Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography

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Science  29 Sep 2017:
Vol. 357, Issue 6358, pp. 1402-1406
DOI: 10.1126/science.aao1498
  • Fig. 1 Japanese tsunami marine debris rafts and associated biota.

    (A) Fisheries dock (JTMD-BF-1) (4) from the Port of Misawa, Aomori Prefecture, washed ashore 5 June 2012 on Agate Beach, near Newport, Lincoln County, Oregon (photograph by J. W. Chapman). (B) A fishing vessel (JTMD-BF-2), washed ashore at Ilwaco, Pacific County, Washington, 15 June 2012, heavily covered with the pelagic gooseneck barnacle Lepas; living Japanese fauna included barnacles, isopods, amphipods, and mussels (photograph by A. Pleus). (C) Japanese barred knifejaw fish Oplegnathus fasciatus in the stern well of the fishing vessel 斎勝丸 (Sai-shō-Maru) (JTMD-BF-40) from Rikuzentakata, Iwate Prefecture, washed ashore 22 March 2013, on Long Beach Peninsula, Pacific County, Washington (photograph by A. Pleus). (D) Post-and-beam wood (JTMD-BF-297) from Tōhoku coast, Honshu, washed ashore 1 April 2013, at Bandon, Oregon, and heavily bored by the Japanese shipworm Psiloteredo sp. (photograph by N. C. Treneman). (E) Buoy (JTMD-BF-207), found floating inside the Charleston Boat Basin in Coos Bay, Coos County, Oregon, on 17 May 2014; living Japanese limpet Siphonaria sirius in center, next to dead Japanese oyster Crassostrea gigas (photograph by L. K. Rasmuson). (F) Buoy (JTMD-BF-216), washed ashore at Dunes City, Lane County, Oregon, with large foliaceous living colonies of the Japanese bryozoan Biflustra grandicella (photograph by A. Marohl).

  • Fig. 2 Cumulative Japanese living protist, invertebrate, and fish species richness by date and object type.

    Species accumulation for 289 taxa detected from Alaska to California and Hawai‘i from June 2012 to February 2017 by object type (table S1 and fig. S2): Vessels are primarily skiffs ranging from 4 to 11.5 m in length; docks are JTMD-BF-1 and JTMD-BF-8, landing in central Oregon (June 2012) and northern Washington (December 2012), respectively (fig. S1); buoys are anchored or attached floats used in aquaculture, small harbors, and navigation; beams are post-and-beam timber (mortise-and-tenon construction) of standard Japanese dimensions; totes include crates, boxes, and cases used in fisheries and for domestic purposes; “other” includes pallets, pontoon sections, ropes, trays, propane tanks, carboys, items associated with the aquaculture and fisheries industries, and many other objects. Post-and-beam pieces detected in 2016 may represent redrift (washed back out to sea after earlier landings), rather than being at sea since 2011. JTMD spring landing concentrations are evident in all years.

  • Fig. 3 Living Japanese macroinvertebrate and fish species richness by object type and taxonomic group.

    (A) Total richness by object type landing from Alaska to California and Hawai‘i, as described in Fig. 2; number of species exclusive (unique) to a given object type are in blue; “n” is the number of objects in each category of the total 510 items (excluding 124 items on which only dead individuals or algae were documented). (B) Species diversity by taxonomic group. Number of species already present (due to natural distribution or previous introductions) on the west (Pacific) coast of North America is in blue. “Other” taxa are Nemertea, Sipuncula, Insecta (Diptera), Pycnogonida, Acarina, and Kamptozoa.

  • Fig. 4 JTMD richness per object and time.

    (A) Quartile plot of richness by year, based on 110 JTMD-HR (higher-resolution) objects (see text and supplementary materials). Peak per capita richness occurred in 2012 to 2013, with richness falling below 20 species per object since 2015. There was a significant decline in high-richness objects over time (r2 = 0.2357; P < 0.05), based on the upper quartile of each year. (B) Quartile plot of richness by object type, based on 110 JTMD-HR objects; two docks in 2012 and vessels (regardless of year) account for all high (>20 species) richness items (Fig. 3A and fig. S4B). (C) Linear regression of per capita JTMD richness (as days since first interception) for HR vessels alone; shaded areas are the 95% confidence intervals around the linear model (slope and y intercept) parameters. Although outlier high-richness events decline (A) there is no significant decline (C) in per capita richness over time for the west coast of North America (WC) (r2 = 0.0039; P = 0.6537) or Hawai‘i (HI) (r2 = 0.1518; P = 0.1221).

  • Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography

    James T. Carlton, John W. Chapman, Jonathan B. Geller, Jessica A. Miller, Deborah A. Carlton, Megan I. McCuller, Nancy C. Treneman, Brian P. Steves, Gregory M. Ruiz

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S11
    • Tables S1 to S5
    • References

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