The Mediterranean Killifish Aphanius fasciatus (Valenciennes, 1821) (Teleostei: Cyprinodontidae) as a Sentinel Species for Protection of the Quality of Transitional Water Environments: Literature, Insights, and Perspectives

Transitional waters are fragile ecosystems with high ecological values, representing the breeding and resting sites for rare and threatened species. They warrant particular attention in regards to protection, as they experience numerous anthropogenic threats. The present review aims to analyze the recent literature on Aphanius fasciatus, currently considered one of the most strictly estuarine-dependent fish species, thus affected by the degradation of lagoon habitats, and to discuss its suitability as a sentinel species for protection of the quality of transitional water environments. The analysis and discussion highlight the potential applicability of the molecular, cellular, and physiological responses of this species as diagnostic tools for detecting the subtle effects induced by environmental pollution on the biota in transitional water environments. Moreover, the suitability of the responses of this species is suggested in the wider framework of the One Health perspective, which considers human and animal health and the environmental state to be highly interconnected, sharing common aspects. To date, omics technologies show great potential in reacquiring novel knowledge on the responses of the organisms to environmental changes and to the alterations of the environmental health status. Therefore, considering the relevant potential of this organism as a sentinel species, many efforts are required in the near future to improve the quantity and quality of the omics tools that refer to A. fasciatus.