Potential Disturbances from Ships in the Arctic

(from ASMA Report 2009)

Sound and Noise Disturbance

All vessels produce sound as a by-product of their operation. Typically, vessels produce low frequency sound from the operation of machinery onboard, hydrodynamic flow noise around the hull and from propeller cavitation, which is typically the dominant source of noise. The sound a vessel produces relates to many factors including size, speed, load, condition, age and engine type. The larger the vessel and/or the faster it is moving, the more noise it produces. Many vessels also employ hydro-acoustic devices such as commercial sonar, echo-sounders, side scan sonar for navigation, depth finding, seafloor mapping or to detect biologics as a regular part of their operations. These types of devices produce short pulses and use frequencies ranging from low to high, depending on their utility.

For most marine vertebrates, making, hearing and processing sounds serve critical biological functions. These include communication, foraging, reproduction, navigation and predator-avoidance. In particular, toothed whales have developed sophisticated biosonar capabilities to help them feed and navigate; large baleen whales have developed long-range communication systems using sound in reproductive and social interaction; and pinnipeds (i.e., seals, sea lion, walrus, etc.) make and listen to sounds for critical communicative functions. Many fish utilize sounds in mating and other social interactions.

The introduction of noise into the environment can adversely affect the ability of marine life to use sound in various ways and can induce alteration of behavior; reduction of communication ranges for social interactions, foraging, and predator avoidance; and temporary or permanent compromise of the auditory or other systems. In extreme cases, too much noise can lead to habitat avoidance or even death. Noise can also affect physiological functions and cause more generalized stress. Determining when impacts of noise exposure from any source become biologically significant to a species is often difficult. Nevertheless, this is an area where additional research is ongoing and needed in key areas.

Where there is an overlap between potential noise sources and the frequencies of sound used by marine life, there is particular concern as to how sound sources can interfere with important biological functions. The predominately low frequency sounds associated with large vessels is similar to the general hearing sensitivity bandwidths of large whales and many fish species. The ambient noise environment in the Arctic is more complex and variable than in many other ocean areas due to the seasonal variability in ice cover. In addition to natural sources contributing to background levels, anthropogenic sources, like vessel traffic, can also have a profound impact on these levels. In most regions in the northern hemisphere, shipping noise is the dominant source of underwater noise below 300 hertz.

Many environmental effects resulting from ship disturbances can be effectively mitigated through the use of best practices and the implementation of management measures. With regard to noise disturbances, such measures could include rerouting to avoid some areas in sensitive periods, lower speed, and alternative engine and hull designs to make ships more silent. There may be a need to plan potential future shipping lanes in the Arctic so as to avoid large seabird colonies, marine mammal haul-outs and other areas where animals are aggregated. In late 2008, the IMO’s Marine Environment Protection Committee (MEPC) formed a correspondence group that is now working to identify and address ways to minimize the introduction of incidental noise into the marine environment from commercial shipping in order to reduce the potential adverse impact on marine life. This group aims to develop non-mandatory technical guidelines for ship-quieting technologies, as well as potential navigation and operational practices for all IMO member states. This work will be aimed at the global shipping industry and is not likely to contain Arctic specific considerations.

Icebreakers and Disturbance

All icebreaking operations, whether by independent commercial icebreaking ships or government icebreaker escort, can potentially cause disturbances to wildlife and local communities both through the noise they create and the trail of open water left astern. Compared to other vessels, icebreakers produce louder and more variable sounds. This is because of the episodic nature of the icebreaking, which involves ramming forward into the ice and then reversing to begin the process again. Some icebreakers are equipped with bubbler systems to aid in clearing ice from the vessel’s path and these can create an additional noise source. Noise from bubbler systems and propeller cavitation associated with icebreaker movement has the potential to alter animal behavior and to disrupt the hearing ability and vocalization of marine mammals.

Wildlife has been found to exhibit a range of behavior in the presence of icebreakers. For example, beluga whales were found to be aware of the icebreaker vessels presence at distances of more than 80 kilometers away, and exhibit strong avoidance response at 35 to 50 km away. However, narwhal whales were found to display only subtle responses to the same disturbance.

The opening of channels through the ice by icebreaking vessels can impact Arctic residents and alter animal behavior. Open water channels take time to freeze and this can disrupt the movements of animals and people over the ice. In many areas of the Arctic in winter, the only naturally occurring ice openings are polynyas caused by winds or ocean currents. Artificially opened water channels can be problematic for marine mammals and other species, which confuse them for polynyas and can get trapped too far from the ice edge as the channel eventually refreezes.

Vessel Strikes on Marine Mammals

Vessel collisions, resulting in death or serious injury of marine mammals, are a threat to marine organisms worldwide. Vessel collisions or ship strikes occur mainly with large whale species, small cetaceans (i.e., dolphins, narwhal, beluga), marine turtles and sirenians (i.e., manatees, dugongs). Records indicate that nearly all large whale species are vulnerable to ship strikes. Vessel collisions with marine mammals can result in death, massive trauma, hemorrhaging, broken bones and propeller wounds.

Databases have been constructed which track the number of ship strikes occurring. These report more than 750 known cetacean vessel strikes through the world’s oceans, including nearly 300 incidents involving large whales. Virtually all motorized vessel types, sizes and classes are represented in these databases. It should be noted, however, that any database will likely underestimate the number of actual occurrences because many go either undetected or unreported. In some cases carcasses are found, but because injuries are internal or due to advanced decomposition, it may be difficult to determine cause of death. When large vessels are involved, the mariner may not be aware that a strike has occurred.

There are relatively few known incidents of Arctic or ice-adapted marine mammal species being involved in ship strikes. The relatively infrequent occurrence is a result of relatively lower vessel traffic in high latitudes as compared to major trading routes and human population centers in lower latitudes. However, of consideration is that certain Arctic species, such as the bowhead and Pacific right whale, have features that make them potentially vulnerable to ship strikes, particularly as vessel traffic increases in their waters. Arctic toothed whales, namely narwhals and beluga whales, are probably less vulnerable to ship strikes, given their greater maneuverability and social behavior that lends them to aggregating in large groups enhancing their detection. It should be noted, however, that records of roughly comparable mid-sized species such as pilot whales, killer whales and various species of beaked whales also appear in ship strike databases.

Vessel speed has been implicated as a key factor in the occurrence and severity of vessel strikes with large species. Several independent studies indicate that vessel speeds of 10-14 knots increase by one-half or greater the probability that a whale will survive a collision with a ship.

As vessel traffic increases in the Arctic, modifications to customary vessel operation in key cetacean aggregation areas or vessel speed restrictions can be an effective measure to mitigate potential impacts on vulnerable species such as bowhead whales and, to a lesser extent, narwhals, beluga whales and other Arctic marine organisms. Where feasible, vessel routing measures may also be applied in order for ships to avoid known cetacean aggregation areas. A number of steps have been taken by some states outside the Arctic region to reduce the threat of ship strikes to endangered large whale species, including shifting shipping lanes and applying to the IMO to establish a vessel “Area to be Avoided.” The IMO’s MEPC is currently working on development of a non-mandatory guidance document for minimizing the risk of ship strikes on cetaceans which will be aimed at the global maritime industry.

Light Disturbance

Birds of all species appear to be attracted to lights. This puts them at risk of collision with lighted structures. The attraction to light and resulting risk of collision varies depending on the weather, season and the age of the bird. The fall migration in the Arctic is when most bird attraction and collision issues emerge, as young birds are traveling for the first time and inclement weather becomes more frequent. Light attraction of marine birds is not yet a significant issue in the Arctic. This is because most birds are in the Arctic in the summer months to breed, when there is little or no darkness; and most Arctic-breeding seabirds are diurnal and, therefore, less active at night.

Despite these factors, there are still risks. During the non-breeding period in ice-free waters and as the presence of lighted ships and structures increases, risks are heightened. A wide variety of nocturnal species nest in the North Pacific, especially in the Aleutian Islands. Storm-petrels are vulnerable in late summer and early fall, when hundreds have been known to pitch on a vessel during foggy conditions. These problems are not unique to the smaller nocturnal species. Common and king eiders, both large ducks, have collided with large shrimp vessels in waters off western Greenland, causing injury or death.

Introduction of Invasive Species

The introduction and spread of alien invasive species is a serious problem that has ecological, economic, health and environmental impacts, including the loss of native biological diversity worldwide. Although the introduction of invasive species into the Arctic environment has been minimally studied, it is an issue that deserves further study in the context of a changing climate and potential increased shipping in the Arctic region. The risk of introduction of invasive species will increase as shipping volume increases in this region. As with ship operations in non-Arctic areas, the threat of introduction comes from four sources: ballast water discharge, hull fouling, cargo operations and casualties or shipwrecks.

• Ballast Water

The IMO’s International Convention for the Control and Management of Ships Ballast Water & Sediments addresses ballast exchange and treatment. As of November 2008, 16 states including Norway, representing about 3.6 percent of the world’s merchant shipping, have ratified this convention. Under the IMO convention standard, a small percentage of viable organisms will still be discharged.

• Hull Fouling

In subarctic waters, transfer of aquatic invasive species on the hulls of ships has become a serious threat to the environment, rivaling ballast water discharge. However, hull coatings on icecapable vessels may be effective antifouling agents, as would the scouring effects of passage through ice.

• Cargo

Most international movements of goods are regulated by fumigation and biosecurity provisions to prevent the movement of invasive species in cargo. This is also applicable to the Arctic region. Much of the sealift and re-supply movements into the Arctic are palletized, increasing the potential for unwanted organisms to be entrained in the cargo.

• Casualty

Ship accidents and sinkings can introduce invasive species into the local environment. As an example, shipwrecks in the Aleutians have caused significant ecological damage through the introduction of predatory rat species onto islands that have large aggregations of nesting seabirds.

Due to climate change and the potential increase in shipping activity, the introduction of invasive species may require more attention than it has received in the past. In particular, trans-Arctic shipping between the North Atlantic and North Pacific could potentially represent a vector for transfer of species in ballast water or on hulls to new areas where the environmental conditions resemble those in their home waters. Introduction of rodent species to islands harboring nesting seabirds, as evidenced in the Aleutian Islands, can be devastating. With limited baseline data on what species might actually be at risk from ship operations such as ballast water discharge, the use of the precautionary approach and proactive preventative actions are encouraged.

Green Ship Technology in the Arctic

Technology has a role to play in the mitigation of environmental impacts in the Arctic and elsewhere. Many of the potential impacts from shipping that have been discussed in this assessment can be effectively reduced or eliminated through the use of current or developing technologies, as well as best practices. Examples include stack scrubbers that remove harmful substances such as sulfur and black carbon from a ship’s emissions; water treatment systems for sewage, bilge water, ballast water and other discharges; technologies that harness wind or solar power to reduce fuel consumption; or the use of cleaner fuels that emit less harmful substances when burned. Given the sensitivity of the Arctic environment and the potential impacts from shipping, the development and application of green ship technologies should be a priority. These new technologies can be expedited through industry incentives, such as the green ship technology fund in Norway; or regulatory requirements, such as the IMO International Convention for the Control and Management of Ships Ballast Water & Sediments.

Arctic Council, 2009, Arctic Marine Shipping Assessment (AMSA), Arctic Council.©