for example, would allow hatchery managers in the region to release their salmon early and give fish farmers enough notice to harvest their penned salmon before the blooms turn toxic.