[MARMAM] new publication: Movements and dive behaviour of a toothfish-depredating killer and sperm whale

[Jared Towers]

Dear all,

Our paper titled "Movements and dive behaviour of a toothfish-depredating
killer and sperm whale" was recently published in the ICES Journal of
Marine Science.

Towers, J. R., Tixier, P., Ross, K. A., Bennett, J., Arnould, J. P. Y.,
Pitman, R. L., and Durban, J. W. Movements and dive behaviour of a
toothfish-depredating killer and sperm whale. – ICES Journal of Marine
Science, doi:10.1093/icesjms/fsy118.

Abstract: Depredation of demersal longlines by killer and sperm whales is a
widespread behaviour that impacts fisheries and whale populations. To better
understand how depredating whales behave in response to fishing activity,
we deployed satellite-linked location and dive-profile tags on a sperm and
killer whale that were depredating Patagonian toothfish from commercial
longlines off South Georgia. The sperm and killer whale followed one
fishing vessel for >180 km and >300 km and repeatedly depredated when
longlines were being retrieved over periods of 6 and 7 d, respectively.
Their behaviours were also sometimes correlated with the depths and
locations of deployed gear. They both dove significantly deeper and faster
when depredating compared with when foraging naturally. The killer whale
dove >750m on five occasions while depredating (maximum: 1087 m), but these
deep dives were always followed by long periods (3.9–4.6 h) of shallow
(<100 m) diving. We hypothesize that energetically and physiologically
costly dive behaviour while depredating is driven by intra- and
inter-specific competition due to the limited availability of this abundant
resource.

The paper can be accessed at
https://academic.oup.com/icesjms/advance-article-abstract/doi/10.1093/icesjms/fsy118/5103434
or by contacting jrtow...@gmail.com

Jared Towers
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[MARMAM] Publication: Fjord habitat use strategies of fin and humpback whales

[Eric Keen]

On behalf of my co-authors, I would like to bring the following publication
in *Marine Environmental Research* to your attention:

*Distinct habitat use strategies of sympatric rorqual whales within a fjord
system*
EM Keen, J Wray, J Pilkington, KL Thompson, CR Picard

Link to article 

*Abstract:*
We used ecosystem sampling during systematic surveys and opportunistic
focal follows, comparison tests, and random forest models to evaluate fin
whale (Balaenoptera physalus) and humpback whale (Megaptera novaeangliae)
habitat associations within an inland feeding ground (Kitimat Fjord System,
British Columbia, Canada). Though these species are sympatric and share a
common prey source, they were attuned to different aspects of the local
habitat. The fin whales were associated with habitat properties reminiscent
of the open ocean. Humpback whales, in contrast, were associated with
features more commonly associated with the inland waters of fjords. Fixed
habitat features, such as seafloor depth and distance from the fjord mouth,
were the most important predictors of fin whale presence, but fixed and
dynamic variables, such as surface properties, predicted humpback whale
presence with equal (moderate) success. With the exception of strong
salinity gradients for humpback whales, habitat conditions were poor
predictors of feeding state. Fin whales practiced a spatially confined,
seasonally stable, and thus more predictable use of certain channels within
the fjord system. These findings are compatible with site loyal behavior,
which is interesting in light of the species' historical, unique use of
this fjord system. The relatively lackluster performance of
humpback-habitat models, coupled with the importance of oceanographic
properties, makes the humpback's habitat use strategy more uncertain. The
fact that two sympatric species sharing a common prey source exhibited
different habitat use strategies suggests that at least one species was
informed by something in addition to prey. Given that the two species are
attuned to different aspects of the fjord habitat, their responses to
habitat changes, including anthropogenic impacts, would likely be different
in both nature and degree. Our findings highlight the value of comparative
studies and the complexity of rorqual habitat use, which must be understood
in order for critical habitat to be identified and protected.


--
Eric M Keen

PhD, Scripps Institution of Oceanography
Visiting Professor, Sewanee: The University of the South
Science Director, North Coast Cetacean Society
Biologist, Marine Ecology & Telemetry Research
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[MARMAM] New paper on cetacean strandings in Denmark 1968-2017

[Morten Tange Olsen]

Dear all

It is my pleasure to announce our new paper on cetacean strandings in Denmark 
1968-2017

Kinze CC, Thøstesen CB, Olsen MT (2018) Cetacean stranding records along the 
Danish coastline: Records for the period 2008-2017 and a comparative review. 
Lutra, 61 (1): 87-105

Abstract:
For the period 2008-2017, finds of stranded cetaceans along the Danish 
coastline are listed and reviewed in comparison to the preceding 40-year period 
(1968-2007). The harbour porpoise (Phocoena phocoena) was by far the most 
commonly stranded species with a total of 1177 individuals for the period 
2008-2017. Of these, 62.4% (n=735) originated from the North Sea and Skagerrak 
coastlines, i.e. the outer Danish waters (ODW), 37.0% (n=435) from the Kattegat 
and Belt Sea, i.e. the inner Danish waters (IDW), and 0.6% (n=7) from the 
waters around Bornholm (WAB), i.e. the Baltic Sea proper. Due to the large 
number and the amount of information for these records only a summary is given. 
In addition, 90 strandings of twelve other cetacean species occurred between 
2008-2017. These comprise 49 white-beaked dolphins (Lagenorhynchus 
albirostris), three white-sided dolphins (Leucopleurus acutus), seven common 
dolphins (Delphinus delphis), a striped dolphin (Stenella coeruleoalba), a 
Risso’s dolphin (Grampus griseus), four long-finned pilot whales (Globicephala 
melas), a killer whale (Orcinus orca), a Sowerby’s beaked whale (Mesoplodon 
bidens), six sperm whales (Physeter macrocephalus), 14 minke whales 
(Balaenoptera acutorostrata), two fin whales (Balaenoptera physalus) and a 
humpback whale (Megaptera novaeangliae). During the last 50 years (1968-2017) 
five additional cetacean species have stranded on the Danish coasts: bottlenose 
dolphin (Tursiops truncatus) in 1968, 1975 and 1976, beluga (Delphinapterus 
leucas) in 1976 and 1987, northern bottlenose whale (Hyperoodon ampullatus) in 
1969 and 1998, Bryde’s whale (Balaenoptera brydei) in 2000, and sei whale 
(Balaenoptera borealis) in 1980. The cetacean fauna around Denmark falls into 
the following categories: 1. native species such as the harbour porpoise, 
white-beaked dolphin, and minke whale; 2. resilient visitors, i.e. species such 
as common dolphin, fin whale and humpback whale that during their occurrences 
adapt well to altered environmental conditions encountered; and 3. erratic 
stragglers of oceanic, pelagic origin failing to adapt, such as long-finned 
pilot whale, Sowerby’s beaked whale and sperm whale.

You can email me for a copy, or see http://www.zoogdierwinkel.nl/lutra

Best
Morten


Morten Tange Olsen
Assistant Professor
Curator of Marine Mammals

Natural History Museum of Denmark
Section for Evolutionary Genomics
University of Copenhagen
Øster Voldgade 5-7
1350 Copenhagen K
Denmark

morten.ol...@snm.ku.dk
(+45)42661525
http://snm.ku.dk/

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[MARMAM] New publication on C-POD dolphin detection validation

[Aran Garrod]

My co-authors and I are pleased to announce the publication of the paper

Garrod, A., Fandel, A.D., Wingfield, J.E., Fouda, L., Rice, A.N., 
Bailey, H. 2018. Validating automated click detector dolphin detection 
rates and investigating factors affecting performance. The Journal of 
the Acoustical Society of America, https://doi.org/10.1121/1.5049802.


Abstract

Passive acoustic monitoring (PAM) is a widely used technique for 
studying the distribution and habitat use of cetaceans. The C-POD, an 
acoustic sensor with an onboard automated click detector, has been 
deployed in diverse acoustic environments, but studies verifying its 
offshore detection rates and factors affecting detection probability are 
scarce. To empirically evaluate the performance of C-PODs in detecting 
bottlenose dolphins (/Tursiops truncatus/), C-PODs were deployed 
alongside archival acoustic recorders 12–30 km offshore in the Northwest 
Atlantic Ocean. The C-POD and acoustic recordings, post-processed using 
PAMGUARD software, were compared for a period of 6852 h. C-POD false 
positive rates were very low (mean 0.003%), and positive hourly 
detection accuracy was very high (mean 99.6%). Analysis of the acoustic 
environment and dolphin click characteristics revealed that true 
positive detections by C-PODs were significantly more likely to occur 
when PAMGUARD detected more clicks and there was increased high 
frequency noise (>20 kHz), likely from distant or unclassified clicks. 
C-PODs were found to be reliable indicators of dolphin presence at 
hourly or greater time scales. These results support the application of 
C-PODs in PAM studies that aim to investigate patterns of dolphin 
occurrence, such as those related to offshore windfarms.


The paper can be found here:

https://asa.scitation.org/doi/10.1121/1.5049802

Aran Garrod

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