Eavesdropping on dolphins!
The Marine Mammal Foundation is all about conducting applied research with real conservation outcomes. We use many different tools to assess the endangered Burrunan dolphins, including acoustics!
Dolphins rely heavily on sound production to navigate, locate prey and communicate. As social animals, being able to recognise familiar individuals and maintain group cohesion is essential for their survival, depending largely on their ability to communicate with each other! With an ever increasing human population and a greater number of vessel on our waterways, the underwater world is fast becoming a very noisy place! Whilst we would love to be on the water across all of our study locations, it is not feasible, so it led us to thinking a little outside the box to explore a new method of detection dolphin presence and noise impact.
This coming field season we are undertaking a new method to passively monitor the underwater world and eavesdrop on our amazing marine mammals, including the endangered Burrunan dolphin. We are looking to install sound stations, called SoundTraps, across both habitats of known resident Burrunan dolphin populations. SoundTraps are compact self-contained underwater sound recorders for ocean acoustic research.
This technology allows us to simultaneously operate as a passive acoustic recorder and a high frequency click detector. Having SoundTraps in place constantly recording will allow us to detect movement patterns of the Burrunan dolphins, and other marine mammals. This will give us a greater picture of the usage habitat usage and movement patterns of the two populations.
The added beauty of these devices is they collect ambient noise, also allowing us to assess the ambient noise levels across our main study areas; assess noise coming from small and large vessel and natural habitat sounds.
Our main study focus is to investigate the impact noise is having on our dolphins. The frequency of the sounds produced by Burrunan dolphins overlaps the sound produced by recreational boats. Research has suggested that in noisy environments, dominated by recreational boating noise, dolphins may adjust call rates and shift their whistle frequencies to the range with lower noise interference in order to increase transmission efficiency and detectability of their acoustic signals (Rako-Gospic and Picciulin, 2016; Luis et al. 2014).
Disturbances can hinder the core biological activities of dolphins and thus the health and condition, in addition, can cause displacement from areas of high impact to areas of low impact. This disturbance and displacement can greatly affect the natural state of the dolphins (feeding, resting, social, calving rate etc). Before we can tell if this is happening, we need to conduct robust research to ascertain the natural and anthropogenic noise in the marine environment, then overlay that with what we know about the Burrunan dolphin acoustic repertoire.
We have been fortunate enough to buy one SoundTrap, via external funding sources, and can possibly lend another SoundTrap for a short period of time, but ultimately we would like to have these passive acoustic monitoring stations throughout our study regions.
How can you help?
Your support will allow us to not only eavesdrop on the amazing underwater world but investigate the threatening processes that may be affecting these endangered populations.
Our aim is to have four SoundTraps in place across both Victorian the resident population.
Each SoundTrap costs $4700
All donations or gifts over $2 are tax deductible.