Highlights
- CO2 effects on the ocellated wrasse predator cue recognition were assessed.
- Behavioural and otolith analyses were performed on Symphodus ocellatus from CO2 seeps.
- Predation risk perception by the ocellated wrasse juveniles was unaffected by CO2.
- High CO2 levels enhanced the S. ocellatus post-settlement growth.
Abstract
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.
Cattano C., Calòc A., Di Franco A., Firmamento R., Quattrocchi F., Sdiri K., Guidetti P. & Milazzo M., in press. Ocean acidification does not impair predator recognition but increases juvenile growth in a temperate wrasse off CO2 seeps. Marine Environmental Research. Article (subscription required).
