Attributes of Red Sea fish species that are associated with the overall rate and temporal change in Lessepsian migration

Background/Question/Methods

Understanding marine species invasion is a fundamental problem in contemporary ecological research. The opening of the Suez Canal removed a geographical barrier that separated two biologically distinct marine entities and allowed the introduction of organisms from the Red Sea to the Mediterranean (Lessepsian migration). Our study aimed at finding traits in the biology and ecology of Red Sea fishes that may allow us to predict future invasions in the Mediterranean Sea. For this, we collected morphological, ecological and physiological data for native Red Sea bony fishes from the literature and analyzed their effect on the introduction rate in the Mediterranean. The cox proportional hazard model was used with time of first record in the Mediterranean as response variable. A total of 30 predictor variables were screened while controlling for false discovery rate and the best combination was selected using the Akaike information criterion. 

Results/Conclusions

The best model showed that the introduction rate is higher among fishes from species-poor families, among demersal living on soft-bottoms, and among pelagic species. The latter two results confirmed results from earlier studies that used a different methodology. We hypothesize that species from families with relatively fewer species tend to be more generalists and therefore better at colonizing new areas. Our analysis also showed that the temporal change of introduction rate differed significantly between demersal and pelagic species over time, and revealed an increase in introduction rate among demersals. This is in contrast with results available from previous work made in the same area. We believe that the recent increase in introduction rate may have been due to the successive deepening of the Suez Canal over time. The possibility that deepening of the canal led to an increase in the introduction rate is particularly relevant in light of recent plans to further enlarge the Suez Canal.