[MARMAM] New paper on scale-dependent foraging ecology of bottlenose dolphins

Enrico Pirotta pirotts at libero.it
Mon Aug 5 01:23:19 PDT 2013


Dear MARMAM colleagues,

We are pleased to announce that the following paper has been published 
online:

Pirotta, E., Thompson, P. M., Miller, P. I., Brookes, K. L., Cheney, B., 
Barton, T. R., Graham, I. M., Lusseau, D. (2013), Scale-dependent foraging 
ecology of a marine top predator modelled using passive acoustic data. 
Functional Ecology. doi: 10.1111/1365-2435.12146

Summary
1. Understanding which environmental factors drive foraging preferences is 
critical for the development of effective management measures, but resource use 
patterns may emerge from processes that occur at different spatial and temporal 
scales. Direct observations of foraging are also especially challenging in 
marine predators, but passive acoustic techniques provide opportunities to 
study the behaviour of echolocating species over a range of scales.
2. We used an extensive passive acoustic data set to investigate the 
distribution and temporal dynamics of foraging in bottlenose dolphins using the 
Moray Firth (Scotland, UK). Echolocation buzzes were identified with a mixture 
model of detected echolocation inter-click intervals and used as a proxy of 
foraging activity. A robust modelling approach accounting for autocorrelation 
in the data was then used to evaluate which environmental factors were 
associated with the observed dynamics at two different spatial and temporal 
scales.
3. At a broad scale, foraging varied seasonally and was also affected by 
seabed slope and shelf-sea fronts. At a finer scale, we identified variation in 
seasonal use and local interactions with tidal processes. Foraging was best 
predicted at a daily scale, accounting for site specificity in the shape of the 
estimated relationships.
4. This study demonstrates how passive acoustic data can be used to understand 
foraging ecology in echolocating species and provides a robust analytical 
procedure for describing spatio-temporal patterns. Associations between 
foraging and environmental characteristics varied according to spatial and 
temporal scale, highlighting the need for a multi-scale approach. Our results 
indicate that dolphins respond to coarser scale temporal dynamics, but have a 
detailed understanding of finer-scale spatial distribution of resources.
 
KEY WORDS: echolocation; feeding buzz; GEEs; habitat preference; modelling; 
multi-scale; PODs; Tursiops 
 
A PDF copy of the work can be downloaded from: http://onlinelibrary.wiley.
com/doi/10.1111/1365-2435.12146/abstract
 
Please do not hesitate to contact me for any question regarding our work.
 
Best Regards,
Enrico Pirotta



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