Seek and you shall find: Detection of alien bryozoans along the Chilean SE Pacific coast with a simple and cost-efficient methodology

Invasions by non-indigenous species (NIS) are among the major problems that coastal ecosystems are facing globally and are driven by anthropogenic activities, such as international vessel traffic and aquaculture. Bryozoans are typical constituents of vessel hull-fouling communities, and the phylum contains several notorious globally invasive species. Few NIS, including bryozoan species, are reported along the Chilean Southeast Pacific coast, which has traditionally been attributed to the local oceanographic and ecologic conditions. However, the low numbers may also be the consequence of insufficient monitoring, as well as the small size and morphologic similarity of many species, which hinders their detection. Here, we deployed artificial floating settlement plates in strategic locations (ports/marinas or aquaculture sites) along the Chilean coast (from 29°S to 41°S), to detect non-indigenous bryozoans. With this method, we found a total of 14 species, including five NIS and four cryptogenic species. Additionally, we report two NIS from opportunistic findings in the rocky intertidal zone and from a piece of plastic litter. Three species represent new records from Chile: Bugulina cf. fulva, Bugulina stolonifera , and Watersipora arcuata . These are described in detail in the present paper. The new records importantly enhance the number of known (bryozoan) invasions along the Chilean coast and corroborate the need for regular monitoring. The installation of artificial settlement plates at high-risk sites (especially ports and marinas) has proven to be a successful and efficient low-cost approach, which can help to detect NIS introductions in their early stages, before spreading to natural environments. Regular monitoring of these sites, as well as compulsory legislation for hull cleaning, both for long-distance (nationally and internationally) travelling and local vessels, could greatly reduce the problem.