Handling dolphin detections from C-PODs, with the development of acoustic parameters for verification and the exploration of species identification possibilities

Robbins, J B; Brandecker, Anja; Cronin, Michelle; Jessopp, Mark; McAllen, Rob; Culloch, Ross M.

doi:10.1080/09524622.2015.1125789

Cited by 17 publications

(12 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar dolphin species compositions have been 624 observed in western Scotland (MacLeod et al, 2005), Ireland (Robbins et al, 2015), California (Soldevilla et al, 2008), and in the 625…”

Section: Distinct 577supporting

confidence: 49%

Categorizing click trains to increase taxonomic precision in echolocation click loggers

Palmer¹,

Brookes²,

Rendell³

2017

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

Passive acoustic monitoring is an efficient way to study acoustically active animals but species identification remains a major challenge. C-PODs are popular logging devices that automatically detect odontocete echolocation clicks. However, the accompanying analysis software does not distinguish between delphinid species. Click train features logged by C-PODs were compared to frequency spectra from adjacently deployed continuous recorders. A generalized additive model was then used to categorize C-POD click trains into three groups: broadband click trains, produced by bottlenose dolphin (Tursiops truncatus) or common dolphin (Delphinus delphis), frequency-banded click trains, produced by Risso's (Grampus griseus) or white beaked dolphins (Lagenorhynchus albirostris), and unknown click trains. Incorrect categorization rates for broadband and frequency banded clicks were 0.02 (SD 0.01), but only 30% of the click trains met the categorization threshold. To increase the proportion of categorized click trains, model predictions were pooled within acoustic encounters and a likelihood ratio threshold was used to categorize encounters. This increased the proportion of the click trains meeting either the broadband or frequency banded categorization threshold to 98%. Predicted species distribution at the 30 study sites matched well to visual sighting records from the region.

show abstract

“…Similar dolphin species compositions have been 624 observed in western Scotland (MacLeod et al, 2005), Ireland (Robbins et al, 2015), California (Soldevilla et al, 2008), and in the 625…”

Section: Distinct 577supporting

confidence: 49%

Categorizing click trains to increase taxonomic precision in echolocation click loggers

Palmer¹,

Brookes²,

Rendell³

2017

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

show abstract

“…In contrast, as dolphins were detected in equal measure throughout the fishery area, we were unable to link occurrence or time spent to habitat variables. The latter result is likely to be confounded as passive acoustic techniques make distinguishing between different broadband echolocating species extremely challenging (see Robbins et al, 2016). Dolphin activity was likely to belong to a number of sympatric species, including those recorded as bycatch (common, bottlenose, dusky, and Risso's dolphins; Mangel et al, 2010Mangel et al, , 2013.…”

Section: Discussionmentioning

confidence: 99%

“…comm.). To remedy this, we also used an additional classifier (GENENC) developed specifically for this project; its use is recommended both to reduce false positive NBHF clicks in areas where porpoises coexist with broadband species, and to reduce false positive broadband clicks in noisy environments (Tregenza, 2014;Robbins et al, 2016). Only acoustic detections classified in the top reliability categories ("Cet Hi" and "Cet Mod") were used (Rayment et al, 2009;Pirotta et al, 2014).…”

Section: Data Processingmentioning

confidence: 99%

Distribution and Habitat Use of a Cryptic Small Cetacean, the Burmeister's Porpoise, Monitored From a Small-Scale Fishery Platform

et al. 2018

View full text Add to dashboard Cite

There is widespread evidence that small-scale fisheries (SSF) bycatch threatens many populations of small cetaceans, yet conservation efforts are often limited by a lack of basic knowledge regarding their abundance, distribution, and habitat use. Here, we used passive acoustic monitoring from an SSF platform-of-opportunity to better characterize the distribution and habitat use of small cetaceans in northern Peru, focussing on the little-known Burmeister's porpoise Phocoena spinipinnis. From 2009 to 2012, acoustic click detectors (C-PODs) were attached to fishing nets for the duration of 116 fishing sets (30 fishing trips). Dolphins (unspecified delphinids) and porpoises were recorded around 71 and 22% of fishing sets, respectively. The probability of occurrence and buzzing behavior (a proxy for foraging), and time spent, were linked to both static and dynamic environmental variables to examine the drivers of habitat use. Dolphin activity was spread evenly throughout the fishing area and was not linked to any habitat variables. In contrast, porpoises were detected in neritic waters, and habitat models performed well, identifying preferences for shallow (<200 m depth) and cooler (17-18 • C) waters, close (<50 km) to shore. The high bycatch rate of small cetaceans in Peruvian SSF gave us the unique opportunity to investigate the link between bycatch and cetacean activity around vessels. We found a positive relationship between the likelihood of a bycatch event and acoustic presence for both dolphins and porpoises, however as we did not know the timing of entanglement, we could not link vocalization rates to mortality events. Nonetheless, as small cetaceans (particularly dolphins) frequently encounter fishing boats, the likelihood of entanglements may be reduced through effective efforts to alert animals to the presence of the net, either acoustically (using acoustic alarms) or visually. This study demonstrates that passive acoustic monitoring from a fisheries platform can provide insights into the distribution and habitat use of small cetaceans at relatively low cost, and is likely to be suitable in regions with low monitoring effort and high fishing pressure.

show abstract

“…Furthermore, determining exactly what area is being sampled and how detectability changes with distance from the centre of the sample plot is extremely challenging (Robbins et al . , Dufour et al . ).…”

mentioning

confidence: 99%

“…For example, species differ in critically important factors, including call frequency, call amplitude and call directionality, all of which influence detectability. Furthermore, determining exactly what area is being sampled and how detectability changes with distance from the centre of the sample plot is extremely challenging (Robbins et al 2015, Dufour et al 2016. Thus there is a pressing need for further studies in a broader range of taxa before the full potential of passive acoustic monitoring can be realized.…”

mentioning

confidence: 99%

Acoustic activity across a seabird colony reflects patterns of within‐colony flight rather than nest density

Arneill

Critchley

Wischnewski

et al. 2019

Ibis

View full text Add to dashboard Cite

Passive acoustic monitoring is increasingly being used as a cost‐effective way to study wildlife populations, especially those that are difficult to census using conventional methods. Burrow‐nesting seabirds are among the most threatened birds globally, but they are also one of the most challenging taxa to census, making them prime candidates for research into such automated monitoring platforms. Passive acoustic monitoring has the potential to determine presence/absence or quantify burrow‐nesting populations, but its effectiveness remains unclear. We compared passive acoustic monitoring, tape‐playbacks and GPS tracking data to investigate the ability of passive acoustic monitoring to capture unbiased estimates of within‐colony variation in nest density for the Manx Shearwater Puffinus puffinus. Variation in acoustic activity across 12 study plots on an island colony was examined in relation to burrow density and environmental factors across 2 years. As predicted fewer calls were recorded when wind speed was high, and on moon‐lit nights, but there was no correlation between acoustic activity and the density of breeding birds within the plots as determined by tape‐playback surveys. Instead, acoustic indices correlated positively with spatial variation in the in‐colony flight activity of breeding individuals detected by GPS. Although passive acoustic monitoring has enormous potential in avian conservation, our results highlight the importance of understanding behaviour when using passive acoustic monitoring to estimate density and distribution.

show abstract

Handling dolphin detections from C-PODs, with the development of acoustic parameters for verification and the exploration of species identification possibilities

Cited by 17 publications

References 18 publications

Categorizing click trains to increase taxonomic precision in echolocation click loggers

Categorizing click trains to increase taxonomic precision in echolocation click loggers

Distribution and Habitat Use of a Cryptic Small Cetacean, the Burmeister's Porpoise, Monitored From a Small-Scale Fishery Platform

Acoustic activity across a seabird colony reflects patterns of within‐colony flight rather than nest density

Contact Info

Product

Resources

About