Concurrent environmental stressors and jellyfish stings impair caged European sea bass (Dicentrarchus labrax) physiological performances.

Mar Bosch-Belmar,Folco Giomi,Alberta Mandich,Gianluca Sarà,Stefano Piraino,Alessandro Rinaldi,Simone Mirto,Verónica Fuentes

doi:10.1038/srep27929

Abstract

The increasing frequency of jellyfish outbreaks in coastal areas has led to multiple ecological and socio-economic issues, including mass mortalities of farmed fish. We investigated the sensitivity of the European sea bass (Dicentrarchus labrax), a widely cultured fish in the Mediterranean Sea, to the combined stressors of temperature, hypoxia and stings from the jellyfish Pelagia noctiluca, through measurement of oxygen consumption rates (MO2), critical oxygen levels (PO2crit), and histological analysis of tissue damage. Higher levels of MO2, PO2crit and gill damage in treated fish demonstrated that the synergy of environmental and biotic stressors dramatically impair farmed fish metabolic performances and increase their health vulnerability. As a corollary, in the current scenario of ocean warming, these findings suggest that the combined effects of recurrent hypoxic events and jellyfish blooms in coastal areas might also threaten wild fish populations.

Highlights

Human activities are transforming coastal and marine ecosystems at local, regional, and global scales, exposing both individual organisms and biological communities to dramatic environmental changes by a complex array of interacting stressors[1,2]
We investigated the sensitivity of fish to the co-occurrence of environmental stressors and jellyfish stings to understand the impact of jellyfish blooms on caged finfish in a global warming scenario
This study presents important eco-physiological data to the overall fish mariculture sector in jellyfish-affected coastal areas and for the scientific community working on the global change susceptibility of wild fish populations

Summary

Introduction

Human activities are transforming coastal and marine ecosystems at local, regional, and global scales, exposing both individual organisms and biological communities to dramatic environmental changes by a complex array of interacting stressors[1,2]. Temperature and dissolved oxygen concentration in the water column are crucial for the development and performance of aquatic organisms through direct effects on their metabolic rates[29,30] Most fish adapt their physiological responses to sustain their metabolic rates when exposed to temperature changes or decreased dissolved oxygen levels[3,31]; additional external factors (such as pollutants or different environmental factor) may impair acclimation processes. In this framework, we investigated the sensitivity of fish to the co-occurrence of environmental stressors (water temperature) and jellyfish stings to understand the impact of jellyfish blooms on caged finfish in a global warming scenario. This study presents important eco-physiological data to the overall fish mariculture sector in jellyfish-affected coastal areas and for the scientific community working on the global change susceptibility of wild fish populations

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Conclusion