SITE FIDELITY, ASSOCIATIONS, AND MOVEMENTS OF CUVIER'S (ZIPHIUS CAVIROSTRIS) AND BLAINVILLE'S (MESOPLODON DENSIROSTRIS) BEAKED WHALES OFF THE ISLAND OF HAWAI‘I

Abstract

Although the Ziphiidae are the second‐most speciose family of cetaceans, information on beaked whale species and populations has been limited by the difficulties in finding and approaching free‐ranging individuals. Site fidelity, patterns of association, and movements of two species, Cuvier's (Ziphius cavirostris) and Blainville's (Mesoplodon densirostris) beaked whales, were assessed using a 21‐yr photographic data set from the west coast of the island of Hawaii. Resightings of individuals of both species spanned 15 yr, suggesting long‐term site fidelity to the area. Long‐term resightings were documented primarily from adult females of both species. Group sizes for both species were small and most groups had only a single adult male present. For Blainville's beaked whales, repeated associations between adult females and adult males were documented for all resightings of adult males over periods from 1 to 154 d. Among adult females, although repeated associations occurred up to 9 yr apart, individuals were seen separately in intervening years. Individuals of both species seen on multiple occasions were typically documented in multiple months/seasons, suggesting they may use the study area throughout the year. Such long‐term site fidelity has implications both for potential population structure and for susceptibility of beaked whale populations to anthropogenic impacts.

Habitat-based models of cetacean density and distribution in the central North Pacific

“…Some species that are known to occur within our study area were not included in the present study, be cause sample sizes were too limited for modeling. Pygmy and dwarf sperm whales (Kogia sima and K. breviceps), and a variety of beaked whales, including Cuvier's beaked whale Ziphius cavirostris, Blain ville's beaked whale Meso plodon den si rostris, Longman's beaked whale Indopacetus pacificus and Deraniyagala's beaked whale Meso plodon hotaula, a newly described species near Palmyra Atoll, are commonly found within the central Pacific study area (Barlow 2006, McSweeney et al 2007, Baird et al 2011, Rankin et al 2011, BaumannPickering et al 2014 but are difficult to observe at sea because of their cryptic surfacing behavior and long (Barlow 2006, Barlow & Rankin 2007, Bradford et al 2013, with 95% log-normal confidence intervals. Model-based confidence intervals are underestimated because they do not include uncertainty in the probability of detecting animals.…”

Marine Mammal Demographics Off the Outer Washington Coast and Near Hawaii

“…Surveys to assess odontocete species occurrence have been undertaken in that area yearly since 2002 (e.g., McSweeney et al 2007, Baird et al 2008a, Baird et al 2008b). Thus there is considerable information on the seasonal presence and relative abundance of different species.…”

Bucking the trend: genetic analysis reveals high diversity, large population size and low differentiation in a deep ocean cetacean

“…It has been assumed that their general biology is similar and most are thought to be deep-diving squid eaters that live in small groups along continental shelf edges. However, much of the information on the biology of these whales is derived from stranded animals combined with extrapolation from data collected on the few species that can be observed at sea (e.g., Wimmer and Whitehead, 2004;McSweeney et al, 2007). Long-term cetacean sighting surveys off the east coast of the United States suggest that beaked whales cluster into ecological niches that are different from all other odontocetes (Schick et al, 2011).…”