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Presentation Abstract

The Robson Bight Michael Bigg Ecological Reserve (RBMBER) is located within the Northern Resident killer whale (NRKW) population’s critical habitat. A recognized social behaviour of the NRKW population is “beach rubbing”, where individuals will come into the shallows of particular beaches to rub their bodies on smooth pebbles. During beach rubbing, the whales are considered to be more sensitive to disturbance. The physical presence of vessels, as well as the noise from vessel engines has the potential to disturb NRKW and interfere with this sensitive behaviour. To reduce the likelihood of disturbance and protect this important cultural behaviour, recreational vessel traffic is restricted from entering the RBMBER. To assess the potential impacts from vessels on beach rubbing behaviour, we evaluated the vocal repertoire associated with beach rubbing and compared the vocalizations to data from non-rubbing beach recorders. The source level of calls from within and outside the reserve were then measured to examine the effect of vessel noise on rubbing beach vocalizations. Acoustic and visual data were collected between July and September 2021 using acoustic recorders, and behavioural assessments were conducted from an observatory with visual line of sight to three rubbing beaches. A theodolite was used to provide precise measurements on the proximity of vessels to both the whales and the beach. We tested the hypotheses that NRKW use social call types during beach rubbing, and that vessel noise has a greater impact on these vocalizations outside of RBMBER compared to inside RBMBER. This knowledge will help inform policy on the RBMBER’s current marine restrictions and coverage to mitigate future vessel noise stressors on the NRKW population. The data from RBMBER will support advice for the development of acoustic sanctuaries in the Salish Sea to protect the endangered Southern Resident killer whale population from acoustic and physical disturbance.

Session Title

Poster Session 2: The Salish Sea Food Web and Cycles of Life

Conference Track

SSE14: Posters

Conference Name

Salish Sea Ecosystem Conference (2022 : Online)

Document Type

Event

SSEC Identifier

SSE-posters-182

Start Date

26-4-2022 4:30 PM

End Date

26-4-2022 5:00 PM

Type of Presentation

Poster

Genre/Form

conference proceedings; presentations (communicative events)

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Subjects – Topical (LCSH)

Killer whale--British Columbia--Robson Bight (Michael Bigg) Ecological Reserve; Noise control--British Columbia--Robson Bight (Michael Bigg) Ecological Reserve; Wildlife conservation--Salish Sea (B.C. and Wash.)

Geographic Coverage

Salish Sea (B.C. and Wash.); Robson Bight (Michael Bigg) Ecological Reserve (B.C.)

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Type

Text

Language

English

Format

application/pdf

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Apr 26th, 4:30 PM Apr 26th, 5:00 PM

Characterization of Northern Resident killer whale (Orcinus orca) call types and source levels during beach rubbing

The Robson Bight Michael Bigg Ecological Reserve (RBMBER) is located within the Northern Resident killer whale (NRKW) population’s critical habitat. A recognized social behaviour of the NRKW population is “beach rubbing”, where individuals will come into the shallows of particular beaches to rub their bodies on smooth pebbles. During beach rubbing, the whales are considered to be more sensitive to disturbance. The physical presence of vessels, as well as the noise from vessel engines has the potential to disturb NRKW and interfere with this sensitive behaviour. To reduce the likelihood of disturbance and protect this important cultural behaviour, recreational vessel traffic is restricted from entering the RBMBER. To assess the potential impacts from vessels on beach rubbing behaviour, we evaluated the vocal repertoire associated with beach rubbing and compared the vocalizations to data from non-rubbing beach recorders. The source level of calls from within and outside the reserve were then measured to examine the effect of vessel noise on rubbing beach vocalizations. Acoustic and visual data were collected between July and September 2021 using acoustic recorders, and behavioural assessments were conducted from an observatory with visual line of sight to three rubbing beaches. A theodolite was used to provide precise measurements on the proximity of vessels to both the whales and the beach. We tested the hypotheses that NRKW use social call types during beach rubbing, and that vessel noise has a greater impact on these vocalizations outside of RBMBER compared to inside RBMBER. This knowledge will help inform policy on the RBMBER’s current marine restrictions and coverage to mitigate future vessel noise stressors on the NRKW population. The data from RBMBER will support advice for the development of acoustic sanctuaries in the Salish Sea to protect the endangered Southern Resident killer whale population from acoustic and physical disturbance.