Ocean-Going Vessels: A Possible Conduit for the Introduction of White-Nose Syndrome Fungus (Geomyces destructans) into Bats in Alaska

Understanding the potential pathways by which epizootics enter uninfected animal populations is essential for management and the control of diseases. White-nose syndrome (WNS) is associated with the fungus Geomyces destructans, a pathogen of unknown origin that has led to population declines of 30 to 99% in cave-hibernating bats in the eastern United States (Blehert and others 2009; Frick and others 2010). This fungus was first detected in New York in February 2006 (Blehert and others 2009), and has since spread westward rapidly (Frick and others 2010) with DNA from G. destructans detected on bats as far west as Oklahoma (USGS 2010). The pathogen likely causes mortality in bats by disturbing their hibernation torpor leading to increased activity, emaciation, and starvation (Boyles and Willis 2010), although the proximate cause of these disruptions has only been hypothesized to date (Cryan and others 2010). The spread of this fungus is likely facilitated by human activities, and understanding and managing the human-caused spread will be necessary to protect bat species in North America. Although WNS has not yet spread to the western United States, it is expected in the near future (USFWS 2010). The spread of G. destructans to Alaska may be deterred by physical obstacles and climatic variables. The migration patterns of Alaskan bats are unknown; however, it is likely that natural factors such as climate and geographic barriers such as mountains, oceans, and glaciers help to isolate bat populations and limit the distribution of bats in Alaska (Parker and others 1997; Boland and others 2009). Anthropogenic mechanisms may allow G. destructans to bypass many of the apparent barriers. We propose the possibility that marine vessels could act as a conduit to transport live infected bats to coastal Alaska. We observed a small brown bat at 20:32 on 21 January 2011, while conducting seabird observations and trawl surveys aboard a 40-m trawler, the Epic Explorer. The observation occurred on the marine waters of the Inside Passage of Southeast Alaska in Port Houghton (UTM: Zone 8V, 62330E, 6354263N, WGS84). This position is approximately 1.8 km from the north shore of Port Houghton, 2.7 km from the south shore, and 1.2 km from the shoreline of Walter Island. At the time of the sighting, the Epic Explorer was moving from west to east at a speed ,3.7 km/h. Conditions at the time of the observation, over 4.5 h after sunset, were dark. The air temperature outside at sea level was 1.036C, a light rain was falling, and a light breeze was blowing (,13 km/h) from the west. The bat flew from left to right along the edge of the roofline just above eye level (6 m above the ocean) and was clearly illuminated by the bright sodium spot lights mounted on the mast. The flight pattern of the bat was not direct, and it fluttered in place several times along the wheelhouse roofline. The bat appeared to be dry and healthy, not lethargic. We were positioned approximately 2 m from the bat on the other side of the front windows of the wheelhouse. Approximately 30 min after the original observation, a 2nd bat sighting occurred under similar conditions. The vessel was returning along the same transect line when a bat fitting AUTUMN 2011 GENERAL NOTES 133