Can Biological Traits Serve as Predictors for Fishes' Introductions, Establishment, and Interactions? The...

The Mediterranean Sea (MED) is prone to species' introductions, induced by human activities and/or climate change. Recent studies focus on the biological traits that result in such introductions, yet on a single-area-type approach. Here, we used, analyzed, and compared biological traits derived from FishBase for MED, non-indigenous (NIS) and neonative (NEO) in the Mediterranean, and adjacent Atlantic (ATL) and Red Sea (RS) species. A quantitative trait-based analysis was performed using random forest to determine the importance of traits in the successful establishment in the Mediterranean. MED fishes were mainly demersal, slow growing and small-medium sized, preferring intermediate temperatures. Conversely, ATL were mainly deep-dwelling species, preferring low temperatures. RS and NIS were predominantly reef-associated, thermophilus, and stenothermic. NEO species were stenothermic with preference to intermediate-high temperatures. Omnivores with preference to animals was the most common trophic group among regions. MED species exhibited higher phylogenetic uniqueness (PD₅₀) compared to RS and NIS, indicating that they have long ancestral branches and few descendants. Preferred temperature, habitat type preference and maximum reported length (L_max) and infinite length (L_inf) were the most important predictors in the establishment process. Overall, the results presented here could serve as a baseline for future research, especially by using more refined and/or additional biological trail estimates.