Data from: Physiological, morphological, and ecological tradeoffs influence vertical habitat use of deep-diving toothed-whales in the Bahamas

Dive capacity among toothed whales (suborder: Odontoceti) has been shown
to generally increase with body mass in a relationship closely linked to
the allometric scaling of metabolic rates. However, two odontocete species
tagged in this study, the Blainville’s beaked whale Mesoplodon
densirostris and the Cuvier’s beaked whale Ziphius cavirostris, confounded
expectations of a simple allometric relationship, with exceptionally long
(mean: 46.1 min & 65.4 min) and deep dives (mean: 1129 m &
1179 m), and comparatively small body masses (med.: 842.9 kg &
1556.7 kg). These two species also exhibited exceptionally long recovery
periods between successive deep dives, or inter-deep-dive intervals (M.
densirostris: med. 62 min; Z. cavirostris: med. 68 min). We examined
competing hypotheses to explain observed patterns of vertical habitat use
based on body mass, oxygen binding protein concentrations, and
inter-deep-dive intervals in an assemblage of five sympatric toothed
whales species in the Bahamas. Hypotheses were evaluated using dive data
from satellite tags attached to the two beaked whales (M. densirostris, n
= 12; Z. cavirostris, n = 7), as well as melon-headed whales Peponocephala
electra (n = 13), short-finned pilot whales Globicephala macrorhynchus (n
= 15), and sperm whales Physeter macrocephalus (n = 27). Body mass and
myoglobin concentration together explained only 36% of the variance in
maximum dive durations. The inclusion of inter-deep-dive intervals,
substantially improved model fits (R2 = 0.92). This finding supported a
hypothesis that beaked whales extend foraging dives by exceeding aerobic
dive limits, with the extension of inter-deep-dive intervals corresponding
to metabolism of accumulated lactic acid. This inference points to
intriguing tradeoffs between body size, access to prey in different depth
strata, and time allocation within dive cycles. These tradeoffs and
resulting differences in habitat use have important implications for
spatial distribution patterns, and relative vulnerabilities to
anthropogenic impacts.