Dispersal of invasive and native brine shrimps Artemia (Anostraca) via waterbirds

Abstract

North American brine shrimp Artemia franciscana have been exported worldwide since the 1950s for use in aquarium trade and fish farming. Aquaculture is expanding along the Mediterranean coast, leading to the release of A. franciscana into native Artemia populations. A. franciscana was first detected in 1981 in Portugal and has since spread to saltworks along the East Atlantic flyway used by shorebirds. Once A. franciscana becomes established in a locality, native Artemia tend to disappear. To test whether migratory shorebirds can disperse invasive and native Artemia between wetlands, we extracted Artemia cysts from feces and pellets collected at Castro Marim (Portugal) and Cadiz Bay (Spain) during southward migration. We found that large numbers of viable eggs of A. franciscana and native Artemia parthenogenetica were dispersed by Redshank Tringa totanus, Blacktailed Godwit Limosa limosa, and other shorebirds migrating through the Iberian Peninsula. This is the most extensive field demonstration to date that invertebrates can disperse readily via gut passage through birds