Safer seafood thanks to science

 By Michelle Leslie

Seafood consumption has doubled in the last fifty years. In fact, the Food and Agriculture Organization points out that, “the global supply of fish for human consumption has outpaced population growth in the past five decades.” This increase is largely connected to the rise of aquaculture or water farming, harvesting plants and other animals in water environments…

This increased demand for seafood isn’t without its challenges and one of the main threats to the aquaculture industry is known as red tide. This frequent but relatively mysterious coastal occurrence dates back hundreds of years, but it is only recently that scientists have analyzed how changes to our ocean environment could play a role in red tide development. Red tides bloom at various times throughout the year, but they are most common from late summer through early fall, when water temperatures are at their peak. This organism, which is easily transported by wind and currents, is mainly found about 10-40 kilometers from the shoreline. Colonies of harmful algae blooms (HABs) can have disastrous impacts on coastal waters and their ecosystems—wiping out fish populations and other marine life by producing potentially fatal toxins. “Biotoxins are produced by certain species of microalgae and can be responsible for human poisoning as well as mass mortalities in marine organisms, including fish, birds, whales or sea turtles,” stated Marie-Yasmine Dechraoui Bottein, Research Scientist at the International Atomic Energy Agency (IAEA) Environment Laboratories in Monaco.

Microcystis bloom in Hamilton Harbor, Lake Ontario (

It’s called Paralytic Shellfish Poisoning (PSP). This potentially fatal condition occurs when people consume shellfish, such as oysters, mussels, crabs and scallops that contain bacteria and toxins within their tissues. It can lead to sickness including dizziness and difficulty swallowing. In extreme cases, it can lead to death. As reported by The Boston Globe, the impacts of a red tide go well beyond the shore line. Following an outbreak of Red Tide in Florida, Emergency Room (ER) admissions rose by over 50 percent due to respiratory distress reported by people living near or visiting the beach. As the ocean climate continues to change, water is becoming warmer and more acidic, making detection of these blooms increasingly difficult for researchers. “Harmful algal species growth and toxin production are impacted by environmental parameters such as temperature and nutrient levels. Over the last decade, HABs have become more and more unpredictable: in some regions, they occur more frequently and are more severe,” said Decharoui Bottein.

Microalgae (CSIRO, Wikimedia)

A recent study on harmful algal blooms found that ocean warming since the early 1980s significantly impacted the growth of toxic algae. Enter a team of scientists with the International Atomic Energy Agency (IAEA) who are relying on a nuclear science technique called receptor binding assay (RBA) to improve monitoring and detection of these harmful algal blooms. Receptors are bound to molecules where they test for paralytic shellfish and ciguatera toxins. This nuclear technique is useful in understanding the relationship between the environment and HAB outbreaks. RBA allows researchers to compare environmental parameters such as ocean temperature and salinity to past outbreaks, providing additional information into what environmental factors could be contributing to outbreaks of these harmful algae. “This technique enables scientists to quickly analyze a large amount of samples, and it results in information on the composite toxic potency of the sample,” said Decharoui Bottein. “In RBA, toxins and radio tracers compete for a limited number of receptors they can bind to. By observing the behavior of the radio tracers, analysis can tell (us) how toxic a sample is and then (we can) inform food safety officials.”

Getting information into the hands of officials and the public following an outbreak is key to protecting populations. Going digital is just one way that the state of Florida is hoping to better inform and engage with people on the impacts of red tide along the Gulf Coast. A new smartphone app, Citizen Science Information Collaboration (CSIC), allows people to self-report on red tide conditions and impacts in their community. Red tide outbreaks pose a major concern to the tourism and aquaculture industry in Florida. According to recent information from the Florida Department of Agriculture and Consumer Services, “Florida ranked seventh among U.S. states in 2014 for fresh seafood production with 99.2 million pounds harvested and a dockside value of $257.7 million.”

Florida Department of Agriculture and Consumer Services (Michael Rivera, Wikimedia)

Working in partnership with other international organizations such as the Intergovernmental Oceanographic Commission of UNESCO, scientists with the IAEA are currently collaborating with almost forty countries to find solutions to enhance the global knowledge of these algae biotoxins. They are hopeful that through better detection of HAB outbreaks, they can control the resulting spread, providing healthier marine environments and safer seafood supplies for humans and ocean life.

SEE MORE: Producing healthy sustainable fish by RP Siegel

about the author
Michelle Leslie
Alberta, Toronto and now Ottawa. Meteorologist, Journalist & Munk School Of Global Affairs Fellow.