Meridian Newsletter: Fall/Winter 2011-Spring/Summer 2012 - Arctic Shipping

Arctic Shipping: a Free Ride for Aquatic Invasive Species?

Farrah T. Chan, Sarah A. Bailey, and Hugh J. MacIsaac

Sea lampreys, zebra mussels, and green crab are among the invasive species familiar to many in southern Canada. Unintentionally introduced in areas outside their native habitat, they have reproduced, spread, and disrupted ecosystems where they have no natural place. So far very few invasions of nonindigenous species have been recorded in the Arctic—but with a warming climate and increasing ship traffic that could change.

Aquatic Nonindigenous Species and Commercial Shipping

Nonindigenous species (also known as non-native, invasive, introduced, exotic, foreign, or alien species) include plants, animals, microbes, and fungi that have established reproducing populations outside their native range, sometimes with negative consequences for the environment, ecology, or even economy of the invaded area.

A typical invasion is a three-stage process: introduction, establishment, and spread (Figure 1). First, a transport vector picks up and carries individuals of the nonindigenous species from its source region and introduces them to a new area. Next, the individuals establish themselves in the new environment by surviving the environmental conditions and interactions with resident species. The established population may then spread and become the source of further invasions.

 
Figure 1. Stages of a typical invasion by a nonindigenous species (left) with possible effects of climate change indicated (right).

[Description of Figure 1:  This graphic illustrates the stages of a typical invasion by a nonindigenous species and the possible effects of climate change at each stage.  A typical invasion is a three stage process:  introduction from a source population, establishment in a new environment, and spread of the established population.  The established population may then become the source of further invasions.  During the introduction stage, climate change can facilitate the transport of aquatic invasive species through natural dispersal and human-mediated transport such as shipping.  Once introduced to a new area, reduced climatic constraints may enhance the survival, growth and competitive ability of aquatic invasive species.]

Profound negative impacts from aquatic nonindigenous species (ANS) have been recorded in aquatic systems worldwide. In Canada, the sea lamprey (Petromyzon marinus) has contributed to the collapse of lake trout fisheries in the Great Lakes; the zebra mussel (Dreissena polymorpha) causes millions of dollars in damage to human infrastructure in the Great Lakes each year; the green crab (Carcinus maenas) has brought about the decline of native shellfish populations on the East and West Coasts; the clubbed tunicate (Styela clava) is threatening fishing and aquaculture industries on the East Coast; and spiny (Bythotrephes longimanus) and fishhook (Cercopagis pengoi) waterfleas interfere with sport and commercial fishing and compete with native fish for food in the Great Lakes (DFO, 2011).

Commercial shipping provides an effective mechanism for invasive species to bypass geographic barriers and reach areas far beyond their natural range. All the species mentioned above, except the sea lamprey, are examples of ship-mediated ANS. Ship hulls and other underwater surfaces like propellers and rudders can harbour fouling organisms such as barnacles, tunicates, and mussels in dense colonies that shelter and protect mobile crustaceans from the strong shearing forces produced when a ship is under way (Figure 2). These organisms drop off and can release larvae during transit or at destination ports, establishing populations anywhere along the ship's route.

 
Figure 2. Barnacle colony fouled on a ship propeller. [Photo: Farrah Chan]

In addition, a menagerie of species from microbes to fish can move around the globe in the ballast water used to control a ship's stability and trim. Organisms in the water column, and sometimes bottom dwelling species in harbour sediment, may be pumped into ballast water tanks during water uptake and travel to the destination port, where they are released when the water is pumped out (Figure 3).

 
Figure 3. A variety of species (shown as round objects) can be moved between ports through the ballast water activities of ships.

To prevent introduction of invasive species Canada has ballast water management regulations that require most transoceanic vessels entering and operating in Canadian waters to replace ballast water loaded near shore with open-ocean saltwater (Canada Shipping Act, 2006). Empirical studies indicate that the process, known as ballast exchange, purges 60-100% of coastal planktonic organisms pumped in at the source port, and it is over 99% percent effective in reducing freshwater species (Gray et al., 2007; Ruiz and Reid, 2007). Open-ocean species in exchanged ballast water are unlikely to thrive in coastal and freshwater environments and thus present a low risk for invasion. Regulations also require transoceanic ships carrying little or no ballast to flush residual ballast water and sediment with open-ocean saltwater. As a result, ballast water from foreign sources is not discharged in Canadian waters, reducing the risk of ballast-mediated ANS introductions.

Ship-Mediated ANS Invasions and the Canadian Arctic

At first glance, the Arctic seems unlikely region for ANS invasions. Ship traffic to northern ports is low compared to temperate locations, and cold temperatures and limited food resources in the Arctic may hinder survival, reproduction, and growth of many organisms. There are no confirmed reports of ship-mediated ANS invasions in Canadian Arctic waters; however, at least nine non-indigenous species have been recorded in Arctic and sub-Arctic waters outside Canada. It is not known how or when they arrived (Molnar et al., 2008). These species include the soft-shell clam (Mya arenaria), zebra mussel (Dreissena polymorpha), Akartia copepod (Acartia tonsa), red king crab (Paralithodes camtschaticusthe), marine pill bug (Sphaeroma walkeri), naval shipworm (Teredo navalis), hydroid (Ectopleura crocea), green algae (Cladophora sericea), and dinoflagellate (Alexandrium affine). All except the red king crab can be introduced through hull fouling and ballast water discharge (Molnar et al., 2008). The small number of ANS recorded in Arctic and sub-Arctic waters may reflect insufficient research efforts and limited taxonomic knowledge of the region (Ruiz and Hewitt, 2009), but nonetheless suggest that invasions to northern regions by temperate ANS are possible under current climatic conditions.

Most Arctic communities are on the coast and, with no road or rail access, rely on marine transport for supplies of food, clothing, materials and equipment, fuels, and consumer goods (Figure 4).

 
Figure 4. Network of shipping routes serving major Canadian Arctic communities, 2004. [Courtesy Susie Harder, Transport Canada]

Ships also carry raw resources, such as minerals, hydrocarbons, and grains, through Arctic waters to domestic and international markets. Churchill's proximity to the Prairies and its connection to the rail system has established it as a major transhipment port for grain, while resource extraction sites, including Raglan Mine in Deception Bay, Quebec, rely on ships to transport mineral concentrates for processing. Ship traffic is far lower than on the Atlantic and Pacific coasts, but is expected to increase in the near future. Several large-scale resource developments have been proposed for the next 20 years, including iron ore at Mary River, Baffin Island, magnetite at Roche Bay, also on Baffin Island, and High/Izok Lake near Yellowknife for lead/zinc/copper concentrates (Arctic Council, 2009). These operations will require shipping for bulk exports, as well as logistics and fuel imports. Plans to diversify international commodity shipments at Churchill and proposals to develop deep-water ports at locations such as Iqaluit may further increase shipping traffic in the region (Stewart and Howland, 2009). The federal government has also announced plans and allocated resources to promote social and economic development through the Northern Strategy (Government of Canada, 2010). The growing popularity of Arctic marine tourism and the cruise industry's plans to expand and diversify the Arctic market may bring increases in ship traffic (Arctic Council, 2009). With increased ship traffic in the Canadian comes greater risk of ship-mediated ANS invasions.

Climate change can also increase the rate and extent of ANS invasions by influencing the dispersal and survival of both native and non-indigenous species (Figure 1; Wassmann et al., 2010). Changes in temperature regimes, ocean currents, sea level, and other key physical processes associated with climate change can directly affect the invasion process by altering natural dispersal. For example, a Pacific diatom (Neodenticula seminae) was found in the North Atlantic Ocean for the first time in 1998. It likely migrated from the North Pacific Ocean via the Arctic Archipelago when receding coastal ice sheets boosted the inflow of water (Reid et al., 2007). Melting sea ice continues to open up waterways and shipping channels in the Arctic Ocean and extend the length of the shipping season (Figure 5; Arctic Council, 2009).

 
Figure 5. The Northeast and the Northwest Passages appear navigable and free of pack ice in the 2010 shipping season. Image modified from University of Illinois Department of Atmospheric Sciences, The Cryosphere Today [available at http://arctic.atmos.uiuc.edu/cryosphere/].

In the summer of 2007, the Northwest Passage was free of pack ice and fully navigable (Cressey, 2007). In 2009 two commercial vessels, unaided by icebreakers, used the Northeast Passage and the Northern Sea Route to dramatically reduce the time and cost of shipping goods from northern Europe to northeast Asia and northwest North America (Smith, 2009).

Furthermore, warming temperatures may enhance survival of introduced ANS by allowing them to reproduce in areas where they previously could not (Hellmann et al., 2008). Once established at the introduction site, their growth and competitive ability may be enhanced by warmer climates and other effects of climate change, promoting their spread and amplifying their environmental impacts.

Uncertainties and Current Research

The increased potential for ship-mediated ANS invasions highlights the need for adaptive management of ANS in the Arctic. Intra-coastal shipping can disperse species within a region at much higher rates than would occur naturally and can also transport them to areas they would not reach through natural mechanisms. Since intra-coastal voyages are often short, high survival in ballast tanks is expected, and a large number of ANS individuals could therefore be released. In addition, ships can directly transport ballast water from Canadian temperate waters to the Canadian Arctic without any form of management, although some vessels do voluntarily conduct ballast water exchange. The direct transfer of domestic ballast water may allow species native to Canadian temperate ports—or ANS that have been previously introduced to temperate Canadian ports—to gain a foothold in the Arctic. What is more, Canada has no management regulations on anti-fouling treatment of hull surfaces.

The importance of hull fouling as a transport vector for ANS in the Arctic is poorly understood. Some research has shown that sea ice can scrape hulls, removing or damaging fouling species (Lee and Chown, 2009). This may decrease the risk of ANS introduction by killing fouling organisms; or, it may increase the risk by releasing them into the water. Some hull fouling species can survive long voyages through a wide variety of marine environments with major changes in salinity and temperature (Davidson et al., 2008). More research on domestic ballast water and hull fouling is needed to fully evaluate the invasion potential of shipping. 

Few studies have examined the magnitude of ship-mediated ANS invasions in Arctic waters, and only one qualitative study has been done for northern Canada (Niimi, 2007). We are therefore conducting a comprehensive study of the potential for ship-borne ANS invasions in Canadian Arctic waters. We have conducted a transit analysis to examine shipping patterns in the Canadian Arctic and to identify high traffic ports. As a result, the ports at Churchill, Manitoba, Deception Bay, Quebec, and Iqaluit, Nunavut have been selected for biological sampling with the assumption that ports receiving greater ship traffic and/or ballast water discharge are more vulnerable to ANS introductions. We are collecting biological samples from the hulls and ballast water of ships arriving at high traffic ports to determine the identity and abundance of any potential ANS (Figures 6a and 6b).

Figure 6a: Collecting zooplankton from the ballast water tank of a cargo ship at the Port of Churchill with a plankton net tow. [Photo: Krista Hanis].

Figure 6b: Surveying the hull of a harbour tug at the same port for fouling organisms. [Photo: Farrah Chan].

 

Farrah T. Chan is a doctoral student in biology at the Great Lakes Institute for Environmental Research, University of Windsor. Sarah A. Bailey is a research scientist with the Department of Fisheries and Oceans. Hugh J. MacIsaac is Professor and Department of Fisheries and Oceans Invasive Species Research Chair at the Great Lakes Institute for Environmental Research, University of Windsor. 

References

Arctic Council, 2009. Arctic Marine Shipping Assessment 2009 Report. Arctic Council, Tromsø. p. 187.

Canada Shipping Act, 2006. Ballast Water Control and Management Regulations (SOR/2006-129). Available from http://www.gazette.gc.ca/archives/p2/2006/2006-06-28/html/sor-dors129-eng.html [accessed August 10, 2009].

Cressey, D., 2007. "Arctic melt opens Northwest Passage", Nature 449(7160): 267.

Davidson, I.C., L.D. McCann, P.W. Fofonoff, M.D. Sytsma and G.M. Ruiz, 2008. "The potential for hull-mediated species transfers by obsolete ships on their final voyages", Diversity and Distributions 14(3): 518-529.

Fisheries and Oceans Canada, 2011. Aquatic Invasive Species. Available from http://www.dfo-mpo.gc.ca/science/enviro/ANS-eae/index-eng.htm [accessed August 26, 2011].

Government of Canada, 2010. Canada's Northern Strategy. Available from http://www.northernstrategy.ca/index-eng.asp [accessed August 10, 2011].

Gray, D.K., T.H. Johengen, D.F. Reid and H.J. MacIsaac, 2007. "Efficacy of open-ocean ballast water exchange as a means of preventing invertebrate invasions between freshwater ports", Limnology and Oceanography, 52(6): 2386-2397.

Hellmann, J.J., J.E. Byers, B.G. Bierwagen and J.S. Dukes, 2008. "Five potential consequences of climate change for invasive species", Conservation Biology, 22(3): 534-543.

Lee, J.E., and S.L. Chown, 2009. "Temporal development of hull-fouling assemblages associated with an Antarctic supply vessel", Marine Ecology Progress Series, 386: 97-105.

Molnar, J.L., R.L. Gamboa, C. Revenga and M.D. Spalding, 2008. Assessing the global threat of invasive species to marine biodiversity, Frontiers in Ecology and the Environment, 6(9): 485-492.

Niimi, A.J., 2007. "Current and future prospect for vessel related introductions of exotic species to the Arctic region", Canadian Technical Report of Fisheries and Aquatic Sciences, 2720. Fisheries and Oceans Canada.

Reid, P.C., D.G. Johns, M. Edwards, M. Starr, M. Poulins and P. Snoeijs, 2007. "A biological consequences of reducing Arctic ice cover: arrival of the Pacific diatom Neodenticula seminae in the North Atlantic for the first time in 800 000 years", Global Change Biology, 13(9): 1910-1921.

Ruiz, G.M., and D.F. Reid, 2007.  "Current state of understanding about the effectiveness of ballast water exchange (BWE) in reducing aquatic nonindigenous species (ANS) introductions to the Great Lakes Basin and Chesapeake Bay, USA: Synthesis and analysis of exiting information", NOAA Technical Memorandum, GLERL-142, National Ocean and Atmospheric Administration, Ann Arbor, MI.

Ruiz, G.M., and C.L. Hewitt, 2009. "Latitudinal patterns of biological invasions in marine ecosystems: a polar perspective." In Smithsonian at the Poles: contributions to International Polar Year Science. Edited by I. Krupnik, M.A. Lang and S.E. Miller. Washington, DC.

Simkanin, C., I. Davidson, M. Falkner, M. Systsma and G. Ruiz, 2009. "Intra-coastal ballast water flux and the potential for secondary spread of non-native species on the US West Coast", Marine Pollution Bulletin 58(3): 366-374.

Smith, A. 2009. Global Warming Reopens the Northeast Passage. Available from http://www.time.com/time/world/article/0,8599,1924410,00.html [Accessed August 10, 2011].

Stewart, D.B., and K.L. Howland, 2009. "An ecological and oceanographical assessment of the alternate ballast water exchange zone in the Hudson Strait Region", Canadian Science Advisory Secretariat Research Document 2009/008. Fisheries and Oceans Canada.

Wassmann, P., C.M. Duarte, S. Agusti and K. Sejr, 2010.  "Footprints of climate change in the Arctic marine ecosystem", Global Change Biology, 17(2): 1235-1249.

 

Return to In This Issue