Bottom contact behaviour by humpback whales in Brazilian waters: first underwater observations at Trindade Island

Flavia C Frizzera Pinheiro,Robson G Santos,Hudson T Pinheiro,Salvatore Siciliano

doi:10.1186/s41200-016-0063-0

Abstract

Few records of humpback whales (Megaptera novaeangliae) have been made in Brazilian oceanic waters. This article reports the first record of bottom contact behaviour by humpback whales in Brazilian waters and adds four new sightings of the species to Trindade, an island located 1160 km from the Brazilian coast. The bottom contact behaviour has been associated with moult and hygienic functions for some cetaceans. The change of water temperature, triggered by the migration from cold Antarctic waters to the warm tropical Trindade coast, could have accelerated the turnover of skin superficial layers and the moulting process to this humpback whale here reported. Despite such uncertain reason of the behaviour, this novel record comes to increase the behavioural repertoire for the humpback whales in Brazilian waters, may be possibly an additional cleaning strategy.

Highlights

The humpback whale, Megaptera novaeangliae, is found in all oceans, its distribution pattern is linked to migratory movements (Zerbini et al 2006)
This note reports the first record of bottom contact behaviour by humpback whales in Brazilian waters and adds four new sightings of the species at Trindade Island (Fig. 1). These sightings were made between May 25 and June 17, 2009, probably, representing the earlier migrants arriving for the breeding season off Brazil, which normally occurs between July and November (Siciliano 1997; Morete et al 2007)
The expected low numbers of whales around Trindade in that period decreases the possibility of communication purposes. Despite such uncertain reason of the behaviour, this novel record comes to increase the behavioural repertoire for the humpback whales in Brazilian waters and may represent an additional cleaning strategy

Summary

Introduction

The humpback whale, Megaptera novaeangliae, is found in all oceans, its distribution pattern is linked to migratory movements (Zerbini et al 2006). This species uses polar zones as feeding grounds in the summer, and tropical and sub-tropical zones as mating and calving grounds in the winter (Zerbini et al 2004). Trindade Island (20°30′30′′S, 29°19′ 30′′W), located at 1160 km from Brazilian coast (Fig. 1), annually receives these whales in its surrounding waters (Siciliano et al 2012). Humpback whales were recorded in Trindade Island surroundings since the whaling period, in the XIX century (Townsend 1935).

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