Review of Data on Diets of Beaked Whales: Evidence of Niche Separation and Geographic Segregation

Abstract

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.

Using passive acoustic monitoring to document the distribution of beaked whale species in the western North Atlantic Ocean

“…The low but consistent acoustic presence of Cuvier's beaked whales in the Gully was surprising, as this species has rarely been encountered along the Scotian Shelf despite several decades of survey efforts (Whitehead 2013). MacLeod et al (2003) hypothesized that Cuvier's beaked whales and northern bottlenose whales compete for similar prey and therefore do not occur sympatrically; in contrast, our results indicate that there is some degree of geographic overlap among these two species. The Gully is critical habitat for a small, highly resident population of northern bottlenose whales known to occupy the canyon and surrounding areas year-round (Fisheries and Oceans Canada 2016), and became a federal marine protected area (MPA) in 2004 (DFO 2004).…”

Description of the skeleton of the fossil beaked whale <i>Messapicetus gregarius</i>: searching potential proxies for deep-diving abilities

“…The best-known modern ziphiids perform regular dives to reach foraging grounds up to 3000 m, beyond the photic zone, where they capture cephalopods, crustaceans, and bathypelagic fish via suction (Clarke, 1996;Heyning and Mead, 1996;Hooker and Baird, 1999;Johnson et al, 2004;MacLeod et al, 2003;Minamikawa et al, 2007;Schorr et al, 2014;. Accordingly, Ziphiidae share a unique set of morphological, physiological, and behavioural adaptations allowing them to optimize the travel time to reach their foraging grounds.…”

No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the Late Miocene of Peru

“…First, data on extant ziphiids (stomach contents, satellite recordings of dives, and geographical distribution in relation to sea floor topography; e.g. [2,4,7]) indicate that it is more parsimonious to characterize the last common ancestor of all modern ziphiids as adapted to deep dives. Second, most stem ziphiids were found in platform deposits, contrasting with the discovery of many fossil crown ziphiid remains in deep-sea deposits [6,[8][9][10][11].…”