The Role of Environmental Drivers in Humpback Whale Distribution, Movement and Behavior: A Review

Abstract

Humpback whales, Megaptera novaeangliae, are a highly migratory species exposed to a wide range of environmental factors during their lifetime. The spatial and temporal characteristics of such factors play a significant role in determining suitable habitats for breeding, feeding and resting. The existing studies of the relationship between oceanic conditions and humpback whale ecology provide the basis for understanding impacts on this species. Here we have determined the most relevant environmental drivers identified in peer-reviewed literature published over the last four decades, and assessed the methods used to identify relationships. A total of 148 studies were extracted through an online literature search. These studies used a combined estimated 105,000 humpback whale observations over 1,216 accumulated study years investigating the relationship between humpback whales and environmental drivers in both Northern and Southern Hemispheres. Studies focusing on humpback whales in feeding areas found preferences for areas of upwelling, high chlorophyll-a concentration and frontal areas with changes in temperature, depth and currents, where prey can be found in high concentration. Preferred calving grounds were identified as shallow, warm and with slow water movement to aid the survival of calves. The few studies of migration routes have found preferences for shallow waters close to shorelines with moderate temperature and chlorophyll-a concentration. Extracting information and understanding the influence of key drivers of humpback whale behavioral modes are important for conservation, particularly in regard to expected changes of environmental conditions under climate change.

Decreases in encounter rate of endangered Northeast Pacific humpback whales in Southern Costa Rica: Possible changes in migration pattern due to warming events

“…and not for thermoregulation, thereby ensuring the survival of the calf (Braithwaite et al, 2015;Meynecke et al, 2021). The energy needs of whales vary according to their sex and reproductive status, being reflected in the temporal variability at the time of arrival to their breeding grounds and in the length of stay (Craig et al, 2003;Avila et al, 2020).…”

“…The energy needs of whales vary according to their sex and reproductive status, being reflected in the temporal variability at the time of arrival to their breeding grounds and in the length of stay (Craig et al, 2003;Avila et al, 2020). In other humpback whale populations, it has been observed that individuals that do not have sufficient energy reserves do not migrate to their breeding grounds so that the abundance of adults and calves decreases in these areas (Frankel et al, 2021;Meynecke et al, 2021;Schall et al, 2021).…”

“…Humpback whale populations that have been monitored for decades showed that the abundance of mothers with calves at breeding grounds decreases considerably when abnormal warm conditions occur at their feeding grounds, as well as temporary changes in the arrival of whales to their feeding grounds related to the early melting of ice (Ramp et al, 2015;Cartwright et al, 2019;Frankel et al, 2021). Humpback whales are modifying the timing of their migration and their distribution, as well as their stay in their breeding and feeding grounds (Avila et al, 2020;Meynecke et al, 2021).…”

Cetacean distribution in relation to oceanographic features at the Kerguelen Plateau

“…Of the nine cetacean species observed, no niche separation was apparent, and all species were observed throughout the survey area. This is an interesting finding, since mysticetes such as humpback whales (Meynecke et al 2021), and odontocetes (such as pilot and beaked whales) have differential life-history patterns and diets that may not all be so reliant on environmental drivers, such as Chl-a. For example, pilot whales, which feed predominantly on mesopelagic fish and deepwater squids (Gannon et al 1997), are known to forage close to shelf breaks and submarine canyons, potentially using specialised foraging behaviours for targeting steep bathymetric gradients, meaning that their latitudinal distribution may be limited to regions where this foraging strategy is effective (Thorne et al 2017).…”

Detection of Habitat Shifts of Cetacean Species: A Comparison Between 2010 and 2017 Habitat Suitability Conditions in the Northwest Atlantic Ocean

“…For highly mobile, large animals, such as cetaceans, their distribution and response to a changing environment is influenced by its feeding behaviors, preferences, and flexibilities, along with its physiological needs and tolerances, particularly those of the newborns. For example, Meynecke et al (2021) reviewed over 148 studies to identify humpback whale habitat preferences during their annual cycle. They found in feeding grounds the explanatory covariates included upwelling strength, high chlorophyll-a concentrations, depth and currents.…”