Modelling the role of alien species and fisheries in an Eastern Mediterranean insular shelf ecosystem

Variola louti ( Perciformes : Epinephelidae ) in the Mediterranean Sea: Incidental introduction or aquarium release?

“…Most Mediterranean alien species (86% of fish species) have actively entered from the Red Sea through the Suez Canal (known as Lessepsian immigrants) and have mostly affected the eastern basin (Coll et al, 2010). These species have altered the functioning of Mediterranean shelf ecosystems (Corrales et al, 2017;Michailidis et al, 2019) and are expected to continue doing so, as new species keep arriving and establishing self-sustaining populations in the region at an increasing rate (e.g. Bariche & Fricke, 2018;Bos & Ogwang, 2018).…”

Advances and challenges in modelling the impacts of invasive alien species on aquatic ecosystems

“…Although most invasion biologists are familiar with risk and impact assessment and related protocols (González-Moreno, Lazzaro et al 2019), very few have applied modelling tools to assess impacts and investigate management options (e.g., Corrales, Ofir et al 2017;Michailidis, Corrales et al 2019). Thus, a comprehensive evaluation of available modelling tools assessing IAS impacts was missing from the literature.…”

Ecosystem approach to fisheries management in the Aegean Sea

“…The index facilitates comparisons with other models, even if those have been developed with a different number of trophic compartments (Christensen & Walters 2004). The quality of both models built in this chapter is about the same as the model in Amvrakikos Gulf (Piroddi et al 2016), but lower compared to the ones in the Thracian Sea (Tsagarakis et al 2010), Cyprus waters (Michailidis et al 2019b) and Gulf of Mersin (Saygu et al 2020), potentially as a result of the input production and consumption values that have been either calculated from empirical equations or derived from other models. In general, comparisons among Ecopath models demand a similar topology of the models with regard to the number of FGs, definition of consumers and primary producers, aggregation across trophic levels, identification of top predators, presence or absence of microbial loop (Heymans et al 2016), but also the ecosystem characteristics and intensity of fisheries exploitation.…”

“…For example, the proportions of the abovementioned unbalanced FGs in their predator's diet were redistributed so that consumption was directed towards other appropriate FGs such as anglerfish, demersal fishes 2, picarels and bogue, sharks and rays. Resulting statistics for both models are presented along with three other models of eastern Mediterranean ecosystems, for comparison purposes (Table 5.4): Thracian Sea and Strymonikos Gulf (henceforth referred to as Thracian Sea: Tsagarakis et al 2010), Gulf of Mersin (Saygu et al 2020) and waters of Cyprus (Michailidis et al 2019b). In spite of the difference in the nature of the systems and the varying exploitation level, these models of nearby areas share similarities relating to the number of FGs, the top predator specifications, the aggregation across trophic levels, and the lack of bacterial FGs and can thus be compared through indicators that are robust to model construction (Heymans et al 2016).…”

“…It has been demonstrat-ed that fishing may lead exploited ecosystems to a less mature state, while prohibiting fishing with towed gears may drive change in bottom complexity, as well as benthos and fish species composition from disturbed to mature ecosystems (Watling & Norse 1998). The ecosystem of Cyprus also seems to be in a more mature state and currently recovering from previous overexploitation, as suggested by a moderate impact of fishing that can probably be related to fisheries management measures taken regarding the reduction of the coastal fleet (Michailidis et al 2019b). It is worth noting that the positive effects of lower fishing effort are evident in Thermaikos Gulf too, whose inner part is protected from large-scale fishing activities and as a result has been shown to host fish and invertebrate populations of higher abundance and of a healthier size structure as opposed to the exploited part (see chapter 4, Dimarchopoulou et al 2018a).…”