| Summary: | The Pacific coast of Peru, Ecuador, Colombia and Panama are important humpback whale wintering grounds where they mate, give birth and nurse their young. Part of the coast off Esmeraldas, in the North of Ecuador, was established as a marine reserve in October 2008 in order to protect part of this breeding area and the marine biodiversity within it. This breeding area is located next to one of the most important ports in Ecuador (Balao), where oil from the Amazon is shipped to various destinations around the world. Human activity is constantly growing in the marine environment including sound contamination caused by oil and gas exploration and maritime traffic. Information on the characteristics of key habitats for cetaceans and their distributions are needed to assist in conservation measures and explain ecological processes, where depth and bottom composition are considered static environmental parameters that could be used to understand habitat preference and behavior acoustic. In this study, we investigated the relationship and distribution of humpback whale social groups and the occurrence of song within the study area in relation to depth (up to 200 m), and substrate type (muddy soft and mixed). Groups of pairs, singletons, and groups with a calf not showed a strong sloped over type bottom and depth. However, spatial analyses revealed all social groups showed a low or moderately clustered distribution. Groups with a calf showed particular preference to mixed bottom substrates, whereas competitive groups displayed a low overall preference for bottom type or depth. Whereas, humpback whale songs were could be recorded frequently for all the study area. Our analyses showed that singers were randomly distributed and were not clustered over the study area. This suggests that singers do not appear to be selecting bottom type or depth. However, songs were recorded more often in shallow water than offshore in this wintering ground. The coast of Esmeraldas could therefore represent a core and vital habitat for the ...
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