Abundance, distribution and behaviour of humpback whales (

Abstract

Context Previous research has shown the presence of an endangered humpback whale population breeding off the Pacific coast of Central America. However, little is known about the density, size, social-group structure and spatial habitat use of this subpopulation. Aim The study goal was to characterise a potential breeding subpopulation of humpback whales in the waters off Nicaragua. Five objectives were used to achieve this goal: (1) estimate abundance, (2) determine encounter rates, (3) define group composition, (4) assess distribution, and (5) document habitat-use patterns. Method Boat-based surveys were conducted between November and April at two study sites along the Pacific coast of Nicaragua in the winters of 2004–2008 and 2016–2020. Key result Inter-annual mark–recapture estimates did not yield a reliable estimate of abundance. Encounter rates were lower for the northern study site than for the southern site. Group composition consisted of groups with calves, singers and competitive males. Conclusion These results confirmed that Nicaragua is a breeding area based on known breeding-ground behaviours observed in other areas, and similar environmental characteristics. Implication Distinct habitats were found at the two study sites, suggesting that Central American humpback whales might use different areas within the broader Central American breeding range according to their needs and activity.

First song description of the humpback whales, Megaptera novaeangliae (Balaenopteridae: Artiodactyla), breeding off Nicaragua

“…This indicates the 2018 Nicaragua CA song did not follow a strict theme order, as described for some other Southern hemisphere populations . The presence of common themes at both sites suggests that a certain level of movement of males takes place; this is in contrast with the low level of photographic recapture observed between sites (De Weerdt et al, 2022). This inconsistency highlights the need for further research to understand whale movements in this area.…”

“…There are 14 recognized Distinct Population Segments (DPS), of which seven located in the North Pacific, and amongst which the Central America DPS (Bettridge et al, 2015), the focus of this study. The Central America whales (hereafter CA whales) migrate to Central America between January and April, from their feeding areas on the West coast of the United States (Calambokidis et al, 1997;Calambokidis et al, 2000;De Weerdt et al, 2022). The waters off Nicaragua are considered important breeding habitats for CA whales with Padre Ramos being used mainly by mother-calf pairs, and San Juan del Sur mainly by adult whales (De Weerdt et al, 2022).…”

“…The Central America whales (hereafter CA whales) migrate to Central America between January and April, from their feeding areas on the West coast of the United States (Calambokidis et al, 1997;Calambokidis et al, 2000;De Weerdt et al, 2022). The waters off Nicaragua are considered important breeding habitats for CA whales with Padre Ramos being used mainly by mother-calf pairs, and San Juan del Sur mainly by adult whales (De Weerdt et al, 2022). CA whales are listed as endangered according to the National Marine Fisheries Service (NMFS) and little information is available on their ecology (Bettridge et al, 2015).…”

Towards the definition of the humpback whale population units along the Mexican and Central American coasts in the Pacific Ocean

“…Humpback whales arrive in Nicaragua in early January, the peak number is during February and March, and the last whales leave the region in mid‐April (De Weerdt et al, 2022). The behavior of the whales is typical of a breeding ground (De Weerdt & Ramos, 2019), although some feeding behavior has been observed.…”

Diel spatio-temporal patterns of humpback whale singing on a high-density breeding ground

“…Densities in Hawai'i are also greater than on many other breeding grounds (e.g. [58,84,[138][139][140][141][142][143]; also cf. [144]).…”