Elevated temperature linked to signs associated with sea star wasting disease in a keystone European species, Asterias rubens

Sea star wasting disease (SSWD) refers to a suite of gross signs affecting Asteroidea species. These include epidermal lesions, everted viscera, arm autotomy, and ultimately, full body disintegration leading to mortality. The common sea star Asterias rubens is a keystone species in the coastal Northeast Atlantic and may be susceptible to the disease. While the precise aetiology of SSWD remains poorly understood, environmental instability, including rising sea temperatures, has been linked to SSWD outbreaks. To investigate this connection, an experiment was conducted to quantify disease sign expression in A. rubens under elevated temperature. We exposed sea stars to either elevated temperature (18°C) or a control treatment (12°C) for a 14 d period. We quantified the presence of disease signs associated with SSWD, the progression of signs, and survival of individuals. Elevated temperature induced a greater number of signs consistent with SSWD and also resulted in mortality for some of those animals. Furthermore, larger individuals were more likely to show increased signs of disease. Our results provide evidence that signs associated with SSWD increase with elevated temperature.