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- Valued Component Features
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Valued Component Features
The Eastern Beaufort Sea beluga population winters in the Bering Strait and migrates eastward through the Alaskan Beaufort Sea during April and May, arriving off the west coast of Banks Island in late May and early June (Moore et al. 1993). Offshore leads are important during this portion of their spring migration (Barber et al. 2001, Richard et al. 2001, Harwood and Smith 2002). Depending on ice conditions, they may first appear near Herschel Island in late April or early May, and come to the shallow waters of the Mackenzie Delta in June to early July. They then move in a southwestward direction along the landfast ice edge off the Tuktoyaktuk Peninsula and into Kugmallit Bay, East and West Mackenzie Bays, Shallow Bay and the Kendall Island area where they aggregate for much of July (Harwood and Smith 2002). These areas are presumed to be of considerable importance to beluga because they return to these areas each summer despite significant hunting pressures (North/South Consultants Inc. 2003). This area, which encompasses approximately 1800 km2 , comprise the only known traditional summer concentration areas for the Beaufort Sea beluga stock. These areas are recognized as special designated lands in the Aklavik, Inuvik and Tuktoyaktuk Community Conservation Plans (CCP) as 711E, 714E and 716E – Beluga Management Zone 1A (WMAC 2000a,b,c). Category E comprise lands and water where cultural or renewable resources are of extreme significance and sensitivity. The CCPs recommend the highest degree of protection of category E lands and there shall be no development in these areas (WMAC 2000a,b,c). The shallow waters, bays and river estuaries of the Beaufort Sea described above are recognized as special designated lands in the Aklavik, Inuvik and Tuktoyaktuk Community Conservation Plans as 712C – Beluga Management Zone 2 (WMAC 2000 a,b,c). Zone 2 extends from Kay Point on the Yukon coast to Baillie Islands (Cape Bathurst) in the east, and includes waters shallower than 20 m. Category C comprise lands and waters where cultural or renewable resources are of particular significance and sensitivity during specific times of the year.
The reasons why belugas come into estuaries were not well understood until recently. Earlier theories included a thermal advantage for calves and food availability. More recently, it has been shown that occupation of these warm, less saline waters is related to their annual moult and is connected with significant hormonal changes correlated with new skin growth (Harwood and Smith 2002). Belugas use these areas for moulting, calving and feeding. Feeding is not always observed and empty stomachs in belugas landed in the subsistence hunt are common. Mother-calf pairs are believed to spend longer periods in shallow water than other age or gender classes. Belugas in these traditional summer concentration areas are harvested by Inuvialuit from Aklavik, Inuvik and Tuktoyaktuk.
Belugas also aggregate offshore in the Beaufort Sea, Amundsen Gulf and Viscount Melville Sound where it is presumed they engage in feeding activities prior to the fall migration (Harwood and Smith 2002; Barber et al. 2001, Richard et al. 2001, DFO 2000). Belugas from the Mackenzie Estuary use deep offshore areas on their way to M'Clure Strait rather than using the shallower waters near Banks Island (Barber et al. 2001). In late August, the return migration consists of a variety of routes, varying from 100 to 400 km offshore of northern Alaska (Harwood and Smith 2002). During their migration to the wintering areas in the autumn, belugas feed heavily on schools of Arctic cod. This appears to be a very important time of the year for the accumulation of a thick layer of blubber, which acts both as insulation and a large reserve of energy. Few whales remain in the area past early September.
Rationale for Selection
The beluga whale was selected because the species was previously cited as a VEC for the Beaufort region (GNWT 2005) and Beluga Management Zones have been identified for the Beaufort Sea in the Community Conservation Plans. Additionally, beluga whales are an important link in the arctic food web as both a predator and as prey. Belugas are known to feed on many species of fish species in the Beaufort Sea and Amundsen Gulf, including Arctic cod (Boreogadus saida), cisco (Coregonus artedii) and halibut (Reinhardtius hippoglossoides) (COSEWIC 2004). Benthic invertebrates are also frequently found in the stomachs of belugas (COSEWIC 2004).
The Eastern Beaufort population of beluga is considered Not At Risk (COSEWIC 2004).
Conserving habitat is fundamental to the viability of the Eastern Beaufort Sea beluga whale population. Belugas occurred most often in the Mackenzie Estuary and within a deep trench in M'Clure Strait and Viscount Melville Sound during the summer. In the fall, the whales occurred in the Mackenzie Estuary and Amundsen Gulf and north along the Yukon Coast (Barber et al. 2001). Presently, approximately 1716 km2 of shallow waters, including Mackenzie Bay at 1160 km2, the Kendall Island area at 193 km2, and Kugmallit Bay at 363 km2 has been identified as important beluga habitat.
Offshore areas in the Beaufort Sea, both within and beyond the Study Area, have also been identified as important, since belugas congregate in these areas and engage in feeding activities from the sea floor before they migrate back to their wintering areas (Harwood and Smith 2002; DFO 2000). The migration routes followed by belugas vary and extend up to 400 km from the shoreline (Barber et al. 2001, Richards et al.. 2001), and these areas will also need to be protected and kept unobstructed if the belugas are expected to continue to use these routes (Harwood and Smith 2002).
Susceptibility to development
The level of industry activity and the number of ongoing projects that may impact beluga populations in the Beaufort Sea is very low. Given the relatively low occurrence of industrial activity in the Arctic, there is little empirical evidence to strongly associate project-specific impacts, or impacts from multiple industrial projects, to population parameters for beluga whales. However, there are two likely means that viability of beluga whale populations can be linked with project-specific impacts:
- industrial activities may reduce the quality and amount of suitable habitat available to beluga whales, especially for feeding, moulting, mating and calving, and
- industrial activities may increase the risk of mortality to individual beluga whales in proximity to developments.
Belugas are vulnerable to anthropogenic threats, such as industry activities because of their strong tendency to return to specific sites of summer aggregation to moult, feed, calve, socialize, rest and avoid predators (COSEWIC 2004; Pippard 1983). They continue to return to traditional areas of aggregation, even in the face of disturbance and harvesting pressures.
Residual effects from industrial activity may result in either complete loss of habitat, as is common with the ‘footprint' of industrial developments, or effective habitat loss, whereby beluga whales avoid habitat in proximity to development. Depending upon the seasonality of occurrence of beluga whales, and the timing of impacts, the habitat loss or avoidance that results from a specific project may be limited to specific seasons.
Development activities to which beluga may be susceptible include:
- industrial pollution and miscellaneous spills;
- noise due to seismic activities and vessel movement; and
- island building or temporary drilling platforms.
Explanations for belugas abandoning these areas include:
- altering the heat budget making the water temperatures too low or unreliable for calving, and
- affecting fish and invertebrate reproduction, thereby reducing the number of prey species.
The population impacts that may result from an oil spill would depend largely on the season, amount and type of contaminants released, climatic factors and response initiated. An oil spill within the shallow waters and river estuaries identified as critical beluga habitat would be the most sensitive and could produce major site-specific impacts. An oil spill further offshore within the feeding, movement and migratory areas and corridors may produce fewer impacts because the beluga can navigate around the spill in these greater water depths. Contact with spilled oil may directly affect the health of individual whales, and/or reduce the availability of food, such as fish and invertebrates.
Noise from marine vessels movements or seismic activities may potentially affect belugas by displacing belugas from the area. The maximum extent of avoidance was predicted to be 50 km in a recent regulatory impact assessment (Devon Canada Corporation 2004). Marine vessels may have the greatest impact (in terms of habitat avoidance) in open water periods when aggregated belugas are feeding in shallow offshore waters. At its most extreme, noise can potentially also affect beluga whales by interfering with mating behaviours, communication and even cause damage to ears or other organs (Erbe and Farmer 1999).
Island building or the installation of temporary drill platforms in shallow waters identified as critical beluga habitat could potentially affect belugas and their habitat by competing with the belugas for space during the summer when they are congregating the shallow waters or by disrupting the habitat during the winter and rendering it unusable.
Seasonality of Development Impacts
Beluga whales that migrate into the Beaufort Sea during open water periods over-winter in waters outside of the study area. Therefore, industrial activities such as ice-platform based drilling, ice road construction, and flaring that occur outside the seasons when beluga whales are present (i.e., during the ice-covered season) are unlikely to result in direct impacts to beluga whales. Open water industrial activities such as seismic, shipping and other marine vessel transport have the greatest potential for direct impacts to beluga whales. Potential accidents from these activities, such as contaminant spills (particularly hydrocarbon spills), have potential for direct impacts. These industrial activities and potential accidents also have a great potential for indirect impacts to belugas via food sources such as fish and invertebrates. If risk has been managed appropriately through prevention measures, and use of these measures is continued, the probability of occurrence of impacts remains low.
Population vs. Individual Level Impacts
Impacts from individual projects would likely be most measurable at the individual or family group level (such as a beluga cow with a calf). However, all such impacts ultimately have population-level consequences. The extent to which they are apparent at the population level (such as lower population numbers) will depend upon the magnitude to which impacts to the individual occur.
Additionally, because the Eastern Beaufort Sea beluga whales utilize waters beyond the Study Area boundaries (e.g., Amundsen Gulf and Viscount Melville Sound), impacts to the population that occur outside the study area may act in a cumulative fashion with impacts within the study area to influence the populations.
There is a variety of potential project types that vary in spatial extent, duration, and intensity (e.g., ice-platform based drilling, ice road construction, seismic, shipping and other marine vessel transport), with a corresponding range in magnitude of impacts that may occur in the project area. Based on the summary of project specific residual effects, the seasonality of beluga whale movements, and the criteria used to define the grid rating, there are several strategies that can be applied to project-specific mitigation planning:
- An oil spill response plan should be developed for areas within the shallow waters and river estuaries identified as critical beluga habitat.
- In open water periods when aggregated belugas are feeding in shallow offshore waters, marine vessel movement activities within these areas should be limited to levels to which the population-level impacts are not apparent.
- Specific sites of summer aggregation to moult, feed, calve, socialize, rest and avoid predators are key areas that are important to the viability of the species, and therefore, impacts here should be mitigated and/or avoided where possible. These areas include the Kendall Island area, Kugmallit Bay, Mackenzie Bay and Estuary and within a deep trench in M'Clure Strait and Viscount Melville Sound. Should development be initiated in such areas, timing should attempt to coincide with periods when belugas are not present (from September to April).
- On-ice activities are generally unlikely to produce residual effects beyond the frozen water season, and may be a preferable option to open water activities, especially if accidents and hazards are controlled.
Global circulation models predict substantial decreases in both thickness and coverage of arctic sea ice due to increased atmospheric CO2. Present climate models are insufficient to predict regional ice dynamics, winds, mesoscale features, and mechanisms of nutrient resupply, which must be known to predict productivity and trophic response (Tynan and DeMaster 1997). However, we can speculate on the potential impacts of observed trends in Arctic climate on wildlife. Changes in the extent and concentration of sea ice may alter the seasonal distributions, geographic ranges, patterns of migration, nutritional status, reproductive success, and the abundance and structure of some species. For cetaceans, the potential detrimental effects of decrease ice extent is more indirect than the loss of ice habitat (Tynan and DeMaster 1997). In the case of the beluga whale, this indirect effect is the potential loss of its predominant prey, the arctic cod (Boreogadus saida) which is intimately associated with ice-edge habitats (Bradstreet 1982). The arctic cod is dependent on the secondary production in these habitats with the latter being sustained by ice algae. Ice algae form a thin, dense layer on the underside of ice at the ice-seawater interface and is well recognized as very important in the food web of marine mammals in the high Arctic (Bradstreet 1982, Tynan and DeMaster 1997).
Retreating ice extent would have an impact on the annual spring and fall migration of the belugas which timed these movements on the opening of ice leads in spring and advancing ice in fall. In summer the pack ice in the Northwest Passage has been the physical barrier separating the western and eastern stocks of belugas. If opening this passage for 100 days in summer comes to pass as predicted, then there is the potential of the mixing of these two stocks leading to reduce genetic diversity across the Arctic (Tynan and DeMaster 1997).
Sensitivity layers and scores
Populations that are concentrated for any part of the year (e.g., staging, moulting, and foraging areas) are vulnerable to site-specific threats because a significant proportion of the population could be affected. As well, populations that occupy geographically restricted habitats (rare, threatened or endangered species) are vulnerable if their habitats are threatened.
Low Sensitivity (1)
Beyond the summer extent of pack ice, using the approximate summer extent of pack ice (defined in Stirling 2002).
Low/Moderate Sensitivity (2)
Area from the limit of summer pack ice to 400 km out from the shoreline (i.e., area south from the limit of summer pack ice to the area north of 400 km out from shore).
Moderate Sensitivity (3)
Polygon includes the area from the shoreline extending out to 400 km offshore. This area is considered seasonal migratory route habitat.
Moderate/High Sensitivity (4)
Polygons includes the area identified as critical summer mating and moulting habitat. The total of these areas include the area designated as Risk Layer 5, therefore the areas that are overlapped carry the higher designated Risk Layer.
High Sensitivity (5)
Proposed Protected Areas; polygons include the area that is being considered for status as a Protected Area.
Beluga whales were considered a VEC because of their important link in the food web of Arctic waters, and because they have been previously selected as a VEC in the Beaufort region. Additionally, the Inuvialuit have long relied on them for subsistence.
Beluga whales are present in the study area during open water periods. In June to early July, belugas are found along the coastlines and in relatively shallow waters of the Mackenzie Delta including Kugmallit Bay, East and West Mackenzie Bays, Shallow Bay and the Kendall Island area. These areas are important as moulting, calving and feeding areas. Beginning in mid-August, belugas move away from the estuarine areas to feed in the deeper waters, and move west towards their winter areas in the Bering Strait and Chukchi Sea in mid-to-late September. Waters near the coastline and extending up to 400 km offshore are important as feeding areas and as spring and fall migration corridors.
Beluga whale habitats most sensitive to industrial activities in the Study Area are the shallow waters and river estuaries. Potential impacts from industrial pollution, miscellaneous spills, and noise are important to mitigate in these areas where possible. Beluga whales that migrate into the Beaufort Sea during open water periods over-winter in waters outside of the study area. Therefore, industrial activities that occur outside the seasons when beluga whales are present (i.e., in frozen water periods) are unlikely to result in direct impacts to beluga whales.
ReferencesSee references used for Beluga information.
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