Minton, Gianna,van Bressem, M. F.,Willson, A.,Collins, T.,Al Harthi, S.,Sarrouf Willson, M.,Baldwin, R.,Leslie, M.,Robbins, J.,Van Waerebeek, K
Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman Technical Report
Document presented to the Scientific Committee of the International Whaling Commission no. 418, 2020.
Abstract | Links | BibTeX | Tags: Arabian Sea, Barnacle, Bycatch, disease, Fisheries, Humpback Whale, killer whale, lesions, megaptera novaeangliae, Oman, pathology, photo identification, predation, scarring, skin, tattoo
@techreport{,
title = {Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman},
author = {Minton, Gianna,van Bressem, M. F.,Willson, A.,Collins, T.,Al Harthi, S.,Sarrouf Willson, M.,Baldwin, R.,Leslie, M.,Robbins, J.,Van Waerebeek, K},
url = {https://arabianseawhalenetwork.org/wp-content/uploads/2020/06/sc_68b_cmp_16_rev1_visual-health-assessment-of-ashw-in-oman-1.pdf},
year = {2020},
date = {2020-01-01},
journal = {Paper presented to the meeting of the Scientific Committee of the International Whaling Commission},
number = {418},
pages = {25},
publisher = {IWC},
institution = {Document presented to the Scientific Committee of the International Whaling Commission},
abstract = {Arabian Sea humpback whales have been a subject of conservation concern in the IWC since 1997. Research conducted primarily off the coast of Oman has contributed to understanding the population’s distribution, abundance, and conservation status, whilst information on the population’s health and specific threats is more limited. This study examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites and human-induced scarring or injury to individuals. Tattoo-like skin disease was detected in 43.4% of 83 adult whales, with a roughly equal distribution between males and females. The prevalence of the disease was significantly higher in 2012-2018 (51.7%) than in 2000-2011 (24.1%). The lesions persisted for two to 14 years in 10 whales and progressed in prevalence and percentage of body cover in six of them. Killer whale tooth rakes were detected in 12% (95% CI 4.5-18%) of individuals based on examination of photographs showing the ventral surface of tail flukes (n=77), but no cookie cutter shark wounds were detected on any body parts of any of the whales examined. Roughly two thirds (66.6%: 95% CI 52-80%) of individuals represented by good quality photos of the caudal peduncle region (n=42) bore scarring patterns considered likely to be associated with entanglement in fishing gear, with no significant differences in entanglement scarring rates between males and females. Four individuals bore injuries consistent with vessel strikes and at least two individuals showed severe injuries and deformations likely to have been caused by interactions with vessels and/or fishing gear. Five documented entanglement events from Oman and Pakistan involved large-mesh nylon gillnets, which are known to be used extensively throughout the Arabian Sea. In light of this population’s endangered status, these findings indicate an urgent need to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions, aimed toward designing effective conservation strategies to mitigate known threats. },
keywords = {Arabian Sea, Barnacle, Bycatch, disease, Fisheries, Humpback Whale, killer whale, lesions, megaptera novaeangliae, Oman, pathology, photo identification, predation, scarring, skin, tattoo},
pubstate = {published},
tppubtype = {techreport}
}
Arabian Sea humpback whales have been a subject of conservation concern in the IWC since 1997. Research conducted primarily off the coast of Oman has contributed to understanding the population’s distribution, abundance, and conservation status, whilst information on the population’s health and specific threats is more limited. This study examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites and human-induced scarring or injury to individuals. Tattoo-like skin disease was detected in 43.4% of 83 adult whales, with a roughly equal distribution between males and females. The prevalence of the disease was significantly higher in 2012-2018 (51.7%) than in 2000-2011 (24.1%). The lesions persisted for two to 14 years in 10 whales and progressed in prevalence and percentage of body cover in six of them. Killer whale tooth rakes were detected in 12% (95% CI 4.5-18%) of individuals based on examination of photographs showing the ventral surface of tail flukes (n=77), but no cookie cutter shark wounds were detected on any body parts of any of the whales examined. Roughly two thirds (66.6%: 95% CI 52-80%) of individuals represented by good quality photos of the caudal peduncle region (n=42) bore scarring patterns considered likely to be associated with entanglement in fishing gear, with no significant differences in entanglement scarring rates between males and females. Four individuals bore injuries consistent with vessel strikes and at least two individuals showed severe injuries and deformations likely to have been caused by interactions with vessels and/or fishing gear. Five documented entanglement events from Oman and Pakistan involved large-mesh nylon gillnets, which are known to be used extensively throughout the Arabian Sea. In light of this population’s endangered status, these findings indicate an urgent need to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions, aimed toward designing effective conservation strategies to mitigate known threats.
Mikhalev,Y.A.
Humpback whales Megaptera novaeangliae in the Arabian Sea Journal Article
In: Marine Ecology Progress Series, vol. 149, no. 154, pp. 13-21, 1997.
Abstract | BibTeX | Tags: Antarctic, Arabian Sea, Distribution, Humpback Whale, humpback whales, India, Indian Ocean, length, megaptera novaeangliae, Northern Hemisphere, Oman, Pakistan, pathology, population, Population Biology, population identity, reproduction, whale, whales, whaling
@article{,
title = {Humpback whales Megaptera novaeangliae in the Arabian Sea},
author = {Mikhalev,Y.A.},
year = {1997},
date = {1997-01-01},
journal = {Marine Ecology Progress Series},
volume = {149},
number = {154},
pages = {13-21},
abstract = {The population identity of humpback whales Megaptera novaeangliae in the Arabian Sea has long been a matter of dispute. New information is presented from this region, based upon whaling and observations conducted by the Soviet Union, primarily in November 1966. In that month, a total of 238 humpbacks were killed off the coasts of Oman, Pakistan and northwestern India; 4 others were killed in 1965. Biological examination of these whales showed that they differed significantly from Antarctic humpbacks in terms of size, coloration, body scars and pathology. In addition, analysis of the length distribution of 38 foetuses indicates that the reproductive cycle of the Arabian Sea whales was unequivocally that of a northern hemisphere population. Mean lengths were 12.8 m for males (range: 9.5 to 14.9 m, n = 126) and 13.3 m for females (range: 9.5 to 15.2 m, n = 112). All whales 12.5 m or more in length were sexually mature. Among 97 females examined, 12 (12.4%) were immature. Of the 85 mature females, 39 (45.9%) were pregnant, 3 (3.5%) were lactating, and 43 (50.6%) were resting. A more plausible pregnancy rate, adjusted for underrepresentation of lactating females, was estimated at 39%. A majority of stomachs examined contained food, including euphausiids and fish. Overall, the data presented here argue strongly that Arabian Sea humpbacks constitute a discrete population which remains in tropical waters year-round, a situation which is unique for this species.},
keywords = {Antarctic, Arabian Sea, Distribution, Humpback Whale, humpback whales, India, Indian Ocean, length, megaptera novaeangliae, Northern Hemisphere, Oman, Pakistan, pathology, population, Population Biology, population identity, reproduction, whale, whales, whaling},
pubstate = {published},
tppubtype = {article}
}
The population identity of humpback whales Megaptera novaeangliae in the Arabian Sea has long been a matter of dispute. New information is presented from this region, based upon whaling and observations conducted by the Soviet Union, primarily in November 1966. In that month, a total of 238 humpbacks were killed off the coasts of Oman, Pakistan and northwestern India; 4 others were killed in 1965. Biological examination of these whales showed that they differed significantly from Antarctic humpbacks in terms of size, coloration, body scars and pathology. In addition, analysis of the length distribution of 38 foetuses indicates that the reproductive cycle of the Arabian Sea whales was unequivocally that of a northern hemisphere population. Mean lengths were 12.8 m for males (range: 9.5 to 14.9 m, n = 126) and 13.3 m for females (range: 9.5 to 15.2 m, n = 112). All whales 12.5 m or more in length were sexually mature. Among 97 females examined, 12 (12.4%) were immature. Of the 85 mature females, 39 (45.9%) were pregnant, 3 (3.5%) were lactating, and 43 (50.6%) were resting. A more plausible pregnancy rate, adjusted for underrepresentation of lactating females, was estimated at 39%. A majority of stomachs examined contained food, including euphausiids and fish. Overall, the data presented here argue strongly that Arabian Sea humpbacks constitute a discrete population which remains in tropical waters year-round, a situation which is unique for this species.