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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13686

Modeling breeding habitats of humpback whales as function of group composition

Aldo S. Pacheco*, Miguel A. Llapapasca, Nadia L. López-Tejada, Sebastian Silva, Belen Alcorta

*Corresponding author:

ABSTRACT: The humpback whale Megaptera novaeangliae is undergoing a population increase after ca. 40 years of a whaling ban. However, anthropogenic activities threaten the recovery in recolonized breeding habitats. Predictive habitat models are important tools that can help create effective conservation measures. Due to the spatially structured distribution of this species that depends on the presence of calves and number of individuals, models must account for specific population variability that could refine management direction. This study aims to model the potential breeding habitats of humpback whales considering group type variability. A total of 10 years of data (3115 sighted humpback whales from 2010 to 2019) obtained from whale watching surveys in the breeding are of northern Peru (4°S, Southeast Tropical Pacific) were used. Maximum entropy models were constructed to predict potential habitats for breeding humpback whales considering groups with and without the presence of calves. Depth and sea surface temperature were used as descriptors for modeling the potential habitat of humpback whale groups. The optimal potential habitat for groups with calves was located between 20 and 50 m depth. Groups without calves ranged in habitat widely, from 20 to 100 m depth. Depth was the main explanatory variable for all models. The predictive character of these models shows segregated potential habitats of breeding humpback whales, which could help refine conservation actions. For example, to limit the number of whale-watching boats with mother and calf pairs in shore waters, while restricting the use of gillnets in transitional neritic to oceanic waters is mandatory to mitigate entanglements.