Fouling and Ships' Hulls: How Changing Circumstances and Spawning Events may Result in the Spread of Exotic Species

Abstract

Organisms fouling ships' hulls are continually in transit worldwide. Although effective antifouling paints incorporating organotins have considerably reduced fouling biomass these paints have a limited period of effectiveness, which may be less than the ships' inter-docking period, depending on sea temperature and abrasion. Vessels immersed over several years can allow fouling communities to develop and spread beyond their native distribution. This process of establishment is not fully understood. This review proposes that short rapid turn-around of vessels with mature attached biota can result in synchronized spawnings and production of sufficient zygotes to form a founder population. Spawning may be induced by changes in temperature or salinity on entry into a port, according to season. The diversity of taxa in transit on ships' hulls includes commercial molluscs, which have the potential to transmit their diseases or pests to port regions. Several factors may act in the further enhancement of exotic species establishment including changes of in-port berthing regions to more marine conditions. Ships today are generally larger, and faster, and have a high frequency of port visits thereby increasing the number of spawning opportunities, perhaps with a larger inoculum size. With trade expansion, new trading routes, political events and changes in climate, new pathways for invasion will emerge. Greater controls on industrial discharges, improved treatments of urban wastes and better management of waste runoff into rivers as well as a phasing out of organotin antifoulants will mean a reduced toxicity in port regions. This may enable a smaller inoculum to colonize by creating opportunities for establishment not present in the previous 25 years. Some invaders will have unwanted consequences for the environment, economies and human health.

Interrupting a multi-species bioinvasion vector: The efficacy of in-water cleaning for removing biofouling on obsolete vessels

“…The high levels of biofouling with little variation among hull locations found on the ORION represent common features of stationary vessels that receive little or no hull husbandry (Brock et al, 1999;DeFelice, 1999;Coutts, 2002;Minchin and Gollasch, 2003;Davidson et al, 2008). Such vessels tend to have extensive biofouling assemblages in both hull and non-hull areas that exceed niche area fouling of most operational ships.…”

Diversity of Bugulidae (Bryozoa, Cheilostomata) colonizing artificial substrates in the Madeira Archipelago (NE Atlantic Ocean)

“…1,2]. This phenomenon has significantly increased in the past years as maritime traffic represents one of the main vectors contributing to the spread and establishment of NIS worldwide, facilitating the transport of species in ship hulls and ballast water [3][4][5]. Floating docks and other artificial substrates are very common in bays and estuaries, particularly in shipping areas and marinas are highly relevant for detecting new NIS arrivals [6][7][8].…”

Population expansion of a new invasive coral species, Tubastraea micranthus, in the northern Gulf of Mexico

“…Vectors for the transport of invasive marine or freshwater species (Kerr et al 2005) include the ballast water of barges or ships (Chesapeake Bay Commission 1995, ICES 2002, the hulls of the same (Minchin & Gollasch 2003), transfer via towing of oil and gas platforms to new sites (Hicks & Tunnell 1993), accidental release of exotic species from mariculture operations (Sapota 2004), and deliberate release of exotics by aquarium hobbyists (Weidema 2000, Christmas et al 2001, Hindar et al 2006. Recent concern regarding invasive marine species has focused on those in the Gulf of Mexico (GOM) (Osman & Shirley 2007).…”