Artificial portable plates: A brand new method for assisted colonization of an endangered marine invertebrate, Patella ferruginea

Abstract

Abstract Limpets play an important role in structuring the intertidal fringe, one of the most heavily impacted marine habitats. A large number of limpet species are listed as Endangered or Vulnerable, including Patella ferruginea, one of the most endangered marine invertebrates in the Mediterranean Sea. Relocation attempts have been made as a conservation tool for reintroductions and population reinforcements for P. ferruginea. Some relocations were mandatory because of port infrastructure repairs in areas where viable populations of this limpet occurred. However, most relocations attempted to date have experienced high mortality rates, leading to the Spanish National Conservation Strategy not recommending this approach for this species. In this study, 84 individuals of P. ferruginea were relocated, using artificial portable plates (APPs) installed on the ripraps of the Port of Ceuta (Western Mediterranean Sea). These plates were divided into two groups and relocated: (i) as a translocation to a nearby site with similar environmental conditions to the donor area (procedural control); and (ii) as a reinforcement translocation to a relatively distant location (30 km, Algeciras Bay) (experimental procedure). The mortality of the translocated individuals in the procedural control after 10 weeks was similar (6.6%) to that expected for natural populations, whereas the mortality rate for individuals in the reinforcement translocation was higher (26.6%). The APPs have been proven to be a feasible method for translocation, as they result in relatively low mortality by preventing the stress and damage caused by limpet detachment from substrata. The constraints caused by reinforcement translocation to a new environment seem to be the cause of the increased mortality, as the translocated limpets changed their home scar at a much higher rate than the control limpets did.