A new toxin-producing microalga, Gambierdiscus australes, has been found for the first time along Spain’s Mediterranean mainland coast. This discovery expands the range of organisms that can lead to seafood poisoning, raising awareness among local officials.
Discovery of Gambierdiscus australes
In a routine seawater sample taken near Dénia and Jávea, researchers from the University of Alicante detected cells of this tropical microalga. This is significant, as past samples showed no trace of this algae. The finding suggests a recent spread into these coastal waters, which are heavily fished.
Gambierdiscus australes produces toxins that can cause ciguatera poisoning in humans. This illness arises from eating fish that have accumulated these toxins after feeding on the algae. Symptoms can include vomiting, diarrhea, and confusion regarding temperature sensation. Importantly, cooking doesn’t eliminate these toxins, underscoring the need for cautious monitoring.
Seeing the Spread
In 2023, researchers conducted two sampling sweeps, both in March and September, across various sites. The spring samples showed the algae in 75% of instances, while September’s samples hit 100%, indicating a potential growth spurt due to rising water temperatures. It’s remarkable that even a slight increase in water warmth can foster a significant rise in algae numbers.
Historically, the Mediterranean has seen rising sea temperatures, affecting local ecosystems. Data from recent years confirms a consistent increase in surface temperatures, which helps Gambierdiscus australes thrive. Now, coastal waters can reach temperatures around 80°F, amplifying the organism’s survival and spread.
Challenges in Detection
Unlike many algae that bloom in open water, Gambierdiscus australes clings to the seafloor and can be tough to spot during routine checks. It often hides among rocks and seagrass, which makes focused sampling around reefs and harbors vital.
With this finding, local authorities must strengthen monitoring strategies. The goal is to quickly flag any signs of dangerous toxins in fish. As César Bordehore from the University of Alicante emphasized, proactive communication and quick response to toxin reports are key.
Lessons from the Past
Before this discovery, Gambierdiscus species had been found predominantly in sheltered areas of the Mediterranean. The algae can hitch rides on currents or even on ship hulls, enabling them to settle in new environments. Prior documentation in the Balearic Islands has indicated the algae’s gradual spread.
Also noteworthy is the importance of archived marine samples. By examining preserved samples, scientists can trace when these microalgae emerged in specific locations. A comparison to samples from a decade ago shows that this algae is a recent newcomer.
Moving Forward
Now that Gambierdiscus australes has made its presence known, targeted monitoring will be essential. Regular assessments of both bottom waters and fish toxins will help authorities manage risks effectively. Without continuous tracking, threats from such organisms could grow unnoticed until a significant problem arises.
As Mediterranean waters continue to warm, ongoing efforts in monitoring and testing are crucial to ensuring seafood safety. This recent discovery is a reminder of how quickly new threats can surface in our oceans.
The original study is published in Harmful Algae News. For ongoing updates, you can follow trusted resources such as the European Centre for Disease Prevention and Control.
By staying informed, we can better protect our seafood and public health.
