scholarly journals Surface activity of Humpback whales Megaptera novaeangliae (Cetacea, Mysticeti) on the northern coast of Bahia, Brazil

2020 ◽  
Vol 21 (1) ◽  
pp. 1-12
Author(s):  
Leonardo Leão Versiani ◽  
Cristiano Schetini Azevedo

Surface activities of humpback whale groups were studied during the reproductive seasons of 2008, 2009 and 2010 on the northern coast of Bahia State, Brazil, near the district of Praia do Forte. The level of surface activity exhibited by 342 groups of whales was evaluated according to the sea state (measured on the Beaufort scale) and cloud coverage. Five behaviours were recorded: breaching, head slapping, tail slapping, pectoral flipper slapping and tail breaching. Most of the sightings occurred with a sea state classified on the Beaufort scale as 2, and with a cloud coverage of 26 to 50%. The most recorded level of surface activity was pectoral flipper slapping. The results showed that humpback whale behaviours do not seem to be influenced by the sea state or by cloud coverage.

2008 ◽  
Vol 25 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Diana G. Lunardi ◽  
Márcia H. Engel ◽  
Regina H. F. Macedo

Behavior of humpback whales was observed during the reproductive period off the northern coast of the state of Bahia (NB, n = 378 groups) and at the Abrolhos Bank (AB, n = 919) to compare patterns and group composition between the two locations. Alone individuals and dyads were most often encountered in both areas, although mother-calf pairs were more common in AB. While these two regions comprise distinct concentrations of humpback whales, with intrinsic environmental differences, behavior patterns were quite similar. The only behavioral differences found where for "tail up" and "resting". The patterns found here may reflect differences in the protection status of the areas or intrinsic environmental differences.


2020 ◽  
Vol 133 (3) ◽  
pp. 263-269
Author(s):  
Anthony J. Gaston ◽  
Neil G. Pilgrim ◽  
Vivian Pattison

We describe observations of Humpback Whales (Megaptera novaeangliae) made along the west side of central Hecate Strait, British Columbia, during the spring and summer of 1990–2018. From none in March, the frequency of sightings increased from early April to a peak in May, then fell in June with few in July. The frequency of sightings during the peak period (1 May–20 June) increased over the course of the study at a mean rate of 6% a year, similar to increases recorded elsewhere in British Columbian waters. The frequency of sightings was highest in years when the Oceanic Niño Index for January–March was low and peaked earlier in years when the Oceanic Niño Index was high. Both of these relationships suggest a connection between Humpback Whale sightings in western Hecate Strait and the larger oceanographic context, with sightings more frequent in years of lower water temperatures.


1999 ◽  
Vol 77 (3) ◽  
pp. 504-508 ◽  
Author(s):  
Dan R Salden ◽  
Louis M Herman ◽  
Manami Yamaguchi ◽  
Fumihiko Sato

We document through photographic identifications three humpback whale (Megaptera novaeangliae) winter ground interchanges between Hawai'i and Japan. Two of these whales, identified as male by their behavioral roles, made multiple interchanges across years; i.e., they were initially seen in Hawai'i, were later observed in Japan, and subsequently, returned to Hawai'i. The third whale was seen in only 2 different years, once in Japan and then in Hawai'i. Prior to this report, there has been only one published report of a Hawai'i-Japan interchange and only eight between Hawai'i and Mexico. None of these involved multiple interchanges. The current findings demonstrate that individual whales may be highly flexible in their annual choice of widely separated winter destinations and suggest that these wanderers may be mainly males. The occurrence of wanderers provides a mechanism for increasing genetic variability in the breeding populations and also suggests a mechanism for noted song similarities across different North Pacific winter grounds.


1986 ◽  
Vol 64 (10) ◽  
pp. 2075-2080 ◽  
Author(s):  
Gregory K. Silber

Humpback whale (Megaptera novaeangliae) social vocalizations (nonsong sounds) were clearly related to whale group size and surface activity. Social sounds occurred almost exclusively in groups containing three or more whales and were rarely heard near single whales, pairs, or cow–calf groups. Large groups (3 to 20 individuals) vocalized at an overall mean rate of 43.1 ± 55.52 sounds per whale/h. Group size changed frequently and a dramatic increase in vocalization rate resulted when a new whale entered a group. Large groups engaged in flurries of surface activity, such as breaching, flipper- and tail-slapping, and underwater bubbling. Aggressive encounters resulted from male–male interaction. Social sounds probably acted to demonstrate aggression or agitation as adult males competed for temporary social dominance within the group and for proximity to the female. Likewise, visual displays may have been used as threats in close quarters and were apparently produced in conjunction with sounds to convey levels of aggression. Although other studies suggested that surface activity increased with group size, I found a negative correlation between activity and group size, both in the group as a whole and per individual. In contrast, social vocalizations per group increased with group size while the vocalization rate per individual did not vary significantly with increasing group size.


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).


2002 ◽  
Vol 80 (4) ◽  
pp. 745-755 ◽  
Author(s):  
Alison S Craig ◽  
Louis M Herman ◽  
Adam A Pack

Male humpback whales (Megaptera novaeangliae) outnumber females on the winter grounds and compete physically for proximity to females. Analyses of identification photographs collected in Hawai'i from 1976 through 1995 and scan samples collected in 1998 showed that (i) reproductive potential (calving rate) for the following winter was greater for females without a calf than females with a calf, (ii) females without a calf were less likely to be found alone and more likely to be found in large pods than females with a calf, (iii) individual females were found in larger pods when without a calf than when with a calf, (iv) the probability of females with a calf being escorted by one or more males increased as the reproductive season progressed, and (v) head lunges occurred more commonly in all-adult pods than in pods containing a calf. We concluded that male humpback whales associate preferentially with females with high reproductive potential, that the attractiveness of individual females varies with their status (with a calf versus without a calf), that males become progressively less choosy over the course of the reproductive season as females without a calf become increasingly rare on the winter grounds, and that males expend more energy in competition over females without a calf than females with a calf.


1987 ◽  
Vol 65 (12) ◽  
pp. 2853-2863 ◽  
Author(s):  
Phillip J. Clapham ◽  
Charles A. Mayo

Humpback whale mother–calf pairs from a currently unexploited population were observed in Massachusetts Bay between 1979 and 1985. During this period, 44 individually identified mature females were observed, with a total of 72 calves. Of the 20 mothers observed with more than one calf during the study period, 12 had two calves and 8 had three calves. The observed calving intervals were 1 year (n = 1), 2 years (n = 16), 3 years (n = 10), and 4 years (n = 1). The crude birth rate varied from a low of 0.045 in 1981 to a high of 0.103 in 1983 (mean = 0.075). An alternative calculation of reproductive rate yielded a range of 0.30–0.43 calves per mature female per year. Mature females were observed significantly more frequently in years when they had a calf than in years when they did not. Females with calves associate with other whales less frequently than females without calves. Observations of calves feeding suggest that weaning may begin when calves are 5–6 months of age. Forty-five of the 49 calves born before 1985 separated from their mothers during the calf's second winter, while 37 of the 49 were observed to return to the study area in 1 or more years after separation from their mothers. One calf is known to have died. Two females born during the study period returned with calves of their own in later years. The high return rate of calves in years after separation strongly suggests that the composition of a humpback whale feeding stock is determined matrilineally.


2016 ◽  
Vol 94 (7) ◽  
pp. 517-527 ◽  
Author(s):  
M.M. MacKay ◽  
B. Würsig ◽  
C.E. Bacon ◽  
J.D. Selwyn

North Atlantic humpback whales (Megaptera novaeangliae (Borowski, 1781)) are increasing in number, necessitating current data from winter areas for assessing potential interactions with humans. Occurrence patterns of humpback whales wintering off Puerto Rico were investigated to predict where whales aggregate in nearshore areas. Here we describe the relationship between group associations of humpback whales and bathymetric features off western Puerto Rico. Data were collected from 2011 to 2014. Effort consisted of 240.9 vessel h, 13.0 aerial h, and 303.6 h of land observations conducted over 165 days. A total of 197 humpback whale groups were observed with n = 331 individuals: 91 (46.2%) singletons, 67 (34%) dyads, 17 (8.6%) mother–calf pairs, 8 (4.1%) competitive groups, 8 (4.1%) mother–calf–escort groups, and 6 (3.1%) mixed-species associations. A linear regression model supported that group composition correlated with hotspots associated with four bathymetric features. Dyads and competitive groups were dispersed among features in deeper water. Singletons were observed farther from a shelf edge, whereas singing males were closely associated with a shelf edge. Mother–calf pairs occurred nearshore in shallow water; however, when mother–calf pairs were sighted with an escort, they were offshore. This study is especially important ahead of possible removal from the Endangered Species list.


2015 ◽  
Vol 33 (2) ◽  
pp. 39 ◽  
Author(s):  
C. Miller ◽  
A. Batibasiga ◽  
S. Sharma-Gounder ◽  
P. Solomona

Intensive commercial whaling caused significant declines in Southern Hemisphere humpback whale (Megaptera novaeangliae) populations. In Fiji, land-based humpback whale surveys undertaken from 1956 to 1958 documented maximum weekly counts of more than 150 humpback whales in parts of the Bligh waters. These records provide an invaluable point of comparison to present-day observations as they occurred immediately prior to very large humpback whale catches in Antarctic waters to the south – and on potential migration routes – of humpback whales breeding in Fijian waters. We report here on a three-year (2010–2012) land-based survey also conducted in the Bligh waters during which a total of 33 individuals over 480 h were counted from Ovalau Island and 68 individuals over approximately 300 h were observed from Makogai Island. These findings suggest a large decrease in numbers of humpback whales seen in Fiji waters since commercial whaling operations.


1978 ◽  
Vol 35 (8) ◽  
pp. 1150-1152 ◽  
Author(s):  
Coleman Levenson ◽  
William T. Leapley

Humpback whale (Megaptera novaeangliae) distribution in the eastern Caribbean Sea was studied by means of solitary sonobuoys deployed from an oceanographic aircraft. Humpback whale sounds were detected on 33 of 82 sonobuoys deployed. It is estimated that 62 whales were detected in an area of 22 140 km2 by this method with whale density calculated at 2.8 × 10−3 whales/km2. For further experiments in selected areas we used a colinear array to obtain accurate counts of humpbacks. A total of 18 humpbacks were detected in this manner with a mean of 2.6 whales per array deployment. Combined acoustic and visual detections indicate a minimum of 119 humpbacks in the area surveyed. This rapid acoustic method could also be applied to detection of almost all odontocete cetaceans and to other marine mammals with distinctive vocal patterns. Key words: cetaceans, whales, acoustic detection, distribution, density, humpbacks, aircraft detectors, sonobuoys


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