Exploring the Interplay of Environmental Factors, Humpback Whale (Megaptera novaeangliae) Occurrence, and Humpback Whale Traits in Mozambique's C1 Breeding Population Through SDM.

Abstract

The complex relationship between environmental factors, individual traits, and behavior plays a central role in shaping the microhabitat usage of populations, including humpback whales (HWs). As capital breeders, HWs undertake extensive annual migrations to seek optimal environmental conditions for mating and calving or feeding. The specific preferences for environmental variables within their breeding grounds can vary depending on the population and location. The C1 population, breeding in the waters of Mozambique is not well researched yet. Through boat surveys conducted over three years, presence-pseudo-absence data on HWs, along with various environmental and HW trait data, were collected and analyzed using species distribution models (SDMs). The findings revealed several key correlations: HW observation was negatively associated with the hour of the day and cloud coverage, with most sightings occurring in 2022, followed by 2020 and 2021. Also, the observation probability increased in the beginning of the breeding season and decreased at the end and there was an optimum in observation probability at a depth of around 100m. Groups with calves were found in areas with less strong tides, females and calves preferred shallower waters where they engaged in less active behavior aimed at protecting the calf and conserving energy. Morning sightings tended to be in shallower waters, while as the day progressed, HWs moved further offshore, likely engaging in mating and courtship behavior before returning to rest in the evening. However, further large-scale research is needed to confirm this daily rhythm. Understanding HW habitat preferences and behavior is essential for developing effective and adaptive conservation strategies, particularly in the face of human-induced habitat changes.

The complex relationship between environmental factors, individual traits, and behavior plays a central role in shaping the microhabitat usage of populations, including humpback whales (HWs). As capital breeders, HWs undertake extensive annual migrations to seek optimal environmental conditions for mating and calving or feeding. The specific preferences for environmental variables within their breeding grounds can vary depending on the population and location. The C1 population, breeding in the waters of Mozambique is not well researched yet. Through boat surveys conducted over three years, presence-pseudo-absence data on HWs, along with various environmental and HW trait data, were collected and analyzed using species distribution models (SDMs). The findings revealed several key correlations: HW observation was negatively associated with the hour of the day and cloud coverage, with most sightings occurring in 2022, followed by 2020 and 2021. Also, the observation probability increased in the beginning of the breeding season and decreased at the end and there was an optimum in observation probability at a depth of around 100m. Groups with calves were found in areas with less strong tides, females and calves preferred shallower waters where they engaged in less active behavior aimed at protecting the calf and conserving energy. Morning sightings tended to be in shallower waters, while as the day progressed, HWs moved further offshore, likely engaging in mating and courtship behavior before returning to rest in the evening. However, further large-scale research is needed to confirm this daily rhythm. Understanding HW habitat preferences and behavior is essential for developing effective and adaptive conservation strategies, particularly in the face of human-induced habitat changes.