A model developed by Tel Aviv University researchers ranks Red Sea fish according to their likelihood of establishing themselves in the Mediterranean. Leading candidates include the star pufferfish, seven-spined wrasse, and yellow-spotted wrasse.
More than 120 species Fish Moved fromRed Sea to the Mediterranean Sea since the opening Suez canal More than 150 years ago. New research fromTel Aviv University Trying to move from documenting the invasions that have already occurred to predicting the species that may arrive and establish themselves here in the future.
The study, published in the Journal of Animal Ecology, presents a statistical model that ranks Red Sea fish species according to their invasive potential. Among the species that topped the list are the star pufferfish (Arothron stellatus), the seven-spined wrasse (Parupeneus heptacantha) and the yellow-spotted wrasse (Turrum fulvoguttatum).
The ranking is not a determination that the species will actually invade, but rather a relative risk assessment based on the characteristics of their habitats and their comparison to species that have already managed to cross into the Mediterranean Sea.
The research was led by Dr. Shahar Chaikin as part of his doctoral thesis at Tel Aviv University, under the supervision of Prof. Yoni Belmker from the School of Zoology and the Steinhardt Museum of Nature. Dr. Tal Gabriel, doctoral student Avery DeVeto, and Shahar Malamud also participated in the research.
Hundreds of hours of underwater photography
To identify the common traits of successful invaders, the researchers placed stereoscopic underwater video cameras at depths of 5–150 meters in the Gulf of Eilat and off the coast of Mediterranean In Israel.
Using hundreds of hours of photography, 179 fish populations were analyzed. The sample included species that had already moved to the Mediterranean Sea alongside species that still only live in the Red Sea.
Unlike previous studies that focused primarily on post-invasion fish, the current study also examined the source populations. This allowed the researchers to distinguish between traits that existed before the migration and changes that occurred after establishment in the Mediterranean.
The coral reef is the barrier.
The key finding was that the most important factor was not necessarily the fish's ability to live in a wide variety of environments. The stronger predictor was its degree of dependence oncoral reefs.
The Suez Canal and the Mediterranean Sea do not offer a succession of reefs similar to those of the Red Sea. Fish that depend on corals for food, shelter, or reproduction may have difficulty completing the transition. In contrast, species that are not dependent on the reef have a higher chance of making the route and establishing themselves in the new environment.
"Apparently, those who succeed in invading are precisely the fish that do not need coral reefs to survive in the first place," explained Dr. Chaikin.
The invaders change habits
The researchers also found that fish that established themselves in the Mediterranean Sea do not necessarily maintain the habitat preferences they had in the Red Sea. After the move, they change their patterns of environmental use and take advantage of the habitats available in the Mediterranean Sea.
Invasive fish also do not settle for "empty ecological niches." In many cases, they use the same areas where native species live. Therefore, competition for food, shelter, and space may be greater than previously estimated.
"Examining species before they even set off allows us to move from explaining invasions that have already occurred to predicting future invasions," said Prof. Belmker.
Early detection checklist
The model could help create watch lists and direct monitoring efforts to species with the highest potential for invasion. Early detection could allow authorities to consider response measures before the species spreads and becomes a permanent part of the ecosystem.
The importance of such monitoring is expected to grow as the Mediterranean warms and becomes more suitable for the establishment of tropical fish. However, the researchers emphasize that the model estimates probability and cannot predict with certainty which species will be the next invader.
Questions and Answers
Have the three fish already invaded the Mediterranean Sea? According to the study, they have not yet established themselves there, but were rated as having high invasion potential.
What is the main factor that predicts the success of an invasion? The degree of dependence on coral reefs. Species that are not dependent on reefs have a higher chance of completing the transition to the Mediterranean Sea.
Do the fish continue to live in the same habitats after the invasion? Not necessarily. The researchers found that invaders may change their preferences and use habitats where native species also live.
Can the model prevent invasions? No, but it can help identify dangerous candidates, in targeted monitoring and early detection.
More on the subject on the science website
- Invasive species: a growing threat to biodiversity in the world and in Israel
- The invader who takes over the Mediterranean
- Suez Canal 2.0
- Dizziness, paralysis and the risk of death: the health dangers of puffer fish
- Maritime migrations – journey from the Red Sea to the Mediterranean Sea
For the scientific article: Opening the scientific article
