Migratory Timing of Humpback Whales (Megaptera novaeangliae) in the Central North Pacific Varies with Age, Sex and Reproductive Status

Craig, Alison S.; Herman, Louis M.; Gabriele, Christine M.; Pack, Adam A.

doi:10.1163/156853903322589605

Cited by 118 publications

(127 citation statements)

References 42 publications

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“…Wintering ground samples are less representative of the entire popula- tion than feeding area samples (Clapham et al 1995), where males are more likely to return and are present in greater numbers than females (Brown et al 1995, Craig & Herman 1997, Smith et al 1999) and juveniles are probably underrepresented (Robbins 2007). Wintering-ground samples could also be biased because of habitat preferences and differences in migratory timing related to age, sex and reproductive status (Smultea 1994, Brown et al 1995, Craig & Herman 2000, Craig et al 2003. Changes in the rate of killer whale attacks over time would affect the proportion of animals with rake marks when the sample is skewed by age class.…”

Section: Discussionmentioning

confidence: 99%

Geographic variation in killer whale attacks on humpback whales in the North Pacific: implications for predation pressure

Steiger¹,

Calambokidis²,

Straley³

et al. 2008

Endang. Species. Res.

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We examined the incidence of rake mark scars from killer whales Orcinus orca on the flukes of humpback whales Megaptera novaeangliae throughout the North Pacific to assess geographic variation in predation pressure. We used 3650 identification photographs from 16 wintering or feeding areas collected during 1990 to 1993 to determine conservative estimates in the percentage of whales with rake mark scarring. Dramatic differences were seen in the incidence of rake marks among regions, with highest rates on wintering grounds off Mexico (26 vs. 14% at others) and feeding areas off California (20 vs. 6% at others), 2 areas between which humpback whales migrate. Although attacks are rarely witnessed, the prevalence of scars demonstrates that a substantial portion of animals are attacked, particularly those that migrate between California and Mexico. Our data also suggest that most attacks occur at or near the wintering grounds in the eastern North Pacific. The prevalence of attacks indicates that killer whale predation has the potential to be a major cause of mortality and a driving force in migratory behavior; however, the location of the attacks is inconsistent with the hypothesis that animals migrate to tropical waters to avoid predation. Our conclusion is that, at least in recent decades, attacks are made primarily on calves at the wintering grounds; this contradicts the hypothesis that killer whales historically preyed heavily on large whales in highlatitude feeding areas in the North Pacific.

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Section: Discussionmentioning

confidence: 99%

Geographic variation in killer whale attacks on humpback whales in the North Pacific: implications for predation pressure

Steiger¹,

Calambokidis²,

Straley³

et al. 2008

Endang. Species. Res.

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show abstract

“…Kellogg 1929, Mackintosh & Wheeler 1929, Brown et al 1995, Dawbin 1997, Craig et al 2003. A (temporally or spatially) segregated and dynamic migration may result in a complex, staggered pattern of ABW movements to and from the feeding grounds, involving continuous arrivals and departures of individuals (see also Mackintosh & Wheeler 1929, Harmer 1931, Samaran et al 2013.…”

Section: Inferring Abw Migratory Movements In the Weddell Sea From Pamentioning

confidence: 99%

Spatio-temporal patterns in acoustic presence and distribution of Antarctic blue whales Balaenoptera musculus intermedia in the Weddell Sea

Thomisch¹,

Boebel²,

Clark³

et al. 2016

Endang. Species. Res.

113

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Distribution and movement patterns of Antarctic blue whales Balaenoptera musculus intermedia at large temporal and spatial scales are still poorly understood. The objective of this study was to explore spatio-temporal distribution patterns of Antarctic blue whales in the Atlantic sector of the Southern Ocean, using passive acoustic monitoring data. Multi-year data were collected between 2008 and 2013 by 11 recorders deployed in the Weddell Sea and along the Greenwich meridian. Antarctic blue whale Z-calls were detected via spectrogram cross-correlation. A Blue Whale Index was developed to quantify the proportion of time during which acoustic energy from Antarctic blue whales dominated over background noise. Our results show that Antarctic blue whales were acoustically present year-round, with most call detections between January and April. During austral summer, the number of detected calls peaked synchronously throughout the study area in most years, and hence, no directed meridional movement pattern was detectable. During austral winter, vocalizations were recorded at latitudes as high as 69°S, with sea ice cover exceeding 90%, suggesting that some Antarctic blue whales overwinter in Antarctic waters. Polynyas likely serve as an important habitat for baleen whales during austral winter, providing food and reliable access to open water for breathing. Overall, our results support increasing evidence of a complex and non-obligatory migratory behavior of Antarctic blue whales, potentially involving temporally and spatially dynamic migration routes and destinations, as well as variable timing of migration to and from the feeding grounds.

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“…Across-season re-sightings suggest that females tend to arrive at and depart from the breeding grounds earlier in years when they do not have a calf than in years when they give birth (Glockner & Venus 1983, Craig et al 2003, Burns et al 2014. As humpback whales have a modal reproductive cycle of 2 or 3 yr (although it can vary between 1 and 5 yr), the migratory timing and habitat use patterns of individual females, and therefore availability for capture on wintering grounds, appears to vary across years depending on reproductive status (Baker et al 1987, Craig et al 2003.…”

Section: Assumption 3: Equal Capture Probabilitymentioning

confidence: 99%

“…As humpback whales have a modal reproductive cycle of 2 or 3 yr (although it can vary between 1 and 5 yr), the migratory timing and habitat use patterns of individual females, and therefore availability for capture on wintering grounds, appears to vary across years depending on reproductive status (Baker et al 1987, Craig et al 2003. While females are likely to return quickly to the feeding grounds after becoming pregnant, mature males remain on the breeding grounds longer, presumably in an attempt to increase mating opportunities.…”

Section: Assumption 3: Equal Capture Probabilitymentioning

confidence: 99%

Assessing the design and power of capture-recapture studies to estimate demographic parameters for the Endangered Oceania humpback whale population

Carroll¹,

Brooks²,

Baker³

et al. 2015

Endang. Species. Res.

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Migratory Timing of Humpback Whales (Megaptera novaeangliae) in the Central North Pacific Varies with Age, Sex and Reproductive Status

Cited by 118 publications

References 42 publications

Geographic variation in killer whale attacks on humpback whales in the North Pacific: implications for predation pressure

Geographic variation in killer whale attacks on humpback whales in the North Pacific: implications for predation pressure

Spatio-temporal patterns in acoustic presence and distribution of Antarctic blue whales Balaenoptera musculus intermedia in the Weddell Sea

Assessing the design and power of capture-recapture studies to estimate demographic parameters for the Endangered Oceania humpback whale population

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