Future Directions in Research on Beaked Whales

Hooker, Sascha K.; Soto, Natacha Aguilar de; Baird, Robin W.; Carroll, Emma L.; Claridge, Diane; Feyrer, Laura Joan; Miller, Patrick J. O.; Onoufriou, Aubrie B.; Schorr, Gregory S.; Siegal, Eilidh; Whitehead, Hal

doi:10.3389/fmars.2018.00514

Cited by 49 publications

(66 citation statements)

References 137 publications

(202 reference statements)

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“…Cuvier’s beaked whales ( Ziphius cavirostris ) are deep diving marine mammals 1 with an almost sub-polar cosmopolitan global distribution 2 . However, due to its diving behaviour, subtle surfacing and typical offshore habitat, this species, like many other beaked whale species, it remains relatively understudied 3 . A global assessment has highlighted the existence of a genetically distinct subpopulation of Cuvier’s beaked whale in the Mediterranean Sea 4 .…”

Section: Introductionmentioning

confidence: 99%

First assessment of POPs and cytochrome P450 expression in Cuvier’s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

Baini

Panti

Fossi

et al. 2020

Sci Rep

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The Cuvier's beaked whale (Ziphius cavirostris) is one of the least known cetacean species worldwide. The decreasing population trend and associated threats has led to the IUCN categorising the Mediterranean subpopulation as Vulnerable on the Red List of Threatened Species. This study aimed to investigate for the first time the ecotoxicological status of Cuvier's beaked whale in the NW Mediterranean Sea. The study sampled around the 20% of the individuals belonging to the Ligurian subpopulation, collecting skin biopsies from free-ranging specimens. The levels of polychlorinated biphenyl (PCBs), polybrominated diphenyl ethers (PBDEs) and induction of cytochrome's P450 (CYP1A1 and CYP2B isoforms) were evaluated. Results highlighted that the pattern of concentration for the target contaminants was PCBs > PBDEs and the accumulation values were linked to age and sex, with adult males showing significantly higher levels than juvenile. Concerns raised by the fact that 80% of the individuals had PCB levels above the toxicity threshold for negative physiological effects in marine mammals. Therefore, these findings shed light on this silent and serious threat never assessed in the Mediterranean Cuvier’s beaked whale population, indicating that anthropogenic pressures, including chemical pollution, may represent menaces for the conservation of this species in the Mediterranean Sea.

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Section: Introductionmentioning

confidence: 99%

First assessment of POPs and cytochrome P450 expression in Cuvier’s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

Baini

Panti

Fossi

et al. 2020

Sci Rep

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“…Generally beaked whales are found in very small groups and are not considered particularly social, however in well studied beaked whales (e.g. Ziphius cavirostris, Berardius sp., Mesoplodon densirostris), there is some evidence of long-term bonds (over months to years) between individuals using photo-ID methods [19,54]. Although McSweeney [61] documented repeated associations over two years between a female Ziphius cavirostris and her calf, and Baird [54] suggests that M. densirostris calves disperse from their mothers between 2-3 years of age, long-term associations with relatively unmarked beaked whale calves are particularly hard to track using photo-identification.…”

Section: Plos Onementioning

confidence: 99%

“…Due to the offshore habitat and elusive nature of deep diving beaked whales (Ziphiidae), there is a lack of baseline data on key aspects of their life history so that reproductive parameters are poorly understood [19]. Much of our understanding of their biology comes from one species, the northern bottlenose whale (Hyperoodon ampullatus), which was the target of a century of commercial whaling across the North Atlantic ending in the early 1970's.…”

Section: Introductionmentioning

confidence: 99%

“…We test the hypothesis that nursing extends beyond one year, in contrast to Benjaminsen & Christensen's [20] inference based on stomach contents of a single calf. Similar to Physeter macrocephalus, another deep diving cetacean with prolonged maternal care [25], beaked whales regularly dive to extreme depths (~1000m) to feed on mesopelagic and epibenthic prey [19]. As a result, juveniles may not be physically capable of independent foraging until they have grown large enough to be competent divers or engage in demanding foraging strategies, the complexities of which are currently poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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Prolonged maternal investment in northern bottlenose whales alters our understanding of beaked whale reproductive life history

et al. 2020

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Nursing and weaning periods are poorly understood in cetaceans due to the difficulty of assessing underwater behaviour in the wild. However, the onset and completion of weaning are critical turning points for individual development and survival, with implications for a species' life history including reproductive potential. δ 15 N and δ 13 C deposited in odontocete teeth annuli provide a lifetime record of diet, offering an opportunity to investigate variation and trends in fundamental biology. While available reproductive parameters for beaked whales have largely been inferred from single records of stranded or hunted animals and extrapolated across species, here we examine the weaning strategy and nursing duration in northern bottlenose whales (Hyperoodon ampullatus) by measuring stable isotopes deposited in dentine growth layer groups (GLGs). Using a collection of H. ampullatus teeth taken from whales killed during the whaling era (N = 48) and from two stranded specimens, we compared ontogenetic variation of δ 15 N and δ 13 C found in annual GLGs across all individuals, by sex and by region. We detected age-based trends in both δ 15 N and δ 13 C that are consistent across regions and males and females, and indicate that nursing is prolonged and weaning does not conclude until whales are 3-4 years old, substantially later than previous estimates of 1 year. Incorporating a prolonged period of maternal care into H. ampullatus life history significantly reduces their reproductive potential, with broad implications for models of beaked whale life history, energetics and the species' recovery from whaling.

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“…Beaked whales (family Ziphiidae) are a group of cetaceans of which relatively little is known. They inhabit the deep waters of the world's oceans, diving to great depths to forage upon deepwater squid and fish, spending relatively little time at the surface in comparison to other whale species (Barlow, 1999;MacLeod et al, 2006;Tyack et al, 2006;Hooker et al, 2019). As their remote offshore habitat, surfacing behaviour and elusive nature makes these animals challenging to study, there is a lack of information on the abundance, distribution and basic biology of many ziphiid species.…”

Section: Introductionmentioning

confidence: 99%

Click characteristics of northern bottlenose whales (Hyperoodon ampullatus) and Sowerby's beaked whales (Mesoplodon bidens) off eastern Canada

Clarke

Feyrer

Moors‐Murphy

et al. 2019

The Journal of the Acoustical Society of America

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Passive acoustic monitoring (PAM) is crucial to expanding the knowledge of beaked whales, including the northern bottlenose whale (Hyperoodon ampullatus) and Sowerby's beaked whale (Mesoplodon bidens). Existing descriptions of clicks produced by these species are limited by sample size, number of individuals recorded, and geographic scope. Data from multiple encounters in the western North Atlantic are used to provide a quantitative description of clicks produced by these species. Recordings from nine encounters with northern bottlenose whales in Nova Scotia and Newfoundland were analyzed (N ¼ 2239 clicks). The click type described had a median peak frequency of 25.9 kHz (10th-90th percentile range: 22.9-29.3 kHz), and a median inter-click interval (ICI) of 402 ms (N ¼ 1917, 10th-90th percentile range: 290-524 ms). Recordings from 18 Sowerby's beaked whale encounters from Nova Scotia were analyzed (N ¼ 762 clicks). The click type described had a median peak frequency of 65.8 kHz (10th-90th percentile range: 61.5-76.5 kHz), and a median ICI of 237 ms (N ¼ 677, 10th-90th percentile range: 130-315 ms). These results will contribute to the development of methods to detect and classify beaked whale clicks to the species level, improving the effectiveness of PAM and enhancing scientific understanding and conservation efforts for cryptic and at-risk cetaceans. V

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Future Directions in Research on Beaked Whales

Cited by 49 publications

References 137 publications

First assessment of POPs and cytochrome P450 expression in Cuvier’s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

First assessment of POPs and cytochrome P450 expression in Cuvier’s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

Prolonged maternal investment in northern bottlenose whales alters our understanding of beaked whale reproductive life history

Click characteristics of northern bottlenose whales (Hyperoodon ampullatus) and Sowerby's beaked whales (Mesoplodon bidens) off eastern Canada

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