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  • 1
    Electronic Resource
    Electronic Resource
    MOVEMENTS AND POPULATION STRUCTURE OF HUMPBACK WHALES IN THE NORTH PACIFIC (2001)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 17 (2001), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Despite the extensive use of photographic identification methods to investigate humpback whales in the North Pacific, few quantitative analyses have been conducted. We report on a comprehensive analysis of interchange in the North Pacific among three wintering regions (Mexico, Hawaii, and Japan) each with two to three subareas, and feeding areas that extended from southern California to the Aleutian Islands. Of the 6,413 identification photographs of humpback whales obtained by 16 independent research groups between 1990 and 1993 and examined for this study, 3,650 photographs were determined to be of suitable quality. A total of 1,241 matches was found by two independent matching teams, identifying 2,712 unique whales in the sample (seen one to five times). Site fidelity was greatest at feeding areas where there was a high rate of resightings in the same area in different years and a low rate of interchange among different areas. Migrations between winter regions and feeding areas did not follow a simple pattern, although highest match rates were found for whales that moved between Hawaii and southeastern Alaska, and between mainland and Baja Mexico and California. Interchange among subareas of the three primary wintering regions was extensive for Hawaii, variable (depending on subareas) for Mexico, and low for Japan and reflected the relative distances among subareas. Interchange among these primary wintering regions was rare. This study provides the first quantitative assessment of the migratory structure of humpback whales in the entire North Pacific basin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.2001.tb01298.x
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  • 2
    Electronic Resource
    Electronic Resource
    REPRODUCTIVE RATES OF HUMPBACK WHALES OFF CALIFORNIA (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 16 (2000), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: From 1986 to 1996 we examined the reproductive rates, calving rates, and reproductive histories of mature females as part of photo-identification studies of humpback whales that feed off California, Oregon, and Washington during summer and fall. Annual reproductive rates were measured by two methods: proportion of all whales that were calves based on sightings (0.6%-5.9% per year, mean = 3.6%, SD = 1.6) and based on individually identified animals (1.1%-8.0% per year, mean = 4.1%, SD = 1.8). The reproductive rate based on sightings varied significantly by year (G test, P 〈 0.001), region (G test, P 〈 0.001), and by month (G test, P 〈 0.05). Seventy-nine sexually mature females were identified with 97 calves out of a total of 844 known individuals over the 11-yr study. Mother-calf separation on the feeding grounds was recorded in several instances. The apparent reproductive rates of this population are considerably lower than rates of 4%–15% reported from other feeding areas for this species. Our estimates are likely biased downward because this population has been increasing at about 5% per year. Calves may have been missed due to early weaning and because of our sampling from small boats late in the season. We also found evidence of geographic segregation of mother-calf pairs within our large study area. Despite these factors, we conclude the reproductive rate of this population appears to be lower than has been reported in other areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.2000.tb00914.x
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  • 3
    Electronic Resource
    Electronic Resource
    INTERCHANGE AND ISOLATION OF HUMPBACK WHALES OFF CALIFORNIA AND OTHER NORTH PACIFIC FEEDING GROUNDS (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 12 (1996), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Humpback whales feed in several high-latitude areas of the North Pacific. We examined the interchange of humpback whales between one of these areas, off California, and those in other feeding grounds in the eastern North Pacific:. Fluke photographs of 597 humpback whales identified off California between 1986 and 1992 were compared with those off Oregon and Washington (29); British Columbia (81); southeastern Alaska (343); Prince William Sound, Alaska (141); Kodiak Island, Alaska (104); Shumagin Islands, Alaska (22); and in the Bering Sea (7). A high degree of interchange, both inter-and intrayear, was found among humpback whales seen off California, Oregon, and Washington., A low rate of interchange was found between British Columbia and California.: two whales seen near the British Columbia/Washington border were photographed off California in a different year, No interchange was found between California and the three feeding areas in Alaska. Humpback whales off California, Oregon, and Washington form a single intermixing feeding aggregation with only limited interchange with areas farther north. These findings are consistent with photographic identification studies in the North Atlantic and with genetic studies in both the North Atlantic and North Pacific.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.1996.tb00572.x
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  • 4
    Electronic Resource
    Electronic Resource
    MOVEMENT OF HUMPBACK WHALES BETWEEN CALIFORNIA AND COSTA RICA (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 7 (1991), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.1991.tb00105.x
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  • 5
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    Distribution and abundance of humpback whales (Megaptera novaeangliae) and other marine mammals off the northern Washington coast (2021)
    In:  http://aquaticcommons.org/id/eprint/15084 | 403 | 2014-05-27 14:45:15 | 15084 | United States National Marine Fisheries Service
    Details
    Publication Date: 2021-07-02
    Description: We examined the summer distribution of marine mammals off the northern Washington coast based on six ship transect surveys conducted between 1995 and 2002, primarily from the NOAA ship McArthur. Additionally, small boat surveys were conducted in the same region between 1989 and 2002 togather photographic identification data on humpback whales (Megaptera novaeangliae) and killer whales (Orcinus orca) to examine movements and population structure. In the sixyears of ship survey effort, 706 sightings of 15 marine mammal species were made. Humpback whales were the most common large cetacean species and were seen every year and atotal of 232 sightings of 402 animals were recorded during ship surveys. Highest numbers were observed in 2002, when there were 79 sightings of 139 whales. Line-transect estimates for humpback whales indicated that about 100 humpback whales inhabited these waters each year between1995 and 2000; in 2002, however, the estimate was 562 (CV= 0.21) whales. A total of 191 unique individuals wereidentified photographically and mark recapture estimates also indicated that the number of animals increased from under 100 to over 200 from 1995 to 2002. There was only limited interchange of humpback whales between this area and feeding areas off Oregon and California. Killer whales were also seen on every ship survey and represented all known ecotypes of the Pacific Northwest, including southernand northern residents, transients, and offshore-type killer whales. Dall’s porpoise (Phocoenoides dalli) were themost frequently sighted small cetacean; abundance was estimated at 181−291 individuals, except for 2002 when we observed dramatically higher numbers (876, CV= 0.30). Northern fur seals (Callorhinus ursinus) and elephant seals (Mirounga angustirostris) were the most common pinnipedsobserved. There were clear habitat differences related to distance offshore and water depth for different species.
    Keywords: Ecology ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 563-580
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  • 6
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    Baleen whales are not important as prey for killer whales Orcinus orca in high-latitude regions (2011)
    Inter-Research
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Inter-Research, 2007. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 348 (2007): 297-307, doi:10.3354/meps07015.
    Description: Certain populations of killer whales Orcinus orca feed primarily or exclusively on marine mammals. However, whether or not baleen whales represent an important prey source for killer whales is debatable. A hypothesis by Springer et al. (2003) suggested that overexploitation of large whales by industrial whaling forced killer whales to prey-switch from baleen whales to pinnipeds and sea otters, resulting in population declines for these smaller marine mammals in the North Pacific and southern Bering Sea. This prey-switching hypothesis is in part contingent upon the idea that killer whales commonly attack mysticetes while they are in these high-latitude areas. In this study, we used photographic and sighting data from long-term studies of baleen whales in 24 regions worldwide to determine the proportion of whales that bear scars (rake marks) from killer whale attacks, and to examine the timing of scar acquisition. The results of this study show that there is considerable geographic variation in the proportion of whales with rake marks, ranging from 0% to 〉40% in different regions. In every region, the great majority of the scars seen were present on the whales’ bodies when the animals were first sighted. Less than 7% (9 of 132) of scarred humpback whales with multi-year sighting histories acquired new scars after the first sighting. This suggests that most killer whale attacks on baleen whales target young animals, probably calves on their first migration from low-latitude breeding and calving areas to high-latitude feeding grounds. Overall, our results imply that adult baleen whales are not an important prey source for killer whales in high latitudes, and therefore that one of the primary assumptions underlying the Springer et al. (2003) prey-switching hypothesis (and its purported link to industrial whaling) is invalid.
    Description: This study was supported in part by funding from the Marine Mammal Commission.
    Keywords: Predation ; Killer whale ; Baleen whale ; Scars ; North Pacific ; Whaling
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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