Diving behaviour of the sperm whale, Physeter macrocephalus, off the Galapagos Islands

Abstract

Sperm whales, Physeter macrocephalus, were tracked by means of a recording depth sounder in the waters off the Galapagos Islands. At depths of less than 300 m the whales generally dived nearly vertically at 60–100 m/min. At greater depths their descents were usually slower. Between February and April 1985, they dived to about 420 m, which is approximately the depth of the oxygen minimum. In 1987, a year of warmer water temperatures, they usually dived about 70 m shallower. There was no apparent diurnal variation in dive depths. None of the whales tracked dived to the ocean floor. Whales dived for about 40 min, followed by 10 min at the surface. Sperm whales usually started to make regular clicks when 150–300 m deep. Young calves appeared not to make prolonged deep dives. Our results are generally consistent with other direct information on the diving behaviour of relatively undisturbed sperm whales, but often conflict with results obtained using sonar for sperm whales being chased by whale catchers.

Diel diving behavior of sperm whales off Japan

“…On the other hand, off the Kumano Coast whales showed no diel rhythm in diving behavior. Similarly, none of the previous studies have shown obvious diel changes in diving depth of sperm whales in any area (Papastavrou et al 1989, Watkins et al 2002, Davis et al 2007). This study is the first to detect obvious diel changes in the diving behavior of sperm whales.…”

“…Matsushita (1955) proposed that the sperm whales in the Antarctic feed mainly at night when the squids rise to the sea surface because it was observed that the stomach contents of whales early in the morning and at night was greater than that of those caught during the day. On the other hand, more recent studies using radio tags, acoustic tracking or satellitelinked dive recorders, found no obvious diel variation in the diving depth of sperm whales (Papastavrou et al 1989, Watkins et al 2002, Davis et al 2007.…”

Scale-dependent correlation of sperm whale distribution with environmental features and productivity in the South Pacific

“…Such studies could outline the range of spatial scales over which food resources are important factors influencing sperm whale distribution. However, as sperm whales are near the top of a very !ong food chain and feed at depths of 400 to 600 m (Gordon 1987, Papastavrou et al 1989, other factors have also to be taken into account. Clarke et al (1993) demonstrated that sperm whales consume a very wide size range of cephalopods, feeding on squid of less than 100 g to squid over 100 kg They obtain about 77% of their food by swimming through luminescent schools of slow and neutrally buoyant cephalopods and about 23 % by chasing faster and larger prey.…”

A digital acoustic recording tag for measuring the response of wild marine mammals to sound

“…The tag must also be tolerant to the pressure experienced during deep dives. Evidence exists for sperm whale dives in excess of 2000 m [12] corresponding to a hydrostatic pressure of over 20 MPa.…”