Líffræðifélag Íslands
Líffræðiráðstefnan 2013
Erindi 24

Acoustic and diving behaviour of two Mysticete species, humpback whales (Megapteranovaeangliae) and blue whales (Balaenoptera musculus) during feeding in Northeast Iceland

Marianne H. Rasmussen, Tomonari Akamatsu og Maria Iversen

National Research Institute of Fisheries Engineering, Ibaraki, Japan

Kynnir/Tengiliður: Marianne H. Rasmussen (mhr@hi.is)

Fixed passive acoustic monitoring is efficient for long term observation of vocalizing cetaceans. In this study, sounds from humpback whales and blue whales were recorded using acoustic biologging systems (AUSOMS-mini, Aqua Sound Inc., Kyoto) during August, 2011 and June, 2012 in Skjálfandí Bay, Northeast Iceland. An accelerometer (ORI4-D3GT, Little Leonardo, Tokyo) to monitor diving behaviour of individual whale was attached to the tag. Three humpback whales were tagged in 2011 and each tag was on for 2 h 30 min, 1 h and 20 min and 10 h and 22 min. The humpback whales dove to a maximum depth of 165 meters, which is close to the maximum depth. Lunge feeding sounds were clearly recorded during this time. During 21 hours recording of two individual blue whales in 2012, 8 h 45 min and 13 h 2 min each, numbers of lunge feeding events were recorded but only four calls were contained. All of them were down-sweep calls ranged from 105 Hz to 48 Hz. Sound duration was 1 s to 2 s. All tags in 2011 and 2012 were retrieved within six km from the tagged position; that suggest the animals did not move long distances and kept feeding. No behavioural alternations suggest limited initial effect of tagging for these animals. Sound production rate of a tagged individual during feeding seem to be relatively low.  However more long time data is needed to link the call production rate of individual animals in comparison with long term passive acoustic monitoring.