Beluga, Delphinapterus leucas, ethogram: A tool for cook inlet beluga conservation?

Abstract

We present the first peer-reviewed wild beluga, Delphinapterus leucas, whale ethogram, a comprehensive description and definition of behavioral states and events exhibited by the endangered stock of Cook Inlet beluga whales (CIBWs). The ethogram can be used to help quantify beluga behaviors and increase the utility of future and ongoing beluga behavioral studies, in Cook Inlet and for other populations. We tested the applicability of the ethogram by quantitatively examining spatial, temporal, and environmental effects on the probability of observing specific beluga behaviors in Eagle Bay and Eagle River (Knik Arm, Cook Inlet). Behaviors were observed and recorded from 2007 to 2011 between May and December when belugas are known to forage in the study area. We found that CIBWs are generally more likely to travel than mill in Eagle Bay, except when the tide is ebbing and above its midpoint, and that traveling occurred more frequently in Eagle River than in either the north or south sections of the bay. The results of our quantitative behavioral analysis can be compared with anecdotal observations of whale activity in the bay, and we encourage further investigation to more fully explain our results. The explicit language used to define this beluga ethogram will facilitate a more standard approach to behavioral studies of CIBWs, provide a means to quantify the response of CIBWs to anthropogenic activities, and allow comparison among multiple populations. Thus, this CIBW ethogram will potentially promote innovative approaches to help manage the endangered CIBW population.