Seen or heard? A comparison of visual and acoustic autonomous monitoring methods for investigating temporal variation in occurrence of southern right whales
Passive acoustic detectors are widely used for monitoring distribution of cetaceans. Autonomous visual methods are less frequently employed; they are limited to detections during daylight and good weather, but offer potential advantages due to certainty of species’ identification and longevity of deployment. To compare performance of acoustic and visual methods, temporal changes in distribution of southern right whales, Eubalaena australis, were monitored in the remote sub-Antarctic Auckland Islands (50°31′S, 166°16′E). A time-lapse camera was deployed for 2 years from August 2010, taking an image every 70 min. The presence of whales was scored for each image taken during daylight (n = 8295). A passive acoustic recorder was deployed in August 2011, recording for 3.75 min every hour until battery life expired after 10 months. Each recording (n = 6978) was aurally reviewed. Both methods revealed a similar seasonal distribution; maximum detection rates were in the austral winter and no whales were detected in January or February. However, at the peak of right whale occurrence, the proportion of samples with whales detected was much higher for the acoustic recorder (93.9% in August) than the time-lapse camera (14.8%). A generalised additive model fitted to the visual data revealed significant effects of sea state and visibility. Acoustic detection rates were higher, probably because detection range is greater, and less affected by weather. The solar-powered time-lapse camera system, however, functioned effectively for much longer. We discuss the relative merits of visual and acoustic detectors and attempt to draw conclusions about their efficacy for different focal species and monitoring locations.
We would like to thank the Foundation for Research Science and Technology (FRST), the New Zealand Whale and Dolphin Trust, and the Marine Science Department at the University of Otago for funding this work. Sincere thanks also to the crew of RV Polaris II, Phil Heseltine, Anthony Davidson, Tim Cole for assistance in the field, Marta Guerra for assistance with image analysis, and New Zealand’s Department of Conservation for permitting. WR was supported by a FRST post-doctoral fellowship, and TW by a University of Otago Ph.D. scholarship. The manuscript was improved thanks to comments from two anonymous reviewers and the assistance of the editors.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
Research was carried out under Marine Mammal Research Permit Per/NO/2010/05 issued by the Department of Conservation to Will Rayment and Steve Dawson. The time-lapse camera was deployed on Enderby Island in compliance with High Impact, Research and Collection Permit SO-28239-RES issued by the Department of Conservation to Will Rayment. The acoustic recorder was deployed in Port Ross in compliance with Permit to Undertake Specified Study within a Marine Reserve SO-31108-MAR issued by the Department of Conservation to Trudi Webster. No ethical approvals were required.
- Burnham KP, Anderson DR (2002) Model selection and multi-model inference: a practical information-theoretic approach. Springer, New YorkGoogle Scholar
- Clark CW (1983) Acoustic communication and behaviour of the southern right whale. In: Payne RS (ed) Behaviour and communication of whales. Westview Press, BoulderGoogle Scholar
- Dawbin W (1986) Right whales caught in waters around south eastern Australia and NZ during the nineteenth and early twentieth centuries. Rep Int Whal Comm 10:261–268 (special issue) Google Scholar
- Gaskin DE (1964) Return of the southern right whale (Eubalaena australis Desm.) to New Zealand waters, 1963. Tuatara 12:115–118Google Scholar
- Hastie TJ, Tibshirani RJ (1990) Generalized additive models. Chapman & Hall, Boca RatonGoogle Scholar
- Kenney RD (2009) Right whales: Eubalaena glacialis, E. japonica and E. australis. In: Perrin WF, Würsig B, Thewissen JGM (eds) Encyclopedia of marine mammals. Academic Press, New YorkGoogle Scholar
- Kroodsma DE, Miller EH (1982) Acoustic communication in birds. Academic Press, New YorkGoogle Scholar
- Morruzzi TL, Fuller TK, deGraaf RM, Brooks RT, Li W (2002) Assessing remotely triggered cameras for surveying carnivore distribution. Wildl Soc Bull 30:380–386Google Scholar
- Munger LM, Wiggins SM, Moore SE, Hildebrand JA (2008) North Pacific right whale (Eubalaena japonica) seasonal and diel calling patterns from long-term acoustic recordings in the southeastern Bering Sea, 2000–2006. Mar Mamm Sci 24:795–814Google Scholar
- Mussoline SE, Risch D, Hatch LT, Weinrich MT, Wiley DN, Thompson MA, Corkeron PJ, Van Parijs SM (2012) Seasonal and diel variation in North Atlantic right whale up-calls: implications for management and conservation in the northwestern Atlantic Ocean. Endang Species Res 17:17–26CrossRefGoogle Scholar
- Patenaude NJ (2000) Southern right whales wintering in the Auckland Islands. Conservation advisory science notes no. 321, Department of Conservation, Wellington, New ZealandGoogle Scholar
- Patenaude NJ, Baker CS (2001) Population status and habitat use of southern right whales in the Subantarctic Auckland Islands of New Zealand. J Cetacean Res Manag Spec Issue 10:111–116Google Scholar
- Payne R (1986) Long term behavioural studies of the southern right whale (Eubalaena australis). Rep Int Whal Commn 10:161–167 (special issue) Google Scholar
- Riede K (1993) Monitoring biodiversity: analysis of Amazonian rainforest sounds. Ambio 2:546–548Google Scholar
- R Development Core Team (2012) R: a language and environment for statistical computing. Version 2.15.0. R Foundation for Statistical Computing, Vienna, Austria. http://www.r-project.org/. Accessed 18 May 2015
- Urick RJ (1967) Principles of underwater sound for engineers. Tata McGraw-Hill EducationGoogle Scholar
- Van Opzeeland I, Kindermann L, Boebel O, Van Parijs SM (2008) Insights into the acoustic behaviour of polar pinnipeds: current knowledge and emerging techniques of study. In: Weber EA, Krause LH (eds) Animal Behaviour: new research. Nova Science Publishers, HauppageGoogle Scholar
- Waddle JH, Thigpen TF, Glorioso BM (2009) Efficacy of automatic vocalization recognition software for anuran monitoring. Herpetol Conserv Biol 4:384–388Google Scholar
- Webster T (2014) Southern right whales (Eubalaena australis): acoustic behaviour and ambient noise. Ph.D. thesis, University of Otago, Dunedin, New ZealandGoogle Scholar
- Wood S, Wood MS (2017) Package ‘mgcv’. R package version, pp 1–7Google Scholar