Tel Aviv University researchers have developed a statistical model that predicts which Red Sea fish are most likely to invade the Mediterranean. Published in the Journal of Animal Ecology, the system identifies three species with high invasion potential, fundamentally shifting research from studying past migrations to anticipating future ones.
For more than 150 years, the opening of the Suez Canal has allowed marine life to cross between bodies of water, resulting in more than 120 fish species migrating from the Red Sea into the Mediterranean. While past scientific efforts focused primarily on documenting species that had already made the journey, a team of researchers shifted their analytical approach by examining the source populations in the Red Sea before the migration begins.
Stereo-BRUVs and Field Observations in Two Seas
To uncover the traits that separate successful migrants from those left behind, the research team deployed stereoscopic underwater video systems, known as stereo-BRUVs, at depths ranging from 5 to 150 meters. The equipment was set up in the Gulf of Eilat and along Israel’s Mediterranean coast. Across hundreds of hours of footage, scientists analyzed 179 fish populations to compare species that successfully invaded the Mediterranean with those remaining in the Red Sea.
The investigation was led by Dr. Shahar Chaikin during his doctoral research at Tel Aviv University. His work was supervised by Prof. Yoni Belmaker from the School of Zoology, the Faculty of Life Sciences, and the Steinhardt Museum of Natural History. Additional contributors included Dr. Tal Gavriel, doctoral student Avery Deveto, and Shahar Malamud, according to the detailed study published in the Journal of Animal Ecology.
Coral Reef Independence as the Primary Driver
Conventional ecological assumptions long held that “generalist” fish—species capable of thriving across wide environmental ranges—held the highest advantage in marine invasions. However, the Tel Aviv University analysis uncovered a different primary factor: independence from coral reefs.
“The Suez Canal and the Mediterranean contain almost no coral reefs like those found in the Red Sea. Species that depend on coral reefs therefore appear unable to complete the journey. The fish that successfully invade are those that did not need coral reefs to survive in the first place.”
Dr. Shahar Chaikin, Tel Aviv University
This habitat requirement acts as a hard filter. Fish tied strictly to reef ecosystems cannot sustain themselves during transit or upon arrival, leaving the path open for species unreliant on those specific structures.
Targeting Three Species on the Future Watch List
By ranking Red Sea fish populations based on their migration likelihood, the newly developed statistical model successfully flagged three specific species with an exceptionally high potential to enter the Mediterranean in the future. Conservation scientists and regional authorities can utilize these targeted watch lists for early detection as warming waters accelerate the northward spread of tropical marine life.
- Stellate pufferfish (Arothron stellatus)
- Cinnabar goatfish (Parupeneus heptacanthus)
- Yellowspotted trevally (Turrum fulvoguttatum)
Habitat Shifts and Competition in Warming Waters
Once these species complete their migration, they do not necessarily maintain their native habits. The study observed that successful arrivals quickly alter their preferences to exploit whatever habitats are available in the Mediterranean.
Furthermore, the findings challenge the long-standing assumption that non-indigenous fish settle exclusively into empty ecological niches
. Instead, the research indicates that migrant fish utilize the exact same habitats as native species, escalating the potential for direct competition over food, shelter, and space.
“Until now, attempts to understand invasions focused mainly on species that had already reached the Mediterranean. We took a step back and examined what characterizes these species before they begin the journey. That distinction allows us to move from explaining invasions that have already occurred to predicting the next ones.”
Prof. Yoni Belmaker, Tel Aviv University
With the Mediterranean continuing to warm at an accelerated pace, tropical species face increasingly favorable conditions for establishment. Integrating predictive tools into routine environmental monitoring programs offers environmental management agencies a vital path forward for protecting native marine ecosystems from compounding pressures.
