| Summary: | Pacific oysters Crassostrea gigas are cultured worldwide and play an important role in global food supply and the sustainable blue economy. Oyster culture sites in Europe, USA, Australasia, and Asia have been experiencing episodic summer mass mortality events. These mortality events can be severely damaging with significant impacts on stock reliability and profitability. Summer mass mortality events are believed to have a multifactorial aetiology driven by high water temperatures and the presence of pathogens, particularly Ostreid herpesvirus-1 and variants (OsHV-1 Var) and bacteria of the genus Vibrio such as V. aestuarianus. UV radiation (UVR) is an intertidal stressor which functions as an ecosystem regulator. UVR has disinfectant properties with the energetic potential to damage nucleic acids of microbes inhabiting surface waters. UVR can also have both positive and negative impacts on animal immune functioning by the activation or inactivation of certain biochemical pathways. Climate model predictions show UV levels changing globally due to changes in cloud cover, aerosols, ozone, and precipitation patterns. This study aimed to investigate the impact of UV radiation (UVR) on oyster health and pathogen performance. Firstly, a desk-based literature review study found that UVR predominantly hinders pathogens, although with varying efficacy, has mixed effects on aquatic invertebrates and has mixed effects on host-pathogen relationships. A clear knowledge gap was identified in that no study could be found which investigated the impact of UVR on bivalve health and survival. Vibrio bacteria are reported to be highly sensitive to UVR while herpesviruses either have high tolerance or can even be activated by solar UVR. UVR can be additive, synergistic, antagonistic, or neutral in outcomes of host-pathogen dynamics. Secondly, novel diagnostic methods for the detection and localisation of Vibrio bacteria within oyster tissues were designed, a generic conventional polymerase chain reaction PCR and a DIG-labelled in ...
|
|---|