Factors influencing local abundance and haulout behaviour of ringed seals (Phoca hispida) on landfast ice of the Alaskan Beaufort Sea

2002 ◽  
Vol 80 (11) ◽  
pp. 1900-1917 ◽  
Author(s):  
Valerie D Moulton ◽  
W John Richardson ◽  
Trent L McDonald ◽  
Robert E Elliott ◽  
Michael T Williams
Keyword(s):  
Beaufort Sea ◽  
Time Of Day ◽  
Intermediate Water ◽  
Phoca Hispida ◽  
Weather Factors ◽  
Industrial Activity ◽  
Ringed Seals ◽  
Landfast Ice ◽  
Local Abundance ◽  
Water Depths

This study investigates how the local abundance of ringed seals (Phoca hispida) on landfast ice of the central Alaskan Beaufort Sea is related to habitat factors and how the haulout behaviour of seals is influenced by temporal and weather factors. An understanding of these relationships is required before the potential impacts of industrial activity on ringed seals can be assessed. Intensive and replicated aerial surveys employing strip transect methodology were conducted during the springs of 1997–1999. Data were examined with χ2 tests and Poisson regression. The overall observed densities of ringed seals over water depths >3 m was 0.43, 0.39, and 0.63 seals/km2 in 1997–1999, respectively. Significantly more seals occurred over intermediate water depths, especially 10–20 m. In all years, seals were widely distributed on the landfast ice, but during breakup, higher numbers of seals occurred near the ice edge. Densities were significantly lower in areas with high ice deformation and extensive melt water. There was no consistent relationship between seal sightings and time of day within the 10:00–18:00 period with surveys. The peak period of haulout occurred around 1 and 2 June. Significantly more ringed seals were observed on warm, cloudy days. There was no indication that limited winter industrial activity, including ice roads and Vibroseis, occurring within the study area in 1997–1999 significantly affected ringed seal density in spring.

Factors Affecting the Observed Densities of Ringed Seals, Phoca hispida, in the Alaskan Beaufort Sea, 1996-99

ARCTIC ◽  
2004 ◽  
Vol 57 (2) ◽  
Author(s):  
Kathryn J. Frost ◽  
Lloyd F. Lowry ◽  
Grey Pendleton ◽  
Helen R. Nute
Keyword(s):  
Beaufort Sea ◽  
Phoca Hispida ◽  
Factors Affecting ◽  
Ringed Seals

Variability in the Diet of Ringed Seals, Phoca hispida, in Alaska

1980 ◽  
Vol 37 (12) ◽  
pp. 2254-2261 ◽  
Author(s):  
Lloyd F. Lowry ◽  
Kathryn J. Frost ◽  
John J. Burns
Keyword(s):  
Stomach Contents ◽  
Late Summer ◽  
Beaufort Sea ◽  
Boundary Region ◽  
Early Summer ◽  
Phoca Hispida ◽  
Arctic Cod ◽  
Ringed Seals ◽  
Saffron Cod ◽  
Crangon Septemspinosa

Analysis of stomach contents of ringed seals (Phoca hispida) collected at eight locations along the Alaskan coast showed significant seasonal and regional differences in diet. During the spring–summer period saffron cod (Eleginus gracilis) was the most important food item in the nearshore zone of the northeastern Bering and southeastern Chukchi Seas. In that period shrimps (Pandalus spp., Eualus spp., Lebbeus polaris, and Crangon septemspinosa) were the major food in the northcentral Bering Sea, hyperiid amphipods (Parathemisto libellula) in the central Beaufort Sea and euphausiids (Thysanoessa spp.) in the boundary region (Barrow area) between the Chukchi and Beaufort seas. During late summer–early autumn hyperiid amphipods were important foods in the central Beaufort and the southeastern Chukchi. The autumn diet of seals in Norton Sound included mainly saffron cod During winter–early spring Arctic cod (Boreogadus saida) predominated the diet at all localities. During spring and early summer in the northeastern Bering and southeastern Chukchi seas the amount of saffron cod consumed was directly correlated with age. In the Beaufort Sea during autumn and winter Arctic cod were eaten in similar amounts by all age-classes. An analysis of the energy value and quantities of prey consumed indicates that prey species that occur in concentrations (Arctic and saffron cods, hyperiid amphipods, euphausiids and some shrimps) are of particular importance in the annual nutrition of ringed seals. These seals may be food limited in areas and during times when these kinds of prey are not available.Key words: food habits, Phoca hispida, ringed seals, Arctic cod, saffron cod, crustaceans, Alaska

Distribution of ringed seals in the southeastern Beaufort Sea during late summer

1992 ◽  
Vol 70 (5) ◽  
pp. 891-900 ◽  
Author(s):  
Lois A. Harwood ◽  
Ian Stirling
Keyword(s):  
Relative Abundance ◽  
Late Summer ◽  
Beaufort Sea ◽  
General Area ◽  
Phoca Hispida ◽  
Sea State ◽  
Ringed Seals ◽  
Aerial Surveys ◽  
Early Fall

The distribution and relative abundance of ringed seals (Phoca hispida) in the southeastern Beaufort Sea were examined through systematic aerial surveys in August–September of 1982 and 1984–1986. All data analyzed were collected by the same observer when sea state was ≤ 2 on the Beaufort Scale and when there was no forward glare. In late summer and early fall of 1982, 1984, and 1986, ringed seals occurred singly and in groups, to an observed maximum of 21 seals. Groups of seals were clumped into large areas of aggregation which appeared to persist for several weeks. Densities in aggregation areas ranged from 121 to 326 seals/100 km2, approximately 6–13 times greater than regional mean densities. The geographic extent of aggregation areas (350–2800 km2) and the numbers (1 in 1984, 2 in 1982, 3 in 1986) and locations of aggregations varied among years. Ringed seals tended to aggregate most frequently and in greatest numbers in waters north of the Tuktoyaktuk Peninsula, in the general area where the Cape Bathurst polynya occurs in winter. The relative abundance of ringed seals varied among the years of the study, reaching a maximum in 1982 (42.20 seals/100 km2), declining through 1984 (14.73/100 km2) and 1985 (7.92/100 km2), and increasing again in 1986 (19.35/100 km2).

EFFECTS OF AN OFFSHORE OIL DEVELOPMENT ON LOCAL ABUNDANCE AND DISTRIBUTION OF RINGED SEALS (PHOCA HISPIDA) OF THE ALASKAN BEAUFORT SEA1

2005 ◽  
Vol 21 (2) ◽  
pp. 217-242 ◽  
Author(s):  
Valerie D. Moulton ◽  
W. John Richardson ◽  
Robert E. Elliott ◽  
Trent L. Mcdonald ◽  
Chris Nations ◽  
...  
Keyword(s):  
Phoca Hispida ◽  
Oil Development ◽  
Ringed Seals ◽  
Local Abundance ◽  
Abundance And Distribution ◽  
Offshore Oil

Distribution and Abundance of Seals in the Eastern Beaufort Sea

1977 ◽  
Vol 34 (7) ◽  
pp. 976-988 ◽  
Author(s):  
Ian Stirling ◽  
W. Ralph Archibald ◽  
Douglas DeMaster
Keyword(s):  
Marine Ecosystem ◽  
Major Change ◽  
Beaufort Sea ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Erignathus Barbatus ◽  
Independent Observations ◽  
Baseline Information ◽  
Reproductive Rates ◽  
Bearded Seals

The objectives of this study were: (1) to design a statistically reliable method for surveying ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) that could be repeated and, (2) to obtain baseline information on the distribution, abundance, and general biology of ringed and bearded seals in relation to other mammals in the pack-ice ecosystem of the eastern Beaufort Sea.Because of the limitations encountered in aerial surveying during the period of optimum haul out, and the heterogeneous environment, we employed a stratified design incorporating a weighted linear regression model. Identical surveys, conducted from June 15 to 29, 1974 and from June 12 to 20, 1975, showed a significant decline in numbers of both seal species in 1975. This conclusion was supported by other independent observations. Observer bias in sighting and identifying the species of seals was tested for and rejected. Neither species was distributed randomly over the heterogeneous habitat but the degree of clumping was different. In general, bearded seals preferred shallower areas and ringed seals deeper ones.When the seal population declined, the reproductive rates of both species dropped markedly and young of the year virtually disappeared from the population. The reduction in numbers of seals stimulated a major change in reproductive rates of the polar bears (Ursus maritimus) and arctic foxes (Alopex lagopus) that depend upon them for food, and the bear and fox populations decreased in size.Some possible causes of the decline are discussed. This unprecedented variability in the stability of the marine ecosystem has serious management implications. Key words: census techniques, Phoca hispida, Erignathus barbatus, seals, interspecific relationships, Beaufort Sea

Haul-out behaviour and densities of ringed seals (Phoca hispida) in the Barrow Strait area, N.W.T.

1979 ◽  
Vol 57 (10) ◽  
pp. 1985-1997 ◽  
Author(s):  
Kerwin J. Finley
Keyword(s):  
Wind Speed ◽  
Early Morning ◽  
Maximum Density ◽  
Stable Population ◽  
The Sun ◽  
High Wind ◽  
Phoca Hispida ◽  
High Wind Speed ◽  
Ringed Seals ◽  
Calm Weather

Numbers of ringed seals hauled out on the ice began to increase in early June. Numbers on the ice were highest from 0900 to 1500 hours Central Standard Time and lowest (average 40–50% of peak) in early morning. Seals commonly remained on the ice for several hours, and occasionally (during calm weather) for > 48 h. Numbers on the ice were reduced on windy days and possibly also on unusually warm, bright and calm days. Seals tended to face away from the wind (particularly with high wind speed) and oriented broadside to the sun. Seals usually occurred singly (60–70% of all groups) at their holes.Numbers of seals hauled out at Freemans Cove remained relatively constant during June (maximum density 4.86/km2), whereas at Aston Bay numbers increased dramatically to a maximum density of 10.44/km2 in late June. The increase was thought to be due to an influx of seals abandoning unstable ice. The density of seal holes at Freemans Cove (5.92/km2) was much higher than at Aston Bay (2.73/km2). The ratio of holes to the maximum numbers of seals (1.12:1) at Freemans Cove represents a first estimate of this relationship in an apparently stable population.

Distribution and abundance of ringed (Phoca hispida) and bearded seals (Erignathus barbatus) in western Hudson Bay

1997 ◽  
Vol 54 (4) ◽  
pp. 914-921 ◽  
Author(s):  
N J Lunn ◽  
I Stirling ◽  
S N Nowicki
Keyword(s):  
Polar Bear ◽  
Hudson Bay ◽  
Phoca Hispida ◽  
Current Estimate ◽  
Ringed Seals ◽  
Erignathus Barbatus ◽  
The Mean ◽  
Western Hudson Bay ◽  
The Relationship ◽  
Bearded Seals

We flew a medium-altitude, systematic, strip-transect survey for ringed (Phoca hispida) and bearded seals (Erignathus barbatus) over western Hudson Bay in early June 1994 and 1995. The mean density (per square kilometre) of ringed seals hauled out on the ice was four times higher in 1995 (1.690) than in 1994 (0.380). The 1994 survey appeared to underestimate seal abundance because it was flown too late. Ringed seals preferred high ice cover habitat (6 + /8 ice) and, within this habitat, favoured cracking ice and large floes. We found no consistent effect of either wind or cloud cover on habitat preference. We estimated a total of 1980 bearded seals and 140<|>880 ringed seals hauled out on the sea ice in June 1995. A recent review of the relationship between ringed seal and polar bear (Ursus maritimus) populations suggests that a visible population of this size should support a population of up to 1300 polar bears, which is in general agreement with the current estimate of 1250-1300 bears in western Hudson Bay.

The scent of rutting male ringed seals(Phoca hispida)

1992 ◽  
Vol 226 (4) ◽  
pp. 681-689 ◽  
Author(s):  
M. Ryg ◽  
Y. Solberg ◽  
C. Lydersen ◽  
T. G. Smith
Keyword(s):  
Phoca Hispida ◽  
Ringed Seals
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