Behavior and acoustic relationships: The significance of

shared calls in the southern resident killer whales

Juliette Nash, Beam Reach Friday Harbor Laboratories, University of Washington,

620 University Road, Friday harbor, WA 98250. Email: dream.of.orcas@gmail.com Phone: 617-510-8335

The Basics

• This study focused on the southern resident killer whales of the Pacific Northwest.

• The SRKW’s are made up

of 3 pods – J, K, & L.

• They communicate

using the same or similar

vocalizations.

Literature Review

• So far, the majority of acoustic studies have focused on the northern resident killer whale community.

• Studies show that there are two types of pulsed calls – those with a single (low frequency) component and those with two components (high and low frequencies). (Ford 1991)

• Two component calls may be directional and used to convey an individuals orientation to conspecifics. (Miller 2002)

• Other studies have shown that certain pulsed calls are stable, while others change over time (Deecke et al. 2000).

• Pods have their own dialects, with some shared calls. The SRKW’s share 3 calls. (Ford 1983, 1987)

• In the northern community, little success has been had finding relationships between specific sounds and particular behaviors.

Relevance of shared calls

• Shared calls are significant to the SRKW Community.

• Shared calls are used in conjunction with behaviors or in activities important to the social & survival needs of the SRKW’s.

Problem statement

• Determine essential needs of SRKW community – social and biological.

- Foraging

- Reproduction

- Social Cohesion

- Synchronized behaviors & activites

• Determine which calls are shared and generate hypothesis on what roles they might play.

• It is presumed shared calls are used within each pod on a relatively frequent basis.

The Logic Behind it

Understanding what a call is related to has important management implications.

• Determine where and how often whales forage

• Day/night activities• Changes in behavior or travel patterns

over time. • Determining critical habitat • Estimation of energetic needs in wild vs

captivity.

S6 – Social cohesion?

• Single-component – may not relay orientation information to kin.

• Frequently repetitious

• Very similar between pods

Could potentially be used to maintain a general sense of cohesiveness while MU or pod members are spread.

S10 – Foraging indicator?

• Two-component call, may relay orientation info to kin

• Often accompanied by echolocation.• Variable within and between pods

A distinctive call, that is different from other pulsed calls structurally and acoustically.

S42 – Synchronous cue?

• Clear two component call

• Not often associated with quantifiable amounts of echolocation

• Sounds very similar between pods

Appears ‘stable’ which may be useful if associated with a range of behaviors.

Behavioral definitions• Foraging- circle swimming, lunging, frequent or

sudden direction changes. Often includes percussive behaviors.

• Milling – no predominant behaviors. Often foraging or social behaviors. Percussive behaviors common. Occasionally resting by individuals or sexual behaviors occur.

• Synchronous behavior – Behaviors deliberately performed in tandem with at least two whales. Occurs frequently across a wide range of behaviors.

• Group Spread – Close – any number of associated whales

within 50ft of one another. – Spread – any number of assoc. whales at a

distance greater than 50ft to one another.

Distance parameter based on average underwater visibility in Haro Strait of ~30ft, and the presumption the whales underwater visual acuity is greater than ours.

Methods

• Research platform was a 42ft biodiesel-electric sailing catamaran, the Gato Verde.

• Surface behaviors were recorded onto a PDA, with data collection software from Dr. Jim Ha.

• Supplemental hand written notes were taken

• Behaviors recorded when the whales were in visual & acoustic range.

• Acoustic range was estimated as the area within 1.5miles of the hydrophone.

• Acoustic data was recorded using a single towed hydrophone and was recorded onto a Marantz recorder.

• Effort was made to identify the behaviors of all animals in acoustic range.

• Acoustic files were analyzed in Raven ™

• After acoustic data had been analyzed individual file times were synchronized with the observation real time.

• Acoustic data was mapped against PDA data.

• Keeping the data sets separate after initial collection and keeping acoustic recording times raw until after analysis negated bias.

Results

• There were 5 encounters that yielded usable data.

• 4 were with Jpod and 1 was K & some L’s

• Whales were vocal during all encounters.

S6

• Determined this call was not involved with social cohesion in interpod settings

• Recorded only 3x during Jpod encounters.

• Recorded 11x while with K&L.

Raises possibility that a shared call is used primarily during intrapod settings.

S10

• A one-factor ANOVA showed there was not a significant relationship with S10 and foraging (F1,26 = 0.22, P = 0.64).

• Frequently heard while whales were visibly observed foraging.

• Less frequently heard during encounters with less observed foraging activity.

• Often lots of echolocation.

S42• Call occurred sporadically and was

frequently repetitious with evenly spaced intervals.

• Preliminary analysis does not show signs of a link with particular behaviors.

• Insufficient sample set of group direction change to analyze.

Discussion

• The one factor ANOVA results may have been caused by a combination of equipment and methodology error.

• Due to the high occurance of foraging and S10’s during foraging, this relationship should be researched further.

• The presence of S6 during the intrapod encounter suggests that it use may be limited to those multipod gatherings.

• An alternative hypothesis is that S6 is used during social gatherings for either biological or social purposes.

A note on milling & distance

• Foraging often occurs during milling, but at a distance it is difficult to identify.

• Whales are in acoustic range, but poor visual range.

• Choosing not to include foraging as a observed behavior during distant milling may have biased the foraging event data.

• S10’s were heard during these times as well as during strong visual range milling

Final thoughts

• More research is warranted on this topic, particularly regarding a vocalization associated with foraging.

Acknowledgements

Thank you to Beam Reach and my instructors – Jason Wood, Donna Hauser, and Scott & Val Veirs. Todd Schuster and the Gato Verde along with our relief captains, Mike Dawson and Glenn ***. Thank you to Dr. Jim Ha for providing me with personalized PDA data collection software. Thank you to all of our guest lecturers for providing your time, knowledge and answering all my questions. Thank you to Friday Harbor Labs and the University of Washington. Thank you to Dori Oringer, Don and Helene Hirschfeld, the Lees, Gordon and Anca Nash, Susan Melnick, Maddie and Tyler Gass, and my parents, Alan and Suzanne Nash for their help and financial support. Thank you to my fellow students for their help, advice, and a great ten weeks. Thank you to my family, L.N, P.K, S.A, A.M, C.I, E.A, P & F M, E.L, K.G, N.H, E.G, C.C, E.F, J.R, C.K, K.L, S.M, M. S, R.L, K.O, D.B, B.H, S.D, L.F, and countless others for their love, friendship, inspiration, and support and for not giving me too hard a time about moving across the country to go study whales. Thank you to my guards, for teaching me about perseverance in the face of enormous and ongoing obstacles, and about the amazing things a small group of dedicated people can accomplish. Thank you to everyone who reviewed and edited this paper and helped me organize my ideas and finalize my methods.

Thank you!