Acoustic evidence that harbor porpoises (<i>Phocoena phocoena</i>) avoid bottlenose dolphins (<i>Tursiops truncatus</i>)

Jacobson, Eiren K.; Forney, Karin A.

doi:10.1111/mms.12154

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…These devices also record boat sonar clicks (Tregenza et al, 2016). C-PODs have been used widely in ecological studies of porpoises and dolphins around the world, including studies of the interaction of harbor porpoises (Phocoena phocoena) and bottlenose dolphins (Tursiops truncatus) (Jacobson, Forney & Harvey, 2015), spatial and temporal variations in Indo-Pacific bottlenose dolphins (Tursiops aduncus) and the Indian Ocean humpback dolphins (Sousa plumbea) (Temple et al, 2016), Baltic harbour porpoise population distribution (Carlén et al, 2018), and studies with multiple dolphins species for categorizing or describing parameters of their click trains (Robbins et al, 2015;Palmer, Brookes & Rendell, 2017).…”

Section: Introductionmentioning

confidence: 99%

Distribution of the acoustic occurrence of dolphins during the summers 2011 to 2015 in the Upper Gulf of California, Mexico

Cárdenas-Hinojosa

Cueva

Gerrodette

et al. 2020

PeerJ

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Baseline knowledge of spatial and temporal distribution patterns is essential for cetacean management and conservation. Such knowledge is particularly important in areas where gillnet fishing occurs, as the Upper Gulf of California, which increases the probability of bycatch of cetaceans. In this area, the vaquita porpoise (Phocoena sinus) has been widely studied, but the knowledge of other cetaceans is scarce and based on traditional visual survey methods. We used data collected by an array of acoustic click detectors (C-PODs) during the summers 2011 to 2015 to analyze the distribution of dolphins in the Vaquita Refuge in the Upper Gulf of California. We recorded 120,038 echolocation click trains of dolphins during 12,371 days of recording effort at 46 sampling sites. Based on simultaneous visual and acoustic data, we estimated a false positive acoustic detection rate of 19.4%. Dolphin acoustic activity varied among sites, with higher activity in the east of the Vaquita Refuge. Acoustic activity was higher at night than during the day. We used negative binomial generalized linear models to study the count of clicks of dolphins in relation to spatial, temporal, physical, biological and anthropogenic explanatory variables. The best model selected for the response variable included sampling site, day-night condition, and vertical component of tide speed. Patterns in the spatial distribution of predicted acoustic activity of dolphins were similar to the acoustic activity observed per sampling season. Higher acoustic activity was predicted at night, but the tide speed variable was not relevant under this condition. Acoustic activity patterns could be related to the availability of prey resources since echolocation click trains are associated with foraging activities of dolphins. This is the first study of the distribution of dolphins in Mexico using medium-term systematic passive acoustic monitoring, and the results can contribute to better management to the natural protected area located in the Upper Gulf of California.

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Section: Introductionmentioning

confidence: 99%

Distribution of the acoustic occurrence of dolphins during the summers 2011 to 2015 in the Upper Gulf of California, Mexico

Cárdenas-Hinojosa

Cueva

Gerrodette

et al. 2020

PeerJ

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“…1), the original seismic survey design would have excluded the Morro Bay harbor porpoise population from nearly all of its primary foraging habitat, with animals pushed either offshore into deeper wa ters, southward beyond the species' eastern Pacific range, or northward into an extremely narrow shelf region along the Big Sur coastline, where few porpoises have been seen on aerial surveys (Forney et al 2014). Any of these options would reduce foraging success for the duration of the displacement, and could increase other risks such as predation, inter-specific aggression (Cotter et al 2012, Wilkin et al 2012, Jacobson et al 2015, bycatch, or harmful stress effects. Harbor porpoises must consume about 5% of their body mass daily to meet metabolic requirements (Yasui & Gaskin 1986, Read & Westgate 1997, Lockyer 2007.…”

Section: Central California Harbor Porpoisesmentioning

confidence: 99%

Nowhere to go: noise impact assessments for marine mammal populations with high site fidelity

Forney¹,

Southall²,

Slooten³

et al. 2017

Endang. Species. Res.

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As awareness of the effects of anthropogenic noise on marine mammals has grown, research has broadened from evaluating physiological responses, including injury and mortality, to considering effects on behavior and acoustic communication. Most mitigation efforts attempt to minimize injury by enabling animals to move away as noise levels are increased gradually. Recent experiences demonstrate that this approach is inadequate or even counterproductive for small, localized marine mammal populations, for which displacement of animals may itself cause harm. Seismic surveys within the ranges of harbor porpoise Phocoena phocoena in California and Mā ui dolphin Cephalorhynchus hectori maui in New Zealand highlight the need to explicitly consider biological risks posed by displacement during survey planning, monitoring, and mitigation. Consequences of displacement are poorly understood, but likely include increased stress and reduced foraging success, with associated effects on survival and reproduction. In some cases, such as the Critically Endangered Mā ui dolphin, displacement by seismic activities risks exposing the remaining 55 dolphins to bycatch in nearby fisheries. Similar concerns about military and industrial activities exist for island-associated species such as melon-headed whales Peponocephala electra in Hawai'i; shelf-break associated species such as Cuvier's beaked whales Ziphius cavirostris off the US Atlantic coast, and whales foraging in coastal habitats, such as the Critically Endangered western gray whale Eschrichtius robustus. We present an expanded framework for considering disturbance effects that acknowledges scientific uncertainty, providing managers and operators a more robust means of assessing and avoiding potential harm associated with both displacement and direct effects of intense anthropogenic noise exposure.

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“…The abundance of the Monterey Bay harbor porpoise population was most recently estimated to be 3715 [Coefficient of Variation (CV) ¼ 0.51; Forney et al, 2014]. Fishery mortality is currently considered to be insignificant for this stock, and there are no known habitat issues (Carretta et al, 2015); however, over the past decade there has been some mortality due to bottlenose dolphin (Tursiops truncatus) attacks on harbor porpoise in this region (Cotter et al, 2011;Wilkin et al, 2012;Jacobson et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Using paired visual and passive acoustic surveys to estimate passive acoustic detection parameters for harbor porpoise abundance estimates

Jacobson

Forney

Barlow

2017

The Journal of the Acoustical Society of America

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Passive acoustic monitoring is a promising approach for monitoring long-term trends in harbor porpoise (Phocoena phocoena) abundance. Before passive acoustic monitoring can be implemented to estimate harbor porpoise abundance, information about the detectability of harbor porpoise is needed to convert recorded numbers of echolocation clicks to harbor porpoise densities. In the present study, paired data from a grid of nine passive acoustic click detectors (C-PODs, Chelonia Ltd., United Kingdom) and three days of simultaneous aerial line-transect visual surveys were collected over a 370 km study area. The focus of the study was estimating the effective detection area of the passive acoustic sensors, which was defined as the product of the sound production rate of individual animals and the area within which those sounds are detected by the passive acoustic sensors. Visually estimated porpoise densities were used as informative priors in a Bayesian model to solve for the effective detection area for individual harbor porpoises. This model-based approach resulted in a posterior distribution of the effective detection area of individual harbor porpoises consistent with previously published values. This technique is a viable alternative for estimating the effective detection area of passive acoustic sensors when other experimental approaches are not feasible.

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Acoustic evidence that harbor porpoises (Phocoena phocoena) avoid bottlenose dolphins (Tursiops truncatus)

Cited by 9 publications

References 35 publications

Distribution of the acoustic occurrence of dolphins during the summers 2011 to 2015 in the Upper Gulf of California, Mexico

Distribution of the acoustic occurrence of dolphins during the summers 2011 to 2015 in the Upper Gulf of California, Mexico

Nowhere to go: noise impact assessments for marine mammal populations with high site fidelity

Using paired visual and passive acoustic surveys to estimate passive acoustic detection parameters for harbor porpoise abundance estimates

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