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First record of Norwegian killer whales attacking and feeding on a harbour porpoise

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Orcinus orca is a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items. Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes ® binoculars (25×, 80 mm). The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel. On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is the first predatory event reported in the literature.
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First record of Norwegian killer whales
attacking and feeding on a harbour porpoise
a. mel cosentino
1,2
1
Institute of Biological and Environmental Sciences, University of Aberdeen, School of Biological Sciences, Tillydrone Avenue,
Aberdeen, AB24 2TZ, UK,
2
Hvalsafari A.S., Hamnegata 1B, 8480 Andenes, Norway
Orcinus orca is a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of
fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items.
Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic
and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales
from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales
follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer
whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based
surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes
w
binoculars (25×, 80 mm).
The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel.
On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales
hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is
the first predatory event reported in the literature.
Keywords: killer whale, diet, behaviour, harbour porpoise
Submitted 8 April 2015; accepted 18 June 2015
INTRODUCTION
The killer whale (Orcinus orca, Linnaeus 1758) is a cosmopol-
itan species and the most widely distributed marine mammal.
It can be found in all of the world’s oceans, from the equator to
polar waters (Forney & Wade, 2007), and shows seasonal
movement patterns that are usually associated with increased
prey abundance (Lo
´pez & Lo
´pez, 1985; Simila
¨et al., 1996;
Ford et al., 1998;In
˜iguez, 2001; Esteban et al., 2013).
Worldwide, its diet includes over 140 species of fish, cephalo-
pods, sea birds, turtles and marine mammals. However, most
studied killer whale populations are specialized to feed on
certain specific prey items (Baird, 1994; Ford et al., 1998;
Pitman & Ensor, 2003; Herman et al., 2005; Pitman et al.,
2007; Esteban, 2008).
The best studied killer whale populations in the world are
found off the west coast of the US and Canada, where three
different ecotypes have been described: a ‘transient’ type
that specializes in feeding on marine mammals and sea
birds; a ‘resident’ type that feeds on fish in nearshore waters
and a piscivorous ‘offshore’ type (Bigg et al.,1990; Ford
et al., 1998; Herman et al., 2005). These ecotypes not only
differ in their diet, but also in their morphological traits,
acoustic behaviour and social structure. Transient and resi-
dent ecotypes killer whales have also been documented off
the Kamchatka peninsula and in the Sea of Okhotsk, in
Russian waters (Burdin et al., 2004).
Using microsatellites and mtDNA, three genetically distinct
populations have been identified in the North Atlantic (Foote
et al.,2011). A piscivorous population A specialized in feeding
on herring (Clupea harengus), the Norwegian, the Icelandic or
the North Sea herring stocks. In turn, this population is divided
into two sub-populations: the Icelandic and the Norwegian
(Foote et al., 2012). Individuals from population A were all
sampled at latitudes above 608N. Killer whales from popula-
tion B feed on both fish and marine mammals, and live in sym-
patry with population A in part of their range, as individuals
were sampled between latitudes 518N and 668N, and from
the North Sea to the West coast of Iceland (Foote et al.,
2011). Population C includes all individuals sampled in the
Strait of Gibraltar, which are specialized in feeding on
bluefin tuna (Thunnus thynnus) (Esteban, 2008), and indivi-
duals sampled in the Canary Islands (Foote et al., 2011),
whose feeding habits are unknown.
Although killer whales have been recorded along the entire
coast of Norway, as well as in offshore waters (Foote et al.,
2007), most of what is known about Norwegian killer whales
comes from research studies carried out in northern Norway,
especially during the winter time. These whales have been
intensively studied since 1983 in the VestfjordTysfjord–
Ofotfjord area (Lofoten Archipelago), where they were
observed to return every year to feed on the over-wintering
Norwegian spring-spawning herring (NSSH) (Simila
¨et al.,
1996;Kuningaset al., 2007). Few killer whale observations
are made during the summer months, but they have been
recorded both off Andenes (Vestera
˚len Archipelago) and the
Lofoten Islands (Simila
¨et al., 1996; Simila
¨,1997; Ugarte,
2001; Stenersen & Simila
¨,2004). These whales show a
Corresponding author:
A. Mel Cosentino
Email: orcinus.orca.1758@gmail.com
1
Marine Biodiversity Records, page 1 of 5. #Marine Biological Association of the United Kingdom, 2015
doi:10.1017/S1755267215000895; Vol. 8; e108; 2015 Published online
preference for herring, and photo-identification and satellite
tags suggest that at least some groups follow the NSSH stock,
year round (Simila
¨et al., 1996;Stenersen&Simila
¨,2004;
Foote et al., 2011). In addition, they have also been observed
feeding on mackerel (Scomber scombrus), cod (Gadus
morhua, Linnaeus 1758), Atlantic salmon (Salmo salar,
Linnaeus 1758) and saithe (Pollachius virens, Linnaeus 1758),
as well as harbour seals (Phoca vitulina, Linnaeus 1758) and,
on rare occasions, sea birds (Simila
¨et al., 1996;Stenersen&
Simila
¨,2004;Vester&Hammerschmidt,2013).
Worldwide, there have been reports of killer whale preda-
tion on more than 20 other cetacean species, ranging from
small porpoises to great whales (e.g. Hoyt, 1990; Jefferson
et al., 1991). However, for the Norwegian population, there
is only a report on a single predation event on northern bottle-
nose whales (Hyperoodon ampullatus, Forster 1770)
(Jonsga
˚rd, 1968 in Simila
¨et al., 1996). Here I report and
describe the first case in which Norwegian killer whales have
been observed hunting and feeding on a harbour porpoise
(Phocoena phocoena, Linnaeus 1758).
MATERIALS AND METHODS
The event reported here occurred off Andenes harbour in
northern Norway, at approximately 69.3348N 16.1618E.
Since 2011, several land-based surveys were carried out in
the area on a daily basis (depending on weather conditions),
as part of a study focusing on sperm whales (Physeter macro-
cephalus, Linnaeus 1758). Such surveys were conducted from
the Andenes lighthouse using BigEyes
w
binoculars (25×mag-
nifications, 80 mm). The lighthouse is located at the northern-
most point of Andøy Island (69.32408N 16.11598E) and the
binoculars are assembled on the gallery deck at approximately
40 meters above sea level. For the above-mentioned sperm
whale surveys, the study area is divided into two contiguous
areas (each 1208wide): Bleik Canyon on the west side and
Andfjord on the east side of the island (Figure 1). Surveys
involve scanning one of the two areas for 2 out of every
5 min, for a period of 1 h (i.e. 12 scans per hour). Data are
collected using an Olympus Recorder WS-750M. Location
of animals at sea is approximated through the use of an intern-
al reticule system and a graduated wheel.
The 24 h of daylight during the summer months in the
study area makes it possible to conduct land-based surveys
at any time of day.
RESULTS
On 24 June 2012 at 03:10, an opportunistic sighting of a group
of 11 killer whales was made off Andenes in Andfjord waters
(69.284868N 16.187328E) (Figure 2). Based on body size, as
well as size and shape of the dorsal fin, it was determined
that the group was composed of four adult males, one calf,
one juvenile and five subadult individuals/adult females. The
whales were slowly travelling northwards in a loose formation,
less than two body lengths from each other (sensu
Barrett-Lennard et al.,1996). After 36 min, during a new
scan, the group was spotted again, still travelling northwards
and in a loose formation. At 03:55 they were seen less than
2000 m north-east off Andenes harbour, in a 20 m deep reef
area (69.329428N 16.176708E). The group was heading north-
east when, suddenly, the entire group turned southwards and
started porpoising at high speed towards the shore. It was then
decided to discontinue the sperm whale survey and perform a
focal follow on the killer whales instead. Within one minute, a
killer whale (a subadult or an adult female) rammed a harbour
porpoise from below forcing it out of the water and exposing
half of its own body at an approximately 758angle. The por-
poise was lifted into the air about 5 m above the killer whale.
High-speed chasing above the water is commonly observed
during killer whale predation on small- and medium-sized
cetaceans in other parts of the world (e.g. Baird, 1994;
Constantine et al., 1998; Visser et al., 2010; Coscarella et al.,
2015); however, this was not the case on this occasion, given
that the porpoise was first observed when rammed in the
air. The rest of the group continued porpoising for a few
seconds, gathering around the spot where both the killer
whale and the porpoise were last seen. After that, for
Fig. 1. Map of the study area in northern Norway.
2 a. mel cosentino
less than 1 min, the entire group remained underwater.
Suddenly a whale (again, a subadult or an adult female) rose
out the water as previously, but this time carrying the porpoise
in its mouth. Once more, the group gathered around the
attacking individual and started swimming erratically in the
area. Within the next few minutes, the porpoise was rammed
in the air once more, though not as high as the first time.
The porpoise was not seen again and the killer whales came
closer to each other, moving slowly, gathering around a
small area and facing towards where the porpoise was last
observed, suggesting prey consumption. Reuniting around
the prey during handling and after the kill suggests prey
sharing (e.g. Hoelzel, 1991; Baird, 1994). The event took
place in just over 6 min. The group remained in the area and
sea birds slowly gathered around, flying in circles above the
killer whales, occasionally plunging around the animals.
Whilst the adult males were not actively involved and
stayed to the side most of the time, the calf remained close
to the group throughout the whole predation event. This
has also been observed in North Pacific transients (Baird,
1994). After the kill, aerial behaviour was observed, including
several breaches and tail slapping, as well as other displays
such as rolling on their bodies and spyhopping, which are
indicative of socialization (Barrett-Lennard et al.,1996).
The whales started slowly moving to the north-east 10 min
after the kill, and divided into two smaller groups after
another 10 min: one male, the calf and three other individuals
remained together in that spot and the rest dispersed and
moved further northwards. Both groups were accompanied
by birds occasionally diving, suggesting the prey was shared
by both subgroups. At 04:45 all five remaining killer whales
started to disperse and also headed northwards. Observation
was then finished due to intense glare.
Harbour porpoises are known to be part of the diet of tran-
sient killer whales’ diets off the west coast of British Columbia,
Canada (Jefferson et al., 1991; Baird & Guenther, 1995).
Despite the fact that the species have overlapping distributions
in Norwegian waters (Bjørge & Øien, 1995; Foote et al.,2007),
no predatory interaction has been described previously in the
scientific literature. In April 2012 a photograph taken by a
tourist in Eikelandsfjorden in Hardanger, Southern Norway,
over 1500 km from our study area, was published in an
online local newspaper,
1
showing a killer whale (a subadult
or an adult female) ramming a harbour porpoise. However,
it is not known whether the porpoise was killed and consumed
by the whales.
It was, unfortunately, impossible to take photographs using
the binoculars from the land station for photo-identification.
However, the short distance to the event made it possible to
make reliable sketches of the dorsal fins of three individuals
that had distinctive nicks: an adult male, a juvenile and a
third individual, most likely to be an adult female. The
sketches and group composition strongly suggest that the
group was the same as one seen near Stø on 21 June 2012
(three days before), less than 30 km south-west of Andenes
(69.174998N 15.393008E). Photographs taken on that occa-
sion identified a total of 11 individuals, including one calf,
one juvenile, and four adult males. It was impossible to
attempt to photographically identify the whale in the photo-
graph published in the online newspaper due to the low
quality of the available image.
DISCUSSION
The above observations can be explained in one of three ways.
First, this may indicate an expansion in the range of
mammal-eating population B. Our current knowledge on
their distribution range is limited and while a range increase
in association with climate change (e.g. MacLeod, 2009)or
other factors should not be disregarded, this situation is prob-
ably unlikely given the distance between the study area and the
known range of population B. The other two possible explana-
tions are that members of population A may have learned to
take new prey animals only recently due to a changing envir-
onment, or that this behaviour has simply gone unnoticed to
date. Both are likely situations given the already reported
opportunistic foraging behaviour of this population, and
that most of what is known about the diet and feeding behav-
iour of Norwegian killer comes from studies carried out in the
wintering grounds of the NSSH stock (Simila
¨et al., 1996;
Simila
¨,1997; Ugarte, 2001; Stenersen & Simila
¨,2004;
Kuningas et al., 2007), despite the fact that several groups
have been observed in different seasons and study areas.
Recent studies suggest that the behavioural ecology of killer
whales off Scotland and Iceland is more consistent with special-
ization in foraging behaviour at the individual or group level
rather than population level (Beck et al., 2011). The possibility
that the Norwegian whales also show group or individual spe-
cialization in foraging behaviour cannot be disregarded. In fact,
Simila
¨et al.(1996) already noticed that at least some groups
had different prey preferences (e.g. young herring instead of
adults) associated with different seasonal occurrences. More
recently, killer whales have been regularly observed feeding
on harbour seals off Stø (northern tip of the island of
Langøya) during the summer months (C. Ilmoni, personal
communication) and on salmon in the Lofoten archipelago
(Vester & Hammerschmidt, 2013), although it is not yet
known if different groups are engaged in these activities.
In addition to the porpoise event, I recorded two observa-
tions of killer whales in what appeared to be foraging behav-
iour in search of seals on rocky islands in nearshore waters
(as described in Beck et al., 2011). The first sighting occurred
on 2 August 2012 off Stø, when a group of five killer whales,
initially observed feeding on fish (possibly mackerel), switched
to actively searching for seals around the rocky islands in the
Fig. 2. Map showing the locations where the killer whales were observed.
1
http://www.nrk.no/hordaland/fekk-blinkskot-av-spekkhoggar-1.8065404
killer whales feeding on harbour porpoise 3
area (Beck et al., 2011). On this occasion, at least one unsuc-
cessful attempt to catch a seal was made. Similar behaviour
was observed by a group of 20 to 25 whales on the 28
November 2012, off Andenes (on the west side of Andøy
Island), although no attempt to catch a seal was observed.
Interestingly, one subgroup in this second sighting caught
(and presumably ate) several sea birds (possibly King Eider
Somateria spectabilis Linnaeus 1758). There are also
reports of killer whales harassing and probably feeding on
puffins (Fratercula arctica Linnaeus 1758) in the area (G.
Mann, personal communication). Together, these observa-
tions may indicate that the killer whales in northern
Norway prey upon an array of fish, sea bird and marine
mammal species, even though its presence in the area is
highly linked to the occurrence of the NSSH (Simila
¨et al.,
1996; Hvalsafari unpublished data). Furthermore, observa-
tions of killer whales harassing other cetacean species (e.g.
minke and sperm whales) off Andenes have been made
since 2011 (Hvalsafari, unpublished data). However, it is not
clear whether or not they were predatory interactions.
The ecological separation of the North Atlantic killer
whales is not as clearly defined as it is in the Eastern North
Pacific (de Bruyn et al., 2013). The NSSH has a complex life
cycle that requires suitable areas for each stage (i.e. spawning,
feeding, nursing and wintering). These areas and their migra-
tions routes vary somewhat unpredictably (Dickson &
Østerhus, 2007), which could explain the more generalist
behaviour observed for this killer whale population.
Baird & Dill (1996) estimated that the optimal group size
that maximizes energy intake for the North-east Pacific transi-
ents is three individuals, which coincides with the typical group
size (Baird, 1994). Other marine-mammal-eating killer whales
also have small group sizes: three individuals for the Punta
Norte (Patagonia) population (Hoelzel, 1991), and five for
killer whales in Scottish waters (Beck et al., 2011). Group size
for Norwegian killer whales, however, ranges from 6 to 30
animals, with a median of 15 (Simila
¨,1997). Foraging techni-
ques are transferred from one generation to the other
through social learning, as observed in Patagonia where killer
whales use an intentional stranding technique to catch seal
pups on the beach (Lo
´pez & Lo
´pez, 1985; Hoelzel, 1991).
As a population, Norwegian killer whales feedon various prey
species, ranging from fish, to birds to other marine mammals,
many requiring different complex hunting techniques that
require a high level of coordination for a successful attack. The
hunting behaviour described here greatly differs from the car-
rousel method used when feeding on herring (Simila
¨&
Ugarte, 1993) or that used for seal hunting (Beck et al., 2011).
Thus, this report increases our knowledge of killer whale diet
and foraging behaviour in the area and may suggest a wider sep-
aration from the Icelandic sub-population than previously
thought. Progress in the knowledge of this killer whale popula-
tion is slow due to the paucity of published reports. Increased
collaboration between research groups in the area will greatly
benefit the understanding of their feeding ecology at an individ-
ual and group level, as well as the ecology and social structure.
ACKNOWLEDGEMENTS
I would like to thank Arctic Whale Tours for providing the
killer whale photographs, and two anonymous reviewers for
their comments on early versions of this manuscript.
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First record of predation on false killer whales (Pseudorca crassidens)
by killer whales (Orcinus orca). Aquatic Mammals 36, 195– 204.
Correspondence should be addressed to:
A. Mel Cosentino
Wild Earth Foundation
Av de las Ballenas 9500
Puerto Pira
´mides, Peninsula Valdes
Chubut, Argentina
email: orcinus.orca.1758@gmail.com
killer whales feeding on harbour porpoise 5
... Some individuals display specialization on fish while others seem more flexible, feeding on both fish and marine mammals Bories et al. 2021). Recent observations of NKWs preying upon harbour seals (Phoca vitulina) and other marine mammals, such as harbour porpoises (Phocoena phocoena;Cosentino 2015;Jourdain et al. 2017;) are consistent with these dietary studies. Studies on NKWs have primarily been conducted in the winter, when they are readily found, associated with overwintering herring along the coast of Norway. ...
... The perception that NKWs primarily feed on herring might therefore be influenced by sampling bias (Jourdain et al. 2019;Lennox et al. 2022). Indeed, field studies conducted at other locations and periods reported NKWs feeding on a wide variety of prey items, such as Atlantic salmon (Salmo salar), mackerel (Scomber scombrus), harbour porpoise (Phocoena phocoena), harbour seals and lumpfish (Cyclopterus lumpus; Vester & Hammerschmidt 2013;Nøttestad et al. 2014;Vongraven & Bisther 2014;Cosentino 2015;Jourdain et al. 2017;Jourdain et al. 2019;. Similar observations of populations of killer whales broadening their diets have been reported in the northeast Pacific (Hanson et al. 2021). ...
... We cannot rule out the possibility that the whales designated as seal-eaters in our study could have also been feeding on porpoises. Norwegian killer whales have been observed to feed on harbour porpoises (Cosentino 2015), a coastal species whose spatial distribution frequently overlaps with that of harbour seals in Norwegian waters (Bjørge & Øien 1996;Cosentino 2015). Foraging on porpoises would result in elevated δ 15 N ratios. ...
Article
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Norwegian killer whales (Orcinus orca) are thought to be generalists that feed primarily on fish, but some individuals have been observed targeting pinnipeds. In the study reported here, field observations of foraging behaviours formed the basis of a priori classification as either seal-eaters or fish-eaters. Concurrent collection of photographic identification and biopsies for stable isotope analysis were used to validate prey choice classification. We found through satellite tracking that whales classified as seal-eaters took different paths south after leaving the northern fjords seemingly optimized for pinniped predation. Specifically, we found that seal-eaters took paths that tightly followed the coastline, remaining on average 6.9 ± 10.7 km (mean ± SD, n = 315) from the coast, whereas fish-eaters moved offshore along the continental shelf, travelling on average 45.1 ± 30.2 km (n = 1534) from the coast. We also found that, compared to fish-eaters, seal-eaters displayed more movements directed towards harbour seal haul-outs (p = 0.001). As expected, our data suggest that the fish-eaters feed primarily on fish, whilst seal-eaters appear to opportunistically use diverse foraging strategies optimized for either fish or seals based on availability and preference. Our findings demonstrate that tracking data can elucidate Norwegian killer whale movements associated with different prey types and selection.
... Harbor porpoises (Phocoena phocoena) are the smallest and one of the most abundant and widely distributed cetaceans in the Northern Hemisphere (Bjørge & Tolley, 2018). From what we know, the main predators of harbor porpoises are killer whales Orcinus orca (Cosentino, 2015), white sharks Carcharodon carcharias (Arnold, 1972), and gray seals Halichoerus grypus (Leopold, 2015); in some regions they are also killed/harassed by common bottlenose dolphins (Tursiops truncatus) without further consumption (Cotter et al., 2012;Jepson & Baker 1998;Ross & Wilson, 1996;Wilkin et al., 2012). ...
... Therefore, discovering a new Senecavirus species in marine mammals from Alaska highlights potential risks for animal health and food security in the region. Specifically, both beluga whales and harbor porpoises are preyed on by other marine predators such as orcas 27 , seals 28 , and sharks 29 , as well as by polar bears, a keystone Arctic species known to hunt and scavenge belugas [30][31][32] . Additionally, cetaceans, including belugas and porpoises, serve as an important food source for indigenous people 33,34 . ...
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Senecavirus A (SVA), an emerging virus that causes vesicular disease in swine, was, until recently, the only member of the Senecavirus genus ( Picornaviridae ). Here, we report the isolation and complete genome sequence of two isolates of cetacean picornavirus 1 ( Senecavirus cetus ), a novel picornavirus species of the Senecavirus genus from dead stranded cetaceans from Alaska. One isolate was from a harbor porpoise stranded in 2017, and another from a beluga whale, stranded in 2019. Whole-genome sequencing of Senecavirus cetus strains showed a genome-wide nucleotide identity of 98.8% and a genome size of 7455 nucleotides. The Senecavirus cetus genomes are most similar to SVA with a 58.3% genome-wide pairwise nucleotide identity. Infection of eleven available cell lines from terrestrial and aquatic animals showed that beluga and sheep cells were susceptible to infection by Senecavirus cetus . Phylogenetic and ancestral state reconstruction analyses supported the novel virus being a member of the Senecavirus genus and provided the first evidence of Senecavirus -like picornavirus infecting marine mammals and likely descending from a terrestrial host ancestor. These discoveries provided important information on the evolutionary relationships and taxonomy of picornaviruses and increased our understanding of the genomic characteristics and potential host range of Senecavirus cetus .
... It took multiple days to organize and mobilize everything for the first trial. Due to the covid19 pandemic, delivery of various equipment took longer than anticipated and having the C&R site ready to live-capture was (Cosentino, 2015;Ford & Reeves, 2008;Vester et al., 2017), suggesting that these odontocete pods might have scared any minke whales close to the area by their vocal behavior. Several of the sound files from the "Loggerhead" hydrophone consisted of high frequent whistles, calls and clicks produced by killer whales (figure 4.1.2d). ...
Thesis
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Studying baleen whales presents numerous challenges due to the infrequent and brief opportunities to observe their habitat, sensory modalities, behavior, and physiology. Despite their crucial role in maintaining a healthy marine ecosystem, these whales face significant anthropogenic threats. Understanding the impact of these threats requires comprehensive knowledge of their sensory physiology, migration patterns, and energy expenditure. Previous research has largely relied on post-mortem investigations, modeling, behavioral analyses, and tagging, which have evolved over time. However, some of these studies need validation through live-capture methodologies. This thesis outlines a potential approach for live-capturing baleen whales to facilitate safe physiological studies. The objectives were to: 1) assess the methodology for live-capturing and restraining baleen whales by reviewing and evaluating documented attempts and our own fieldwork experiences; 2) discuss the sensory modalities baleen whales may use to navigate around nets; 3) review potential studies that could be conducted on a restrained whale; and 4) address animal welfare considerations associated with live-capture and experimental studies. In June 2021, a large entrapment was created in Vestfjord, Norway. We attempted to measure the distance of baleen whales from various nets, designed to be detectable by different sensory methods, using recording hydrophones. The results lacked sufficient statistical power to determine which sensory apparatus cetaceans might use to detect the entrapment setup. Although we succeeded in guiding baleen whales between islets and trapping them with nets, we were unable to restrain any for direct measurements. Nonetheless, the ongoing 4-year SOST minke hearing project shows promise and may provide crucial insights into the physiology of these immense but vulnerable creatures.
... Analyzing data from GPS trackers attached to the animals, the authors note the high speed of movement of killer whales migrating to the Barents Sea and find some similarities in their movement behavior with carnivorous killer whales of the Southern Hemisphere. It is known that the diet of some killer whales in the NEA is not limited to fish and may include seals and porpoises (Jourdain et al. 2017;Cosentino 2015). According to the TAS 2019-2022 killer whales were recorded both in areas with capelin aggregations of varying densities and in areas without schools of fish. ...
Article
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Biophysical changes occurring in Arctic marine ecosystems under the influence of climatic factors may affect cetaceans staying here. For this reason, the urgent task is to conduct regular monitoring of marine mammals in order to assess the state of their populations and preserve the biodiversity of species. We analyzed the results of ship-based surveys of marine mammals carried out by the Polar branch of VNIRO in January-March 2019-2023 in the south of the Barents Sea and compared them with the observation data of earlier years. As the studies have shown, the winter cetacean fauna is currently represented by six species of baleen Mysticeti and toothed Odontoceti whales. White-beaked dolphin Lagenorhynchus albirostris Gray, 1846 was the most abundant and widespread species among all cetaceans; however, since 2022 we have seen a decrease in both the number of observations and abundance of this species. Fin whale Balaenoptera physalus Linnaeus, 1758 and killer whale Orcinus orca Linnaeus, 1758 were regularly registered in the study area, while sightings of harbor porpoise Phocoena phocoena Linnaeus, 1758 and humpback whale Megaptera novaeangliae Borowski, 1781 were single. Comparative analysis of the obtained data with the materials of 2012-2013 revealed some changes in the cetacean fauna that occurred during the last decade. In the waters of the southern part of the Barents Sea, there began met species that had not been previously recorded in our surveys, first of all, minke whale Balaenoptera acutorostrata Lacépède, 1804 and humpback whale. The materials we collected expanded our understanding of cetaceans staying in the western sector of the Russian Arctic during the winter.
... Therefore, discovering a new Senecavirus species in marine mammals from Alaska highlights potential risks for animal health and food security in the region. Speci cally, both beluga whales and harbor porpoise are preyed on by other marine predators such as orcas 53 , seals 54 , and sharks 55 , as well as by polar bears, a keystone Arctic species known to hunt and scavenge belugas 56-58 . Additionally, cetaceans, including belugas and porpoises, serve as an important food source for indigenous people 59,60 . ...
Preprint
Full-text available
Senecavirus A (SVA), an emerging virus that causes vesicular disease in swine, was, until recently, the only member of the Senecavirus genus ( Picornaviridae ). Here, we report the isolation and complete genome sequence of two isolates of cetacean picornavirus 1 ( Senecavirus cetus ), a novel picornavirus species of the Senecavirus genus from dead stranded cetaceans from Alaska. One isolate was from a harbor porpoise stranded in 2017, and another from a beluga whale, stranded in 2019. Whole-genome sequencing of Senecavirus cetus strains showed genome-wide nucleotide identity of 98.8% and a genome size of 7455 nucleotides. The Senecavirus cetus genomes are most similar to SVA with a 58.3% genome-wide pairwise nucleotide identity. Infection of eleven available cell lines from terrestrial and aquatic animals showed that beluga and sheep cells were susceptible to infection by Senecavirus cetus . Phylogenetic and ancestral state reconstruction analyses supported the novel virus being a member of the Senecavirus genus and provided the first evidence of Senecavirus -like picornavirus infecting marine mammals and likely descending from a terrestrial host ancestor. These discoveries provided important information on the evolutionary relationships and taxonomy of picornaviruses and increased our understanding of the genomic characteristics and potential host range of Senecavirus cetus .
... When feeding on small cetaceans, such as harbor porpoises, killer whales often perform highspeed chases, including porpoising; this has been observed in Iceland ) and in Norway, where the whales rammed the prey, forcing it out of the water (Cosentino 2015). Prolonged chases of minke whales ending in ramming and/or asphyxiation have also been reported in the Northeast Pacific (Ford et al. 2005) and a similar event was later reported in Iceland . ...
... This suggests that Norwegian waters may be a suitable location for young calves to develop in the absence of the large predators (such as sharks) at lower latitudes, but it is not known if this species is resident or transient in this region. Killer whales (Orcinus orca) are not known to prey on pilot whales in Norway but mainly feed on fish such as Atlantic herring (Clupea harengus), lumpfish (Cyclopterus lumpus) and Atlantic mackerel (Scomber scombrus) in addition to harbour seals (Phoca vitulina) and harbour porpoises (Phocoena phocoena) (Cosentino 2015;Remili et al. 2023). Pilot whales have been noted to chase killer whales in Norway and Iceland on occasion (Selbmann et al. 2022). ...
Article
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Long-finned pilot whales (Globicephala melas) are a widespread, highly social deep-diving cetacean species ranging from the sub-tropics to the High Arctic. Information on this species’ life history at higher latitudes is limited. Opportunistic observations of pilot whale calves were made in the spring and summer of 2020, summer of 2022 and spring of 2023 from commercial whale-watching boat trips out of Andenes, on Andøya, about 300 km north of the Arctic Circle, in northern Norway. Eighteen observations were made of long-finned pilot whale groups where 14 neonates and 32 other calves less than one year old were present. Additionally, a neonate with deep foetal folds and a folded-over dorsal fin, indicating very recent birth, was observed within Bleik Canyon on 21 June 2020.
... The proximity of the Bleik canyon provided a unique opportunity to study adult male sperm whales in high latitudes, about which we still know very little. Since 1987, dozens of scientific manuscripts have been published by researchers working for, or in collaboration with, Whalesafari on topics ranging from the acoustic characteristics of sperm whale sounds [24,25], to killer whale hunting techniques [26,27], and the impact of whale watching on the target animals [28]. The bulk of the work, however, is focused on different aspects of sperm whale distribution, abundance, and ecology [29][30][31]. ...
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Nature-based tourism activities are often sold as ‘ecotourism’, yet not all are educational, environmentally friendly, provide economic benefits to local communities, nor help achieve conservation goals. Whale-watching has the potential for ecotourism due to opportunities for supporting cetacean research, environmental education, and community engagement. Whalesafari, the first whale-watching company in the Arctic, is based in Norway and combines whale-watching with research, interpretation, and benefits for the local community. Researchers from around the world have carried out research on several aspects of sperm whales (the main target species), from abundance to diving behaviour, as well as other species. Tourists learn about cetaceans during a guided experience in the company’s museum before the trip. This whale-watching model has attracted over 350,000 tourists over the years, benefiting the local community (e.g., hotels, restaurants, other attractions). Tourism and whale research can establish synergistic relationships, involving several agents and promoting research careers, while at the same time leading to innovative advances in the ecology and tourism fields. Here, we summarise over 30 years of whale-watching eco-tourism activities and research in Northern Norway, highlighting synergistic examples and the opportunities opened through linking marine tourism and research.
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Despite well-documented experimental evidence of echolocation in toothed whales, virtually nothing is known about the use and functional significance of cetacean sonar in the wild. Here, the patterns of echolocation sounds produced by killer whales, Orcinus area, off British Columbia and Alaska are described. Two sympatric populations with divergent food habits differed markedly in sonar sound production. Individuals belonging to the fish-eating 'resident' population produced trains of characteristic sonar clicks, on average, 4% of the time, 27 times more often than marine mammal-eating 'transient' killer whales. The click trains of residents averaged 7 s, more than twice as long as the trains of transients. Click repetition rates within resident's trains were constant or changed gradually; within transient's trains they often fluctuated abruptly. Transients produced isolated single or paired clicks at an average rate of 12/h, four times as often as residents. In general, the isolated clicks and infrequent, short and irregular trains of transients were less conspicuous against background noise than the sonar of residents. This difference in acoustic crypticity may reflect a flexible response to the probability of alerting prey, because marine mammals have more acute hearing than fish in the frequency range of sonar clicks. In both populations, echolocation use per individual decreased with increasing group size, suggesting the sharing of information between group members. No relationships were found between echolocation activity and water clarity for whales of either population. Transient whales often travelled or foraged without discernibly echolocating, suggesting that passive listening provides cues for prey detection and orientation.