Ocean acidification does not impair predator recognition but increases juvenile growth in a temperate wrasse off CO2seeps

8 pages, 4 figures, supplementary data https://doi.org/10.1016/j.marenvres.2017.10.013
Fish behavioural effects under Ocean Acidification (OA) rely on changes expected to occur in brain function, which can be reversed by gabazine, a GABA-A antagonist. Here, using standard two-channel choice flume, we assessed OA effects on the predator recognition ability of both gabazine-treated and -untreated Symphodus ocellatus post-settlers living off CO2 seeps in the Mediterranean Sea. To estimate the post-settlers background predation risk we evaluated the density of their predator in the wild and through otolith aging techniques we assessed their post-settlement growth. Results showed that: 1) post-settlers predator recognition was unaffected under OA; 2) post-settlers living in elevated CO2 were on average 15% bigger in size than those from ambient conditions. Our results support fish behavioural tolerance to OA, potentially mediated by pre-exposure to high-risk predation levels, and speculate that by increasing body size, juvenile fish might more efficiently avoid their predators
This research was supported by FFR-A (R2FFRAD14+PNFG) funds from University of Palermo to M.M and a PhD grant to C.C.