1. The study examined the haul-out behaviors of harbor seals at two sites in Washington State, including their behavioral time budgets, frequencies of aggressive behaviors, and how these factors related to location, abundance, and tide height. 2. The most common behaviors observed were resting and vigilance, which varied depending on location relative to the waterline and abundance. 3. Foreflipper scratching was the most frequent aggressive behavior observed. The frequency of aggression was found to relate to abundance, distance from the waterline, and tide height in complex ways depending on the features of each site.

1. Haul-out behavior of harbor seals (Phoca vitulina)
in Washington State
Tasha Hartwig

2. Overview
• harbor seal haul-out behaviors
• research goals
• study results/discussion
• conclusions

3. Introduction
• haul out 40-50% of time
• benefits:
o rest/sleep
o thermoregulation
o aquatic predator avoidance
• haul out behaviors

4. Washington State History
• History: ↓ populations in early 20th century
• Today: most abundant pinniped in WA
• hundreds of haul out sites
Jeffries et al. 2003

5. Objectives
To compare for two sites:
1. behavioral time budgets relative to location, abundance
2. frequency of different aggressive behaviors
3. frequency of aggression relative to waterline, abundance, tide height

6. Methods: Study Sites
Cattle Point
● Southwest San Juan Island
● Haul out on beach & rock outcroppings
● Disturbance from vessel traffic
● Olympia, WA
● Haul out on log booms and dock
● Little disturbance, protected area
Wildlife Recreation
Woodard Bay

7. Methods: Observations
• Aug. 7 – Oct. 21
• Two sampling methods
o Scan sampling - general behavior
o Opportunistic sampling - aggressive behavior

8. Methods: General Behaviors (scan)
• Scan sample every five minutes
• Record behavior of each harbor seal
• Behaviors of interest:
o Resting

9. Methods: General Behaviors (scan)
• Scan sample every five minutes
• Record behavior of each harbor seal
• Behaviors of interest:
o Resting
o Vigilance

10. Methods: General Behaviors (scan)
• Scan sample every five minutes
• Record behavior of each harbor seal
• Behaviors of interest:
o Resting
o Vigilance
o Locomotion

11. Methods: General Behaviors (scan)
• Scan sample every five minutes
• Record behavior of each harbor seal
• Behaviors of interest:
o Resting
o Vigilance
o Locomotion
o Flush Response

12. Methods: General Behaviors (scan)
• Scan sample every five minutes
• Record behavior of each harbor seal
• Behaviors of interest:
o Resting
o Vigilance
o Locomotion
o Flush Response
o Aggression

13. Methods: Aggressive Behaviors (opportunistic)
Foreflipper wave
Closed Mouth
Head Thrust
Foreflipper scratch
Open Mouth
Head Thrust
Sullivan (1982)

14. Results: General Behavior
Cattle Point
Hours: 49
Days: 10
Season: Summer
Scans: 583
Woodard Bay
Hours: 41
Days: 7
Season: Fall
Scans: 488

15. Results: Behavioral time budget
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Resting Vigilence Locomotion Aggression
Mean(%)Frequency
Cattle Point
≤1 m
>1 m
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Resting Vigilance Locomotion Aggression
Mean(%)Frequency
Woodard Bay
≤1 m
>1 m

16. Results: Resting vs. Abundance
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 50 100 150 200
Mean(%)Resting
Relative Abundance
Cattle Point
≤1 m
>1 m
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 20 40 60 80 100 120 140 160 180
Mean(%)Resting
Relative Abundance
Woodard Bay
≤1 m
>1 m

17. Results: Vigilance vs. Abundance
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 20 40 60 80 100 120 140 160
Mean(%)Vigilance
Relative Abundance
Cattle Point
≤1 m
>1 m
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 20 40 60 80 100 120 140 160 180
Mean(%)Vigilance
Relative Abundance
Woodard Bay
≤1 m
>1 m

18. Results: Abundance relative to tide height
0
20
40
60
80
100
120
140
160
180
-0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
MeanAbundance
Tide Height (m)
Woodard Bay
Cattle Point

19. Discussion: Behavioral time budget
• spent most time vigilant and resting at both sites
• Cattle Point
o resting farther from waterline = safety
o vigilance at waterline = disturbance
• Woodard Bay
o more resting and vigilance at waterline since majority are
located there
 could be different if evenly distibuted

20. Discussion: General behaviors relative to abundance
• greater abundance = more rest, less vigilance
• grouping as an anti-predator strategy
o “Watchman’s Song” Hypothesis (Terhune and Brillant 1996)
o larger groups = safer

21. Results: Aggressive Behavior
• Cattle Point
oTotal # aggressive behaviors = 684  rate of 14/hr
• Woodard Bay
oTotal # aggressive behaviors = 195  rate of 5/hr

22. Results: Aggressive behaviors differ between sites

23. Results: Rate of aggression relative to abundance
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120 140 160 180
#ofAggressiveBehaviors/hr
Mean Abundance/hr
Cattle Point
Woodard Bay

24. Results: Aggression relative to distance above waterline
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
<1 m >1 m water
Mean(%)Frequency
Distance Above Waterline
Cattle Point
Woodard Bay

25. Results: Rate of aggression changes with tide height
0
0.5
1
1.5
2
2.5
3
-0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
RateofAggression
Tide Height (m)
Cattle Point
Woodard Bay

26. Discussion: Aggressive behaviors differ between sites
• Foreflipper Scratching most common at both sites
• Cattle Point
o Closed Mouth Head Thrust = 2nd most common
 requires more energy, more room
• Woodard Bay
o Foreflipper Wave = 2nd most common
 requires less energy, less room
Sullivan 1982

27. Discussion: Effect of abundance on aggression rates
• Cattle Point
o greater abundance = more aggression
 personal space invaded from all angles
• Woodard Bay
o no trend
 aggressive acts more costly
 extra movement may cause seals to slip off logs into
water

28. Discussion: Aggression relative to distance above
waterline
• Cattle Point
o more aggression farther from waterline
 trapped when crowded, difficult to escape
• Woodard Bay
o more aggression at waterline
 majority are located here; could be different if
evenly distributed

29. Potential factors affecting harbor seal
aggression in Washington State
• competition for favorable haul out space
• increased populations
• warmer weather
• molting
Kristin Campbell

30. Implications for aggression
• may have health consequences on an
individual level
• but likely not detrimental to
population

31. Summary
1. Resting and vigilance = most common behaviors
o behavior varies relative to location above waterline, abundance
2. Foreflipper Scratching = most frequent aggressive
behavior
3. Frequency of aggression varies relative to three factors:
o abundance: ↑ aggression at higher abundance
o waterline: variable based on site features
o tide height: ↑ aggression at low tide

32. Acknowledgements
A special thank you to Kristin Laidre,
Eric Anderson, Breck Tyler, and Olivia
Davis. This project would not have
happened without them.

33. Questions?
National Geographic