Vertical sonar beam width and scanning behavior of wild belugas (Delphinapterus leucas) in West Greenland

Echolocation signals of wild beluga whales (Delphinapterus leucas) were recorded in 2013 using a vertical, linear 16-hydrophone array at two locations in the pack ice of Baffin Bay, West Greenland. Individual whales were localized for 4:42 minutes of 1:04 hours of recordings. Clicks centered on the recording equipment (i.e. on-axis clicks) were isolated to calculate sonar parameters. We report the first sonar beam estimate of in situ recordings of wild belugas with an average -3 dB asymmetrical vertical beam width of 5.4°, showing a wider ventral beam. This narrow beam width is consistent with estimates from captive belugas; however, our results indicate that beluga sonar beams may not be symmetrical and may differ in wild and captive contexts. The mean apparent source level for on-axis clicks was 212 dB pp re 1 μPa and whales were shown to vertically scan the array from 120 meters distance. Our findings support the hypothesis that highly directional sonar beams and high source levels are an evolutionary adaptation for Arctic odontocetes to reduce unwanted surface echoes from sea ice (i.e., acoustic clutter) and effectively navigate through leads in the pack ice (e.g., find breathing holes). These results provide the first baseline beluga sonar metrics from free-ranging animals using a hydrophone array and are important for acoustic programs throughout the Arctic, particularly for acoustic classification between belugas and narwhals (Monodon monoceros).

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Polychlorinated biphenyls and organochlorine compounds in brain, liver and muscle of beluga whales (Delphinapterus leucas) from the Arctic and St. Lawrence estuary

Marine Environmental Research ◽

10.1016/s0141-1136(98)00107-x ◽

1999 ◽

Vol 47 (1) ◽

pp. 1-15 ◽

Cited By ~ 29

Author(s):

C Metcalfe ◽

T Metcalfe ◽

S Ray ◽

G Paterson ◽

B Koenig

Keyword(s):

Polychlorinated Biphenyls ◽

Organochlorine Compounds ◽

The Arctic ◽

Delphinapterus Leucas ◽

Lawrence Estuary ◽

Beluga Whales ◽

St Lawrence Estuary

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The summer soundscape of a shallow-water estuary used by beluga whales in the western Canadian Arctic

Arctic Science ◽

10.1139/as-2019-0022 ◽

2020 ◽

Vol 6 (4) ◽

pp. 361-383 ◽

Cited By ~ 2

Author(s):

William D. Halliday ◽

Kevin Scharffenberg ◽

Dustin Whalen ◽

Shannon A. MacPhee ◽

Lisa L. Loseto ◽

...

Keyword(s):

Marine Protected Area ◽

River Estuary ◽

Canadian Arctic ◽

Time Of Day ◽

The Arctic ◽

Delphinapterus Leucas ◽

Marine Animals ◽

Frequency Bands ◽

Beluga Whales ◽

Important Habitat

The soundscape is an important habitat component for marine animals. In the Arctic, marine conditions are changing rapidly due to sea ice loss and increased anthropogenic activities such as shipping, which will influence the soundscape. Here, we assess the contributors to the summer soundscape in the shallow waters of the Mackenzie River estuary within the Tarium Niryutait Marine Protected Area in the western Canadian Arctic, a core summering habitat for beluga whales (Delphinapterus leucas Pallas, 1776). We collected passive acoustic data during the summer over four years, and assessed the influence of physical variables, beluga whale vocalizations, and boat noise on sound pressure levels in three frequency bands (low: 0.2–1 kHz; medium: 1–10 kHz; high: 10–48 kHz) to quantify the soundscape. Wind speed, wave height, beluga vocalizations, and boat noise were all large contributors to the soundscape in various frequency bands. The soundscape varied to a lesser degree between sites, time of day, and with tide height, but remained relatively constant between years. This study is the first detailed description of a shallow summer soundscape in the western Canadian Arctic, an important habitat for beluga whales, and can be used as a baseline to monitor future changes during this season.

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Temporal shifts in intraguild predation pressure between beluga whales and Greenland halibut in a changing Arctic

Biology Letters ◽

10.1098/rsbl.2017.0433 ◽

2017 ◽

Vol 13 (11) ◽

pp. 20170433 ◽

Cited By ~ 13

Author(s):

David J. Yurkowski ◽

Nigel E. Hussey ◽

Aaron T. Fisk ◽

Kendra L. Imrie ◽

Ross F. Tallman ◽

...

Keyword(s):

Intraguild Predation ◽

Prey Availability ◽

The Arctic ◽

Delphinapterus Leucas ◽

Forage Fish ◽

Greenland Halibut ◽

Predator Species ◽

Beluga Whales ◽

Decadal Scale ◽

Temporal Shifts

Asymmetrical intraguild predation (AIGP), which combines both predation and competition between predator species, is pervasive in nature with relative strengths varying by prey availability. But with species redistributions associated with climate change, the response by endemic predators within an AIGP context to changing biotic–abiotic conditions over time (i.e. seasonal and decadal) has yet to be quantified. Furthermore, little is known on AIGP dynamics in ecosystems undergoing rapid directional change such as the Arctic. Here, we investigate the flexibility of AIGP among two predators in the same trophic guild: beluga ( Delphinapterus leucas ) and Greenland halibut ( Reinhardtius hippoglossoides ), by season and over 30 years in Cumberland Sound—a system where forage fish capelin ( Mallotus villosus ) have recently become more available. Using stable isotopes, we illustrate different predator responses to temporal shifts in forage fish availability. On a seasonal cycle, beluga consumed less Greenland halibut and increased consumption of forage fish during summer, contrasting a constant consumption rate of forage fish by Greenland halibut year-round leading to decreased AIGP pressure between predators. Over a decadal scale (1982–2012), annual consumption of forage fish by beluga increased with a concomitant decline in the consumption of Greenland halibut, thereby indicating decreased AIGP pressure between predators in concordance with increased forage fish availability. The long-term changes of AIGP pressure between endemic predators illustrated here highlights climate-driven environmental alterations to interspecific intraguild interactions in the Arctic.

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Sexing beluga whales (Delphinapterus leucas) by means of DNA markers

Canadian Journal of Zoology ◽

10.1139/z91-273 ◽

1991 ◽

Vol 69 (7) ◽

pp. 1971-1976 ◽

Cited By ~ 10

Author(s):

Moira W. Brown ◽

Ree Helbig ◽

Peter T. Boag ◽

David E. Gaskin ◽

Bradley N. White

Keyword(s):

Y Chromosome ◽

Zinc Finger Protein ◽

Restriction Enzymes ◽

Delphinapterus Leucas ◽

Gene Probe ◽

Beluga Whales ◽

Zinc Finger Protein Gene ◽

Dna Restriction ◽

Male Specific ◽

Free Ranging

Few methods are available for determining the sex of free-ranging individual whales, dolphins, and porpoises of species that are not obviously sexually dimorphic. We have developed a technique for sexing beluga whales (Delphinapterus leucas) by using a Y-chromosome-specific DNA restriction fragment. Genomic DNA was extracted from liver samples of 18 beluga whales (9 males, 9 females) sexed at dissection. DNA from males and females was digested with five restriction enzymes, electrophoresed, and transferred to membranes by Southern blotting. When probed with the labelled human Y-chromosome zinc finger protein gene probe pDP1007, male-specific bands and bands common to both sexes, but more intense in females than in males, were observed. The DNA digested with EcoRI provided the clearest sex-discriminating banding pattern. Even when DNA of various qualities digested with EcoRI was used, all the males showed a 3.4-kilobase (kb) band, presumably from the Y-chromosome, as well as a 2.1-kb band. Females showed the 2.1-kb band, but all lacked the 3.4-kb band. This 3.4-kb EcoRI male-specific band permits unambiguous sex determination, which will facilitate examination of sex-related differences in population structure and habitat use of belugas, which have important implications for management decisions.

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An Index of the Relative Abundance of Wintering Belugas, Delphinapterus leucas, and Narwhals, Monodon monoceros, off West Greenland

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-257 ◽

1993 ◽

Vol 50 (11) ◽

pp. 2323-2335 ◽

Cited By ~ 16

Author(s):

M. P. Heide-Jørgensen ◽

H. Lassen ◽

J. Teilmann ◽

R. A. Davis

Keyword(s):

Relative Abundance ◽

Delphinapterus Leucas ◽

Late Winter ◽

The West ◽

Baffin Bay ◽

West Greenland ◽

Abundance Estimate ◽

Monodon Monoceros ◽

Pack Ice ◽

Ice Conditions

Systematic aerial surveys of the wintering grounds of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros, in southern Baffin Bay and northern Davis Strait were conducted in late winter of 1981, 1982, 1990, and 1991. Most belugas were found between 67°N and 69°N and none were seen more than 80 km off the coast of West Greenland. Compared with the surveys in 1981 and 1982, a decline in relative abundance of belugas along West Greenland was evident in 1991. This decline was significant at a probability level of 0.13 of the bootstrapped distribution of the combined abundance estimate. Pod sizes declined significantly between the 1981–82 and 1990–91 surveys. The variations in ice conditions between years did not seem to affect the distribution, clumping, or pod sizes of the belugas. Narwhals were widely distributed in the close pack ice offshore between 65°N and 72°N. Along the West Greenland coast, narwhals were primarily seen at the mouth of Disko Bay. No change in relative abundance or pod sizes could be detected for narwhals.

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A Submarine Sonar Study of Arctic Pack Ice

Journal of Glaciology ◽

10.3189/s002214300003447x ◽

1975 ◽

Vol 15 (73) ◽

pp. 349-362 ◽

Cited By ~ 1

Author(s):

Williams Elizabeth ◽

Swithinbank Charles ◽

G.DE Q. Robin

Keyword(s):

Arctic Ocean ◽

Beam Width ◽

The Arctic ◽

First Year ◽

Nuclear Submarine ◽

The North ◽

Pack Ice ◽

The Arctic Ocean ◽

Radio Echo Sounding ◽

Level Ice

AbstractA continuous profile of the Arctic Ocean ice canopy from Spitsbergen to the North Pole was made with 48 kHz echo sounders mourned on a nuclear submarine. A semi-automatic digitizer was used to measure coordinates from the records at a frequency of about 1 000 points per linear kilometre of track. Methods derived for the reconstruction of subglacial relief from 35 MHz radio-echo sounding records were applied to eliminate part of the distortion due to the 20° beam width of the sounders. A corrected profile was used to obtain ice drafts at 2 m intervals. Data were analysed in 10 km sections and figures were summarized for each degree of latitude. The results include: mean ice draft, percentage of ice less than 0.3 m draft, and percentage of level ice. Histograms show the level ice drafts which occur most frequently, and these may indicate the ratio of first-year to older ice. The number of ice keels is listed together with their mean draft and draft distribution. Definitions are found to be of overriding importance in the comparison of data from different areas.

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