Rare Sightings of a Bryde’s Whale (Balaenoptera edeni) and Sei Whales (B. borealis) (Cetacea: Balaenopteridae) Northeast of O‘ahu, Hawai‘i.

v. ill. 23 cm.QuarterlyIn the Hawaiian Islands small numbers of Bryde’s whales (Balaenoptera edeni) have been documented only in the Northwestern (leeward) Hawaiian Islands, and sei whales (B. borealis) have only recently been confirmed near the islands of Maui and Hawai‘i. In November 2007, one Bryde’s whale and two sei whale groups (including three subadults) were documented during a 7-day, systematic vessel-transect survey conducted east and northeast of O‘ahu. The Bryde’s whale sighting is the first in nearshore (<70 km) waters of the main Hawaiian Islands, and the two sei whale sightings are the first near O‘ahu, including the first documented subadult sei whales there. The latter information suggests that Hawai‘i may be a reproductive area for the endangered sei whale, whose breeding and calving ground locations remain unknown in the Pacific Ocean. Other than rare incidence, the lack of historical sightings of these two species despite many years of previous shipboard and aerial surveys off Hawai‘i may be due to misidentification and/or poor sea conditions prevalent in deep, offshore windward waters of the Hawaiian Islands. We recommend conducting more offshore vessel surveys for, and biopsy sampling of, these species to clarify habitat use and current stock boundaries and numbers, information important for management of Pacific populations

A Note on Suckling Behavior and Laterality in Nursing Humpback Whale Calves from Underwater Observations

We investigated nursing behavior on the Hawaiian breeding grounds for first year humpback whale (Megaptera novaeangliae) calves. We observed and video-documented underwater events with nursing behavior from five different whale groups. The observed nursing events include behaviors where a calf positions itself at a 30–45° angle to the midline of the mother’s body, with its mouth touching her mammary slit (i.e., suckling position). On two occasions, milk in the water column was recorded in close proximity to a mother/calf pair, and on one occasion, milk was recorded 2.5 min after suckling observed. Nursing events, where the calf was located in the suckling position, were found to be short in duration with a mean of 30.6 s (range 15.0–55.0, standard deviation (SD) = 16.9). All observations of the calf in the suckling position (n = 5, 100%) were with the calf located on the right side of the mother, suggesting a potential for right side laterality preference in the context of nursing behavior. Our study provides insight into mother/calf behaviors from a unique underwater vantage. Results supplement previous accounts of humpback whale nursing in Hawaiian waters, validate mother/calf positioning, document milk in the water column, and introduce the potential for laterality in nursing behavior for humpback whale calves

A Visual Sighting and Acoustic Detections of Minke Whales, Balaenoptera acutorostrata (Cetacea: Balaenopteridae), in Nearshore Hawaiian Waters.

v. ill. 23 cm.QuarterlyMinke whales, Balaenoptera acutorostrata (Lace´pe`de), have been considered a rare species in Hawaiian waters due to limited sightings during visual and aerial surveys. However, our research suggests that they are more common than previously considered. In spring 2005, a combined visual-acoustic survey of cetaceans in Hawaiian waters resulted in the sighting of a minke whale within 22 km of Kaua‘i. Minke whale vocalizations were also detected at several other locations near Kaua‘i and O‘ahu. These 2005 reports are the first from nearshore (<50 km) Hawaiian waters despite years of previous shipboard and aerial surveys. The lack of historical sightings is likely due to misidentification or the inability to detect these animals during poor sighting conditions. We recommend that future cetacean surveys in Hawaiian waters include a passive acoustic component to increase the likelihood of detecting minke whales