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Hatfield Marine Science Center

Oregon State University

Newport, Oregon 97365
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donors.

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Kuvlum 61

Oceanography

PART 3: DIVE AND SURFACING BEHAVIOR 75

Period Lengths 76

Surfacing Rate/Blow Rate 77

Dive Duration Data 83

Distribution of Dive Durations 83

Longest Dive During Summary Period 101

Comparisons of Longest Dives Among Animals 109

Duration of First Dive to Maximum Depth in Summary Periods 111

Dive Depth Information 113

Deepest Dives 115

Distribution of Dives in Depth Bins 115

HI
iv
Figure 13. Track of whale 831. 51

Figure 14. Track of whale 10824. 54

Figure 15. Track of whale 10824 from 2 - 18 September . . 55

Figure 16. Cumulative faIl (September and October. 1979-1989) distribution

and sightings for the Bering Sea bowhead stock. 56

Figure 17. Schematic illustration of a bowhead whale surfacing through thin,

unbroken ice. 58

V
Figure 28. Percentage of sounding dives in each duration bin and longest dive by

summary period: tag 10827 92

Figure 29. Percentage of sounding dives in each duration bin and longest dive by

summary period: tag 10828 93

Figure 30. Percentage of sounding dives in each duration bin and longest dive by

summary period: tag 10830 94

vi
Figure 39. Time series depth information by summary period and day

from a bowhead whale tagged in 1992: Tag 10825 118

Figure 40. Time series depth information by summary period and day

from a bowhead whale tagged in 1992: Tag 10826. 119

Figure 41. Time series depth information by summary period and day

from a bowhead whale tagged in 1992: Tag 10827 120

vii
Figure 51. Percentage of time in depth bins by summary period and day

from a bowhead whale tagged in 1992: Tag 10826. 140

Figure 52. Percentage of time in depth bins by summary period and day

from a bowhead whale tagged in 1992: Tag 10827. 141

Figure 53. Percentage of time in depth bins by summary period and day

from a bowhead whale tagged in 1992: Tag 10828. 142
ix
Table 11. Blowrate (blows/rn in) during summary periods 84

Table 12. Comparison of Longest Dives for Duration/Depth Tags

in 1, 3, and 5 Hour Summary Periods 110

Table 13. Deepest dive during summary periods for duration/depth tags 125

Table 14. Percentage of summary period tags were exposed to air 128

Table 15. Percentage of time tagged bowheads were potentially visible

from the air during summary periods 135

x
obtained from only eight whales. Three tags with poor attachment or placement provided

the least amount of data. One was heard from only five times, but provided the longest

documented tag attachment (49 days). Only six tags (depth/duration) reported battery

voltage in their utility status message. Five of these reported low voltage toward the end

of their operation suggesting that they quit due to battery exhaustion from frequent

transmissions (every surfacing) in a very cold environment. The number of messages sent

by each tag varied from 524 to 8164 ( = 3180) at the time of their last status message.

1
Of the 42,332 dive durations recorded for nine animals, most (77.3%) were 1 mm

whereas only 1.4% were> 19 mm. The longest recorded dive was 62 -64 mm. Five other

tags recorded dives of 61 mm in one or more summary periods. The longest dive for

the other three tagged whales returning duration data, were 33 - 35 mi 44-46 mm, and

55 - 57 mm. The longest dive was <33 mm in 506 (89.4%) of the 566 summary periods

recorded. The mean surfacing rate for individuals ranged from 18.2 to 47.0 surfacings/h.

2
13.5 and 14.4 mm (n = 562 summary periods); however 99.1% of surfacings were < 3.5

mm. Based on our sensor data, the percentage of time animals were potentially visible

from the air was comparable to previous observational studies of bowhead surfacing and

dive behavior, but individual ranges exceeded literature values. The sensor information

revealed characteristics of diving depths and durations that can affect aerial or shipboard

surveys affecting population estimates due to regionally different behaviors.

3
prey preferences and available water depths than a limitation to the animal's diving

capability. We have no information that would indicate that 500 m is a limitation of the

animal's diving ability.

This study provides the first data on route and rate of movement for the fall

bowhead migration from Canada to Russia. These data indicate areas of importance to

bowhead whales in the Beaufort Sea and suggest that the heavy ice front may be the

principle migratory cue for navigating across the Chukchi Sea. The changes in dive

4
5
them between different villages.

Information on seasonal movements of Bering Sea bowheads is incomplete. During

spring, part of the population is known to migrate north through the Bering Strait along

the northwest Alaska coast in the Chukchi Sea and then east into the Beaufort Sea for

the summer. Observations in Russia suggest that part of the population also oversummers there (Bessonov et al., 1990). It is not yet clear if this is a distinct stock but it

seems likely. The wintering area of bowheads that summer in the Beaufort Sea is

6
seasons (1989 - 1991) of tagging North Atlantic right whales, Eubalaena alacialis, (Mate

et al., 1992; Mate and Nieukirk, 1993; Mate et al., in press) under the same contract.

Both bowheads and right whales are members of the right whale family and are found in

areas of proposed, or present, offshore oil and gas development. Because similar

interests and concerns exist in the Canadian Beaufort Sea, this bowhead study received

additional support from the Canadian Department of Indian and Northern Affairs (DINA).

7
intensive study of bowhead dive behavior, almost nothing is known of the depths to which

bowheads can dive, where in the water column they spend their time, and whether their

dive behavior exhibits die variation. The results reported here reveal important

information about the dive habits and underwater depth preferences of bowhead whales.

8
The 1992 bowhead study area was the Beaufort and Chukchi Seas of the

Canadian, U.S., and Russian Arctic (Figure 1). Tags were deployed in the Canadian

Beaufort in order to obtain information on bowhead whale feeding habits during the last

part of the open water feeding season. This also allowed information to be collected along

the entire length of the westward migration from the Canadian Beaufort past Pt. Barrow.

Permits were obtained from the U.S. National Marine Fisheries Service (NMFS)

authorizing tagging activities under the Marine Mammal Protection Act (MM PA) and the

9

Islander twin engine aircraft on 26 August and conducted a modest one-day aerial survey

of the nearshore waters west of the Tuktoyuktuk Peninsula, 40 km east into Amundsen

Gulf, and from the Mackenzie River west to Herschel Island. Under clear skies, with sea

state < Beaufort 2, only three whales were sighted in the peninsula and Gulf regions.

Eleven whales were seen in the smaller area west of the Mackenzie River despite

Beaufort 4 conditions. As a result, we concentrated our tagging efforts in the latter region.

11
duration/depth tags. All parts were (and are) available wfth OSU- specified software and

functions. Few small batteries are able to withstand the pulsed load demand. We used

eight Duracell® 2/3-A manganese dioxide batteries. The batteries were arranged in two

parallel strings of four cells in series with a diode to prevent a shorted cell from draining

both strings. The result was a 12-volt supply with 3400 milliamp hours capacity.

Components were packaged in a stainless steel cylinder (Figure 2). Cylinders measured

189 mm long x 49 mm diameter (duration tags) or 192 mm long x 54 mm diameter

12
ct

p
Attachment

The tag was applied as a projectile. A modified Bamett 68 kg (150 pound)

compound crossbow was used to accurately apply tags at distances up to 8 m. An

aluminum shaft with a C-shaped tag holder fell away after tagging (Figure 3). A bobbinwound, 9 kg (20 pound) test line was used to recover the shaft (and the tag if it missed

its mark).

14

barbs. Thus, the body of the tag would not be resting against the animal's skin. In our

previous experiment with right whales we saw no signs of rubbing damage to the skin

from animals observed up to 58 days after tagging (16 days after tag loss).

Bowhead whales have been observed to break through ice up to 0.6 m thick in

order to breathe (George et aL, 1989). Observations of scarring and abrasions on the

raised area around their blowholes (Albert et al., 1980; Carroll et at., 1987; Nerini et al.,

1984) combined with underlying dense fibrous connective tissue up to 25 cm thick (Henry

16
along the whale's length for the tagger to deliver the tag to the desired spot without

shooting Mforward or to the rear (Figure 5).

A perpendicular trajectory results in the long axis of the tag being parallel to the

whale's long axis, reducing drag to the cross-sectional surface of the tag end. Forward

or rearward trajectories result in an angular tag placement relative to the forward progress

of the whale and thus greater drag. Additionally, the two tines do not start into the whale's

17
I

Va) 00
Figure 5
0000 GMT each day. A software error in the duration/depth tags resulted in one 1-h

summary period, six 3-h summary periods, and one 5-h summary period each day (Table

3).

The saltwater switch measuring conductivity was interrogated to determine if the

tag was submerged. Duration tags interrogated the saltwater switch every 0.25 s and

counted time in 2 5 intervals. Duration/depth tags counted time in 6 s intervals, but

interrogated the saltwater switch, pressure transducer, and temperature sensor at varabIe

20
21
p

CRC

Total Duration Packet Bits

22

6

64
33 m to 48 m 3.6 mm 6 1.7 225.0

49 m to 96 m 3.6 mm 6 1.7 225.0

97 m to 200 m 3.6 mm 5 1.7 110.8

201 m to 400 m 3.6 mm 4 1.7 52.2

401 m to 800 m 3.6 mm 4 1.7 53.2

> 801 m 3.6 mm 3 1.7 23.4

Longest Surfacing 1 mm 6 0.4 62.5

Total Surface lime 1 mm 7 0.4 126.5

Error detection CRC 6

Total Time At Depth Bits 64

23
Dives and surlacings were recorded in the summary period in which they ended.

Each dive was registered in one of eight (duration tags, Table 1) or nine (duration/depth

tags, Table 2) duration bins. The pressure transducer in the duration/depth tags measured

ambient pressure and registered the equivalent depth of sea water in 8-m increments.

Periodically the pressure transducer offsets were automatically reset when at the surface

to correct for any drift in the sensor. Duration/depth tags registered each dive in one of

eight depth bins based on the maximum depth monitored during the dive (Table 2). The

24
> 40 s since the last transmission. Normal duration/depth tag transmissions included four

of the six data packets from the two previously completed summary periods on a rotating

basis (Table 2). After 15 transmissions duration/depth tags transmitted a special status

packet that included total number of transmissions, battery voltage, surface water

temperature, and pressure transducer offsets.

Transmissions were triggered by the tag's conductivity sensor (saltwater switch).

A 400 mW signal was transmitted at 401.650 MHz for either 0.440 s (duration tags) or

25
location class (LC) 0 to 3. A location can be calculated from as few as two transmissions,

but the accuracy of such a location is unknown (LC 0). Argos estimates that at least 67%

of the locations classified as LC 1, 2, 3 are within 1000 m, 350 m, and 150 m,

respectively, of the true position (Table 4). In our laboratory (terrestrial) experiments and

the field experience of others (Stewert et al., 1989; Harris et aL, 1990; Keating et aL,

1991) a lower percentage of locations met these distance criteria than are claimed by

Service Argos. Most difficult to interpret are the location class 0 locations. These have no

26
latitudes greater than 750 and as few as six orbits/day along the equator (Figure 6). In the

Arctic area inhabited by bowheads, an average of 24 passes were available to receive

bowhead data daily. Satellites must be within a clear iine-of-sight to transmitters to

receive messages. From a fixed point on earth, the satellites move from horizon to

horizon in 8 - 15 mm and are within reception range of a transmitter for an average of 10

mm during each pass. In 1992, Argos charged $12/day for the number of days it collected

data for each transmitter.

27
Data Screeninq

Locations

Each location was plotted using CAMRIS® software on an IBM-based PC.

Shorelines and depth contours were digitized into CAMRIS® from either NOAA chart

#16003 or U.S. Defense Mapping Agency chart #15026. Locations were eliminated when

they were either: 1) conspicuous'y on land (more than 5 km inland allowing for ambiguity

in Argos 'ocations nearshore), or 2) resulted in minimum speeds 25 km/h between

28
locations). In fact, the edit criteria actually also proved disadvantageous to the more

frequently transmitting duration-depth tags in that locations which were determined within

a few hours of each other sometimes produced high swimming speeds due to a lack of

accuracy in one or both locations. When applying the editing criteria, we looked at the

effect of eliminating either of the locations which resulted in a high swimming speed for

its ripple effecr on adjacent speeds. Our overall intent with the editing criteria was to

eliminate locations which were so erroneous as to result in unreasonable speeds. All

29
Because duration tags reported the time submerged in increments of 1.8 mm, we

added halt of that increment (0.9 mm or 0.5% of the period) to the reported value to avoid

a consistent downward bias.

For duration/depth tags, the number of dives in a period came from the duration

packet, the depth packet, or both (Table 2). For periods where duration/depth tags

reported both the duration packet and the depth packet, the minimum and maximum

number of dives in each packet were compared to obtain the smallest possible range of

30
Figure 6. Representation of a NOAA TIROS-N satellite in polar orbit receiving

transmissions from whales.

31
Canada's Ice Centre Ottawa and/or satellite images collected at the Anchorage branch

of the U.S. National Weather Service.

Statistical Methods

Statistical comparisons were made with parametric tests when possible. Data were

log-transformed for parametric tests where appropriate. Mean, standard deviation, and

sample size are reported. When data were log transformed, geometric mean and 95%

32
have trouble tagging whales once we found an advantageous circumstance in the shallow

waters of the Mackenzie Delta. Experience since the bowhead tagging with blue whales

and humpback whales, suggest that open water tagging of larger animals in deeper water

would likely also be feasible for bowhead whales but may require a little time to develop

suitable approach techniques.

33
a sudden roll by the whale in response to the close approach by the boat.

Transmitter Performance

Transmissions were received from all 12 tags. Locations were calculated for eight

whales, and valid sensor information was received from 11 tags (Table 6). Position of the

tag on the animal critically affected tag performance. Few transmissions, and

consequently little or no data, were received from four tags (Table 6). Three of these tags

34
y g

satellite when they did. The reasons for poor performance by tag 10822 are unknown.

On the basis of battery capacity and estimated number of transmissions, we

predicted a functional life of transmitters to be 30 days. Tags were monitored from 4 to

49 days after tagging (Table 6) for a total of 211 days. The best longevity was from a tag

which was poorly positioned (10829) and was heard from only five times. Each contact

was a single message, so no locations were ever obtained. The long battery life was

likely due to the very infrequent use of power for transmissions. Of six tags with utihty

35
locations. Those that remained met editing criteria which allowed for 25 km/h travel, which

we consider a reasonable upper limit for any extended period of time. Thus, animals

which had few locations per day may be most suspect. The 384 screened locations plus

the tagging locations accounted for 111 days of tracking over a distance of 9565 km

(Table 8). Individual whales were located from 6 to 204 times over 3 to 33 days and

traveled from 70 to 4053 km. There was a significant correlation between the number of

days tracked and the distance traveled (r = 0.80, p = 0.016). The number of locations per

36
*Time 

Table 6. Tag 

Tag 

108108108108108108108108108108

008008Tot
Table 7

=

' Batte

00 
39

10827 35 20 9 0 0 64

10828 15 4 2 0 11 32

10830 30 6 0 0 6 42

828 10 0 0 0 0 10

831 14 0 1 0 1 16

Total 255 86 22 7 22 392
were LC 1. Only 29% of this whale's locations survived screening criteria (Table 8),

resulting in 1.7 locations/day and dramatically reducing the whale's overall distance and

average speed (1.0 km/h). All locations were in water < 20 m deep and no ice was

encountered by this animal.

Whale 828 traveled at least 619 km during 23 days between the tagging site and

nine LC 0 locations (5 = 0.4 locations/day). Sixty percent of satellite-acquired locations

survived editing (Table 8) and all of these were within 185 km of the tagging site (Figure

40
percentage of locations after editing (79%) and averaged 5.7 locations per day (Table 8).

The whale's locations were in water 10 to 200 m deep. 01 63 satellite-acquired locations,

eight were LC 1, all the rest were LC 0. After spending several days west of Herschel

Island in depths <50 m, this animal moved east into waters with depths of 50 to 200 m

at the head of Mackenzie Canyon with a short excursion back into Mackenzie Bay. The

difference in water depth between the west and east side of Herschel Island make these

two regions quite different. This wha'e was never located near any ice.

41

43
period the animal went to Herschel Island, returned to Mackenzie Bay, went northwest

toward the shelf break off Demarcation Bay, then inshore to Demarcation Bay for three

days before moving back offshore and east to Mackenzie Canyon into water > 300 m

deep. Prior to the Canyon, all locations were < 50 m deep (89% of all locations). All

locations were LC 0 and only 45% survived screening criteria (Table 8). Nonetheless,

there was a big difference in the rate locations were acquired in specific areas. Nearshore

by Demarcation Bay, 11 locations in 52 h ( = 5.1 locations/day) were received. During

44

Ic'J

were three LC 1 and three LC 2 locations, all in shallow (<50 m) water. LC 1 locations

occurred once in Mackenzie Bay one day after tagging and twice very close to shore at

Demarcation Bay. The three LC 2 locations occurred within eight hours while traveling

north in water 20 to 50 m deep in Mackenzie Bay eight days after tagging. As with whale

10828, contact was lost in the deep water of the Arctic basin where speeds were higher

than average and ice was encountered by both whales. The last five locations were in ice

cover of 50%, 20%, 40%, 70% and 40%, all on 14 September.

48
Figure 12. Track of whale 10830.

49
described here is not accurate. All LC 0 locations for this animal (and all others with very

few daily locations) are more prone toward err than those that have more locations/day

because the editing criteria do not provide as strong a basis for editing locations.

After three days in Mackenzie Bay, whale 831 went northwest through Mackenzie

Canyon and then west (north of Herschel Island) to an area between Herschel Island and

Demarcation Bay before heading offshore to water > 500 m north of Demarcation Bay.

From 18 to 21 September, the whale was in 20 - 50 m water moving west across

50

ice observations at the site reported 'arge first and multi-year ice floes were adjacent to,

or over, the Kuvlum site (Brewster et al., 1993). With the exception of the Kuvlum drill

site, ice cover from day nine until the end of tracking was 30% until the most westerly

location at 150°W which was 90+% covered.

Whale 10824 was tracked farther (4053 km) and for a longer period (33 days)

than any other whale (Figure 14). Of 277 satellite-acquired locations, 203 (73%) were

retained, providing 6.2 locations/day and an average speed of 5.1 km/h, the second

52
72°N latitude to within 30 km of Wrangell Island; then south 150 km to within 175 km of

the Siberian coast. This is the first record of the detailed route and speed of migration for

a bowhead from Canada to Russia. The route in the U.S. Beaufort Sea was quite similar

to the highest density of bowhead sightings (Figure 16) from pooled aerial survey data

from 1979 to 1989 (Moore and Reeves, 1993).

Ice was encountered by whale 10824 in several areas: 30% at its most northern

Mackenzie Canyon location; 40% from Demarcation Bay to Pt. Martin; 30 to 80% in

53
= 

Figure Moore 

eg U'
locations> LC 0 in the Chukchi occurred along the edge of this feature.

There were 26 locations> LC 0. Sixteen of these (62%) occurred east of 151°W

in open water or light ice cover and 10 (38%) occurred west of 151 °W in 90+% ice cover.

Most locations > LC 0 were acquired where many locations were clustered (Figure 16)

and the whale traveled at speeds < 5 km/h suggesting periods of milling or feeding

behavior. Even if LC 0 locations were eliminated, the remaining higher quality locations

(Figure 18) would describe the route west of Camden Bay (Figure 14) reasonably well.

57
g

unbroken ice. The dorsal surface of the head is highly arched with the blowhOles

at the apex of a high promontorY, over which the ice is lifted and cracked apart for

access to air (George et ci. 1989).

58

instead of eight whales traveling 9633 km over 111 tracking days at a mean speed of 3.4

km/h, five whales (63% less) wou'd have covered 2766 km (71% less) in 63 days (57%

less) at 1.8 km/h (53% less). For whaJe 10824, such an analysis would result in a 55%

shorter track (1843 km) and slower average speed (2.3 km/h).

60
off position by 16 September due to heavy ice and did not resume drilling operations until

24 September (Brewer et al., 1993). The KULLUK was forced off-station by massive floes,

at least one of which became grounded to the west. Winds during the time period were

basically out of the west at 31 knots and the ice tended to drift toward the southeast.

During this time, up to three ice breakers were involved in ice management activities at

and near the site. Most important to the overall consideration, however, is the accuracy

of the whale locations and their proximity to the operations. While referring to Appendix 2

61
h of travel. This graphically depicts how 'generous' the editing criteria are and how it is

ineffective in helping to define the location of widely spaced (in time) individual locations.

Thus, we have no confidence in placing accuracy bounds or limits on any of the individual

points for whale 831 with the exception of three locations. One was .6 of an hour after

tagging and a pair of locations on 14 September which were 1.4 hours apart. Therefore,

we cannot estimate how close whale 831 came to the Kuvlum site.

62
higher quality locations would be important. Tags should also transm it frequently enough

to obtain locations from many orbits and thus provide clusters of locations where

additional confidence in the whales' activities could be assured. Concurrent acoustic

measurements in the vicinity would be necessary to determine the levels of noise to

which whales were exposed if the potential affects of acoustic stimuli on whale trajectory

are to be evaluated.

63
Beaufort Sea is low due to the stable Arctic Surface Layer and ice that prevents wind

mixing and advection of nutrients into the euphotic zone (Niebauer and Schell, 1993).

Productivity is especially low in the Mackenzie River plume where the high turbidity of

fresh water from the Mackenzie River limits sunlight penetration (Grainger 1975). Few

bowheads were seen in the Mackenzie River plume and zooplankton sampling confirmed

the low biomass there (Bradstreet and Fissel, 1986; Bradstreet et at., 1987; Thompson

et al., 1986). Several processes that increase productivity or concentrate zooplankton in

64
1986; Richardson, 1987; Cubbage and Calamobokidis, 1987). Additional sex and age

segregation may exist (Koski et al., 1993; Zeh et al., 1993), but these distributions are

thought to be variable both between and within years (Davis et al., 1983). According to

size distributions (Koski et al., 1993) tagged whales in this study were yearlings and subadults, none were considered sexually mature.

Moore and Reeves (1993) have summarized the distributions of whales in the

general vicinity of the Canadian and U. S. Beaufort Sea. Their observations coincide

65
days offshore from Demarcation Bay at the shelf break. Two whales spent 2.5 days

nearshore between Demarcation Bay and Barter Island. There was a tendency for whales

to revisit these areas. Six of eight whales (75%) changed travel direction rather than

simply moving from east to west during the late summer. The two whales (10826 and

828) which never left the Mackenzie Bay/delta represent 12 of the 34 whale-days (35%)

spent in that area by all whales. The time spent in these areas and revisitat ions lend

66
67


pair were observed to move 85 km east in two weeks in August 1980 (Würsig et al.,

1985). During photo-identification studies near Herschel Island in August 1982, 13

individuals were observed to move an average of 31 km in five days (Davis et al., 1983).

The two longest movements recorded were 154 km in five days and 147 km in 13 days.

Richardson et al. (1987) also documented movements of photo-identified bowheads in

1985/1986. Times and distances between successive resighting of individuals were

generally short (2 - 24 km over periods of 2- 11 days for seven whales in 1985, and 1 -

70
identifiable marks and react less to aircraft, so it may be easier to re-identify adults than

juveniles (Davis et al., 1983; Rugh 1990). The fact that juveniles were resighted more

often and over longer periods than adults suggested that adults were migrating through

the area. The time between first and last sighting of juveniles were taken to be minimum

residence times (Richardson. et at., 1987). Similar conclusions about residency times of

right whales in the Bay of Fundy proved erroneous; satellite-monitored radio tagging

studies showed animals making long range movements and returning to the region

71
contour, and one moved along the 20 m contour. All individuals crossed the

U.S./Canadian border between 21 to 25 September. Our observations suggest that

animals moved at a relatively uniform pace once they had passed 145°W longitude. Prior

to that time it was not uncommon to see animals stay in one area for one to three days

and then move up to 160 km in a single day to another region. Migrating whales moved

between 80 and 150 km per day in ice-free areas. One of the whales radio tagged by

72
particularly important and novel through the Chukchi Sea where far offshore logistics

constraints, cost, and weather have limited how much could be learned from conventional

aerial and shipboard surveys in the fall. Moore and Clarke (1990) speculated that there

were two travel routes west of Pt. Barrow, one north and one south of 72° N. The authors

admitted that the northerly line was drawn without a statistical basis but it fits the track

of whale 10824 reasonably well. It is extrem ely hard to estimate what proportion of the

population may travel each of these routes as the opportunities to observe both routes

73
and Smithhisler, 1980; Bums et al., 1981; George et al., 1989), but bowheads dying in

the ice have also been documented (Philo et al., 1993). Many of the differences we

observed in sensor data we believe are attributable to the animals' change in breathing

habits in moderate to heavy ice. Many animals lost their tags shortly after encountering

reasonably moderate ice but it is unknown whether ice contributed to the early loss of the

tags.

74
(Bessonov et al., 1990; Bogoslovskaya et al., 1982). The movements of animals in these

regions may be appropriate problems to study with satellite-monitored telemetry where

conventional telemetry or survey data would be impossible, inefficient, or too expensive.

PART 3: DIVE AND SURFACING BEHAVIOR

Some valid sensor data were received for eleven of the twelve tagged whales

(Table 9). Logical consistency checks invalidated some depth-related information in a few

75
duration of the longest dive or the first dive to maximum depth overflowed ( 61 mm)

were not included in this analysis (see discussion under dive duration data below).

Summary period length did not affect the number of dives per hour, the percentage

of time submerged or at the surface, the log-transformed average duration of sounding

dives, the duration of the first dive to the maximum depth, or the maximum depth reached

for any of the six tags, p-value > 0.1 for period length coefficient and p-values > 0.05 for

76
extensive ice cover (see section on ice cover under environmental variables). Extreme

outlier values for three summary periods (Figure 22) explain the departure from normality

for tag 10830. Exclusion of these three periods from the analysis below did not

significantly alter the dftferences in mean surfacing rates among individual animals.

Interestingly, these three summary periods composed one seven-hour block: periods 1-3

on 13 September. It seems this animal was engaged in distinctly different behavior during

this 7-h interval than during the other 197 hours that surfacing rate was monitored. The

77

high blow rates (WOrsig and Clark, 1993).

The mean surfacing rate ranged from 1 8.2/h for tag 10825 to 47.0/h for tag 828.

There were significant differences in the mean surfacing rates among the eight animals

(ANOVA, F7 = 21.5, approximate p-value << 0.0001). Because the assumption of

equal variance was not met, the p-value is approximate, but results from a non-parametric

test (Kruskal-Wallace ANOVA by ranks) confirmed the differences in surfacing rates

among tagged whales. The mean for tag 828 (47.0 surfacings/h) was significantly higher

79
procedures used. Method 1 divides the total number of blows during a series of surfacingdive cycles by the total duration of those cycles (Sumich 1983; WUrsig et al., 1986).

Method 2 consists of calculating a blow rate for each surfacing-dive cycle and calculating

a mean for the number of surfacing-dive cycles observed (Würsig et al., 1984; Dolphin

1987a, 1987b). Dorsey et al. (1989) reviewed the two methods and concluded that

method 1 gives a better estimate of overall blow rate because method 2 can give biased

results because each cycle is weighted equally regardless of its duration. Method 1 can

80
(Table 11).

Any or all assumptions may be violated during any given summary period. If

assumption 1 was violated, blow rate for the period was overestimated. If assumptions

2 or 3 were violated, blow rate for the period was underestimated. Without extensive

follow up observation of tagged animals, a quantitative evaluation of bias in our sampling

method is not possible. However, our sampling method was more likely to underestimate

than overestimate blow rates because violations of two of the three assumptions result

81
=
Data on dive durations were reported from nine tags (Table 6). A total of 42,332

dives in 566 summary periods were reported. Overall, 77.3% of all dives recorded were

1 mm or less, and 1.4% were greater than 19 mm. Distribution of dives in the duration

bins was highly skewed for every tag that returned data for more than one summary

period, with most dives being one mm or less (Figure 23). Dives 1 mm comprised from

64.0% (tag 10826) to 82.9% (tag 828) of the total number of dives recorded for each

83
00 
U' '
analyses because the duration of the longest dive was unknown (overflow value 61 mm

for durations/depth tags). Summary period values for all animals combined ranged from

2.6 to 30.4 mm ( = 10.5 ± 4.6 mm, n = 536). Mean values across periods for individuals

ranged from 6.9 ± 3.0 mm (n = 19) for tag 10826 to 14.1 ± 4.6 mm (n = 41)for tag 10825

'E(# caves m iration bin * mid-pornt of the bin W(total # of soundng cves). For caves in the longest bin (>19 mm for raion

gs, >25 mm fo iratioru/depth tags) the ciration of the longest dye (and the first dye to maximum depth to iration/depth

tags) was known and used m the cacuIation. Subsequent thes m this bin were muftiplied by the mid-point between the longest

cive and 19 or 25 mm, respectivety.

86
Duration Bin

Figure 24.. Distribution of dives in duration bins for tag 10822.

This tag returned data for only one period. Duration bins are same

as in Figure 23.

87
88
N- 0'7 N- 

' (0 ' C

' 

C

'- 

A 

.EE 

FIg

ta

- 

F

t
1 0' N

('(

00

F

t


a surfacing sequence, we expect these dives to comprise 69 - 92% of all dives. Seven

of the nine tags returning dive duration data fell within this range.

Two tags fell below the expected range. Tag 10822 returned only one period of

dive duration data in which 33.3% of its dives were 1 mm. The longest submergence

in the period was 61 mm. Consequently, the data returned from this tag may be suspect

(see discussion of longest submergences below). During the 19 periods tag 10826

returned dive duration data, 64.0% of the 1455 dives recorded were 1 mm. This tag

97

blows, its mean blow rate (0.42 blows/mm, the median value for all of the tagged whales)

would be an underestimate. Finally, this whale may have utilized a different respiration

strategy than other animals: short sounding dives, more surfacing sequences with fewer

bbws per surfacing sequence. The lack of long dives is consistent with this hypothesis.

Of course, these are not mutually exclusive explanations. The slightly lower than expected

percentage of short dives recorded by this tag could result from a combination of these

behaviors.

99
mean dive times were shorter for animals socializing in shallow ( 50 m) water (2.65 ±

3.82 mm, n = 94) than for whales feeding in deep water (11.05 ± 9.95 mm, n = 43) or

migrating in fall (14.56 ± 8.62 mm, n = 42).

The average duration of sounding dives for individual bowhead whales tagged in

this study varied greatly across summary periods. The range of values reported by most

animals (Figure 33) was greater than the range of mean dive times reported in the cited

studies (Table 10). This demonstrates tremendous plasticity in dive behavior. Close

100
The distributions of the longest dive duration during periods for duration/depth tags

(when n> 1 period) which returned more than one period of data are shown in Figure 34.

These distributions show all summary periods reported (1, 3, and 5 h) including those with

overflow ( 61 mm) values. The longest dive in the one period of duration data from tag

10822 was 61 mm. Figure 35 shows the distribution of longest dive durations, including

underi low (< 12 mm) values, for duration tags.

101

0 10 20 30 40 50 60

duration (mm)

Figure 35. Frequency histogram distributions of longest dive duration in

summary periods for durations tags. Unshaded bars indicate underfiow

values (< 12 mm).

103
be biased upward since all signals may not be received during a surfacing sequence, but

the bias should be relatively small compared to the duration of the dive. During our

tagging operations we stayed with a tone bowhead whale for approximately four hours.

We had good sighting conditions, winds of less than 22 km/h (12 kts) and good visibility,

with the captain and three experienced observers to spot the animal when it surfaced.

Most of the long sounding dives we observed were between 18 and 22 mm. The longest

104
expose their blowholes or break ice to breathe. Given these circumstances, tags would

register longer and fewer dives than actually occurred. Surfacing behavior in ice cover

could explain some of the very long dives recorded. To investigate this hypothesis we

examined predicted ice conditions at the Argos determined locations of tagged whales.

Of the 31 periods where the duration of the longest submergence was 61 mm,

25 (80.6%) were reported by tag 10824. Twenty-three of the 25 periods were recorded

in the Chukchi Sea during late September where ice cover was predicted to be 90%,

105
recorded were longer than 19 mm. Eleven of these (73.3%) took place in the three

summary periods received for 29 September. In only four (12.1%) of 33 summary periods

was the duration of the longest dive longer than 30 mi Three of these periods occurred

on 29 September when the animal was in ice cover 90%: a 56 - 58 mm dive in period

2; a 30 - 32 mm dive in period 4; and a 62 - 64 mm dive in period 5. No location was

determined during the other period with a submergence longer than 30 mm. However,

106
D
possible that resting bowhead whales would not expose the tags to the surface for over

an hour. However, these three animals first reached the maximum depth for the period

(56 - 71 m for 10822, and 8 - 23 m for 10825 and 10827) during the 61 mm

submergence so they could not have been resting at the surface the whole time.

Overall, 91.5% of the longest submergences reported in 566 summary periods

from nine tags were less than 41 mm. In summary, we are unable to conclude whether

108
included in the calculations and analysis presented here. This biases our mean values

for the longest dive duration downward for five of the six animals considered. The bias

is important only if these are indeed real dives and not artifacts of surfacing behavior.

Because the longest dive recorded during a period was significantly affected by

summary period length, comparisons between animals was done for periods of equal

length. Data were log transformed. For 3-h periods (the largest sample sizes) there were

significant differences in the geometric mean of longest dives among the six individual

109
110

1hour periods 3hour periods 5hour periods

mm n mm n mm n

10826 9.8 2 11.3k 14 15.0 3

10827 13.5 8 162b 62 22.4 7

10830 13.8 7 16.9 49 17.2 7

10824 13.2 24 18.1 152 18.9 21

10825 16.2 5 20.3 32 20.9 4

10828 15.4 7 20.r 42 22.4 8
maximum depth during the summary period, a regression analysis was performed for

each tag. The 38 summary periods with 0 or 61 mm durations for the first dive to the

maximum depth were not included in the following analysis. Duration significantly

increased with the depth of dive for five whales, but the linear model explained less than

half of the variation around the mean in all cases (Figure 37). One outher value strongly

influenced the analysis for tag 10830 (Figure 37). A significant positive relationship was

still found if the outlier was excluded from the analysis (p-value = 0.03).

111
20

V 10

0

20

10

0

0C)( 001 00010010(710 0000000 0 0010010010 0000000

depth (m) depth (m)

Figure 37. Regression plots of duration vs depth for the first dive to the maximum depth

reached during the summary period.

112
duration are positively correlated for many air breathing aquatic animals in the wild.

Examples include leatherback sea turtles, Dermochelys coriacea (Eckert et al., 1986),

cormorants, Phalacrocorax sp. (Stoneho use 1967), penguins, Aptenodytes patagon icus

and Pygoselis papua (Kooyman et al., 1992; Williams et al., 1992), fur seals, Callorhinus

ursinus and Arctocephalus pusillus (Gentry et al., 1986; Kooyman and Gentry, 1986),

California sea lions, Zalphus califomianus (Felkamp et al., 1989), beluga whales,

Deiphinapterus leucas (Martin and Smith, 1992), narwhals, Monodon monocerus (Martin

113
percentage of dives in the period to each of the depth bins for the six tags that returned

depth data for more than one summary period.

Deepest Dives

Maximum depths reached during a summary period ranged from <8 to 455 m

(Table 13). The deepest dive was < 153 m in 428 (91.5%) of the 468 summary periods

reported by all nine animals. Seven tags reported dives > 100 m; three tags reported

114
Several tagged whales (10824, 10827, 10828, 10830) showed a secondary peak

in the overall number of dives to between 48 and 96 m or to between 96 and 200 m (tag

10825, Figure 44). Time series graphs of the percentage of dives to each depth bin by

period (Figures 38 - 43) reveal that the higher frequency of dives to a specific depth bin

resulted from bouts of repeated dives to that depth regime during relatively few of the

periods monitored. For example, animal 10825 reported dive depth information for 44

summary periods, but all dives deeper than 48 m were recorded during only four periods:

115
indicate were possible. For instance, tag 10826 recorded a dive to 128 m, but all location

fixes for this whale were in shallow (<20 m) water. In this case, sensor malfunction

seems most likely. Sometimes the discrepancy may be attributed to the uncertainty

associated with Argos-determined locations. Most Argos fixes obtained were of unknown

116
nax

aci) 

o 

c

Cl) 

- ci)--J 

0 

F

GBS0H
iiiax

E 0) 

C 

Cl) 0) > 

G

BS
ma

-- 

B

aci

Ua> 
m

- o

5 

BS
m

--

0 
ma

.E I 

i

F

G

B

S

0 5 10 15 20 25 30 35 40

% of period exposed to air

Figure 45. Percent of period tags were exposed to air. Sample size (n) is number

of summary periods.

124
Tab

ta10111111010

10
these depths and beyond.

Surface Time and Time Underwater

Total Surface Time During Summary Period

Two tags (10820 and 10831) reported time spent at the surface information for

only one summary period each. Both tags were placed low on the animaIs body and

probably didn't come out of the water on most normal surfacings. Both tags recorded

126
considered in the statistical comparison of individuals. There were significant differences

in the percent of a summary period at the surface among the remaining eight individual

animals (Kruskal-Wallace ANOVA by rank, p << 0.0001). Multiple comparisons between

indMdual animals (a =0.05, Bonferroni method, Hettmansperger, 1984) revealed two

groups: three animals with the lowest surface times and five animals with the highest

127
Longest Surface Durations

Although the resolution was different, both types of tag recorded the longest

duration at the surface for each summary period. Whales rarely exposed the tags to the

air for very long. Neither duration tag was exposed to the surface for even 3 mm (Figure

46) at one time. Four duration/depth tags (10824, 10825, 10827, and 10828) were

exposed to the air 3.5 mm or longer (Figure 47). This occurred in only five (0.89%) of the

128
periods).

Few published reports for bowhead whale surface time are comparable to what our

tags collected. As migrating bowheads passed Pt. Barrow in the spring, some exposed

part of the body was visible to ice-based observers for 3.1% (Carroll and Smithhistler,

1980) and 5.2% (Zeh et al., 1993) of the time. Means for time visible above water during

each roll in a surfacing sequence during spring migration were 4.7 s (Carroll and

Smithhistler, 1980; Zeh et al., 1993) and 6.1 s (Rugh and Cubbage, 1980) with the

129
(Leatherwood et al., 1982; Zeh et al., 1993) and has been used to calculate correction

factors for bowheads missed during surveys (Davis et al., 1982; Richardson et al., 1987).

Because of the advantages of aerial surveys, the motivation to develop unbiased

estimators of abundance for this technique has been strong (Hiby and Hammond, 1989).

Many observational studies (Carroll and Smithhistler, 1980; Dorsey et al., 1989;

Richardson et al., 1987; Würsig et al., 1984; Zeh et al., 1993) report the proportion of

time bowheads were potentially visible from the air. Like mean blow rates, the methods

130
131

E

10

0 I I I I I I I I I I I I I I I I 01 23456789101112131415

longest surface duration (mm)

Figure 46. Longest surfacing during summary periods for duration tags.
20

40 Tag 10830 n6lperiods

0 I I I I I I I I I 01 23456789101112131415

surface duration (mm)

Figure 47. Longest surfacing in period for duration%depth tags. The first histogram

bin is half the size of other bins and represents surfacings < 0.5 mm.

132
difference would be small. Based on these calculations, tagged animals were potentially

visible from the air between 0.9 and 42.1% of a summary period (n = 539 periods for

eight animals). Mean percent of summary period visible from the air for individuals ranged

from 8.5 - 16.4% (i = 11.1 ± 2.4%, n = 8, Table 15).

All the calculations above assume whales to be visible from the air between serial

dives during a surfacing sequence, but not before or after a sounding dive. In the field,

the depth to which whales dive and environmental conditions such as water turbidity, sea

133
frequently spent substantial portions of summary periods in one of the deeper depth bins.

Four animals (10824, 10825, 10827, and 10828) spent more than half of some periods

at depths > 48 meters.

During periods 4 through 8 (17 h) on 10 September, tag 10825 spent an average

of 70.6% (sd = 5.6, n =5, range 61 - 78%) of each period between 96 and 200 m (Figure

50). Dive depth information was reported only for the middle three of these five periods

where the maximum depths reached were: 128, 160, and 144 meters. This animal was

134

-

C.' 
137

CLU 0) 0c 

,E
CU

o

E 

o 
C 0a 

c a E

0 

c E 

.00 
Canyon. For 6 h on 9 September, whale 10828 spent most of periods 2 and 3 deeper

than 96 meters. During period 2 its time was split nearly equally between the 97-200 m

bin (30%) and the 201-400 m bin (26%). During period 3, however, 62% of its time was

spent in the 201-400 m bin and only 8% in the 97-200 m bin. The deepest dive in this

period was between 248 m and 263 m. This animal may have continued to spend

substantial time at these depths, but no time-at-depth data were received for the next

three periods (4 - 6). This was especially unfortunate because the deepest dive (440 -

144
(84.7%) occurred after 20 September when whale 10824 encountered heavy ice

conditions.

This is the first detailed information about where bowhead whales spend their time

in the water column. Animals favored certain depth regimes for extended periods. Feeding

is believed to be the predominant activity for bowhead whales summering in the Beaufort

Sea (Würsig et al., 1985). Bowheads feed primarily on zooplankton, especially copepods,

euphausilds, and mysids (reviewed by Lowry, 1993). Bowheads likely spend time in the

145
al., 1984; Maclellan 1967; Prygunkova 1968; Pertsova 1971 cited in Arashkevich and

Kosobokova, 1988). Q. hyperboreous and C. alaciatis that have descended to deeper

water in summer have substantially greater lipid content than those near the surface

(Head and Harris, 1985; Kosobokova 1990) and would be a high caloric food source for

bowheads. Although we can offer no direct proof, we suspect that animals 10825, 10827,

and 10828 were feeding in the water column or near the bottom on dense zooplankton

14(5
The whale first encountered ice covering more than half the water's surface on 15

September. Location fixes for the next four days put this animal in water with 30 - 80%

ice cover. From 20 September to 5 October, the whale was probably in 90% ice

cover. Irnplications of time at depth data for this animal are discussed in the section on

ice below.

147
For most animals, we found no significant differences in the log transformed

average duration of sounding dives between day, night, or twilight periods (ANOVA pvalues > 0.05). However, average sounding dive duration did differ significantly with light

level for two tags: 828 (ANOVA F2 = 7.14, p-value = 0.003) and 10830 (AN OVA F2

= 4.30, p-value = 0.018).

Although day and night periods did not differ significantly for tag 828, the geometric

mean of the average duration of sounding dives during twilight periods (12.3 mm, 95%

148
than for twilight periods (geometric mean = 8.0 mm, 95% Cl = 6.8 - 9.4, n = 14). Daylight

summary periods had intermediate average sounding dive durations (geometric mean =

10.0 mm, 95% Cl 9.0 - 11.1, n = 33) and did not differ significantly from either night or

twilight periods.

For many air breathing nekton species, diel changes in dive behavior have been

linked to diel vertical migration of their prey. Examples include leatherback sea turtles,

Dermochelys coriacea (Eckert et al., 1989), king and gentoo penguins, Aptenodytes

149
comparisons of variables in different ice conditions. Unfortunately, the effect of ice cannot

readily be separated from changes in behavior that may be related to migration. From 20

September until the last transmissions received on 5 October, Argos locations indicate

animal 10824 was in waters where ice covered 90% or more of the surface. We

compared data for periods when ice cover was 90% or more (heavy ice) with data for

periods when ice cover was < 90%. Sensor data recorded dramatic and significant

differences in the behavior of this animal in heavy ice conditions.

150
was heavy, on average, tag 10824 recorded half the number of short dives per hour (

= 12.7 ± 6.9/h, n = 122 summary periods) that were recorded for periods before 20

September when ice cover was light (i = 25.4 ± 6.9/h, n = 100 summary periods). This

difference was significant (Students t-test, t = 13.7 on 220 dl, two-tailed p-value

<<0.0001). Although the mean rate (#/hr) of short dives was significantly less for periods

with heavy ice conditions, the overall proportion of short dives declined only slightly:

79.5% of 11,621.5 dives recorded in duration bins (n = 122 summary periods) were mm

151
(13.2 mm) was 1.7 times longer (95% C.l. 1.6 - 1.9 times) than for periods before 20

September (7.7 mm). The difference was significant (Student's t-test, t = 13.1, df = 195,

two-tai'ed p-value <<0.0001). Twenty-three (92%) of 25 periods where the duration of

the longest dive was 61 mm (overflow value) occurred when ice covered at least 90%

of the surface. The median duration of the longest dives was significantly longer in heavy

ice conditions than in lighter ice for all period lengths (Mann-Whitney U test, Z = 3.71,

8.53, and 2.95, df 24, 168 and, 24 for 1, 3, and 5-h periods respectively, two-tailed

152
spent in the other three depth bins to 96 m were also significant (Mann-Whitney U test,

Z = -3.63, 4.7, and 8.9 on 221 df for % time 17 - 32 m, 33 - 48 m, and 49 - 96 m

respectively, p-values <<0.0001). This animal spent less time in the two shallow bins (the

upper 32 m) and more time in the next two deeper bins (from 33 to 96 m) in heavy ice

conditions (Figure 56).

Statistics cannot establish cause and effect in this study, but data returned from

this animal in heavy ice cover ( 90%) were significantly different than when less ice was

153
Smithhistler, 1980; George et al., 1989). WUrsig et al. (1984) noted longer dive times and

more blows per surfacing for whales in ice than for those in open water. About 75% of

the animals observed in ice rested quietly when at the surface. Richardson et al. (1995)

reported significantly shorter dive times for bowheads migrating through areas with 65 -

90% ice cover in fall 1983 (5.5 mm) than for whales migrating through areas with < 10%

ice cover at the same time of year in 1985-86 (18.2 mm), but noted that the 1983 dive

times were probably biased downward by the difficulty of resighting animals in heavy ice

154
123456789

duration bin

Figure 55. Frequency histogram of dive durations for whale 10824 in ice

cover < 90% (3-19 September) and 90% (20 September to 5 October).

155
2
how bowheads navigate through areas of heavy ice. Bowheads migrating under a frozen

lead where the water was 30 m deep avoided an area of deep-keeled multi-year ice and

left bottom sediments in and around the hummocks created where they broke 14 - 18 cm

newly formed ice to breathe (George et al., 1989). Traveling at greater depths may allow

bowheads to travel more directly through areas with deep keeled ice. Ellison et al., (1987)

suggested that bowheads could use the differential surface reverberations of their calls

(at distances of 1 to 2 km) to discriminate between areas of rough bottomed, deep

157
reasonably reliable and getting smaller. Because drag is probably a major contributing

factor to tag loss, reducing tag size will be helpful. When tags are small enough to be

implantable, longer operation may be expected. An external antenna will still be needed

so controlling infection at the transcutaneous site will be important. Battery life for tag

performance in this study was a limiting factor and is a special problem in cold Arctic

temperatures. Battery capability is related to size and thus places limits on reducing tag

size. Battery technologies are unlikely to change dramatically in the near future. The use

158
movements in areas far from shore which might be important for feeding but difficult to

reach for tagging.

Tagging bowhead whales in the late summer or early fall in Canada could

provide more information about feeding habits and range, as well as movement west

through proposed oil and gas lease areas in both Canadian and U.S. waters.

Tagging near Pt. Barrow in the fall could: 1) determine the routes animals use

to move west across the Chukchi Sea and south through the Bering Strait, 2) further

159
healing which are desirable for long-term attachment. Transcutaneous sealing

technologies have been developed for humans and may prove useful to extend

implantable tag longevity.

The dive behavior of tagged bowheads suggests several areas where

zooplankton sampling at depths below 50 m in late sumrner and early fall would be

worthwhile. Mackenzie Canyon, the shelf break, and the Chukchi Sea were the sites of

160
161
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Pages 369-415 in W. J. Richardson, ed. Importance of the eastern Alaskan

Beaufort Sea to feeding bowhead whales, 1985-86. By LGL Ecological Research

Associates, Inc., for U.S. Minerals Management Service, Anchorage,

AK 547 pp. (NTIS PB88-150271/AF).

Schell, D. M., S. M. Saupe, and N. Haubenstock. 1989a. Natural isotope abundances

in bowhead whale (Balaena mysticetus) baleen: markers of aging and habitat

usage. Ecological Studies 68:260-269.

171
ed. Importance of the eastern Alaskan Beaufort Sea to feeding bowhead

whales, 1985-86. Report by LGL Ecological Research Associates Inc. to U.S.

Minerals Management Service NTIS No. PB 150271/AS.

Treacy, 5. 1988. Aerial surveys of endangered whales in the Beaufort Sea, fall 1987.

U. S. Minerals Management Service, Alaska OCS Region. NTIS No. PB89

1 687885/AS. 76 pp. + appendices.

Treacy, S. 1990. Aerial surveys of endangered whales in the Beaufort Sea, fall 1989.

U.S. Minerals Management Service, Alaska OCS Region. 66 pp. + appendices.

U.S. Department of Commerce 1992. Tide Tables 1992. High and Low Water

Predictions. West Coast of North and South America, Including the Hawaiian

Islands.238 pp.

172
Würsig, B., E. M. Dorsey, M. A. Fraker, R. S. Paine, and W. J. Richardson. 1985.

Behavior of bowhead whales, Balaena mysticetus, summering in the Beaufort

Sea: a description. Fishery Bulletin. 83: 357-377.

Würsig, B., E. M. Dorsey, M. A. Fraker, R. A. Paine, W. J. Richardson, and R. S.

Wells. 1984. Behavior of bowhead whales, Balaena mysticetus, summering in

the Beaufort Sea: surfacing, respiration, and dive characteristics. Can. J. Zool.

62: 1910-1921.

Würsig, B. J., J. Guerrero, and G. K. Silber. 1993. Social and sexual behavior of

bowhead whales in fall in the western arctic: a re-examination of

seasonal trends. Marine Mammal Science 9:103-11 1.

173
174
1
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2
1992-09-07 01:08:02 0 69.915N 140.710W 1.0 0.9 1.198

1992-09-07 13:13:28 0 70.001N 139.038W 64.4 12.1 5.325

1992-09-07 18:16:08 0 70.586N 137.821W 79.4 5.0 15.739

1992-09-08 00:56:49 0 70.239W 141 .405W 138.9 6.7 20.805

1992-09-08 02:33:57 0 70.265N 141.277W 5.6 1.6 3.463

1992-09-08 06:38:59 0 70.288*4 141.560W 10.9 4.1 2.673

1992-09-08 13:01:15 0 70.411N 141.850W 17.4 6.4 2.738

1992-09-08 14:41:24 0 70.35211 141.444W 16.5 1.7 9.888

1992-09-08 16:23:39 0 70.427N 141.825W 16.5 1.7 9.665

1992-09-08 18:06:00 0 70.385N 141.759W 5.3 1.7 3.154

1992-09-08 19:45:13 0 70.436N 141.884W 7.3 1.7 4.348

1992-09-08 21:57:46 0 70.427N 141.950jJ 2.7 2.2 1.200

1992-09-09 01:14:38 0 70.408N 141.921W 2.4 3.3 0.723

1992-09-09 06:12:42 1 70.50511 141.97611 11.0 5.0 2.208

1992-09-09 07:53:13 0 70.59211 141.9161J 9.9 1.7 5.921

1992-09-09 11:06:59 0 70.474N 142.039W 13.9 3.2 4.298

1992-09-09 21 :30:57 0 70.48511 141.981W 2.5 10.4 0.238

1992-09-10 00:30:33 0 70.437N 141.894W 6.2 3.0 2.084

1992-09-10 07:34:49 0 70.45311 141.342W 20.6 7.1 2.914

1992-09-10 15:54:52 0 70.57511 141.051W 17.3 8.3 2.078
1992-09-16 02:03:52 0 70.24911 144.701W 18.0 1.6 11.229

1992-09-16 07:04:50 0 70.403W 144.740W 17.2 5.0 3.424

1992-09-16 11:21:43 0 70.43311 144.859W 5.5 4.3 1.295

1992-09-16 17:20:09 0 70.508W 145.137W 13.3 6.0 2.221

1992-09-16 18:04:18 1 70.51511 145.009W 4.8 0.7 6.534

1992-09-16 18:57:33 0 70.56611 145.251W 10.6 0.9 11.943

1992-09-17 01 :44:07 0 70.469W 145.615W 17.3 6.8 2.548

1992-09-17 03:22:17 0 70.547W 145.525W 9.3 1.6 5.676

1992-09-17 05:05:59 0 70.446W 145.340W 13.2 1.7 7.611

1992-09-17 12:54:06 0 70.381W 146.127W 30.2 7.8 3.870

1992-09-17 19:28:46 0 70.65611 146.10W 30.6 6.6 4.647

1992-09-17 22:48:17 0 70.68111 146.375W 10.3 3.3 3.090

1992-09-18 02:12:24 0 70.84911 147.602W 48.6 3.4 14.297

1992-09-18 12:34:13 0 70.97211 145.495W 77.8 10.4 7.504

1992-09-18 15:59:45 0 70.93211 146.984W 54.2 3.4 15.815

1992-09-18 18:20:21 0 70.883W 146.942W 5.7 2.3 2.413

1992-09-18 19:26:12 0 70.89111 147.053W 4.1 1.1 3.767

1992-09-18 19:58:22 2 70.92011 147.107W 3.8 0.5 7.038

1992-09-18 21:38:31 2 70.91011 147.273W 6.1 1.7 3.674

1992-09-19 00:23:17 1 70.91811 147.443W 6.2 2.7 2.272
1992-09-23 07:57:11 0 71.609W 156.377W 5.1 1.7 2.991 1992-09-23 13:16:12 0 71.625W 156.715W 12.0 5.3 2.252

1992-09-23 14:59:50 0 71.614W 157.067W 12.4 1.7 7.175

1992-09-23 18:13:37 0 71.640W 157.544W 17.0 3.2 5.249

1992-09-24 04:15:16 0 71.406W 158.482W 42.0 10.0 4.192

1992-09-24 05:52:41 0 71.427W 158.475W 2.3 1.6 1.445 1992-09-24 16:10:09 0 71.433W 159.696W 43.2 10.3 4.199

1992-09-24 19:31:35 0 71.556W 159.740W 13.8 3.4 4.097

1992-09-25 02:14:26 0 71.407W 160.284W 25.4 6.7 3.776

1992-09-25 04:10:53 0 71.404W 160.492W 7.4 1.9 3.801

1992-09-25 14:37:42 0 71.229W 161.476W 40.1 10.4 3.834

1992-09-25 15:51:38 0 71.172W 161.995W 19.6 1.2 15.933

1992-09-25 17:59:52 0 71.148W 161.736W 9.7 2.1 4.524

1992-09-25 19:13:20 1 71.168W 162.069W 12.2 1.2 9.927

1992-09-25 22:35:51 0 71.132W 162.235W 7.2 3.4 2.126

1992-09-26 04:02:15 0 71.081W 162.882W 24.0 5.4 4.404

1992-09-26 05:13:00 0 71.085W 162.920W 1.4 1.2 1.220 1992-09-26 05:44:57 0 71.008W 162.927W 8.6 0.5 16.072

1992-09-26 06:47:40 0 71 .030W 163.495W 20.7 1.0 19.776

1992-09-26 08:30:03 0 71.053W 163.379W 4.9 1.7 2.875
1992-09-29 20:32:59 0 71.835W 168.799W 20.5 1.2 17.751 1992-09-29 21:13:19 0 71.834W 168.696W 3.6 0.7 5.310

1992-09-29 22:44:07 0 72.052)1 169.085W 27.7 1.5 18.291 1992-09-30 05:27:28 0 71.869)1 169.140W 20.4 6.7 3.038

1992-09-30 07:05:17 1 71.755W 169.689W 22.9 1.6 14.028 1992-09-30 13:35:59 0 71 .653W 170.007W 15.9 6.5 2.435 1992-09-30 20:24:07 0 71.436W 170.145W 24.6 6.8 3.616

1992-10-01 00:01:57 0 71.555W 170.179W 13.3 3.6 3.657

1992-10-01 02:56:29 0 71 .406W 170.614W 22.6 2.9 7.762

1992-10-01 06:42:48 0 71.367W 170.925W 11.9 3.8 3.142

1992-10-01 13:25:14 0 71.309)1 171.508W 21.7 6.7 3.236

1992-10-01 16:59:59 0 71.440)1 171.564W 14.7 3.6 4.105

1992-10-01 18:39:52 0 71.544W 171.496W 11.8 1.7 7.089

1992-10-02 01:07:02 0 71.442*1 172.550W 38.9 6.5 6.023

1992-10-02 02:52:20 0 71 .471W 172.763W 8.2 1.8 4.665

1992-10-02 04:29:27 0 71.45811 172.425W 12.0 1.6 7.430

1992-10-02 06:15:13 0 71.399)1 172.400W 6.6 1.8 3.753

1992-10-02 18:13:58 0 71.290)1 172.982W 24.0 12.0 2.001 1992-10-03 18:07:01 0 71.311W 176.553W 127.2 23.9 5.326 1992-10-04 05:51:25 0 70.614)1 175.883W 81.2 11.7 6.913



199209-09 19:26:54 0 69.81311 139.528W 3.2 6.7 0.474 1992-09-09 19:52:09 0 69.86011 139.502W 5.3 0.4 12.632 1992-09-10 00:32:41 0 69.881W 139.770W 10.5 4.7 2.248

1992-09-10 02:14:32 0 69.83811 139.351W 16.7 1.7 9.854

1992-09-10 03:53:51 0 69.74411 139.030W 16.2 1.7 9.757

199209i0 05:51:37 1 69.857W 138.974W 12.7 2.0 6.490

1992-09-10 07:32:51 0 69.82011 138.880W 5.5 1.7 3.239

1992-09-10 12:33:22 0 69.868)1 139.003W 7.1 5.0 1.421 1992-09-10 14:27:17 1 69.90111 139.010W 3.7 1.9 1.937

19920910 16:08:59 0 69.834W 138.976W 7.6 1.7 4.459

1992-09-10 17:33:01 0 69.77111 138.94811 7.1 1.4 5.056

1992-09-10 17:48:35 1 69.82641 138.946W 6.1 0.3 23.552

199209-10 19:18:46 0 69.78911 138.844W 5.7 1.5 3.775

1992-09-10 21:13:39 0 69.777W 138.637W 8.1 1.9 4.209

1992-09-11 00:26:17 0 69.74911 138.834W 8.2 3.2 2.550

1992-09-11 02:03:24 0 69.74011 138.834W 1.0 1.6 0.618

1992-09-11 03:47:13 0 69.72011 138.747W 4.0 1.7 2.323

1992-09-11 07:11:11 0 69.69311 138.64611 4.9 3.4 1.446

1992-09-11 12:25:20 0 69.693W 138.414W 8.9 5.2 1.709

1992-09-11 15:44:48 0 69.67911 137.888W 20.3 3.3 6.121

1992-09-11 03:53:07 0 71.080)1 136.876W 23.3 1.8 13.118

1992-09-11 07:11:33 0 71.032)1 136.336W 20.2 3.3 6.107

TotaL distance traveLed = 621.6
TotaL distance traveLed = 1429.4

1992-09-12 01:49:10 0 69.511W 137.427W 60.9 10.1 6.058

1992-09-12 13:46:24 0 69.413W 137.004W 19.8 12.0 1.653 1992-09-12 22:06:12 2 69.472W 136.825W 9.6 8.3 1.150

1992-09-12 22:12:28 2 69.459W 136.846W 1.7 0.1 15.893

1992-09-13 01:36:07 0 69.579W 136.947W 13.9 3.4 4.095

1992-09-13 06:26:56 2 69.865W 137.139W 32.6 4.8 6.731

1992-09-13 13:41:37 0 69.99811 136.938W 16.6 7.2 2.298

1992-09-13 20:23:41 0 70.329W 137.258W 38.7 6.7 5.776

1992-09-14 01:09:16 0 70.913W 137.488W 65.4 4.8 13.749

1992-09-14 06:05:13 0 70.491W 138.239W 54.4 4.9 11.028

1992-09-14 14:42:29 0 70.90811 139.003W 54.2 8.6 6.283

1992-09-14 16:23:53 0 70.985W 138.539W 18.9 1.7 11.172

1992-09-14 19:45:38 0 71.03811 138.061W 18.3 3.4 5.430