Surgeonfish with ‘Razor Blades’ Arrives in the Adriatic Sea: A Sign of Warming Waters?
The Adriatic Sea is now home to a new and potentially dangerous, tropical visitor: the Monrovia surgeonfish (Acanthurus monroviae). Originally from the warm waters of Liberia and the eastern Atlantic, this species has been documented as having moved into Croatian waters, raising concerns for divers, and fishermen.
What is a Surgeonfish?
The surgeonfish gets its name from the two erectable, razor-sharp bony spines located at the base of its tail. These spines are used for defense, delivered with quick, whip-like movements. The fish can grow up to 48 centimeters in length and weigh around 500 grams. Its body is brownish, marked with 20 longitudinal yellow and blue-violet lines. Vibrant yellow oval patches on its sides highlight the dangerous caudal “blades,” warning potential threats.
The Risks to Humans
Experts warn against handling or attempting to interact with surgeonfish. The caudal spines can inflict deep cuts that are prone to infection. Even after the fish is dead, the spines remain sharp, posing a risk to those handling it for food. The species is edible, but caution is advised.
First Sightings and Expert Commentary
The first specimen was spotted on June 2, 2024, near Kostrena, Croatia, in the Gulf of Quarnero, at a depth of just 3-5 meters. Professor Cataldo Pierri, a marine zoology professor at the University of Bari, stresses the need for caution, advising people not to attempt to touch or catch the fish.
“Meridionalization” of the Adriatic
Scientists believe this isn’t an isolated incident of aquarium release, but a natural migration. The surgeonfish’s journey through the Strait of Otranto into the northern Adriatic is a clear indication of what Professor Pierri calls “meridionalization” – the warming of the Adriatic Sea is making it an increasingly tropical-like habitat.
Ecological Impact: A Changing Ecosystem
Although the surgeonfish isn’t expected to drastically disrupt the ecosystem immediately, it primarily competes for food with the sarpa salpa, a small, striped herbivorous fish. The arrival of this species is another sign of the biological transformation occurring in the Adriatic Sea. Currently, there are only 7 species of Acanthuridae (surgeonfish and unicornfish family) known globally out of a total of 84.
Frequently Asked Questions
What is a surgeonfish?
A surgeonfish is a tropical fish named for the sharp spines at the base of its tail, which it uses for defense.
Is the surgeonfish dangerous?
Yes, the spines can cause deep, easily infected cuts. Caution should be exercised when near or handling these fish.
Why are surgeonfish appearing in the Adriatic Sea?
Warming water temperatures are making the Adriatic Sea a more hospitable environment for tropical species like the surgeonfish.
What does “meridionalization” mean?
“Meridionalization” refers to the process of a sea becoming more similar to warmer, southern climates due to rising temperatures.
Learn more about marine life in the Adriatic Sea here.
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