Possible Sexing Technique for Humpback Whales (Megaptera novaeangliae)

1980 ◽  
Vol 37 (12) ◽  
pp. 2362-2364 ◽  
Author(s):  
V. P. Jurasz ◽  
D. McSweeney ◽  
C. M. Jurasz
Keyword(s):  
Morphological Feature ◽  
Megaptera Novaeangliae ◽  
Pregnant Female ◽  
Humpback Whales ◽  
Reasonable Accuracy ◽  
Southeast Alaska ◽  
Dorsal Fin ◽  
Breeding Grounds

By comparing photographs of humpback whales (Megaptera novaeangliae) photographed at the peak of their arch during a dive, we found some to be smooth and others to be scalloped middorsally caudal to the dorsal fin. Out of 410 photographs taken in southeast Alaska and Hawaii, 66% were found to be smooth and 34% scalloped. All females with calves were smooth. One pregnant female was smooth and only one female who was pregnant was slightly scalloped. One known male was scalloped and one "singer" on the Hawaiian breeding grounds was scalloped. We suggest that the smoothness or scalloping of this region is a morphological feature and can be used with reasonable accuracy to determine sex in humpback whales.Key words: humpback whales, morphology, sex

Site fidelity and residence times of humpback whales (Megaptera novaeangliae) on the Brazilian coast

2012 ◽  
Vol 92 (8) ◽  
pp. 1783-1791 ◽  
Author(s):  
Clarêncio G. Baracho-Neto ◽  
Elitieri Santos Neto ◽  
Marcos R. Rossi-Santos ◽  
Leonardo L. Wedekin ◽  
Mariana C. Neves ◽  
...  
Keyword(s):  
Residence Time ◽  
Site Fidelity ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Brazilian Coast ◽  
Northern Coast ◽  
Occupancy Rate ◽  
Breeding Grounds ◽  
Minimum Number ◽  
Using Data

Humpback whales (Megaptera novaeangliae) migrate between their feeding grounds, located in high latitudes, and their breeding grounds, located in low latitudes, exhibiting certain levels of site fidelity to their migratory destinations. The residence time, also known as occupancy rate, can be defined as the minimum number of days that those individuals remained in the same area. In this paper, site fidelity and residence time of humpback whales that breed off the northern coast of Bahia, Brazil were investigated. Data were collected between 2000 and 2009 on-board research cruises and whale watching vessels. This paper also studies possible differences between males and females with respect to site fidelity off the Brazilian coast, using data collected since 1989. A total of 841 whales were photo-identified. The vast majority of the whales (96%, N = 809) were seen only once in the studied area, while 4% (32 individuals) were seen twice. Most of the resights occurred within the same season (72%, N = 23), while 9 resights (28%) occurred in different years. None of the individuals were seen more than twice. The average site fidelity rate was 1% and the occupancy rate varied from one up to 21 days (mean = 5.3; SD = 5.4, N = 23).

Dorsal fin scars as indicators of age, sex, and social status in humpback whales (Megaptera novaeangliae)

1988 ◽  
Vol 66 (2) ◽  
pp. 416-420 ◽  
Author(s):  
Kevin Chu ◽  
Sharon Nieukirk
Keyword(s):  
Social Status ◽  
Breeding Season ◽  
Intrasexual Competition ◽  
Megaptera Novaeangliae ◽  
Physical Contact ◽  
Humpback Whales ◽  
Dorsal Fin ◽  
Large Groups

We compared the number of linear marks and the shapes of dorsal fins of different classes of humpback whales during the breeding season. Male humpbacks tend to have more marks than females. Such marks are probably scars resulting from physical contact during intrasexual competition for mates. Not all males have marks; therefore, an unmarked adult humpback could be a male or a female. An adult with many marks is likely a male, however. Differences in the dorsal fins of principal and secondary escorts in large groups of competing males suggest that not all escorts have the same chance of attaining principal escort status. Therefore, male – male competitions in large groups should not necessarily be viewed as contests between equals. Principal escorts showed significantly more of some types of marks than did lone escorts of cows with calves, suggesting that not all lone escorts may retain their position if challenged.

Interchange of humpback whales (Megaptera novaeangliae) between northern Philippines and Ogasawara, Japan, has implications for conservation

2020 ◽  
Vol 26 (4) ◽  
pp. 378
Author(s):  
Shotaro Nakagun ◽  
Laetitia I. Smoll ◽  
Takayuki Sato ◽  
Cynthia A. A. Layusa ◽  
Jo Marie V. Acebes
Keyword(s):  
North Pacific ◽  
Site Fidelity ◽  
Western North Pacific ◽  
The Philippines ◽  
Scientific Data ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Breeding Grounds ◽  
High Site ◽  
Pass Through

Humpback whales (Megaptera novaeangliae) in the western North Pacific breed in the Philippines and Japan, where there is relatively little scientific data available, leading to uncertainty about their population status and structure. This study investigates links between humpback whale populations in northern Philippines and Ogasawara, Japan, through a comparison of the most recent fluke identification catalogues. The Philippines catalogue (1999–2016) included 234 individuals, and the Ogasawara catalogue (1987–2014), 1389 individuals. The number of matched individuals was 86 (including 14 known females and 40 known males), corresponding to 36.8% of the Philippines and 6.2% of the Ogasawara catalogues. The findings included four within-season matches, with travel times as short as 25 days. The results suggest that a considerable portion of whales utilising Philippine waters pass through and also utilise the Ogasawara region, but the majority of whales found off Ogasawara either stay in that location, move to different breeding grounds, or remain out of the sampling area. Nevertheless, in light of the high site fidelity of individuals in the Philippines and Ogasawara area, as well as constant evidence of breeding activities, these regions are of importance to the lesser known western North Pacific subpopulation. Humpback whales migrating to this part of the world are estimated to be in relatively low abundance, therefore continued conservation attention is needed.

Local and migratory movements of humpback whales (Megaptera novaeangliae) satellite-tracked in the North Atlantic Ocean

2014 ◽  
Vol 92 (1) ◽  
pp. 9-18 ◽  
Author(s):  
A.S. Kennedy ◽  
A.N. Zerbini ◽  
O.V. Vásquez ◽  
N. Gandilhon ◽  
P.J. Clapham ◽  
...  
Keyword(s):  
Dominican Republic ◽  
North Atlantic ◽  
Gulf Of Maine ◽  
North Atlantic Ocean ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
The North ◽  
Breeding Grounds ◽  
Multiple Feeding ◽  
Feeding Grounds

North Atlantic humpback whales (Megaptera novaeangliae (Borowski, 1781)) migrate from high-latitude summer feeding grounds to low-latitude winter breeding grounds along the Antillean Island chain. In the winters and springs of 2008 through 2012, satellite tags were deployed on humpback whales on Silver Bank (Dominican Republic) and in Guadeloupe (French West Indies) breeding areas. Whales were monitored, on average, for 26 days (range = 4–90 days). Some animals remained near their tagging location for multiple days before beginning their northerly migration, yet some visited habitats along the northwestern coast of the Dominican Republic, northern Haiti, the Turks and Caicos islands, and off Anguilla. Individuals monitored during migration headed towards feeding grounds in the Gulf of Maine (USA), Canada, and the eastern North Atlantic (Iceland or Norway). One individual traveled near Bermuda during the migration. This study provides the first detailed description of routes used by North Atlantic humpback whales towards multiple feeding destinations. Additionally, it corroborates previous research showing that individuals from multiple feeding grounds migrate to the Antilles for the breeding season. This study indicates that North Atlantic humpbacks use an area broader than the existing boundaries of marine mammal sanctuaries, which should provide justification for their expansion.

scholarly journals Photo-identification of individual Southern Hemisphere humpback whales (Megaptera novaeangliae) using all available natural marks:

2020 ◽  
Vol 21 (1) ◽  
pp. 71-83
Author(s):  
Wally Franklin ◽  
Trish Franklin ◽  
Peter Harrison ◽  
Lyndon Brooks
Keyword(s):  
Poor Quality ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Parameter Estimates ◽  
Photo Identification ◽  
Dorsal Fin ◽  
Matching Process ◽  
Lateral Body ◽  
Logistic Mixed Effects Model ◽  
Natural Marks

Misidentification errors in capture-mark recapture studies of humpback whales (Megaptera novaeangliae) related to poor quality of photographs as well as changes in natural marks can seriously affect population dynamics parameter estimates and derived estimates of population size when using sophisticated modelling techniques. In this study we used an innovative photo-identification matching system to investigate and examine the long-term stability and/or changes in natural marks on ventral-tail flukes, dorsal fin shapes and lateral body marks from a sample of 79 individual humpback whales, resighted in 2 to 11 years over timespans ranging from 2 to 21 years. A binary logistic mixed effects model, on a pair-matched sample of the 79 individual whales, found no significant differences in the proportions of ventral-tail fluke marks, dorsal fin shapes and lateral body marks, that displayed changes in primary and/or secondary characteristics over years (F=0.939, df=1/156, p =0.334). The results of this study substantiate the value and reliability of using primary and secondary natural marks on the ventral-tail flukes, in conjunction with dorsal fin shapes and secondary lateral body marks as double-tags. This provides a means of maximising observations of individual humpback whales over years, while minimising and managing misidentification errors in the photo-identification matching process, thus significantly improving modelling outcomes.

Photo-identification matches of humpback whales (Megaptera novaeangliae ) from feeding areas in Russian Far East seas and breeding grounds in the North Pacific

2017 ◽  
Vol 34 (1) ◽  
pp. 100-112 ◽  
Author(s):  
Olga V. Titova ◽  
Olga A. Filatova ◽  
Ivan D. Fedutin ◽  
Ekaterina N. Ovsyanikova ◽  
Haruna Okabe ◽  
...  
Keyword(s):  
North Pacific ◽  
Russian Far East ◽  
Far East ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Photo Identification ◽  
The North ◽  
Breeding Grounds ◽  
The North Pacific

Foraging dive patterns of humpback whales, Megaptera novaeangliae, in southeast Alaska: a cost–benefit analysis

1988 ◽  
Vol 66 (11) ◽  
pp. 2432-2441 ◽  
Author(s):  
William Ford Dolphin
Keyword(s):  
Cost Benefit Analysis ◽  
Dominant Role ◽  
Accurate Determination ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Energy Costs ◽  
Southeast Alaska ◽  
Prey Patch ◽  
Underwater Cameras ◽  
Time And Energy

The foraging behavior of humpback whales (Megaptera novaeangliae) summering in southeast Alaska was studied from 1979 to 1984 using surface observations, a 120-kHz echo sounder, and remotely operated underwater cameras. Considerations of foraging costs as well as profits appear to play a dominant role in determining feeding dive patterns of the whales. The energy costs of diving, based on observed blow rates, estimated tidal volume, and O2 extraction efficiency, have previously been shown to increase with increasing depth of dive during foraging episodes. Time spent diving into and returning from a prey patch, and time spent at the surface recovering from a dive represent the time costs of foraging. The percentage of time available for actual capture of prey decreased with increasing depth of dive. Thus, time and energy costs were highly correlated with the depth of the target prey patch. In conjunction with acoustic scans, the underwater cameras made possible the accurate determination of potential prey patch depths, densities, and vertical extent. Prey patches were ranked using a derived weighted density value and associated time and energy expenditure required of the whales to feed upon the patch (viz., gain–cost representation). Foraging models incorporating prey patch density value and time and energy costs of diving resulted in the best fit when compared with observed foraging patterns of the humpback whales.

Observations on the migrations of North Pacific humpback whales (Megaptera novaeangliae)

1985 ◽  
Vol 63 (2) ◽  
pp. 308-314 ◽  
Author(s):  
James D. Darling ◽  
Daniel J. McSweeney
Keyword(s):  
British Columbia ◽  
North Pacific ◽  
Ventral Side ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Prince William Sound ◽  
White Pigment ◽  
Southeast Alaska ◽  
Black And White ◽  
Northeast Pacific

Migratory destinations of northeast Pacific humpback whales (Megaptera novaeangliae) were determined by repeat sightings of photographically identified individuals, using the black and white pigment patterns on the ventral side of the flukes. Individuals identified between 1975 and 1982 included 1056 in Hawaii, 420 in southeast Alaska, 54 in Prince William Sound, Alaska, 8 in British Columbia, and 12 in the Revillagigedo Islands, Mexico. Of these, 51 were found in Hawaii and southeast Alaska, 8 in Hawaii and Prince William Sound, 1 in Hawaii and British Columbia, and 1 in Mexico and Hawaii. Some travelled for four, five, and six successive seasons between Hawaii and southeast Alaska. One whale was found in British Columbia one summer and in southeast Alaska the next; the same individuals were commonly found off both Kona, Hawaii, and West Maui in winter. The study suggests that separate summer feeding areas may exist in the northeast Pacific where individuals prefer to feed. Migratory connections suggest that all humpbacks in the eastern North Pacific are of the same stock.

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