Aquatic Invasions (2013) Volume 8, Issue 3: 249–260 doi: http://dx.doi.org/10.3391/ai.2013.8.3.01 Open Access © 2013 The Author(s). Journal compilation © 2013 REABIC Research Article Port-by-port accumulations and dispersal of hull fouling invertebrates between the Mediterranean Sea, the Atlantic Ocean and the Pacific Ocean John W. Chapman1*, Ralph A. Breitenstein2 and James T. Carlton3 1 Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Dr., Newport OR 97366 USA 2 Hatfield Marine Science Center, Oregon State University, 2030 Marine Science Dr., Newport OR 97366 USA 3 Williams College – Mystic Seaport Program Maritime Studies Program, P. O. Box 6000, Mystic CT 06355 USA E-mail: [email protected] (JWC), [email protected] (RAB), [email protected] (JTC) *Corresponding author Received: 8 May 2013 / Accepted: 19 August 2013 / Published online: 2 September 2013 Handling editor: Vadim Panov Abstract The R/V Oceanus completed a 9,789 km, 28 day passage from Woods Hole, Massachusetts, in the Atlantic Ocean, through the Panama Canal to Yaquina Bay, Oregon, in the Pacific Ocean on 21 February 2012. The Oceanus had previously operated in the Mediterranean Sea and Atlantic Ocean (including the Caribbean Sea). We document the sequential acquisition of the barnacles Balanus trigonus and Amphibalanus venustus and the oyster Ostrea equestris on the Oceanus on its high and low latitude transoceanic, intra-oceanic, and inter- oceanic travels before she was surveyed in Yaquina Bay. The close correspondence between hull fouling accumulations and the detailed two year Oceanus working history reveals B. trigonus settlement occurred in every tropical port visited by the Oceanus, that some populations survived through two of three Woods Hole winters, and that some of these populations passed through the freshwater Panama Canal. These results suggest that marine hull-fouling species are continuously transported globally between most ports of call by most ship passages. Key words: hull fouling; introduced species; Atlantic; Pacific; Caribbean; Mediterranean; marine; Balanus trigonus; Amphibalanus venustus; Ostrea equestris some of Kerckhof et al.’s (2010) and Floerl and Introduction Coutts’ (2009) predictions. The freshwater Gatun Lake in the Panama Canal, for instance, is The port-by-port development of fouling commonly assumed to limit dispersal of marine communities on vessels over their cruise tracks organisms between the Atlantic and Pacific oceans. is well known but rarely studied (Darwin 1854; However, marine species survival through the Pilsbry 1916; Kerckhof et al. 2010; Carlton 2011; canal on the hulls of ships has been reported Carlton et al. 2011) and was not quantitatively or multiple times (Cohen 2006), and passage through experimentally examined relative to a detailed the Canal in salt water ballast water avoids vessel itinerary until the 1980s (Carlton and exposure to Gatun Lake. Bishop (1947) reported Hodder 1995). Kerckhof et al. (2010) and Floerl that three species of barnacles, Austrominius and Coutts (2009) proposed that more invasions modestus (Darwin, 1854) (= Elminius modestus), from hull fouling species are to be expected Amphibalanus amphitrite (Darwin, 1854) (=Balanus because global shipping has increased, and ships amphitrite) and Amphibalanus improvisus (Darwin, are faster and increasing their numbers of ports 1854) (= Balanus improvisus) arrived alive in of call. Kerckhof et al. (2010) considered also Liverpool, England, after a 30-day voyage from the increased potential of dispersal on ships that Australasia, via the Panama Canal. Menzies operate for long periods of time in local areas (1968) found high survival through Gatun Lake and then periodically sail to distant areas. of marine intertidal snails, crabs, and barnacles Major intra- and inter-ocean salinity and and subtidal isopods suspended in a cheesecloth temperature variation could limit the scope of bag that was towed from a ship transiting the 249 J.W. Chapman et al. Figure 1. Western hemisphere cruise areas and homeports (white stars) of the R/V Oceanus in 2009–2011 and the 01/25/2012–02/21/2012 course from Woods Hole, MA to Newport, OR (solid line). Canal. Davidson et al. (2008) found surviving moving between local and transoceanic ports barnacles, bryozoans, and isopods, among other across major ocean barriers. The sister ship of the hull fouling species, on ships that passed through Oceanus, the R/V Wecoma, was immediately the Panama Canal in transit from a low salinity adjacent to the Oceanus at this time and had been area of San Francisco Bay, California, to continuously moored at the dock for several months Brownsville, Texas. and was covered by a local species community Between 1975 and 2012, the Atlantic Ocean was that could be compared with the Oceanus species the home port and research arena of the 54 m long community. We therefore surveyed the hull of R/V Oceanus of the Woods Hole Oceanographic the Wecoma simultaneously with the Oceanus. Institution, Woods Hole, Massachusetts. The Oceanus was drydocked and cleaned in Jacksonville, Methods Florida, between February and March 2009 and then operated between 2009 and 2011 in marine Oregon State University (OSU) and Oregon Coast waters of the Mediterranean Sea, Atlantic Ocean Aquarium (OCA) scientific divers surveyed the (including the Caribbean Sea) before she was hull of the Oceanus by direct sampling and by transferred to the Pacific Ocean via the Panama underwater videos on 23 February 2012. All Canal in 2012. The Oceanus took 28 days (25 accessible macro-fouling invertebrate assemblages January to 21 February 2012) to travel the 9,789 were sampled. Samples were scraped into plastic km from Woods Hole to Yaquina Bay, Oregon. bags that were then transferred into seawater The passage included an approximately 6 hour (4 baths at the OSU Hatfield Marine Science Center to 5 February) transit through the Panama Canal (HMSC) facilities. Samples were sorted and (Figure 1). preserved within 24 hours. Invertebrates were We surveyed the hull of the R/V Oceanus on separated from these samples, photographed, its arrival in Yaquina Bay to partially test Cohen’s identified to the lowest possible taxonomic level, (2006), Kerckhof et al.’s (2010), and Carlton’s and preserved in 95% ethanol. The specimens are (2009) proposals of persistent dispersal and deposited at the Natural History Museum of Los survival by hull fouling organisms on modern ships Angeles County, Los Angeles, California. 250 Barnacle dispersal by ships We compared the size structures of species We used the distinction of size modes to test populations among sequential settlement layers whether barnacle recruitment was constant or contained in the fouling communities of both irregular and distinguished population size- vessels. We noted the order of occurrence of species frequency modes using the FAO FiSAT_II software among these fouling layers and the cohort size- (FAO 2005). FiSAT_II decomposes composite distributions within these species populations. size distributions into their component cohorts We inferred the order of settlement and relative (means, standard deviations and population sizes rates of individual growth on the Oceanus by of modes) and subjectively identifies and “links” comparing population size-frequency modes. We the mean sizes of the most likely common cohorts. then back calculated the timing of their settlement The FiSAT_II procedure uses the Bhattacharya relative to the timing of Oceanus voyages and method for distinguishing particular size modes home port layovers. The timing and destinations and the NORMSEP program therein decomposes of the Oceanus cruises since its last drydocking composite size modes by the simplex algorithim and cleaning (in February-March 2009) and its to a maximim fit of estimated and observed total passage from Wood Hole, Massachusetts, to abundances across entire size distributions. Adjacent Yaquina Bay, Oregon, were determined from the size modes are accepted as significantly different online Oceanus cruise log (http://www.whoi.edu/ in the FiSAT_II procedure when their separation main/ships/schedules) and from additional indices (S.I.) are greater than two (FAO 2005). information provided by Oceanus Captain Jeff We tested the significance of estimated size Crews (pers. com.). frequencies (the sum of all modes) by their We assumed thermal tolerances of barnacles correlations with the observed size frequency on the Oceanus to be similar to other populations distributions. of the same species (e.g., Werner 1967) in order to assess their survival in Woods Hole sea water Oyster settlement dates temperatures. We obtained Woods Hole 12 m depth seawater temperature records from the Martha’s We back calculated the probable oyster settlement Vineyard Coastal Observatory (MVCO 2012) dates from estimated growth rates derived from database. Missing temperature data were interpo- two Atlantic populations of the crested oyster lated between the nearest beginning and ending Ostrea equestris Say, 1834 (averaging 18 and 20 dates of available data. mm in length) that had settled onto buoys that Barnacles and oysters containing fresh tissue were exposed for 12 months (Galtsoff and Merrill were classified as alive at time of sampling. 1962). We assumed these populations began Conversely, these invertebrates were classified settlement in November when the buoys were as dead at time of sampling when they lacked placed out