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Faecal sampling using detection dogs to study reproduction and health in North Atlantic right whales (Eubalaena glacialis)


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Conservation and management of many cetaceans is hindered by the difficulty of acquiring samples from free-swimming individuals to obtain essential data on health, diet, reproduction and physiological impacts of environmental and anthropogenic stressors. This is particularly true for large whales, which are logistically difficult to live-capture for sampling. In North Atlantic right whales (Eubalaena glacialis), a significant decline in reproduction and health in the 1990s led to the application of faecal-based analyses to study stress and reproductive endocrinology, marine biotoxin exposure and prevalence of disease-causing protozoa. However, this approach was limited by low sample acquisition rates with opportunistic faecal (scat) collection methods. The work presented here evaluates the relative sampling efficiency of scent detection dogs trained to locate North Atlantic right whale scat versus opportunistic scat collection during photoidentification surveys. Three years of sample collection using both detection dogs and opportunistic methods are summarised. Faecal sample collection rates using detection dogs were over four times higher than opportunistic methods. The use of detection dogs for scat collection from free-swimming right whales has for the first time provided adequate numbers of samples for statistical analyses. The endocrine, disease, genetic and biotoxin studies currently being performed on these samples markedly improve the ability to address fundamental questions vital to effective conservation and management of highly endangered right whales.
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Effective conservation and management of many cetaceans
has been hindered by insufficient non-lethal methods to
acquire data on feeding ecology, reproductive parameters,
individual and population health and the physiological
impacts of environmental and anthropogenic stressors (e.g.
marine biotoxins, contaminants, global climate change).
This has been particularly problematic for large whales,
which are elusive and extremely difficult to live-capture for
sampling of blood or tissues. While remote biopsy darting
provides samples for genetic, contaminant and fatty acid
analyses, the data that can be obtained from skin and
blubber cores are limited.
A significant decline in reproduction and health in the
western North Atlantic right whale population (Eubalaena
glacialis) in the late 1990s raised concern among managers
and researchers (Kraus et al., 2001; Pettis et al., 2004;
Hamilton and Marx, 2005). In response, the International
Whaling Commission (IWC) Workshops on the
Comprehensive Assessment of Right Whales, and Status
and Trends of Western North Atlantic Right Whales (IWC,
2001a; b) gave priority recommendations to develop
methods for assessing health, stress and reproductive
failure. Subsequently, a suite of faecal-based studies were
validated and applied to northern right whales to assess the
reproductive status of individual whales, and to study
factors potentially affecting health and fecundity.
Measurement of faecal metabolites of steroid hormones
has now been used to determine reproductive status of free-
swimming right whales (Rolland et al., 2005). That study
showed that concentrations of reproductive hormone
metabolites were reliable predictors of gender, pregnancy
and lactation in females and sexual maturity in males.
Current extensions to this work involve identifying
individuals by creating genetic profiles using right whale
DNA isolated from their faeces (R. Gillett, unpublished
data) and measuring metabolites of adrenal hormones to
assess relative stress levels (Hunt et al., 2006). Faecal
parasitology studies have shown that right whales have the
highest prevalence of infection with potentially pathogenic
protozoa (Giardia spp. and Cryptosporidium spp.) of any
marine mammal yet examined (Hughes-Hanks et al., 2005).
In that study, over 70% of the faecal samples collected from
right whales were Giardia spp. positive and 24% were
positive for Cryptosporidium spp. Finally, faecal
measurements of the paralytic shellfish poisoning (PSP)
toxins produced by the ‘red tide’ organism Alexandrium
showed that sampled right whales were being exposed to
this potent neurotoxin by feeding. In some cases, toxin
levels reached 0.5mg saxitoxin equivalents g
faeces, near
the levels at which human advisories for shellfish are issued,
although the biological effects on right whales remain
unknown (Doucette et al., 2006). All of these studies were
derived from multiple assays of the same faecal (scat)
samples where the individual whale can frequently be
identified either photographically (by comparison with the
North Atlantic Right Whale Catalogue; Hamilton and
Martin, 1999) or genetically (by comparing scat DNA
profiles to biopsy DNA profiles of known whales).
Preliminary results show that at least 14 whales have been
sampled more than once within a field season and/or in
multiple years (R. Rolland, unpublished data). These studies
represent the foundation of an individual-based profile of
health and reproductive status, that when integrated with
the Right Whale Catalogue, provide insights into
population-based models of reproduction, health, mortality
and trends.
J. CETACEAN RES. MANAGE. 8(2):121–125, 2006
Faecal sampling using detection dogs to study reproduction and
health in North Atlantic right whales (Eubalaena glacialis)
Contact e-mail:
Conservation and management of many cetaceans is hindered by the difficulty of acquiring samples from free-swimming individuals to
obtain essential data on health, diet, reproduction and physiological impacts of environmental and anthropogenic stressors. This is
particularly true for large whales, which are logistically difficult to live-capture for sampling. In North Atlantic right whales (Eubalaena
glacialis), a significant decline in reproduction and health in the 1990s led to the application of faecal-based analyses to study stress and
reproductive endocrinology, marine biotoxin exposure and prevalence of disease-causing protozoa. However, this approach was limited by
low sample acquisition rates with opportunistic faecal (scat) collection methods. The work presented here evaluates the relative sampling
efficiency of scent detection dogs trained to locate North Atlantic right whale scat versus opportunistic scat collection during photo-
identification surveys. Three years of sample collection using both detection dogs and opportunistic methods are summarised. Faecal sample
collection rates using detection dogs were over four times higher than opportunistic methods. The use of detection dogs for scat collection
from free-swimming right whales has for the first time provided adequate numbers of samples for statistical analyses. The endocrine,
disease, genetic and biotoxin studies currently being performed on these samples markedly improve the ability to address fundamental
questions vital to effective conservation and management of highly endangered right whales.
New England Aquarium, Central Wharf, Boston, MA 02110-3399, USA.
Packleader Detector Dogs, 14401 Crews Road KPN, Gig Harbor, WA 98329-4192, USA.
Natural Resources DNA Profiling and Forensic Centre, Department of Biology, Trent University, 1600 East Bank Drive, Peterborough, Ontario K9J
7B8, Canada.
Center for Conservation Biology, Department of Biology, Box 351800, University of Washington, Seattle, WA 98195-1800, USA.
Despite the wealth of data available from these analyses,
this approach has been restricted by the difficulty of
opportunistically locating scat at sea, limiting the number of
available samples. This led to evaluating the use of domestic
dogs (Canis familiaris) professionally trained to detect
wildlife scat (Wasser et al., 2004) to increase sample
collections from right whales. In terrestrial studies,
detection dogs significantly increased scat collection rates
from kit foxes (Vulpes macrotis mutica; Smith, D.A. et al.,
2003), grizzly (Ursus arctos) and black bears (U.
americanus; Wasser et al., 2004). In those studies, dogs
located scat from targeted wildlife with 100% accuracy
(based on genetic species confirmation), and increased
sampling rates four-fold, compared to experienced human
observers. This paper describes the use of detection dogs to
locate faecal samples from right whales over three years.
Faecal sampling efficiency of surveys with dogs is
compared to opportunistic methods and species identity is
confirmed genetically for a subset of samples.
Study area and survey methods
This work was conducted during August and September,
2003-05 in the waters around Lubec, Maine (training) and in
the Bay of Fundy, Canada (surveys), where right whales
congregate seasonally to feed (Murison and Gaskin, 1989).
Faecal sample collection surveys using detection dogs were
conducted aboard a 6.4m boat with a global positioning
system (GPS) chart plotter. The chart plotter was used to
mark the location of tracklines and positions where dogs
detected scent from right whale scat, and helped orient the
boat relative to wind and tide direction to locate samples.
The crew included one dog and three to four people (dog
handler, driver, photographer/data recorder). In addition,
opportunistic faecal sample collections occurred aboard a
9.0m vessel with a crew of six to eight people conducting
standardised right whale photo-identification surveys.
Surveys used two detection dogs alternately in 2003 and
2004, and a single dog in 2005. Given the demands of
working on a boat, dogs that had good physical stability,
persistence in locating samples and a calm disposition were
selected. Scat detection dog training follows techniques
used for narcotic, search and rescue and bomb detection
dogs (Wasser et al., 2004). When the dog detects the
targeted scent there is a characteristic change in behaviour
(recognised by tense body posture and ear position),
motivated by the expectation of a reward. Scent from right
whale scat was added to these dogs’ repertoires through
initial exposure using a scent box (Wasser et al., 2004),
followed first by searches on land, then from the bow of a
boat. Previously collected scat samples from male and
female right whales of varied ages were used for training.
Initial training occurred over a period of nine days, and
‘refresher’ work for both handlers and dogs occurred
annually for one or two days prior to the start of each field
All surveys using dogs were conducted with a Beaufort
sea state 53 and wind speeds 510 knots. Boat transects
were conducted perpendicular to the wind direction at a
speed of five to seven knots, downwind from aggregations
of right whales or areas where right whales had been
previously sighted. The dogs were positioned on the bow for
the duration of the trial. On land, the dog leads the handler
directly to the sample by following the scent cone along an
increasing odour gradient. On the water, since the dog could
not lead the handler, the helmsman steered according to the
direction indicated by the dog (as interpreted by the handler)
until the sample was located (Fig. 1). If the dog lost the scent
during the approach, perpendicular transects were resumed
until the dog’s behaviour indicated that the vessel was back
in the scent cone from the sample (Fig. 2). When faecal
samples were successfully collected, the dog was rewarded
immediately by playing with a tennis ball on a string.
Sample collection
Floating pieces of clumped right whale scat were collected
using a 300mm nylon dipnet (Sea-Gear Corp., Melbourne,
Florida, USA; Rolland et al., 2005). Scat samples were
identified in the field by size, shape, brown-orange colour,
characteristic odour and presence of fine baleen hairs. Salt
water was drained off the faeces, samples were stored in
polypropylene jars and placed on ice until frozen at 220°C
for subsequent analyses. The date, time and position of
collection were recorded for each sample. When defecation
was witnessed, the whale was photographed for subsequent
photo-identification analysis (Kraus et al., 1986).
Comparison of sample collection methods
The sampling efficiency of the detection dog surveys was
calculated by dividing the number of faecal samples
collected per day by the total time that the dog was working.
Hours of dog survey effort were defined as the total time the
dog was working ‘on watch’ during transects. These results
were compared with opportunistic faecal sample collections
made during right whale photo-identification surveys.
Opportunistic collections occurred when whales were
observed defecating at the surface or observers detected scat
by odour. Hours of opportunistic effort were defined as the
time observers were ‘on watch’ between the first and last
whale photographed that day. Samples collected per hour of
survey effort were calculated over three years (2003-05).
Comparisons between opportunistic surveys and detection
dog surveys were only made on days when both vessels
were working to control for variability in weather conditions
and whale density.
Data analysis was performed using SPSS 13.0 (SPSS Inc.,
Chicago, Illinois, USA). The data were not normally
distributed, thus non-parametric tests were used. Differences
Fig. 1. The dog handler signalling to the helmsman the direction to
steer as indicated by the detection dog during a search for a right
whale scat sample.
et al.:
were considered significant if p<0.05. The number of
samples collected per day and the sampling efficiency using
detection dogs were compared to results from opportunistic
collection methods using a Mann-Whitney U test.
Differences in sampling efficiency between years were
analysed for each method separately using the Kruskal-
Wallis test. The detection distance for each sample located
by the dogs was estimated by calculating the distance
between the GPS positions of the first observed change of
behaviour (indicating scent acquisition) and the location of
sample collection. These are estimates of distance because
tidal motion may have moved the scat (closer or farther
depending on the stage) relative to the location of the dog’s
first detection.
Genetic analyses
Species identity was determined genetically for 54 samples
collected in 2003 by extraction and amplification of
mitochondrial control region DNA. DNA was extracted in
duplicate from frozen, lyophilised faecal samples using a
modified Qiagen DNeasy extraction protocol (Qiagen,
Valencia, CA). Nucleic Acid Purification Grade Lysis Buffer
(1X, 1.6ml; ABI) was added to ~70-90mg of the each
sample, then samples were vortexed (1min) and incubated
(65°C, 1hr). Following incubation, 25ml Proteinase K
(>600mAU ml
; Qiagen) and 600mL AL buffer (Qiagen)
were added. Tubes were inverted and incubated for an
additional hour. Ethanol was added (100%, 600ml), the tubes
were mixed, and the contents were run through a silica spin
column. Samples were washed and eluted following steps
four through seven of the Qiagen DNeasy protocol,
incubated (65°C, 10min) to evaporate any residual ethanol
and frozen at 220°C.
The mitochondrial control region was amplified using the
polymerase chain reaction (PCR) with the primers UP098
and LP282 (Malik et al., 2000; Rastogi et al., 2004).
Amplification consisted of a 25ml reaction (0.3mg bovine
serum albumin, 1X PCR Buffer, 0.2mM of dNTP mix, 2mM
magnesium chloride, 0.3mM each primer, 0.1U Taq DNA
polymerase and ~1.5ng template DNA) with the following
cycling conditions: 94°C for 5min; 50 cycles of 94°C for
30s, 52°C for 60s, 72°C for 60s; 60°C for 45min. Extraction
and PCR negative controls were included to test for
Results from the detection dog and photo-identification
surveys were compared for 19 days (2003-05) on which
both detection dog and opportunistic survey vessels were
working. Detection dog surveys located significantly more
samples (n=97) compared to the opportunistic method
(n=30; Mann-Whitney U test, Z=-3.418, p<0.001).
Detection dogs located many scat samples in areas where
the human crew did not observe whales in close proximity.
The mass of faeces collected varied from approximately 20g
to 0.5kg or more. Mean sampling efficiency of the detection
dog surveys from 2003-05 was 1.1 samples hr
(range: 0.80
to 1.43 samples hr
), significantly greater than 0.25
samples hr
(range: 0.15 to 0.32 samples hr
) for
J. CETACEAN RES. MANAGE. 8(2):121–125, 2006
Fig. 2. An example of the search pattern the research vessel followed (?) to locate a right whale scat sample
with a detection dog. As the vessel enters the scent cone coming from the sample (striped area), the dog
detects the odour (0) as indicated by a change in the dog’s ear set and body position, prompting the boat
driver to steer into the wind. The dog loses the odour when the vessel leaves the scent cone (X). The
vessel then resumes a transect perpendicular to the wind until the dog has another detection, turning into
the wind again to find the sample. The human crew smelled the sample just before it was collected (4).
The distance from the first scent detection by the dog to the final position of sample collection was
opportunistic surveys (Table 1; Mann-Whitney U=5.000,
Z=-5.129, p<0.001). Although the sampling efficiency of
both methods appeared to be higher in 2005 (Table 1), there
were no significant differences between years for either
method, indicating consistency in the survey methodologies.
Estimated detection distances for the dogs ranged 22m to
1.93km (just over one nautical mile). In 2003, the only year
that this was measured, humans detected seven samples (by
smell) at 56-359m, while the dogs detected the same
samples at 150-563m. All faecal samples found by the dogs
and humans in 2003 have been confirmed to be from right
whales by mitochondrial DNA analyses, and the remainder
are currently undergoing analysis.
Statistical comparisons only included a subset of samples
collected on days when both research vessels were working
in the Bay of Fundy. Another 72 faecal samples were
obtained between 2003-05 on other survey days, in other
habitats or by other vessels in the Bay of Fundy (total
samples from 2003-05 = 199). Prior to using detection dogs
(1999-2002), an additional 86 samples were collected
opportunistically, bringing the total samples for all faecal-
based studies to 285. All samples were collected for
reproductive and stress hormone analyses. In many cases
sufficient faecal material was collected to allow for sub-
dividing of samples for multiple assays, so that 128 of these
samples are also being examined for marine biotoxins, and
111 for parasites. Additionally, all samples will eventually
be characterised genetically using mitochondrial and
nuclear markers to confirm the species of origin and
determine individual whale identity.
These results demonstrate that scat detection dogs can work
from boats to dramatically increase faecal sampling rates
from free-swimming right whales. Sampling efficiency of
detection dogs was over four times higher than opportunistic
collection methods over a three-year period. In addition,
dogs detected samples from as far as one nautical mile away,
greatly increasing the area that can be sampled. The success
of this method depended upon the involvement of a
professional dog trainer, an experienced handler and dogs
and a boat driver with intimate knowledge of the local tide
and wind patterns. It also involved use of a dedicated vessel
for detection dog surveys, because of methodological
conflicts between visually-based photo-identification
surveys and detection dog survey protocols. Nevertheless,
using dogs to collect large numbers of scat samples from
right whales has significantly increased sample sizes,
enhancing the utility of the diversity of faecal analyses in
quantitatively assessing this population’s status.
These assays and faecal collection methods are
potentially useful in multiple species, and can address a
wide array of questions. Faeces have been collected
opportunistically from bottlenose dolphins (Tursiops
truncatus) for genetic studies (Parsons et al., 2003), sperm
whales (Physeter macrocephalus) for feeding ecology
research (Smith and Whitehead, 2000), blue whales
(Balaenoptera musculus) and humpback whales (Megaptera
novaeangliae) to study marine biotoxin exposure (Lefebvre
et al., 2002) and North Atlantic right whales for
environmental toxicology (Weisbrod et al., 2000). Faecal
analyses provide estimates of exposure to synthetic
chemicals and biotoxins, both issues of concern to cetaceans
worldwide because of increasing human impacts on the
marine environment.
In addition to the assays described here, DNA markers
from prey species in scat are being used in cetaceans to
identify dietary components and diversity to understand
marine food webs with more accuracy than previous work
relying on analysis of hard parts of prey in faeces or stomach
contents (e.g. Jarman et al., 2002). Recent advances in
extraction and amplification of host nuclear and
mitochondrial DNA from scat samples permits PCR-based
studies using genetic markers to determine species, sex and
individual identity (Wasser et al., 2004). Although faecal
DNA tends to be more degraded than that obtained by
biopsy, in this study 100% of the faecal samples analysed
yielded sufficient DNA for species determination.
Many cetaceans are at-risk or poorly studied, and
researchers require physiological and biomedical data to
assess population health and reproductive status. Such
information is not easily obtained using conventional
methods. Enhanced sampling of cetacean scat by using
detection dogs, coupled with endocrine, toxicological and
molecular analyses, opens a new window into the
physiology, health and genetic status of free-swimming
whales that can contribute greatly to their conservation and
The authors are very grateful to Phillip Clapham for his
early support for this work. We are indebted to the New
England Aquarium Right Whale Research team, Laurie
Murison and many other researchers and assistants who
collected samples in the Bay of Fundy for these studies.
Special thanks to Kerry Lagueux for assistance with
graphics. Fisheries and Oceans Canada granted permits to
approach and photograph right whales in the Bay of Fundy.
Our thanks to the North Atlantic Right Whale Consortium
for access to the North Atlantic Right Whale Catalogue and
database and to Todd O’Hara and Nick Gales for helpful
comments on the manuscript. This work was supported by
contracts (to RMR) from NOAA Fisheries.
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Date received: November 2005
Date accepted: April 2006
J. CETACEAN RES. MANAGE. 8(2):121–125, 2006
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... several orders of magnitude higher than in individuals of other reproductive states) has been linked to gestation (reviewed in [11], but see [47]). Accordingly, pregnancy in several mysticete species has been assessed via P4 analysis of skin [48], blubber [5,[49][50][51], faeces [52], respiratory vapour [53,54], and baleen [19][20][21][22][23][24]. Applying the conventional interpretation that high tissue P4 indicates pregnancy status (i.e. ...
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Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales (Balaena mysticetus) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ¹⁵N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8–5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation.
... In the past, fecal samples from cetaceans have been collected (1) using scat-detecting dogs (e.g., Rolland et al., 2006;Ayres et al., 2012), (2) by simply following behind animals and watching for fecal plumes (i.e., the reddish-brown diffuse and spreading cloud of feces as the animal defecates) or looking for fecal material in the fluke prints (e.g., Hanson et al., 2010;Ford et al., 2016), or (3) opportunistically when defecations were observed while working with cetaceans for other reasons. While trying to collect both fecal and prey samples from fish-eating killer whales (Orcinus orca) in the murky waters of the Salish Sea, Washington, one of us (RWB) followed directly behind the whales while the sampler, positioned on a bow pulpit, would scan the fluke prints in case samples were welling up to the surface (see Hanson et al., 2010). ...
... Although most scent detection research has focussed on dogs' detection of terrestrial species, they also appear to be effective for detecting aquatic organisms. Rolland et al. (2007) trained dogs to detect North Atlantic right whale (Eubalaena glacialis) scat from a boat and compared their relative sampling efficiency to opportunistic scat collections by human searchers. Faecal sample collection rates were four times higher using dogs than opportunistic methods. ...
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Carp (Cyprinus sp.) are a highly invasive fish that pose a significant threat to freshwater ecosystems worldwide. At high biomasses (i.e., ≥100 kg/ha), the benthic feeding behaviour of carp can have deleterious ecosystem effects, often changing clear, macrophyte dominant waterbodies to turbid-phytoplankton dominant ecosystems. To prevent carp from reaching ecologically harmful biomasses, early detection (i.e., before population establishment) and rapid control actions are vital. Boat electrofishing, netting, and environmental DNA (eDNA) are commonly used to survey for carp, but these methods are expensive or time inefficient when fish densities are low. Scent-detection dogs have proven efficacious at detecting terrestrial and aquatic species and could represent an efficient method for early detection of carp invasions. Here, we investigated a dog’s sensitivity and specificity to carp scent using a multiple probe design experiment. The dog was trained to use an automated carousel independently of its handler and assessed water samples from aquaria containing either no fish scent (n = 3, non-target), goldfish (Carassius auratus) scent (n = 5, non-target) or carp scent (n = 9, target). The goldfish samples and six of the target samples were presented to the dog at a standard fish biomass concentration of 15.5 mg/L. The remaining three target samples (probes) were systematically diluted to determine the dog’s detection threshold. Results showed that the dog could detect carp housed under laboratory conditions down to a dilution equivalent biomass of 9.3 kg/ha (i.e., 0.5 mg carp/L), which is well below the likely biomass threshold of carp known to cause significant ecological impacts. The dog’s scent-detection performance was then compared with eDNA an existing survey method. Quantitative PCR conducted on DNA extracted from laboratory aquaria filtrate revealed that the species-specific primer could detect carp at 9.3 kg/ha, but amplification rates at this dilution were low, as were all dilutions below the limit of quantification (≈160 kg/ha). These findings suggest that dogs could provide an accurate and highly sensitive method invasive fish detection. However, before deployment as a carp surveillance method, dogs’ performance on water samples collected from natural aquatic systems (i.e., lakes, ponds, rivers) needs to be evaluated. To our knowledge this is the first published study of its kind comparing a dog’s sensitivity to eDNA, and investigating the potential utility of dogs as an invasive fish detection method.
... Detection dogs are increasingly deployed to support conservation efforts and provide an alternative to traditional visual and acoustic surveys. Detection dogs are particularly effective for low-density species (Cristescu et al., 2015), in areas of challenging terrain (Chandler, 2015), where traditional survey methods cause disturbance (McGregor et al., 2016), in eradication programs (Springer, 2011) and where other survey techniques may not be available (Rolland et al., 2006). The use of scent dogs often provides a complementary survey tool, increasing opportunities for the detection of rare and cryptic species (Thomas et al., 2020). ...
Dogs as research assistants in wildlife conservation have been used since the twentieth century. The experimental and quasi-experimental research on their efficiency, accuracy, and reliability is more recent and does not exceed a few decades. We start by discussing the potential and overlooked conceptual and methodological contributions of psychophysics to the training and assessment of wildlife conservation canines. We then briefly discuss issues around transects in search and question the validity and relevance of this anthropocentric approach. The remainder of this chapter is a comprehensive and critical review of the literature. An important part of this review is a summary table (appendix) of the main research we collated identifying the specific goals, species, methods, and the overall results and conclusions of each peer-reviewed publication.
Understanding reproductive physiology in mysticetes has been slowed by the lack of repeated samples from individuals. Analysis of humpback whale baleen enables retrospective hormone analysis within individuals dating back 3-5 years before death. Using this method, we investigated differences in four steroid hormones involved in reproduction and mating during confirmed pregnant and non-pregnant periods in two female humpback whales (Megaptera novaeangliae) with known reproductive histories based on sightings and necropsy data. Cortisol, corticosterone, testosterone, and estradiol concentrations were determined via enzyme immunoassay using subsamples of each baleen plate at 2 cm intervals. There were no significant differences in cortisol or corticosterone during pregnancy when compared to non-pregnancy (inter-calving interval), but there were significant differences between the two whales in average glucocorticoid concentrations, with the younger whale showing higher values overall. For testosterone, levels for the younger female peaked at parturition in one pregnancy, but also had spikes during non-pregnancy. The older female had three large spikes in testosterone, one of which was associated with parturition. Estradiol had large fluctuations in both whales but had generally lower concentrations during non-pregnancy than during pregnancy. There were peaks in estradiol before each pregnancy, possibly coinciding with ovulation, and peaks coinciding with the month of parturition. Both estradiol and testosterone could be useful for determining ovulation or impending birth. Using baleen to investigate retrospective steroid hormone profiles can be used for elucidating long-term patterns of physiological change during gestation. Lay summary: Case studies of two pregnant humpback whales whose hormones were analyzed in baleen may illuminate when humpback whales ovulate, gestate, and give birth. These physiological metrics could assist in accurate population growth assessments and conservation of the species. This study shows that baleen hormone analysis can be a useful tool for understanding whale reproductive physiology.
The Indian peafowl, Pavo cristatus, is the largest of the pheasants and ground-nesting bird. Because this species was introduced in Okinawa, Japan about 40 years ago and is now increasingly recognized as a pest in the Yaeyama region, and the extermination of this species has been promoted for ecosystem conservation. It was thought that there is need to develop a method to reduce the peafowl population and dogs were trained to detect them. We faced two difficulties in developing sniffer dogs to detect peafowl nests as below; (i) it is difficult to obtain a sufficient number of eggs to train the detection dogs, (ii) another difficulty is that the nesting period of peahens and the preferred vegetation used for nesting in Okinawa have not been reported. At first, we screened and trained two dogs of Welsh Corgi Pembroke and one dog of Brittany Spaniel for peafowl nest detection dogs with peahen feathers instead of peahen eggs. These dogs demonstrated a 100% sensitivity rate and there were no false-positives of their precision test. In second step, display survey of peacock to predict the nesting period of peahen was conducted in Kohama (KHM) and Kuroshima (KRS) islands, and the earliest dates of trail displays were observed in late February between 2014 and 2019 in both Islands. We predicted that the eggs would begin hatching in early April. We surveyed peahen nests for a total of 837 h and 1,153 km on 962 transects with sniffer dogs and detected 423 peahen’s nests in KHM and KRS islands between 2014 and 2019. Peahens made her nests mainly in Poaceae or Asteraceae plants in research areas. The peak hatching was between mid-April and early May. In this study, we were able to detect peahen nests in the field by dogs trained with peahen feather, and we also identified the exact nesting season and preferred vegetation in Okinawa to control of Indian peafowl as an invasive species.
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Two forms of killer whale (Orcinus orca), resident and transient, occur sympatrically in coastal waters of British Columbia, Washington State, and southeastern Alaska. The two forms do not mix, and differ in seasonal distribution, social structure, and behaviour. These distinctions have been attributed to apparent differences in diet, although no comprehensive comparative analysis of the diets of the two forms had been undertaken. Here we present such an analysis, based on field observations of predation and on the stomach contents of stranded killer whales collected over a 20-year period. In total, 22 species of fish and 1 species of squid were documented in the diet of resident-type killer whales; 12 of these are previously unrecorded as prey of O. orca. Despite the diversity of fish species taken, resident whales have a clear preference for salmon prey. In field observations of feeding, 96% of fish taken were salmonids. Six species of salmonids were identified from prey fragments, with chinook salmon (Oncorhynchus tshawytscha ) being the most common. The stomach contents of stranded residents also indicated a preference for chinook salmon. On rare occasions, resident whales were seen to harass marine mammals, but no kills were confirmed and no mammalian remains were found in the stomachs of stranded residents. Transient killer whales were observed to prey only on pinnipeds, cetaceans, and seabirds. Six mammal species were taken, with over half of observed attacks involving harbour seals (Phoca vitulina). Seabirds do not appear to represent a significant prey resource. This study thus reveals the existence of strikingly divergent prey preferences of resident and transient killer whales, which are reflected in distinctive foraging strategies and related sociobiological traits of these sympatric populations. 1471
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Reproductive failure in mammals due to exposure to polychlorinated biphenyls (PCBs) can occur either through endocrine disrupting effects or via immunosuppression and increased disease risk. To investigate further, full necropsies and determination of summed 25 poly-chlorinated biphenyls congeners (∑PCBs lipid weight) in blubber were undertaken on 329 UK-stranded female harbour porpoises (1990-2012). In sexually mature females, 25/127 (19.7%) showed direct evidence of reproductive failure (foetal death, aborting, dystocia or stillbirth). A further 21/127 (16.5%) had infections of the reproductive tract or tumours of reproductive tract tissues that could contribute to reproductive failure. Resting mature females (non-lactating or non-pregnant) had significantly higher mean ∑PCBs (18.5 mg/kg) than both lactating (7.5 mg/kg) and pregnant females (6 mg/kg), though not significantly different to sexually immature females (14.0 mg/kg). Using multinomial logistic regression models ΣPCBs was found to be a significant predictor of mature female reproductive status, adjusting for the effects of confounding variables. Resting females were more likely to have a higher PCB burden. Health status (proxied by " trauma " or " infectious disease " causes of death) was also a significant predictor, with lactating females (i.e. who successfully reproduced) more likely to be in good health status compared to other individuals. Based on contaminant profiles (>11 mg/kg lipid), at least 29/60 (48%) of resting females had not off-loaded their pollutant burden via gestation and primarily lactation. Where data were available , these non-offloading females were previously gravid, which suggests foetal or newborn mortality. Furthermore, a lower pregnancy rate of 50% was estimated for " healthy " females that died of traumatic causes of death, compared to other populations. Whether or not PCBs are part of an underlying mechanism, we used individual PCB burdens to show further evidence of reproductive failure in the Northeast Atlantic harbour porpoise population , results that should inform conservation management.
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The North Atlantic right whale, Eubalaena glacialis (Muller, 1776), is one of the world's most endangered large cetaceans. It is widely believed that Basque whalers caused the most dramatic decline of this species in the western North Atlantic during the early-16th and 17th centuries. Previous osteological analysis of 17 historic bones suggested that 50% of the Basque harvest consisted of right whales and 50% of bowhead whales, Balaena mysticetus L., 1758. This 50:50 ratio has been used to estimate pre-exploitation population size, which has subsequently formed the basis of recovery goals and plans for the North Atlantic right whale. Genetic analysis of 21 bones, 13 identified as right whales and 8 as bowhead whales through osteological examination, indicates that in fact only 1 bone was a right whale and 20 were bowhead whales. Additionally, preliminary microsatellite analyses of this specimen are not consistent with the hypothesis that whaling resulted in the low genetic variation found in this species today. These results differ from what would be expected based on any previous view of Basque whaling, and raise questions regarding the impact of Basque whaling on this species.
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Intensive study of the highly endangered western North Atlantic right whale Eubalaena glacialis over the past 25 yr has yielded evidence of reproductive dysfunction and compromised health, particularly in the late 1990s. Among the factors identified as potentially contributing to this phenomenon, exposure to marine biotoxins associated with harmful algal blooms has received little consideration, We assessed the occurrence of paralytic shellfish poisoning (PSP) toxins (saxitoxin [STX] analogues) in E. glacialis and in the co-occurring zooplankton assemblage dominated by Calanus finmarchicus, the primary food for this whale species in the North Atlantic. Samples of E. glacialis feces collected during August/September 2001 from at least 11 different whales in the Bay of Fundy, Canada, tested positive for PSP toxins using a receptor binding assay and were also quantified by high-performance liquid chromatography with fluorescence detection, indicating concentrations as high as 0.5 mu g STX equivalents g(-1) of feces. Zooplankton samples collected in the Bay of Fundy during the same period contained similar levels of PSP toxins by weight using both methods. Additional data from the Bay of Fundy revealed the presence of PSP toxin-producing dinoflagellates, Alexandrium spp., immediately before and during the sampling period. Associated PSP toxin levels in shellfish from nearby Cheney Passage, New Brunswick, exceeded regulatory limits over the same time frame. These findings provide direct evidence for the occurrence of PSP toxins in E. glacialis and suggest that trophic transfer of marine algal toxins is a factor contributing to the failure of the endangered North Atlantic right whale population to recover.
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PCB contamination was measured in the milk and serum of grey seal Halichoerus grypus mothers and in the serum of their pups sampled from 2 to 5 times between parturition and weaning on the Isle of May, Scotland, in 1998 and 2000. Blubber biopsies were also taken from the lactating females at early and late lactation in 2000. Concentrations of PCBs in milk stayed constant during the first part of lactation (0.31 +/- 0.17 mug g milk(-1)) and then increased at late lactation (0.67 +/- 0.42 mug g milk(-1)). Curiously, it did not follow the changes of milk lipid content, which increased at early lactation and then stayed constant until the end of the nursing period. As a result, even when expressed per unit of milk lipids, PCBs underwent a rise at the end of lactation. The changes in milk PCBs were accompanied by similar dynamics in maternal serum as well as in pup serum. Increased concentrations of PCBs at late lactation in serum and milk may be explained in part by the changes observed in maternal blubber. PCB levels increased significantly between early and late lactation in inner blubber, suggesting that PCBs are less easily mobilised from blubber than lipids. At late lactation, the retention capacity of the reduced blubber layer for PCBs might have reached its maximum. The mobilization of less polar lipids from blubber might also occur at this stage. In both cases, this could result in a higher mobilization of PCBs at this time. While inner blubber was significantly less concentrated than outer blubber at early lactation (1.26 +/- 0.72 mug g lipids(-1) in inner blubber vs 3.16 +/- 1.34 mug g lipids(-1) in outer blubber), these variations disappeared at late lactation (3.24 +/- 2.60 mug g lipids(-1) in inner blubber vs 3.59 +/- 1.46 mug g(-1) lipids in outer blubber). Newborn pups already had significantly higher serum levels of PCBs than their mothers, revealing an important placental transfer (11.9 +/- 7.0 ng ml serum(-1) in pups vs 6.7 +/- 3.5 ng ml serum(-1) in mothers). These differences were even greater in late lactation, due to the ingestion of milk (27.9 +/- 18.1 ng ml serum(-1) in pups vs 12.2 +/- 7.2 ng ml serum(-1) in mothers). As lactation progressed, PCB levels in pup serum increased exponentially as compared to the levels in the serum of their mothers.
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We report the development and application of a method using domestic dogs (Canis familiaris Linnaeus, 1758) to systematically locate wildlife scat over large remote areas. Detection dogs are chosen for their strong object orientation, high play drive, and willingness to strive for a reward. Dogs were trained to detect grizzly bear (Ursus arctos Linnaeus, 1758) and black bear (Ursus americanus Pallas, 1780) scats over a 5200-km2 area of the Yellowhead Ecosystem, Alberta, Canada. DNA from scat provided the species and (for grizzly bears only) sex and individual identities of the animal at each location. Concentrations of fecal cortisol and progesterone metabolites from these same grizzly bear scats provided indices of physiological stress and reproductive activity (in females), respectively. Black and grizzly bears were most concentrated in the northern portion of the multiuse study area, where food is most abundant yet poaching-related mortality appears to be heaviest. Physiologic stress was also lowest and female reproductive activity correspondingly highest for grizzly bears in the north. The scat-based distributions corresponded to concurrently collected hair-snag data in 1999 and global positioning system radiotelemetry data (of grizzly bears) in 1999 and 2001. Results suggest that the scat dog detection methodology provides a promising tool for addressing a variety of management and research questions in the wildlife sciences.
Biologic sample collection in wild cetacean populations is challenging. Most information on toxicant levels is obtained from blubber biopsy samples; however, sample collection is invasive and strictly regulated under permit, thus limiting sample numbers. Methods are needed to monitor toxicant levels that increase temporal and repeat sampling of individuals for population health and recovery models. The objective of this study was to optimize measuring trace levels (parts per billion) of persistent organic pollutants (POPs), namely polychlorinated-biphenyls (PCBs), polybrominated-diphenyl-ethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclobenzene, in killer whale scat (fecal) samples. Archival scat samples, initially collected, lyophilized, and extracted with 70 % ethanol for hormone analyses, were used to analyze POP concentrations. The residual pellet was extracted and analyzed using gas chromatography coupled with mass spectrometry. Method detection limits ranged from 11 to 125 ng/g dry weight. The described method is suitable for p,p'-DDE, PCBs-138, 153, 180, and 187, and PBDEs-47 and 100; other POPs were below the limit of detection. We applied this method to 126 scat samples collected from Southern Resident killer whales. Scat samples from 22 adult whales also had known POP concentrations in blubber and demonstrated significant correlations (p < 0.01) between matrices across target analytes. Overall, the scat toxicant measures matched previously reported patterns from blubber samples of decreased levels in reproductive-age females and a decreased p,p'-DDE/∑PCB ratio in J-pod. Measuring toxicants in scat samples provides an unprecedented opportunity to noninvasively evaluate contaminant levels in wild cetacean populations; these data have the prospect to provide meaningful information for vital management decisions.
Exposure to toxicants is one factor hypothesized to influence population growth of the northern right whale. Organochlorines in right whale skin, feces, and prey were measured and used to identify factors influencing exposure and bioaccumulation. Concentrations of 30 polychlorinated biphenyls (PCBs) and 20 pesticides in skin biopsies were consistent with other baleenopterids. Concentrations in feces and prey were two orders of magnitude less than in biopsies. In principal component analysis, organochlorines in biopsies matched those from Bay of Fundy, Canada, zooplankton, whereas feces were like Cape Cod, USA, copepods. Year of biopsy collection was the principal factor associated with differential accumulation of nonmetabolizable PCBs, 4,4{prime}-DDE, and dieldrin. Biopsies collected during winter had lower concentrations of lipid and metabolizable compounds than biopsies collected during summer. Concentrations of metabolizable PCBs increased with age in males. The bioaccumulation patterns implied that blubber burdens change annually because of the ingestion of different prey or prey from distinct locations and the release of some organochlorines stored in blubber during lipid depletion in winter. Because biopsy concentrations were lower than those found in marine mammals affected by PCBs and DDTs, the authors do not have evidence that the endangered whales bioaccumulate hazardous concentrations of organochlorines.