Age at attainment of sexual maturity in humpback whales, Megaptera novaeangliae

1992 ◽  
Vol 70 (7) ◽  
pp. 1470-1472 ◽  
Author(s):  
Phillip J. Clapham
Keyword(s):  
West Indies ◽  
Sexual Maturity ◽  
Gulf Of Maine ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Annual Growth Rate ◽  
Growth Layer ◽  
The West ◽  
Similar Range ◽  
Layer Groups

Twelve female humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine produced first-observed calves at ages ranging from 5 to 7 years. These data confirm that most females of this species attain sexual maturity at an average age of approximately 5 years. Observations in the West Indies of two males, aged 6 and 7 years, engaged in breeding-related behavior that is characteristic of mature animals suggests that males attain sexual maturity within a similar range of ages to females, although they may not be able to successfully engage in intrasexual competition until later in life. These data imply that the examination of ear plugs to determine the age of dead humpback whales should be based upon an assumed annual growth rate of two growth layer groups, not one.

scholarly journals A note on the age at sexual maturity of humpback whales

2020 ◽  
pp. 71-73
Author(s):  
Peter B. Best
Keyword(s):  
Sexual Maturity ◽  
Gulf Of Maine ◽  
Accumulation Rate ◽  
Age Determination ◽  
Biological Data ◽  
Humpback Whales ◽  
Natural Mortality ◽  
Growth Layer ◽  
Younger Age ◽  
Layer Groups

The conclusion of researchers in the 1950s that humpback whales reached sexual maturity at about age five was largely influenced by their interpretation of baleen tracings, and to achieve consistency with these tracings the accumulation rate of ear plug laminations (growth layer groups: GLGs) was assumed to be two per year. However, ovulation and natural mortality rates calculated by these researchers under the same assumption produced estimates that are difficult to reconcile with other biological data or with more recent estimates using individual re-sighting data. Such disparities are reduced or disappear when an annual accumulation rate is used, in which case their ear plug data would have indicated a mean age at sexual maturity of 9–11 years. Recent estimates of the age of female humpback whales at first calving using longitudinal studies of photoidentified individuals have produced conflicting results, some (from southeastern Alaska) being compatible with the earlier age-determination studies, others (from the Gulf of Maine) suggesting a much younger age.

Occurrence, population composition, and habitat use of humpback whales in Samana Bay, Dominican Republic

1994 ◽  
Vol 72 (11) ◽  
pp. 1898-1907 ◽  
Author(s):  
David K. Mattila ◽  
Phillip J. Clapham ◽  
Oswaldo Vásquez ◽  
Robert S. Bowman
Keyword(s):  
Dominican Republic ◽  
North Atlantic ◽  
West Indies ◽  
Gulf Of Maine ◽  
Humpback Whales ◽  
Mammal Species ◽  
The West ◽  
The North ◽  
The Mean ◽  
Almost All

A study of humpback whales (Megaptera novaeangliae) was conducted between 1988 and 1991 in Samana Bay, Dominican Republic. Humpbacks were observed as early as the earliest survey (3 January) and as late as the latest (16 March). Local abundance varied from 0 whales per hour to a maximum of 3.2 whales per hour (mean = 1.70, SD = 0.79), and densities calculated from track surveys ranged from 0.09 to 0.82 whales per square nautical mile (mean = 0.31). Abundance generally peaked in February, but variation was observed both within a season and between years. Almost all whales were observed in the eastern part of the bay, towards or at its mouth. In all, 397 individuals were photographically identified during the study period. Of these, 18 were observed in more than 1 year (17 in 2 years, 1 in 3 years). A total of 15.8% of identified individuals were observed on more than 1 day in a year (maximum 5 days), with mothers representing 33.3% of all resightings. Observed occupancies of resighted animals ranged from 1 to 33 days (mean = 6.3 days, SD = 7.14). The mean group size was 1.95 (range = 1–15, SD = 1.30, n = 652 groups). Ninety-nine groups contained a calf, and all groups larger than three (n = 45) were competitive in nature. Comparisons of fluke photographs with the North Atlantic Humpback Whale Catalogue revealed 141 matches of 118 individuals to other areas. Of these, 76 were to high-latitude feeding grounds (including the Gulf of Maine, Newfoundland, Labrador, the Gulf of St. Lawrence, and west Greenland), while the remaining 65 were to other areas of the West Indies (Silver Bank, Navidad Bank, Puerto Rico, Virgin Bank, or Anguilla Bank) or to Bermuda. We suggest that Samana Bay is one of the most important winter habitats in the West Indies for humpback whales from all over the western North Atlantic, although whaling records suggest that the abundance of whales in this area may be a relatively recent phenomenon. Sightings of other marine mammal species in Samana Bay are summarized.

Population Estimate of the Humpback Whale (Megaptera novaeangliae) in the West Indies by Visual and Acoustic Techniques

1975 ◽  
Vol 32 (4) ◽  
pp. 499-506 ◽  
Author(s):  
H. E. Winn ◽  
R. K. Edel ◽  
A. G. Taruski
Keyword(s):  
North Atlantic ◽  
West Indies ◽  
Total Population ◽  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
New Method ◽  
Population Estimate ◽  
The West ◽  
Acoustic Techniques

Visual track census and a new method, acoustic counting, were used to estimate the humpback whale (Megaptera novaeangliae) population in the West Indies. Results produced by the two methods differed to some extent. The average or best estimate was 1018 whales with a range of 785–1157. Silver and Navidad banks, containing approximately 85% of the total population, are presently the major nursery grounds in the West Indies. The humpback whale population in the western North Atlantic has increased since the early part of the century.

scholarly journals Humpback Whale (Megaptera novaeangliae) observations in Laskeek Bay, western Hecate Strait, in spring and early summer, 1990–2018

2020 ◽  
Vol 133 (3) ◽  
pp. 263-269
Author(s):  
Anthony J. Gaston ◽  
Neil G. Pilgrim ◽  
Vivian Pattison
Keyword(s):  
British Columbia ◽  
Humpback Whale ◽  
Early Summer ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
The West ◽  
Peak Period ◽  
West Side

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.

scholarly journals Sexual maturation in free-ranging Chilabothrus angulifer (Serpentes: Boidae)

2016 ◽  
Vol 15 (2) ◽  
pp. 163
Author(s):  
Tomás M. Rodríguez-Cabrera ◽  
Javier Torres López ◽  
Ruben Marrero ◽  
Ernesto Morell Savall ◽  
Ana Sanz Ochotorena
Keyword(s):  
Growth Rate ◽  
Natural History ◽  
Reproductive Biology ◽  
Sexual Maturation ◽  
West Indies ◽  
Sexual Maturity ◽  
Limited Information ◽  
The West ◽  
In Captivity ◽  
Free Ranging

The Cuban Boa (C. angulifer) is the only boid snake in Cuba. It is the largest member of the genus, as well as the largest snake in the West Indies (> 400 cm in snout-vent length); as such, it is an iconic species of the Cuban herpetofauna. Although the snake’s natural history is poorly known, several studies describe aspects of its reproductive biology in captivity. Herein we document the sizes and ages at which both sexes reach sexual maturity in nature, and show that the Cuban Boa reaches adulthood at a much smaller size than previously reported for captive snakes. Based on the limited information on the growth rate of C. angulifer in nature, males must reach breeding size after 3 years and females after 5 years

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 Earlier Sightings of Humpback Whales in Antarctica

Oryx ◽  
1982 ◽  
Vol 16 (5) ◽  
pp. 430-430
Author(s):  
Peter Kinnear
Keyword(s):  
Antarctic Peninsula ◽  
West Coast ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
The West ◽  
British Antarctic Survey ◽  
The Antarctic

Nigel Bonner has documented sightings of humpbacks Megaptera novaeangliae off the west coast of the Antarctic Peninsula which seem to indicate some recovery of stocks (Oryx 16, 3: 231–232). It may therefore be worth placing on record the following sightings of this species made from Argentine Islands for 1970/72, when I was stationed at the British Antarctic Survey base.

Stable social associations among humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine

1991 ◽  
Vol 69 (12) ◽  
pp. 3012-3019 ◽  
Author(s):  
Mason T. Weinrich
Keyword(s):  
Gulf Of Maine ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Net Energy ◽  
Feeding Styles ◽  
Adult Females ◽  
Stable Association ◽  
Social Associations ◽  
Stable Pairs ◽  
Net Energy Gain

Groups of humpack whales (Megaptera novaeangliae) were observed from 1980 to 1987 on their feeding grounds in the southern Gulf of Maine. Although most groups were together for only brief periods, two types of stable association were found: 'continuous' (individual whales associated for at least 7 consecutive days; n = 30) or 'recurring' (individuals associated at least five times in a 6-week period; n = 21). Thirty-seven stable pairs and 3 stable trios involving 56 individual whales were recorded; 11 stable pairs re-associated during more than 1 year. Continuous associations lasted up to 79 days (mean 29.65). Thirty of the 40 associations (75.0%) contained only adults. Females were present in 22 adult associations (73.3%), whereas males were present in only 8 (26.6%). Females sighted with a calf the following year, and therefore pregnant, were members of 6 of the 11 (54.5%) associations that reformed. It is hypothesized that stable associations allow adult females to maximize their net energy gain through cooperative feeding, and may be comprised of closely related animals or individuals with compatible feeding styles.

Seasonal occurrence and annual return of humpback whales, Megaptera novaeangliae, in the southern Gulf of Maine

1993 ◽  
Vol 71 (2) ◽  
pp. 440-443 ◽  
Author(s):  
Phillip J. Clapham ◽  
Lisa S. Baraff ◽  
Carole A. Carlson ◽  
Margaret A. Christian ◽  
David K. Mattila ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Megaptera Novaeangliae ◽  
Rate Of Return ◽  
Seasonal Occurrence ◽  
Humpback Whales ◽  
The Mean

A study of 518 individually identified humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine between 1979 and 1988 showed high rates of both within-season occurrence and annual return. On average, 77.3% of whales were resighted on more than 1 day during the year (maximum 83 days), with occupancies ranging from 1 to 324 days (mean 88.1 days). The mean rate of return of individuals in consecutive years was 73.2% (range 59.1–87.4%), and the majority of whales were still being resighted up to 10 years later. Only 13 humpbacks were recorded during 50 midwinter surveys. Variation in the occurrence of individuals appears to be related to variability in the abundance of prey and perhaps to regional preferences.

Sign in / Sign up

Export Citation Format

Share Document