Can Biological Traits Serve as Predictors for Fishes’ Introductions, Establishment, and Interactions? The Mediterranean Sea as a Case Study

Abstract

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 (Lmax) and infinite length (Linf) 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.

Cumulative Negative Impacts of Invasive Alien Species on Marine Ecosystems of the Aegean Sea

“…Recent studies on the spatiotemporal distribution patterns of marine ICAS throughout the Greek Seas have reported similar patterns, showing a higher ICAS richness and abundance of records in the South Aegean areas and gradually decreasing towards the North [33,39]. These distribution trends are believed to be related to speciesspecific ecological traits and introduction pathways [33,65]. For instance, most alien fish in the Mediterranean are thermophilous species of Indo-Pacific origin, introduced through the Suez Canal in the southeastern part of the Mediterranean [33].…”

Looking at the Expansion of Three Demersal Lessepsian Fish Immigrants in the Greek Seas: What Can We Get from Spatial Distribution Modeling?

“…in the eastern Mediterranean Sea [67,68], especially under limiting trophic resources. Thus, the competitive displacement, decrease in the biomass and/or narrowing of the native species' trophic niche in the eastern Mediterranean have been proposed ( [3] and references therein) but it has also been hypothesized that alien species might also occupy available and underexploited niches, due to stressors such as overfishing or a shift in environmental conditions [1,69], as has been suggested for both S. luridus and S. rivulatus [70]. Gut-content analysis has also shown different feeding preferences of S. luridus and the native herbivore Sarpa salpa (Linnaeus, 1758), indicating good resource partitioning [71].…”

“…Introductions of non-indigenous (also called "alien", a term hereafter used as synonym to "non-indigenous") species have been considered a major driver of change in the Mediterranean Sea [1], one of the most invaded marine basins worldwide [2]. To date, 183 documented alien, mainly thermophilic, fish species have entered through the Suez Canal [3], commonly called "Lessepsian immigrants" [4]. The number of alien species is higher in the eastern part of the basin [5], apparently due to the proximity to the canal and the propagule pressure exerted by it [6].…”

Decoding the spread of non-indigenous fishes in the Mediterranean Sea

“…In the Mediterranean, interdisciplinary scientific initiatives have attempted to disentangle the phenomenon of marine invasions either through the ecological investigation of species’ dispersal and the responses of NIS in native communities 20 , the integration of species’ traits to interpret NIS successive expansion 21 , 22 , or by employing a time series approach to explore the rate of introductions 23 . In the last decade, an additional novel approach has emerged by using advanced ecological models to project the distribution of NIS in the near future (i.e., Species Distribution Models—SDMs) based on predicted environmental thresholds 24 , 25 .…”