ROPE ENTANGLEMENT OF BOWHEAD WHALES (<i>BALAENA MYSTICETUS</i>)

Philo, L. Michael; George, J. C.; Albert, Thomas F.

doi:10.1111/j.1748-7692.1992.tb00414.x

Cited by 18 publications

(12 citation statements)

References 5 publications

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“…Most of the mark types found on bottlenose whales were similar to those found in other cetacean species and may have been caused by a variety of natural and anthropogenic sources (see Gowans 1999 for more details). Of the reliable mark types, notches and back indentations have been well documented and persist for many years (e.g., Kraus 1990, Philo et al 1992, Wells et a/. 1998.…”

Section: Mark Distributionmentioning

confidence: 99%

PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS

Gowans¹,

Whitehead²

2001

Marine Mammal Science

112

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The use of natural marks in capture‐recapture studies can lead to unequal capture probabilities. This paper examined a catalog of northern bottlenose whale (Hyperoodon ampullatus) photographs from the Gully, Nova Scotia, to identify potential sources of heterogeneity. This information can be used to select appropriate individuals and photographs to include in analyses. Individual northern bottlenose whales were sufficiently marked to uniquely identify individuals (x̄= 14.5 marks/individual; range 1‐67), but not all mark types persisted over time. Reliable marks were defined as mark types that were not lost over the nine‐yeat study period (notches, back indentation, and mottled patches). Individuals were considered reliably marked if they possessed at least one back indentation or mottled patch (located within one dorsal fin width, at the base of the dorsal fin) or a notch on the dorsal fin. Sixty‐six percent (SE = 5%) of the population were reliably marked. Longterm analyses (months to years) should use only reliably marked individuals, and the results scaled to account for the rest of the population. Our results also showed that photographic quality affected an observer's ability to identify individuals. For this catalog, quantitative analysis indicated only photographs of Q ≥ 4 (on a 6‐point scale with 6 representing the highest quality) should be included in mark‐recapture analyses sensitive to heterogeneity.

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Section: Mark Distributionmentioning

confidence: 99%

PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS

Gowans¹,

Whitehead²

2001

Marine Mammal Science

112

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“…This approach has been used with a number of species of cetaceans to assess the relative frequency and outcome of fisheries interactions ( e.g ., Philo et al . , Robbins and Mattila , Kiszka et al . , Bradford et al .…”

mentioning

confidence: 99%

“…In the absence of observer data, the number of live false killer whales with scarring that can be attributed to fisheries interactions may be used as an indicator of the relative frequency of nonfatal fishery interactions for particular species or populations. This approach has been used with a number of species of cetaceans to assess the relative frequency and outcome of fisheries interactions (e.g., Philo et al 1992, Robbins and Mattila 2004, Kiszka et al 2008, Bradford et al 2009). False killer whales hooked on longlines have been observed struggling against the taut line, and Baird and Gorgone (2005) suggested that injuries to the dorsal fin or other appendages may occur as the animals struggle.…”

mentioning

confidence: 99%

False killer whales and fisheries interactions in Hawaiian waters: Evidence for sex bias and variation among populations and social groups

Baird

Mahaffy

Gorgone

et al. 2014

Marine Mammal Science

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We assessed scarring patterns as evidence of fisheries interactions for three populations of false killer whales in Hawai'i. Bycatch of the pelagic population in the tuna longline fishery exceeds their Potential Biological Removal level. Scarring was assessed by seven evaluators as consistent, possibly consistent, or not consistent with fisheries interactions, and average scores computed. Scores were highest for scarred main Hawaiian Island (MHI) false killer whales, followed by pelagic and Northwestern Hawaiian Island (NWHI) individuals. Considering only whales for which the majority of evaluators scored scarring as consistent revealed significant differences among populations in the percentage of individuals scarred; MHI: 7.5%, pelagic: 0%, NWHI: 0%. Assessment by social cluster for the MHI population showed that 4.2% of Cluster 1, 7.1% of Cluster 2, and 12.8% of Cluster 3 individuals had such scarring, although differences between clusters were not statistically significant. There was a significant sex bias; all sexed individuals (n = 7) with injuries consistent with fisheries interactions were female. The higher proportion of MHI individuals with fisheries-related scarring suggests that fisheries interactions are occurring at a higher rate in this population. The bias towards females suggests that fisheriesrelated mortality has a disproportionate impact on population dynamics.

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“…Two species for which this behavior is common are northern gannets and double-crested cormorants. Right whales (Kraus 1990), humpback whales (National Marine Fisheries Service 1991; Wiley et al 1995), bowhead whales (Philo et al 1992), and gray whales (Heyning and Lewis 1990) have been observed with rope and line trailing from their mouths or entangled around flippers and flukes. Gannets collect nesting material almost exclusively from offshore areas, and the most common debris reported from their nests were scraps of fishing net, rope, and line.…”

Section: Animal Behaviormentioning

confidence: 99%

Marine Debris

1997

Springer Series on Environmental Management

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ROPE ENTANGLEMENT OF BOWHEAD WHALES (BALAENA MYSTICETUS)

Cited by 18 publications

References 5 publications

PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS

PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS

False killer whales and fisheries interactions in Hawaiian waters: Evidence for sex bias and variation among populations and social groups

Marine Debris

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