Deep Diving in Wild, Free-Ranging Beluga Whales, Delphinapterus leucas

Three adult female beluga whales, Delphinapterus leucas, were captured during summer in the Canadian high Arctic and equipped with satellite-linked radio transmitters that measured and recorded ambient pressure every 20 s. Diving behaviour was divisible into three distinct categories: (1) near-surface, (2) "spike" dives to 20–150 m depth, and (3) prolonged, flat-bottomed dives to a maximum depth of 350 m. The duration of these prolonged dives was 9.3–13.7 min, but the upper bound is known to be underestimated. Average descent rates varied between dives in the range 1.43–2.20 m/s and ascent rates between 1.23 and 1.84 m/s. Within periods of 20 s duration, maximum descent and ascent rates were 2.55 and 2.35 m/s, respectively. After most prolonged dives the rate of ascent declined progressively as the surface was approached, particularly in the final 100 m. Such dives were usually to, or near to, the seabed and were probably for foraging. Up to 42% of an animal's time could be spent at depths of 8 m or more.

[1]  H. Whitehead,et al.  Behaviour and Vocalizations of Two Single Sperm Whales, Physeter macrocephalus, Off Nova Scotia , 1988 .

[2]  R. Crawford,et al.  Density Distribution of Fish in the Presence of Whales at the Admiralty Inlet Landfast Ice Edge , 1990 .

[3]  S. Ridgway,et al.  Diving and blood oxygen in the white whale , 1984 .

[4]  J. Scott.  Depth, Temperature and Salinity Preferences of Common Fishes of the Scotian Shelf , 1982 .

[5]  David C. Douglas,et al.  Satellite Telemetry: A New Tool for Wildlife Research and Management, , 1988 .

[6]  Hal Whitehead,et al.  Diving behaviour of the sperm whale, Physeter macrocephalus, off the Galapagos Islands , 1989 .

[7]  W. E. Evans,et al.  ORIENTATION BEHAVIOR OF DELPHINIDS: RADIO TELEMETRIC STUDIES , 1971, Annals of the New York Academy of Sciences.

[8]  T. G. Smith,et al.  Distribution and Abundance of Belugas, Delphinapterus leucas, and Narwhals, Monodon monoceros, in the Canadian High Arctic , 1985 .

[9]  D. Sergeant.  Biology of White Whales (Delphinapterus leucas) in Western Hudson Bay , 1973 .

[10]  Carl H. Key,et al.  Satellite telemetry: performance of animal-tracking systems , 1991 .

[11]  K. S. Norris,et al.  a Theory for the Function of the Spermaceti Organ of the Sperm Whale (physeter Catodon L) , 1972 .

[12]  Yasuhiko Naito,et al.  Prolonged, continuous, deep diving by northern elephant seals , 1989 .

[13]  C. Hudon.  Distribution of Shrimp and Fish By-Catch Assemblages in the Canadian Eastern Arctic in Relation to Water Circulation , 1990 .

[14]  P. Brodie.  A Reconsideration of Aspects of Growth, Reproduction, and Behavior of the White Whale (Delphinapterus leucas), with Reference to the Cumberland Sound, Baffin Island, Population , 1971 .