Temporal trends and effects of noise on upsweep calls of Eastern South Pacific southern right whales

dc.contributor.author Jacobs, Ellen Rose
dc.contributor.author Landea-Briones, Rafaela
dc.contributor.author Sayigh, Laela
dc.date.accessioned 2023-03-23T15:00:50Z
dc.date.available 2023-03-23T15:00:50Z
dc.date.issued 2022-08-30
dc.description © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Jacobs, E., Landea-Briones, R., & Sayigh, L. Temporal trends and effects of noise on upsweep calls of Eastern South Pacific southern right whales. Frontiers in Remote Sensing, 3, (2022).: 909309, https://doi.org/10.3389/frsen.2022.909309.
dc.description.abstract Eastern South Pacific southern right whales (ESPSRW) are a subpopulation of southern right whales (Eubalaena australis) off the coasts of Peru and Chile recognized by the International Union for the Conservation of Nature (IUCN) as critically endangered as a result of heavy whaling efforts in the late 18th to 20th centuries. Most recent population estimates put their numbers around 50 individuals. To test for the efficacy of passive acoustic monitoring of this population, we recorded 5 months of continuous acoustic data (January 2012-June 2012) off the southwestern tip of Isla de Chiloé. To test for trends in occurrence, we identified 11,313 individual ESPSRW upsweep calls, which have been associated with maintaining contact with conspecifics. Call occurrence increased over the course of the deployment and peaked between April and June, indicating an increase in use of this area. A clear diel pattern in which upsweep calls were predominately detected during dusk and night hours was identified, indicating ESPSRW are likely foraging during daylight hours, as upsweep calls are inversely related to foraging behavior. We quantified noise levels in the frequency range of their communication (100 Hz third octave) to understand the change in active space whales may be experiencing. We measured noise levels from 90 dB re 1 μPa to 111 dB re 1 µPa (5th and 95th percentile), a 21 dB fluctuation that results in an order-of-magnitude decrease in active space area. We identified sources of high noise at or above the 75th percentile as predominately blue whale calls (occurring in 71.6% of total sampled minutes) and ship noise (occurring in 69.4% of total sampled minutes). Ship noise was responsible for outliers in excess of 140 dB re 1 µPa. In a population as diminished as ESPSRW, such disruptions of their communication range could result in significant barriers to maintaining contact with conspecifics. Passive acoustic monitoring is a powerful tool for monitoring populations as rarely sighted as ESPSRW. Understanding trends in presence and behavior as well as potential sources of disruption to their calling behavior is vital to determining conservation measures that will be most effective toward helping this critically endangered population.
dc.description.sponsorship Financial support for expeditions, deployments, and retrievals of MARUs, and for some data analysis, was provided by Fundacion MERI, Av. Pdte. Kennedy 5682, Vitacure, Región Metropolitana, Chile. Most data analysis for this study was carried out without external funding.
dc.identifier.citation Jacobs, E., Landea-Briones, R., & Sayigh, L. (2022). Temporal trends and effects of noise on upsweep calls of Eastern South Pacific southern right whales. Frontiers in Remote Sensing, 3, 909309.
dc.identifier.doi 10.3389/frsen.2022.909309
dc.identifier.uri https://hdl.handle.net/1912/65819
dc.publisher Frontiers Media
dc.relation.uri https://doi.org/10.3389/frsen.2022.909309
dc.rights Creative Commons Attribution 4.0
dc.rights.uri https://creativecommons.org/licenses/by/4.0/
dc.subject Passive acoustic monitoring
dc.subject Southern right whales
dc.subject Diel trends
dc.subject Temporal trends
dc.subject Third octave levels
dc.subject Active space
dc.title Temporal trends and effects of noise on upsweep calls of Eastern South Pacific southern right whales
dc.type Article
dspace.entity.type Publication
relation.isAuthorOfPublication 5542c73e-ae72-4382-bdb4-62b60122d2c5
relation.isAuthorOfPublication a71f9370-0498-41d7-b594-9643eb3082f1
relation.isAuthorOfPublication f7cc7c57-c911-4cf1-a45f-230c37f0a632
relation.isAuthorOfPublication.latestForDiscovery 5542c73e-ae72-4382-bdb4-62b60122d2c5
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
frsen-03-909309.pdf
Size:
1.44 MB
Format:
Adobe Portable Document Format
Description:
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.88 KB
Format:
Item-specific license agreed upon to submission
Description:
Collections