[MARMAM] *ECS Workshop announcement: Estimating the probability of detection from passive acoustic data*

Anna Cucknell acucknell at mcr-team.co.uk
Thu Feb 20 03:57:28 PST 2014

Hello ECS and MARMAM readers


Apologies for cross posting.


On Saturday 5th April 2014 at the upcoming European Cetacean Society
conference in Liege a discussion workshop on "Estimating the probability of
detection from passive acoustic data" will be held in the Aquarium.  The
workshop will cost 10 Euros and will run from in the afternoon from


Background: Assessing the status of cetacean populations, and the impacts of
and level of risk associated with anthropogenic activities is hampered by
limited abundance estimates for many areas. While abundance estimation by
visual means is possible for cetaceans, surveys are often limited by weather
conditions, eye height of observers, availability bias, high cost and
observer inconsistency. For those species that vocalise routinely, passive
acoustic techniques have been proposed as a more accurate and efficient
method of detection and can be utilised in poor weather conditions and at
night time.

Absolute abundance and population estimates from acoustic data have been
derived for animals which vocalise loudly and predictably, such as sperm
whales. However for animals which do not vocalise constantly or produce
vocalisations that may be relatively quiet or highly directional, the
probability of detection, needs to be determined empirically in order to
calculate absolute abundance or density estimates from acoustic edata.
Abundance estimation using acoustic techniques rely on deriving a
probability of detection which not only accounts for the amount of time an
animal vocalises, but also accounts for those times when vocalisations might
not be detected when animals orientate away from the hydrophone, temporarily
reduce the source level of vocalisations or when the depth of a vocalising
animal may influence likelihood of detection. Several research groups have
collected acoustic data sets utilising static recorders or line transect
methodologies and due to weather constraints, logistical limitations, poor
planning or suboptimal sighting conditions, were not able to collect visual
and / or acoustic data which would allow the probability of detection and
the level of responsive movement to be characterised. 

These data could substantially increase our knowledge on the seasonal and
regional abundance of species and inform critical conservation and
management actions. 


Objectives: For this workshop we aim to bring together interested scientists
in order to discuss and brainstorm methodologies suitable for providing
probabilities of detection in order to 'unlock' the previously collected
datasets, albeit with some caveats. Additionally we would like to stimulate
discussion on the development of best practise for estimating probability of
detection when acoustic data are being collected, especially for those areas
and species where visual techniques are significantly constrained.

The workshop will discuss methods to estimate the probability of detection
for towed and static passive acoustic studies with particular focus on
discussing the challenges animal group size, vocalisation depth, background
noise and behavioural adaptations to vocalisation rate and detectability add
to estimating the probability of detection.


If you would like to attend or offer to do a presentation at the workshop
please contact:  <mailto:acuknell at mcr-team.org> acuknell at mcr-team.org.



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