Cumulative Environmental Effects of Oil and Gas Activities on Alaska's North Slope (2003) / Chapter Skim
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8. Effects on Animals
8. Effects on Animals
Pages 98-131
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From page 98... ...
On land, animals can be affected by noise associated with seismic exploration, routine industrial activities, vehicle and aircraft traffic, and disturbance of dens. In addition, animals can be indirectly affected by changes in vegetation caused by industrial activities, contaminant spills, withdrawal of water from lakes and streams, and by the availability of anthropogenic food sources.
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From page 99... ...
There are inadequate data to properly evaluate the importance of the Alaskan portion of the Beaufort Sea as feeding habitat for bowhead whales, especially during their fall migration. Because this is the time when they are susceptible to disturbance by the noise of exploration for oil, the information is needed for a full assessment of the effects of noise on bowheads.
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From page 100... ...
from Hammerhead, received sound was generally 105-130 dB. Estimating Future Accumulation of Effects In~lustrial Noise If oil- and gas-related activities continue in the Alaskan waters of the Beaufort Sea, the major noise will be generated CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS by marine seismic exploration.
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From page 101... ...
The toxic effects of inhaled oil vapors and ingested oil on bowhead whales would probably be similar to those described below for seals and polar bears. A modest amount of attention has been devoted to studying the likely effects of spilled oil on bowheads (for example, see Albert 1981b, Hansen 1985 and Beaufort-Sea-related EISs)
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From page 102... ...
on fallmigrating bowhead whales in the Alaskan portion of the Beaufort Sea. · There are inadequate data regarding the importance of the Alaskan portion of the Beaufort Sea as feeding habitat for the bowhead whale, especially during the fall migration.
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From page 103... ...
Since 1988, hunting of polar bears from the southern Beaufort Sea stock has been controlled by a conservation agreement between the Inupiat of northern Alaska and Inuvialuit of the western Canadian Arctic who hunt a shared population (Nageak et al. l991~; the number of animals taken each year is well documented.
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From page 104... ...
However, because so far the marine waters of the Beaufort Sea have seen only limited and sporadic industrial activity, it is likely that there have been no serious effects or accumulation of effects on ringed seals or polar bears. Permitting Inciclental Take The Marine Mammal Protection Act prohibits the taking of marine mammals including polar bears and ringed seals except in specifically permitted circumstances.
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From page 105... ...
, it will be impossible to verify whether the effects occur, to measure their magnitude, or to explain their causes. Finclings · Industrial activity in marine waters of the Beaufort Sea has been limited and sporadic and likely has not caused serious accumulating effects on ringed seals or polar bears.
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From page 106... ...
· Climate warming at predicted rates in the Beaufort Sea region is likely to have serious consequences for ringed seals and polar bears, and those effects will accumulate with the effects of oil and gas activities in the region. · Unless studies to address potential accumulation of effects on North Slope polar bears or ringed seals are designed, funded, and conducted over long periods, it will be impossible to verify whether such effects occur, to measure them, or to explain their causes.
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From page 107... ...
of the four Alaska barren-ground caribou herds (PCH, Porcupine Caribou Herd; WAH, Western Arctic Herd; CAH, Central Arctic Herd; TLH, Teshekpuk Lake Herd)
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From page 108... ...
Delayed weaning enhances calf survival, but extended lactaCUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS tion precludes breeding that year (Gerhart et al. 1997a,b; Russell and White 2000~.
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From page 109... ...
Seismic exploration crews on the coastal plain of the Arctic National Wildlife Refuge in the 1980s had no contact with caribou of the PCH, which winters south and east of the Brooks Range. Even when seismic testing was conducted on winter range, the direct effects on caribou were probably temporary and minor.
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From page 110... ...
During construction of the TransAlaska Pipeline, 1975-1978, calves were increasingly underrepresented among caribou observed from the Dalton Highway; calf percentages, on average, were 69% lower than regional estimates determined by aerial survey. Caribou sightings within, and crossings of, the pipeline corridor in 1976-1978 averaged 30% and 80% less, respectively, than did those in 1975 (Cameron and Whitten 1979b, Cameron et CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS al.
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From page 111... ...
. Only those few caribou that winter on the coastal plain are likely to interact with oil fields, and the effects appear to be minor.
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From page 112... ...
, especially when insects were relatively inactive. During periods of moderate to high insect activity, caribou south of the complex often divert eastward, into the prevailing northeasterly winds, to the Sagavanirktok River and move downstream to the coast (Lawhead et al.
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From page 113... ...
FICURE 8-5 Locus of r~dio-coU~ed Me caribou Timid 850-~2 coasts quits in seldom to insect ~cUvi~. Ceded Arctic Herd, Alaska, summer 1980-1993.
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From page 114... ...
are correlated with estimates of net calf production the CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS 30 CO ° 20 _ x N .
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From page 115... ...
The expansion will likely be eastward on state lands from the Badami unit, southward into the foothills of the central Brooks Range, and westward into the National Petroleum Reserve-Alaska from the Alpine unit. Unless the density of new access roads and new production and support facilities can be substantially reduced relative to infrastructure now in place, conflicts with CAH caribou east of the Sagavanirktok River will increase during the calving and insect-harassment periods.
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From page 116... ...
· As a result of conflicts with industrial activity during calving and an interaction of disturbance with the stress of summer insect harassment, reproductive success of Central Arctic Herd female caribou in contact with oil development from 1988 through 2001 was lower than for undisturbed females, contributing to an overall reduction in herd productivity. The decrease in herd size between 1992 and 1995 may reflect the additive effects of surface development and relatively high insect activity, in contrast to an increase in the herd's size from 1995 to 2000, when insect activity was generally low.
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From page 117... ...
1983~. The density and rate of occupancy of dens and the sizes of litters are greater in oil fields than in adjacent areas, so the fox population has grown larger and more stable (Burgess 2000, Eberhardt et al.
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From page 118... ...
Studies of the grizzly bear populations that use Prudhoe Bay oil fields showed that bears that consumed human food resources had higher than average cub survival (possibly because of a scarcity of natural predators such as wolves, wolverines, and adult male bears)
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From page 119... ...
Given the small numbers representing any individual species, power line collisions are unlikely to represent an important source of mortality in the oil fields. This source of mortality is likely to remain confined to the core areas of the Prudhoe Bay and Kuparuk oil fields if new fields continue the recent trend of placing power lines on pipeline supports or burying them in roads.
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From page 120... ...
Few estimates of nest success for other sites in Alaska are available for comparison. There is evidence that nesting success for other ground-nesting birds is unusually low in the oil fields (Anderson et al.
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From page 121... ...
2002~. Low nest success is associated with high predator populations in the oil fields.
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From page 122... ...
Conclusions ancl Projections of Future Effects Because of higher predator densities, increased predation on nests is the most apparent effect of oil development on birds that nest in the oil fields. Reduced nest success is sufficient in some cases to cause population declines, so the apparent stability of some oil-field populations is presumably the result of immigration.
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From page 123... ...
· Inadequate disposal of garbage has resulted in artificially high densities of gulls, ravens, and mammalian predators in the oil fields. The resulting increased predation of 123 birds' nests and young has likely made some oil-field populations dependent on immigration from more productive populations elsewhere.
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From page 124... ...
Diadromous species, such as Dolly Varden char, arctic cisco, broad whitefish, and least cisco (Coregonus sardinellaJ, migrate each summer between upriver overwintering areas and feeding grounds in coastal waters. That group is more abundant along the Beaufort Sea coast than along the northeastern Chukchi coast, possibly because of a lack of large rivers and because of the Chukchi's less-productive coastal region (Fechhelm et al.
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From page 125... ...
Fish from the Sagavanirktok River population move through the Prudhoe Bay coastal region and enter lakes attached to small drainage systems (Morris 2000~. During summer, broad whitefish are distributed throughout the drainages and coastal plain water bodies.
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From page 126... ...
Much of the water needed in the established oil fields is now obtained from reservoirs that are replenished with runoff during spring ice break-up; most of the water used in exploration is taken from lakes. Ice thickness has a great influence on the distribution of fish in lakes across the Arctic Coastal Plain.
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From page 127... ...
The effects of summertime seismic exploration with airguns on coastal and marine fish in the Beaufort Sea have not been investigated. Coastal Development Coastal development that poses the greatest risk of causing effects that accumulate in nearshore habitats includes facilities that change physical conditions that are important to nearshore biota.
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From page 128... ...
. main Issues: · effects of causeway-induced changes in circulation and hydrography on the migration of young-of-the-year arctic cisco from Canada to the Colville River, · effects of causeway-induced changes in circulation and hydrography on the nearshore migration corridor used by most species of diadromous fish, · changes to temperature and salinity of the nearshore habitat and ramifications of those changes to the population of broad whitefish inhabiting the Sagavanirktok River, and · effects of causeway-induced changes to fish and fish habitat on the fisheries that harvest arctic and least cisco in the Colville River.
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From page 129... ...
Any effects resulting from the causeways will exist until the structures are removed, or are made porous enough that fish movements are unaffected. Future Scenario The potential effects on freshwater systems have become clear during the development of the existing oil fields, so those effects probably will be addressed during the design and permitting of new fields and field expansions.
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From page 130... ...
Subsurface spills from pipelines released over extended periods could affect benthic communities close to the release. Epibenthos and infauna are usually not abundant in very nearshore waters in the Beaufort Sea.
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From page 131... ...
The epontic communities under the ice have not been specifically studied, but it is unlikely that operations have affected them. · The committee found no data showing that discharges to the Beaufort Sea have had effects on biota.
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