Passive acoustic monitoring of coastal dolphins
Dr Christine Erbe, Centre for Marine Science and Technology, Curtin University
Australian snubfin and Indo-Pacific humpback dolphins are two dolphin species particularly vulnerable to local extinction. This is because they occur in small populations within a fragmented distribution, and their coastal distribution overlaps with areas of highest human use in the marine environment. One of the major threats to these species is coastal zone development, and in Australia there are currently many large-scale coastal developments associated with the mining industry underway or proposed throughout much of these species range.
Both species are of international conservation significance. However, there are currently large gaps in the knowledge of these species’ distribution and abundance throughout their potential range in Australia. Their shallow, turbid habitat, small population sizes, fragmented distribution and cryptic behaviour make visual surveys challenging and expensive whereas passive acoustic monitoring of these dolphins is a non-invasive and potentially cost-effective alternative.
Passive acoustic surveys are increasingly used as either a stand-alone method or for complementing visual survey methods, for detecting cetaceans and identifying abundance and habitat use. This method relies on using the vocalisations of the animals to monitor their movement and behaviour.
The overall objective of this project is to develop a method for conducting passive acoustic surveys of Australian snub-fin and Indo-Pacific humpback dolphin populations in developed and remote coastal environments, to monitor distribution and identify habitat use.
To achieve this objective, we will:
1. Calibrate a high frequency, broadband acoustic system and develop automated detection algorithms
2. Validate the acoustic system with concurrent boat-based visual surveys, and
3. Test the efficacy of passive acoustic systems for detecting snubfin and humpback dolphins in un-surveyed areas.
Passive acoustic monitoring is potentially a powerful, non-lethal, non-invasive method for assessing dolphin abundance and trends, defining habitat use and monitoring population characteristics. This technique could be applied throughout the range of this species and provide data that will inform assessments of the status of Australian snubfin and humpback dolphins under the Environmental Protection and Biodiversity Conservation Act 1999 and parallel state legislation.
This project is being funded by the Australian Marine Mammal Centre, a part of the Australian Antarctic Division.