Sex-related site fidelity of humpback whales (Megaptera novaeangliae) to the Fueguian Archipelago feeding area, Chile

2013 ◽  
Vol 30 (2) ◽  
pp. 433-444 ◽  
Author(s):  
Jorge Acevedo ◽  
Carla Mora ◽  
Anelio Aguayo-Lobo
1997 ◽  
Vol 75 (11) ◽  
pp. 1923-1933 ◽  
Author(s):  
Alison S. Craig ◽  
Louis M. Herman

Humpback whales (Megaptera novaeangliae) perform extensive seasonal migrations between high-latitude summer feeding grounds and low-latitude winter reproductive grounds. To investigate gender-related site fidelity to the Hawaiian Islands, an important wintering area for North Pacific humpback whales, photographically based resight histories of 224 females and 416 males observed in Hawai'i from 1976 through 1991 were compiled. Results indicated that the mean number of years in which they were seen was higher for males than for females, that the probability of an individual being resighted across years was higher for males than for females, and that more males than females were seen in consecutive years. Potential sources of bias favoring the photographic capture of males were considered, but none were judged to be significant contributors to the results obtained. It was proposed instead that not all females undertake or complete the migration to the winter grounds each year. Because of the high energy costs of migration and reproduction, some females may overwinter in high latitudes, while others may become pregnant en route to the area traditionally associated with breeding and return to the feeding grounds before arriving at the terminal winter destination.


Author(s):  
Clarêncio G. Baracho-Neto ◽  
Elitieri Santos Neto ◽  
Marcos R. Rossi-Santos ◽  
Leonardo L. Wedekin ◽  
Mariana C. Neves ◽  
...  

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).


2020 ◽  
pp. 119-128
Author(s):  
Rebecca Leaper ◽  
Samantha Peel ◽  
David Peel ◽  
Nick Gales

There is potential value in exploring multi-stock models to address situations where humpback stocks are mixing. However, sensitivity to the assumptions underlying these models has yet to be fully explored. Using a simple simulation approach, the assumptions of a population model that allows for mixing of humpback whale (Megaptera novaeangliae) stocks D and E on feeding areas has been explored by relaxing the assumptions of the original Johnston and Butterworth model in a number of plausible ways. First the ability of the model to estimate parameters was checked for a situation where simulated data are generated from an underlying model of exactly the same form for which the actual values of these parameters are known (Scenario 1). Then the ability of the model to estimate these parameters when alternative forms and assumptions were used for the underlying model generating the data was investigated. Specifically, stocks were allowed to mix non-uniformly across each feeding area and catch was non-uniformly distributed across each feeding area (Scenario 2). The consequences of density dependence implemented on feeding rather than breeding areas (Scenario 3) were also examined. The original mixing model was robust to alternate mixing and catch allocation scenarios in all but one of the simulations, but when density dependence acted at the level of the feeding rather than the breeding areas, the model produced estimates that were quite different from the underlying population. It is recommend that the inclusion of density dependence on feeding areas in models that allow for mixing of whales on these grounds be investigated further.


2007 ◽  
Vol 3 (5) ◽  
pp. 467-470 ◽  
Author(s):  
Alison K Stimpert ◽  
David N Wiley ◽  
Whitlow W.L Au ◽  
Mark P Johnson ◽  
Roland Arsenault

Humpback whales ( Megaptera novaeangliae ) exhibit a variety of foraging behaviours, but neither they nor any baleen whale are known to produce broadband clicks in association with feeding, as do many odontocetes. We recorded underwater behaviour of humpback whales in a northwest Atlantic feeding area using suction-cup attached, multi-sensor, acoustic tags (DTAGs). Here we describe the first recordings of click production associated with underwater lunges from baleen whales. Recordings of over 34 000 ‘megapclicks’ from two whales indicated relatively low received levels at the tag (between 143 and 154 dB re 1 μPa pp), most energy below 2 kHz, and interclick intervals often decreasing towards the end of click trains to form a buzz. All clicks were recorded during night-time hours. Sharp body rolls also occurred at the end of click bouts containing buzzes, suggesting feeding events. This acoustic behaviour seems to form part of a night-time feeding tactic for humpbacks and also expands the known acoustic repertoire of baleen whales in general.


2020 ◽  
Vol 26 (4) ◽  
pp. 378
Author(s):  
Shotaro Nakagun ◽  
Laetitia I. Smoll ◽  
Takayuki Sato ◽  
Cynthia A. A. Layusa ◽  
Jo Marie V. Acebes

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.


2017 ◽  
Vol 95 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Briana H. Witteveen ◽  
Kate M. Wynne

We describe feeding-site fidelity in terms of the rate of annual return by individual humpback whales (Megaptera novaeangliae (Borowski, 1781)) to Kodiak Archipelago and Shumagin Islands feeding areas and the rate of exchange between these Gulf of Alaska feeding aggregations. Individual whales were photo-identified in both regions between 1999 and 2015 during vessel surveys, either throughout the feeding season (Kodiak region) or in brief 7- to 10-day windows (Shumagin Islands). Feeding-site fidelity was assessed in terms of individuals’ annual return rate, sighting interval, total number of years sighted, and movement between feeding areas. We found similarly high degrees of site fidelity in both regions and limited movement of individuals between them, suggesting that the Shumagin Islands and Kodiak Archipelago represent distinct feeding aggregations. Results did not appear affected by temporal differences in sampling strategy in these study areas.


2010 ◽  
Vol 26 (4) ◽  
pp. 787-802 ◽  
Author(s):  
Leonardo L. Wedekin ◽  
Mariana C. Neves ◽  
Milton C. C. Marcondes ◽  
Clarêncio Baracho ◽  
Marcos R. Rossi-Santos ◽  
...  

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