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Kate Stafford

Senior Principal Oceanographer

Affiliate Associate Professor, Oceanography

Email

stafford@apl.washington.edu

Phone

206-685-8617

Department Affiliation

Acoustics

Education

B.A. French Literature, Minor: Biology, University of California - Santa Cruz, 1989

M.S. Wildlife Biology, Oregon State University, 1995

Ph.D. Interdisciplinary Oceanography, Oregon State University, 2001

Publications

2000-present and while at APL-UW

Exploring movement patterns and changing distributions of baleen whales in the western North Atlantic using a decade of passive acoustic data

Davis, G.E., and 32 others including K.M. Stafford, "Exploring movement patterns and changing distributions of baleen whales in the western North Atlantic using a decade of passive acoustic data," Global Change Biol., EOR, doi:10.1111/gcb.15191, 2020.

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25 May 2020

Six baleen whale species are found in the temperate western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. There is mounting evidence of distributional shifts in many species, including marine mammals, likely because of climate‐driven changes in ocean temperature and circulation. Previous acoustic studies examined the occurrence of minke (Balaenoptera acutorostrata) and North Atlantic right whales (NARW; Eubalaena glacialis). This study assesses the acoustic presence of humpback (Megaptera novaeangliae), sei (B. borealis), fin (B. physalus), and blue whales (B. musculus) over a decade, based on daily detections of their vocalizations. Data collected from 2004 to 2014 on 281 bottom‐mounted recorders, totaling 35,033 days, were processed using automated detection software and screened for each species’ presence. A published study on NARW acoustics revealed significant changes in occurrence patterns between the periods of 2004–2010 and 2011–2014; therefore, these same time periods were examined here. All four species were present from the Southeast United States to Greenland; humpback whales were also present in the Caribbean. All species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. Each of the species showed significant changes in acoustic occurrence after 2010. Similar to NARWs, sei whales had higher acoustic occurrence in mid‐Atlantic regions after 2010. Fin, blue, and sei whales were more frequently detected in the northern latitudes of the study area after 2010. Despite this general northward shift, all four species were detected less on the Scotian Shelf area after 2010, matching documented shifts in prey availability in this region. A decade of acoustic observations have shown important distributional changes over the range of baleen whales, mirroring known climatic shifts and identifying new habitats that will require further protection from anthropogenic threats like fixed fishing gear, shipping, and noise pollution.

Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types

Malige, F., and 9 others including K.M. Stafford, "Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types," Sci. Rep., 10, 8121, doi:10.1038/s41598-020-64613-0, 2020.

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15 May 2020

A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed. There was a linear decline in both parameters for the more common song type (southeast Pacific song type n.2) between 1997 to 2017. An abbreviated analysis, also showed a frequency decline in the scarcer southeast Pacific song type n.1 between 1970 to 2014, revealing that both song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequency to examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song types reported in the literature and a discussion on the reasons of the frequency shift are presented.

Overview of the IWC SOWER cruise acoustic survey data and analyses of Antarctic blue whale calls within the dataset

Shabangu, F.W., and 9 other including K.M. Stafford, "Overview of the IWC SOWER cruise acoustic survey data and analyses of Antarctic blue whale calls within the dataset," J. Cetacean Res. Manage (special issue), 4, EOR, 2020.

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15 May 2020

The International Whaling Commission (IWC) carried out blue whale research within its annual austral summer Southern Ocean Whale and Ecosystem Research (SOWER) cruises between 1996 and 2010. Over 700 sonobuoys were deployed to record blue whale vocalisations during 11 Antarctic and three low latitude blue whale cruises off Australia, Madagascar and Chile. The recorded acoustic files from these deployments were collated and reviewed to develop a database of both the digital acoustic files and the associated deployment station metadata of 7,486 acoustic files from 484 stations. Acoustic files were analysed using the automated detection template and visual verification method. We found a significant difference between the total number of acoustic recording hours (2,481) reported for these cruises (in the associated cruise reports) and the currently available number of acoustic recording hours (1,541). Antarctic blue whale vocalisations (9,315 D-calls and 24,902 Z-calls) were detected on 4,183 of the 7,486 acoustic files. December had the lowest call rates whilst January and February yielded high call rates. Although the majority (63%) of the sonobuoys were deployed between 1800hrs and 0600hrs the following day, most calls (62%) were detected during observation periods between 0600hrs and 1800hrs. The recently described southeastern Pacific 2 song of the Chilean pygmy blue whale was also found in Chilean blue whale cruise acoustic data. The difference between the available and reported data is of concern and a reconciliation of these and any future IWC acoustic data is strongly recommended.

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In The News

The singing ocean (in Polish)

The Universal Weekly (Kraków), Maria Hawranek

Kate Stafford is interviewed about her research on recording whale songs in the Arctic.

30 Apr 2020

The sea is getting warmer. Will the shrimp get louder?

Wired, Eric Niiler

Kate Stafford's research in the Arctic has shown that ambient sound levels are increasing as the result of the loss of sea ice. "We are altering the soundscape of the Arctic," she says.

28 Feb 2020

La vida del Ártico ya ha cambiado por el cambio climático

El País, Miguel Criado

Kate Stafford comments on the results from the paper she and colleagues published recently in Nature Climate Change.

26 Feb 2020

More News Items

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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