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International shipping as a potent vector for spreading marine parasites
Citation:
Pagenkopp Lohan, K., J. Darling, AND G. Ruiz. International shipping as a potent vector for spreading marine parasites. Diversity and Distributions. Blackwell Publishing Limited, Oxford, Uk, 28(9):1922-1933, (2022). https://doi.org/10.1111/ddi.13592
Impact/Purpose:
This manuscript describes the diversity of marine parasites associated with shipping vessels, as determined by DNA metabarcoding. The primary purpose of the research is to better understand how global shipping, via both ballast water transport and hull biofouling, contributes to the transfer and introduction of parasite species beyond their historical range limits. This will inform current and future risk management of these important vectors for marine species invasions. A second purpose of the research is to further explore and develop DNA metabarcoding as a method for understanding biodiversity in aquatic systems.
Description:
Aim The global shipping fleet, the primary means of transporting goods among countries, also serves as a major dispersal mechanism for marine invasive species. To date, researchers have primarily focussed on the role of ships in transferring marine macrofauna, often overlooking transfers of associated parasites, which can have larger impacts on naïve host individuals and populations. Here, we re-examine three previously published metabarcode datasets targeting zooplankton and protists in ships' ballast water to assess the diversity of parasites across life stages arriving to three major US ports. Location Port of Hampton Roads in the Chesapeake Bay, Virginia; Ports of Texas City, Houston and Bayport in Galveston Bay, Texas; and Port of Valdez in Prince William Sound, Alaska. Methods We selected all known parasitic taxa, using sequences generated from the small subunit gene (SSU) from ribosomal RNA (rRNA) amplified from (1) zooplankton collected from plankton tows (35 and 80 μm datasets) and (2) eukaryotes collected from samples of ships' ballast water (3 μm dataset). Results In all three datasets, we found a broad range of parasitic taxa, including many protistan and metazoan parasites, that infect a wide range of hosts, from teleost fish to dinoflagellates. Parasite richness was highest in the 3 μm dataset and relatively uniform across arrival regions. Several parasite taxa were found in high relative abundance (based on number of sequences recovered) either in ships entering a single or across multiple regions. Main Conclusions The ubiquity, diversity and relative abundance of parasites detected demonstrate ships are a potent vector for spreading marine parasites across the world's oceans, potentially contributing to reported increases in outbreaks of marine diseases. Future research is urgently needed to evaluate the fate of parasites upon arrival and the efficacy of ballast water treatment systems to reduce future transfers and colonization.
