Assessment of stress markers in snakelocks anemone (Anemonia viridis) in response to induced asexual reproduction

Anemonia viridis is a species of sea anemone (Cnidaria:Anthozoa) currently experiencing negative environmental impacts on their natural populations in the Mediterranean Sea. This species has excellent regeneration capacity, such that asexual reproduction can be induced in captivity via longitudinal bisection, but there is no information about the impact of this procedure on the animal's physiology beyond short-term responses. The goal of this work was to assess the stress response of A. viridis during and after regeneration. We measured oxidative and immunological state markers in control and bisected anemones, at 4 weeks post-injury and 20 weeks post-injury. We then performed Principal Component Analysis (PCA) to identify trends at the multivariate level. Additionally, we carried out a histological evaluation of the wound healing process during the first 7 days post-injury. Higher antioxidant enzymatic activity was found in bisected anemones, mainly in catalase and glutathione-dependent enzymes. This response was often reverted by 20 weeks post-injury in tentacles. No differences in lipid peroxidation were observed. Phosphatase activities were unaltered within the studied time-frame. Histological analysis indicated recruitment of amoebocytes, the immune effector cells in anthozoans, and appearance of fibrillar mesoglea, detectable between 6 h and 24 h post-bisection. Results suggest the antioxidant response was effective containing oxidative damage. Longitudinal fission appears to be a viable technique for inducing asexual reproduction in A. viridis without triggering a stress response, and could reduce dependence of the market on the natural environment.