Minton,G.,Collins,T.J.Q.,Findlay,K.P.,Baldwin,R,Ersts,P.J.,Rosenbaum,H.C.
Seasonal distribution and population characteristics of humpback whales in Oman Technical Report
no. 413, 2006, ISBN: SC/A06/HW48.
Abstract | BibTeX | Tags: Australia, cetacean, Distribution, habitat, habitat preference, habitat preferences, Humpback Whale, humpback whales, Oman, population, population characteristics, Southern Hemisphere, whale, whales
@techreport{,
title = {Seasonal distribution and population characteristics of humpback whales in Oman},
author = {Minton,G.,Collins,T.J.Q.,Findlay,K.P.,Baldwin,R,Ersts,P.J.,Rosenbaum,H.C.},
issn = {SC/A06/HW48},
year = {2006},
date = {2006-01-01},
journal = {Document presented to the Workshop on the Comprehensive Assessment of Southern Hemisphere Humpback Whales, Hobart, Australia, April 2006},
volume = {SC/A06/HW48},
number = {413},
pages = {1-48},
abstract = {Previously published data on the occurrence of humpback whales (Megaptera novaeangliae) in the Arabian Sea suggest that the region hosts a non-migratory population that adheres to a Northern Hemisphere breeding cycle. Twelve small boat surveys were conducted at three main locations off the coast of Oman between February 2000 and November 2004 to investigate the distribution and seasonal abundance of humpback whales and other cetaceans. An even ratio of males and females were observed and sampled during surveys in the Gulf of Masirah in October and November (n=38), while almost all whales sampled in Dhofar February/March were male (n=28). Song was detected frequently in the Kuria Muria Bay in February/March, but observations of mother-calf pairs were sparse, and competitive groups were absent. Feeding was observed in both October/November and February/March, but behavioural and environmental observations indicate that the Gulf of Masirah is primarily an important feeding ground, while the Dhofar region, particularly the Kuria Muria Bay, appears to be a breeding area. However, a lack of recent observations of both mother-calf pairs and competitive groups raises the possibility that the primary mating, calving and nursing areas are yet to be identified. Of the 64 whales that have been identified using photographs of dorsal fins or tail flukes, six individuals have been observed on at least two surveys, four individuals on three surveys, one on four surveys and one on five separate surveys. Individually identified whales were re-sighted in both the Gulf of Masirah and Dhofar at different times of the year and across survey years, indicating year-round residence off the coast of Oman. A Chapman's modified Petersen estimator was applied to various data pairings to calculate abundance in the areas surveyed. All pairings yielded estimates of less than 100 individuals, but sample sizes were small there are various sources of possible bias. Analysis of scarring on the caudal peduncle region of individually identified whales in Oman indicate that between 30 and 40% of identified whales are likely to have been involved in entanglements with fishing gear. Comparison of the Oman photo-identification catalogue with those from Zanzibar, Antongil Bay (Madagascar) and Mayotte and the Geyser Atoll (Comoros Archipelago), yielded no photographic matches, and support the hypothesis of a discrete population as did comparison of the distribution of fluke pigmentation rankings from the Oman catalogue, which varied significantly from those of Madagascar and Mayotte. In general the data examined in this study suggest that the population or sub-population of humpback whales off the coast of Oman is resident year-round, small and potentially discrete, warranting further research and conservation efforts.},
keywords = {Australia, cetacean, Distribution, habitat, habitat preference, habitat preferences, Humpback Whale, humpback whales, Oman, population, population characteristics, Southern Hemisphere, whale, whales},
pubstate = {published},
tppubtype = {techreport}
}
Previously published data on the occurrence of humpback whales (Megaptera novaeangliae) in the Arabian Sea suggest that the region hosts a non-migratory population that adheres to a Northern Hemisphere breeding cycle. Twelve small boat surveys were conducted at three main locations off the coast of Oman between February 2000 and November 2004 to investigate the distribution and seasonal abundance of humpback whales and other cetaceans. An even ratio of males and females were observed and sampled during surveys in the Gulf of Masirah in October and November (n=38), while almost all whales sampled in Dhofar February/March were male (n=28). Song was detected frequently in the Kuria Muria Bay in February/March, but observations of mother-calf pairs were sparse, and competitive groups were absent. Feeding was observed in both October/November and February/March, but behavioural and environmental observations indicate that the Gulf of Masirah is primarily an important feeding ground, while the Dhofar region, particularly the Kuria Muria Bay, appears to be a breeding area. However, a lack of recent observations of both mother-calf pairs and competitive groups raises the possibility that the primary mating, calving and nursing areas are yet to be identified. Of the 64 whales that have been identified using photographs of dorsal fins or tail flukes, six individuals have been observed on at least two surveys, four individuals on three surveys, one on four surveys and one on five separate surveys. Individually identified whales were re-sighted in both the Gulf of Masirah and Dhofar at different times of the year and across survey years, indicating year-round residence off the coast of Oman. A Chapman's modified Petersen estimator was applied to various data pairings to calculate abundance in the areas surveyed. All pairings yielded estimates of less than 100 individuals, but sample sizes were small there are various sources of possible bias. Analysis of scarring on the caudal peduncle region of individually identified whales in Oman indicate that between 30 and 40% of identified whales are likely to have been involved in entanglements with fishing gear. Comparison of the Oman photo-identification catalogue with those from Zanzibar, Antongil Bay (Madagascar) and Mayotte and the Geyser Atoll (Comoros Archipelago), yielded no photographic matches, and support the hypothesis of a discrete population as did comparison of the distribution of fluke pigmentation rankings from the Oman catalogue, which varied significantly from those of Madagascar and Mayotte. In general the data examined in this study suggest that the population or sub-population of humpback whales off the coast of Oman is resident year-round, small and potentially discrete, warranting further research and conservation efforts.