Foodborne illnesses linked to seafood on the rise in the U.S.

The California coast is home to an abundance of sea creatures. But their home has changed a great deal over the past few decades.

BIANCHI: So climate change is obviously driving enormous changes in the land and oceanic ecosystems. Warming is probably the most direct influence of climate change and it’s caused by greenhouse gasses. So it starts in the atmosphere and as the atmosphere warms, the ocean warms as well. And in fact, the oceans are taking up most of the heat.

Daniele Bianchi is an Associate Professor at UCLA in the Oceanic Science Department and an Oceanographer with a specialty in ocean biogeochemistry. Bianchi’s work shows that not all aquatic environments experience warming at the same rates.

BIANCHI: This warming in the ocean starts at the surface of the ocean. So we have been observing higher and higher temperatures right at the surface of the ocean. In general, coastal water might warm faster because, you know, it’s harder to mix them as deep as they are at the very open ocean or close to the poles.

According to the California Department of Public Health, an outbreak of Norovirus infections, an illness that causes vomiting, stomach cramping, and in some cases, a fever and chills, was linked to raw oysters imported from British Columbia, Canada.

Oysters cluster in coastal waters, near the surface - an area ripe for higher ocean temperatures. A study from the United Kingdom’s, University of Plymouth Marine Biology Centre found “that the enhanced accumulation of copper in Pacific oysters may be of future concern in terms of consumption safety.”

But rising ocean temperatures are also causing a scarcity issue within the seafood industry. Tim Ratcliff is owner of Shin Sushi, a restaurant in Hollywood, California.

RATCLIFF: It causes problems with receiving services to be out of stuff and just unsure when we’ll be able to get in. It was just literally, “I’m sorry, I can’t do anything about it.” But yeah, we’re still going. Right now at the start of the season, uni, we should be able to get it, still struggling to get that one to.

Bianchi thinks that climate change is likely to blame for this issue too.

BIANCHI: One impact of warming on fisheries is really migration of species. And so some of the changes in, for example, in parasites or diseases carried by raw seafood consumption may also have to do with the movement of fish stocks or changes in the population that are driven by the warming.

Changes in movement means fish populating in areas that are different from their normal migration patterns. For seafood suppliers, this means adopting a better understanding of those patterns in conjunction with climate change.

BIANCHI: We have been seeing over the years, periods of relatively warmer or cooler conditions that have very different species. Sometimes you have tropical species coming in when one is especially warm, and then if the conditions cool again, more and more certain species come in.

So how do you avoid getting sick while still enjoying your favorite seafood? The CDC suggests understanding the quality of water in the area you are getting your seafood from. If you’re eating from an area experiencing an algae bloom, avoid shellfish altogether.

Annenberg Media reached out to California Department of Public Health for a direct comment but we have not heard back.