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Bryde's whales, Balaenoptera edeni, observed in the Azores: A new species record for the region

Authors:
  • Whale Watch Azores
  • Okeanos Centre - University of the Azores

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Bryde's whales, Balaenoptera edeni, were observed during the summer of 2004. The first sighting was of a mother and calf pair on 3 July. This pair was seen on several other occasions during the summer. In addition five other individuals were observed separately from the mother–calf pair. These observations represent the first appearance of this species in the Azorean Archipelago.
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Bryde’s whales, Balaenoptera edeni, observed in the Azores:
a new species record for the region
Lisa Steiner*§, Monica A. Silva, Jasmine Zereba and Maria João Leal
*Whale Watch Azores, c/o 1b Museum Square, Keswick, Cumbria, CA12 5DZ, UK. Departamento de Oceanograa e Pescas, Universidade
dos Açores, 9901-862 Horta, Azores, Portugal. Peter Cafe Sport, Rua Tenente Valadim, 9, Horta, 9900-027, Azores, Portugal. Present address:
Norberto Diver, Rua do Paiol, 12, Horta, 9900-026, Azores, Portugal. Espaço Talassa Lda., Rua dos Baleeros, 9930 Lajes do Pico, Pico, Portugal.
§Corresponding author, e-mail: wwa2@yahoo.com
Bryde’s whales, Balaenoptera edeni, were observed during the summer of 2004. The rst sighting
was of a mother and calf pair on 3 July. This pair was seen on several other occasions during the
summer. In addition ve other individuals were observed separately from the mother–calf pair.
These observations represent the rst appearance of this species in the Azorean Archipelago.
INTRODUCTION
Bryde’s whales are the least known of the large baleen whales (Kato, 2002). Their occurrence
has been reported from all tropical and warm temperate waters between 40°N and 40°S and the
animals in the North Atlantic are the least well known of all the Bryde’s whale populations (Kato,
2002). In the eastern Atlantic they are thought to range from the Strait of Gibraltar south past the
Cape of Good Hope and from Virginia south to Brazil in the west, including the Gulf of Mexico,
Caribbean and off Venezuela (Kato, 2002).
In past times they have often been confused with sei whales, distinguished by only three longitudinal
ridges along the rostrum (Reeves et al., 2002). Bryde’s whales were routinely recorded as part of
the sei whale catch as late as the 1970s (Cummings, 1985). There has been whaling in Chile since the
1880s, with most of the whales caught in the area identied as sei whales, but following a research
cruise in February 1982, it was discovered that in all probability, these were actually Bryde’s whales
(Gallardo et al., 1983). After talking to the local whalers and looking at baleen samples, it was
discovered that the baleen of the whales killed was much coarser than the baleen found in sei
whales, consistent with Bryde’s whales (Gallardo et al., 1983).
There are thought to be at least two different forms of Bryde’s whale off the coast of South
Africa, as well as a small or dwarf form around the Gulf of Thailand, Burma, New Guinea and
the Solomon Islands (Kato, 2002), that appears to be restricted to coastal and shelf waters. The
‘ordinary’ (Balaenoptera brydei) and ‘pygmy’ (B. edeni) forms have been distinguished on the basis of
morphological and genetic data (mitochondrial DNA and cytochrome b gene) (Dizon et al., 1996;
Yoshida & Kato, 1999). In South Africa the inshore form is usually within 20 miles of the coast and
the offshore form is generally more than 50 miles offshore. The inshore form is slightly smaller than
the offshore form and does not exhibit oval scarring on its sides; they often have scrapes on the
underside of the ukes from contact with the bottom (Best, 1977). As the taxonomy of Bryde’s
whales is still being reviewed with no conclusions yet reached for the North Atlantic, we use
Balaenoptera edeni as the standard form, although in future Bryde’s whales may be separated into
two species with one form changing to Balaenoptera brydei (Kato, 2002).
Bryde’s whales are opportunistic feeders and will feed on schooling pelagic sh such as sardines,
mackerel and herring as well as others. They will also eat euphausids, copepods, cephalopods and
pelagic crabs (Kato, 2002). Bryde’s whales have been observed in south-east Brazil feeding on
sardines on several occasions, most likely following them inshore as they move towards the coast
for spawning (Siciliano et al., 2004).
Bryde’s whales do not exhibit the normal migration patterns of baleen whales. There is no marked
north–south migration, although there may be slight seasonal movements in some populations.
Calving for the pelagic type is thought to occur in winter (Kato, 2002), although in the inshore form
off the Cape Province, South Africa breeding appears to be unrestricted (Best, 1977). Bryde’s whales
have the least well dened populations and their distribution is not completely known but appears
to be composed of relatively localized sub-populations in tropical and sub-tropical regions, which
carry out only limited migrations (Gaskin, 1977).
In the Gulf of California, Bryde’s whales feed predominantly at dawn and twilight, whereas n
whales feed throughout the day (Tershy, 1992). Bryde’s whales moved less between feeding locations
than n whales, which may be related to the heavier reliance of Bryde’s whales on more predictable,
although patchy, food resources. Bryde’s whales are known to concentrate in areas of predictable
biological abundance, such as along the continental shelf break in the north-eastern Gulf of Mexico
L. Steiner et al. Bryde’s whales in the Azores
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(Davis et al., 2000) and in areas of upwelling, such as off the Chilean coast (Gallardo et al., 1983) or
in the eastern tropical Pacic (Palacios, 2003).
Until 2004, ve species of baleen whales had been encountered in the Azores in recent years: blue,
(Balaenoptera musculus), n, (Balaenoptera physalus), sei, (Balaenoptera borealis), minke, (Balaenoptera
acutorostrata), and humpback, (Megaptera novaengliae). North Atlantic right whales, Eubaleana glacialis,
are also listed as a species observed in the Azores but have not been seen in recent times. These
are in addition to another 20 species that have been observed in the archipelago (Appendix 2).
Most observations have been made during the summer months, May–October, although recently
observations have taken place as early as March, from whale watching vessels and vessels from the
University of the Azores. In this paper we present the rst conrmed occurrence of Bryde’s whales
in the Azores.
MATERIALS AND METHODS
Bryde’s whales were seen by various whale watching boats: ‘Physeter’ a 12 m motor catamaran,
‘Baleias Express’ a 9 m motor catamaran, ‘Gil de Brum’ a 9.6 m rigid hull inatable, and from the
University of the Azores, ‘Arion’, a 5 m rigid hull inatable all contributing to the sightings mentioned
here. The whales were usually located by shore-based lookouts, ‘vigias’, using 20x binoculars, who
then gave directions to the boats. The crews of the vessels also kept a good general lookout for
blows and other signs of cetaceans.
Upon approaching the whales, ‘Arion’, ‘Baleias Express’ and ‘Physeter’ recorded the initial time and
location (determined by Global Positioning System (GPS)), group size and composition, behaviour
and direction of movement of the whales, as well as environmental data (Beaufort sea state, wind
and wave direction). GPS readings were not available for the sightings made by ‘Gil de Brum’.
Surface water temperature was taken on board ‘Physeter’ using a digital thermometer. Identication
photographs of dorsal ns were taken with digital cameras (Canon 10D with a Tamron 28–300 mm
lens (f3.5–6.4), Nikon E5700 and a Nikon F-90X auto focus camera equipped with a Nikkor AF
70–300 mm (f4–5.6) zoom lens).
RESULTS
On 3 July a mother and calf Bryde’s whale pair was
observed off Faial, an island of the central group of
the Azores Archipelago which is located around 900
miles east of Lisbon (Figure 1). Sightings of this species
continued until the end of August. These represent the rst
conrmed sightings of this species in the archipelago.
Bryde’s whales were observed on 24 occasions
(Appendix 1). The mother and calf pair was observed
most frequently with the rst sighting on 3 July followed
by 12 more sightings. There were sightings from all three
of the central group islands Faial, Pico and São Jorge
(Figure 2).
The mean surface water temperature recorded on
‘Physeter’ was 22.15 ±0.213°C, ranging from 21.6 to
23.5°C.
The depth for all sightings ranged from 500 to 1000 m.
(Figure 2).
The group size for all sightings was either one or
two. Only on one occasion were two adult individuals
observed together, all other sightings were of single
adults or the mother and calf pair.
On all occasions the whales were milling, making
random movements, dives of 3–5 min with 3–5 blows
on the surface in between dives, suggesting foraging
behaviour, although sh were not actually observed.
Another indication of feeding was the presence of Cory’s
shearwaters, Calonectris diomedea borealis, ying above
the whales. Lunging was seen several times and breaching
was observed three times. The whales were identied
as Bryde’s whales by three longitudinal ridges along the
rostrum (Figure 3). In four cases (in Appendix 1 marked
with an asterisk), there was no clear view of the top of
Figure 1. Location of the Azores Archipelago in the North Atlantic.
Figure 2. Sightings of Bryde’s whales with depth contours.
Bryde’s whales in the Azores L. Steiner et al.
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the head and the three ridges were not seen, but the behaviour of the whales was similar to that
observed from Bryde’s whales on previous occasions and different to that generally observed from
sei whales also seen in the Azores.
The whales all had circular depressions along the anks in the area around the dorsal n in
addition to unhealed white scars (Figure 4). These circular marks were most probably caused by
cookie cutter sharks (Isistius sp.).
Using photo-identication, seven individual whales were identied: the mother and calf pair, as
well as ve other animals.
Figure 3. Breaching Bryde’s whale showing the three longitudinal ridges on top of the rostrum.
Figure 4. Cookie cutter scars.
L. Steiner et al. Bryde’s whales in the Azores
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DISCUSSION
Bryde’s whales have never been observed in the Azores before. There is much confusion over
identication of Bryde’s whales as illustrated in Mead (1977); strandings of Bryde’s whales along
the US eastern coast, Gulf of Mexico and the Caribbean are consistently being misidentied as sei
whales. The Bryde’s whales observed in the Azores were most likely to be an offshore temperate
form based on location, 900 nm off the coast of Portugal. The whales seen had a mix of the offshore
and inshore characteristics given for the South African Bryde’s whales (Best, 1977). The oval scars
along their anks probably caused by cookie cutter sharks conform to the offshore type described
by Best (1977, 2001), although the presence of a calf in summer is not consistent with an autumnal
breeding season as described for the offshore form in South Africa (Best, 1977). However, Evans
(1987) states that the breeding season of the Bryde’s whales is protracted and in some cases year
round while Kato (2002) states that peaks for breeding and calving of pelagic stocks are in winter,
which would be more consistent with the presence of a calf in summer. The calf observed in these
encounters did not appear to have been weaned, although it was probably not that far from it, if as
Kato (2002) suggests suckling only lasts for six months. The calf was roughly ¼ the size of the adult
and several times it was seen in a position just behind the mother’s dorsal n which would be close
to a suckling position when submerged. Calves were also observed in the summer of 2005 in the
Canary Islands (Ritter & Neumann, 2006).
Water temperature does not appear to play a major role in locations of Bryde’s whales. They
are found in a wide range of temperatures. Cummings (1985) lists the preferred temperatures as
15–20°C for Bryde’s whales. Siciliano et al. (2004) reported Bryde’s whales in the upwelling areas
off Chile, 15.9–18.6°. Off South Africa, another area of upwelling, Best (1977) found the greatest
number of sightings between 12 and 13°C decreasing rapidly after that with increased temperature
with a secondary peak in abundance at 18–19°C before again dropping off rapidly. In the Hauraki
Gulf in New Zealand, an area without upwelling, Bryde’s whales were sighted in water temperatures
ranging from 17 to 24.3°C with an average of 19.7°C (O’Callahan & Baker, 2002).
The Bryde’s whales observed in the Azores were feeding on unidentied schools of sh. The most
likely prey was horse mackerel, Trachurus trachurus, which can be found in abundance around the
Azores, although other species of sh can also be found there: sardines, Sardina pilchardus, blue jack
mackerel, Trachurus picturatus and chub mackerel, Scomber japonicus, are three other possibilities.
During night observations off Chile, under articial lights, large populations of juvenile jack mackerel
were observed in the areas of Bryde’s whale concentrations and mackerel were also present in
many of the specimens caught (Gallardo et al., 1983). Bryde’s whales caught in pelagic whaling by
the Japanese in the North Pacic had a greater preponderance of euphausids in their stomachs
as opposed to sh (Nemoto & Kawamura, 1977). These differing food preferences conrm that
Bryde’s whales are opportunistic feeders and it would appear that when observed in the Azores,
sh were more abundant than euphausids. At another time or in a different population, euphausids
may play a more important role in their diet. The group size of 1–2 individuals feeding here is similar
to that observed in other regions. Gaskin (1977) reports that Bryde’s whales generally feed in
singles or mother–calf pairs.
The dorsal ns of Bryde’s whales can be used for photo-identication. This method was also used
by O’Callahan & Baker (2002) in the Hauraki Gulf in New Zealand and in the Canaries (Ritter &
Neumann, 2006). In contrast to the high proportion of marked animals in New Zealand, most of
the individuals observed in the Azores did not have markings on the dorsal n; rather the shape of
the n differed between individuals. This difference may be caused by the different types of habitat
involved. The New Zealand whales are found in much shallower water than the Azorean ones. Some
individuals had chevron markings, similar to those seen on n whales, visible on the ank behind
the blowhole. The pattern of scars caused by cookie cutter sharks may also be useful for matching
individuals.
The Bryde’s whales observed here were sighted at depths of between 500 and 1000 m while the
mean water depth for Bryde’s whales sighted in the Hauraki Gulf was only 43.2 m (O’Callahan &
Baker, 2002). In the Gulf of Mexico, Bryde’s whales are usually sighted in waters 100 m deep (Davis
et al., 1998, 2000). The Bryde’s whales were observed in the Gulf foraging 90.9% of encounters and
on every occasion they were seen in the Azores they appeared to be feeding.
CONCLUSIONS
Bryde’s whales are elusive whales to observe. They do not remain at the surface for long periods
of time and do not surface in a predictable manner. This also makes positive species identication
difcult. The sightings here may represent a range expansion of the eastern Atlantic Bryde’s whale
population. If this is the case, in the future this species may become regular visitors to this archipelago,
where there is abundant prey during the summer months, or be observed year round due to higher
Bryde’s whales in the Azores L. Steiner et al.
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productivity around the islands than other parts of the eastern Atlantic. Care must be taken to be
sure that whales are positively identied as Bryde’s whales since they can be confused with some
of the other baleen whales passing the islands.
Identication photographs need to be compared with photographs taken in different parts of the
eastern Atlantic such as Madeira and the Canaries, to determine if any of the whales observed here
have previously been seen elsewhere. This will be feasible through the Europhlukes programme,
although currently there are not many Bryde’s whale photographs in the database.
The authors wish to thank the crews of all boats involved in these sightings, the lookouts who spotted
the whales from the shore and the whale watching clients who made the voyages possible. The authors
are very grateful to the Portuguese Science and Technology Foundation (FCT) for funding the CETAMARH
project (POCTI/BSE/38991/01, co-participated by the Community Support Framework—FEDER) as well
as M.A.S.’s doctoral grant (SFRH/BD/8609/2002). IMAR-DOP/UAç is the R&D Unit no. 531 funded through
the pluri-annual and programmatic funding schemes of FCT-MCTES and DRCT-Azores. The authors wish
to thank Maria Inês Seabra for generating the GIS maps. This research was conducted under license of the
Environment Directorate of the Regional Government of the Azores. Whale watching boats are all licensed by
the Department of Tourism.
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Submitted 19 February 2007. Accepted 22 May 2007.
Date Time Latitude (°)Longitude (°) No. Calf Boat
03/07/2004 1603 38.465 –28.747 2 Y Physeter
12/07/2004 0929 38.482 –28.762 2 Y Expresso
12/07/2004 1500 38.485 –28.673 2 Y Expresso
13/07/2004 0922 38.41 –28.497 2 Y Expresso
13/07/2004 1143 38.37 –28.458 2 Y Arion/Gil
13/07/2004 1404 38.388 –28.418 2 Y Arion
13/07/2004 1630 2 Y Gil
14/07/2004 1116 38.547 –28.08 1 N Physeter
17/07/2004 1144 38.638 –28.29 1 N Physeter
29/07/2004 1130 2 Y Gil
31/07/2004 1000 38.415 –28.72 2 Y Expresso
31/07/2004 1100 38.427 –28.83 1 N Expresso
31/07/2004 1617 38.435 –28.732 2 Y Expresso
01/08/2004 1530 38.435 –28.725 1 N Expresso
02/08/2004 1012 38.413 –28.573 2 Y Physeter
02/08/2004 1508 38.433 –28.637 2 Y Physeter
08/08/2004 1130 2 Y Gil
09/08/2004* 1050 38.436 –28.76 1 N Expresso
11/08/2004 1625 38.39 –28.573 2 Y Arion
12/08/2004 1820 38.345 –28.49 2 N Expresso
19/08/2004* 0940 38.45 –28.733 1 N Expresso
23/08/2004* 0937 38.417 –28.733 1 N Physeter
26/08/2004* 0950 38.413 –28.538 1 N Physeter
28/08/2004* 1222 38.447 –28.78 1 N Physeter
30/08/2004 1700 38.453 –28.878 1 N Expresso
*, Longitudinal ridges not observed.
Appendix 1. Sightings of Bryde’s whales.
Blue whale
Fin whale
Sei whale
Minke whale
Humpback whale
Sperm whale
Pygmy sperm whale
Dwarf sperm whale
Right whale (not in recent history)
Northern bottlenose whale
Cuvier’s beaked whale
Sowerby’s beaked whale
Gervais beaked whale
Blainville’s beaked whale
True’s beaked whale (L. Steiner personal communication)
Bottlenose dolphin
Risso’s dolphin
Common dolphin
Atlantic spotted dolphin
Striped dolphin
Rough-tooth dolphin
Orca
False killer whale
Short-nned pilot whale
Harbour porpoise
Barreiros et al. 2006; Goncalves et al. 1996; Gordon et al. 1990;
Reiner, 1986,1993; Steiner, 1995.
Appendix 2. Cetacean species of the Azores.
... Evidence suggests that unlike other baleen whales, Bryde's whales do not make extensive seasonal migrations to high-latitude feeding grounds but instead move across ocean basins throughout their range (Lockyer & Brown, 1981;Weir, 2010;Kato & Perrin, 2018). In the East Atlantic, the species has been identified from the Azores to the African coast as far as South Africa, and in the western Atlantic from the Gulf of Mexico to Argentina (Reiner, dos Santos & Wenzel, 1996;Notarbartolo di Sciara et al., 1998;Hazevoet & Wenzel, 2000;Best, 2001;Steiner et al., 2008;Bastida & Rodriguez, 2009;De Boer, 2010;Weir, 2010;Rosel & Wilcox, 2014;Tardin et al., 2017;Kato & Perrin, 2018). ...
... Studies of Bryde's whales in the North-East Atlantic have mainly relied on sighting data in the Macaronesia biogeographic region (Ritter & Neumann, 2006;Steiner et al., 2008;Freitas et al., 2012), except for a foraging behavioural study that gave a brief insight into the dive behaviour and seasonal site fidelity of two individuals across 4 years in the Madeira Archipelago . ...
... obs.), in pairs of adults, or sporadically in inter-specific associations (Alves et al., 2018b). In the Canaries, Bryde's whales are frequently seen from spring to autumn (Ritter & Neumann, 2006;Pérez-Valazza et al., 2008;Carrillo, Pérez-Vallazza & Alvarez-V azquez, 2010), whereas in the Azores, they were first identified in 2004 and are rare visitors during the summer months (Steiner et al., 2008;Silva et al., 2014). ...
Article
• The conservation of marine megafauna presents numerous difficulties owing to their high mobility over difficult-to-access oceanic areas that impairs the collection of basic, but essential, biological information. • The Bryde's whale (Balaenoptera edeni) is one of the most elusive species of baleen whales, and although it is known to be a seasonal visitor to several archipelagos in Macaronesia (the Azores, Madeira, and Canaries), there are no studies regarding its occurrence or geographical connectivity in this area of the Atlantic. • A 14-year photographic database was used to determine short-term (intra-seasonal) and long-term (inter-annual) Bryde's whale site fidelity and to estimate individual residency times in Madeira, whereas photographic catalogues from Madeira and the Canaries were compared in order to assess large-scale movements (i.e. on the scale of hundreds of kilometres). • In Madeira, 59 individuals were identified, 27 (45.8%) of which were recaptured. Of these, 10 individuals (37.0%) presented short-term site fidelity and 17 individuals (63.0%) presented long-term site fidelity, with a maximum recapture interval of 12 years. Lagged identification rates showed that five individuals (SE = 2) remained in the area for 32 days (SE = 108 days) before leaving and not returning during the same year. Seven individuals were seen both in Madeira and the Canaries (catalogue comprising 51 individuals), three of which were identified multiple times in both archipelagos, with a minimum of 43 days between consecutive sightings. • This information combined with the fact that this species is commonly sighted accompanied by calves and feeding in both archipelagos highlights the ecological importance of this area for Bryde's whales. This should be taken into consideration by policymakers when implementing conservation measures, where coordination of effort among countries is needed. This study also reinforces the value of using data from platforms of opportunity and of making photographic data open access.
... The Bryde's whale (B. edeni) although not present in these records, was sighted by the company for the first time in July 2004 (Steiner et al., 2007). ...
... The daily checklist registries from 2001 to 2004 included at least 20 of the 27 cetacean species sighted so far in the archipelago. Species not present have been observed only once, have not been sighted for more than 30 years or have been only positively identified from strandings or photographs (Chaves, 1924;Clarke, 1981;Reiner, 1981Reiner, , 1986Reiner et al., 1993;Gonçalves et al., 1996;Steiner, 1995;Simas et al., 1999;Barreiros et al., 2006;Steiner et al., 2007; plus G. melas and two beaked whales, Rui Prieto, personal communication). ...
... The reference of the company's first sighting of Balaenoptera edeni, was actually among the sources of data for the first article mentioning the species in the Azores (Steiner et al., 2007). It is a clear indication of how important data becomes with any additional information, reiterating the urgent need to motivate biologists and skippers working on/ with WW to publish their observations. ...
... The same authors hypothesize that interannual climate oscillations and oceanographic indexes (such as the ENSO) could explain some of the variability observed, recognizing that other environmental variables rather than the SST might influence the whales' movements. Therefore, depending on general circulation patterns, the animals might move to Madeira, to northern latitudes, up to the Azores (Steiner et al., 2008), or could remain in southern latitudes. ...
... While the Blue whale and Bryde's whale have been reported earlier from both east and west coasts of India, humpback whale has been reported only from west coast (Sutaria et al. 2017). Bryde's whales are mostly residential and are confined to tropical and warm temperate waters between 40ºN and 40ºS, which however are known to move towards higher altitudes in summer and towards equator during the winter (Steiner et al. 2008;Sudhan et al. 2017). ...
... While the Blue whale and Bryde's whale have been reported earlier from both east and west coasts of India, humpback whale has been reported only from west coast (Sutaria et al. 2017). Bryde's whales are mostly residential and are confined to tropical and warm temperate waters between 40ºN and 40ºS, which however are known to move towards higher altitudes in summer and towards equator during the winter (Steiner et al. 2008;Sudhan et al. 2017). ...
Article
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Seasonal occurrence of baleen whales along Odisha coast is investigated based on critical evaluation of the stranding data collected from beach surveys, citizen reports and unpublished records during2016- 2020. The study reveals that there have been 18 instances of whale stranding in Odisha of which baleen whales accounted for 12 (66.6%) and Bryde’s whale (Balaenoptera edeni) alone accounted for 11 instances (61%). Two of the incidents were noted while data review and 16 were investigated in the field and by observing photographs. As the lengths of 55% of the individuals of Bryde’s whale stranded in Odisha were less than the size at which they attain sexual maturity (<39 feet), their seasonal migration to this coast could not be conclusively attributed to mating, breeding or calving purposes. However, a critical review of the seasonal distribution data showed that 91% of the strandings of Bryde’s whale in Odisha beaches occurred during post-monsoon season (November-February), which coincides with the period of high productivity and availability of plenty of food. This leads us to hypothesize that Bryde’s whales, the inhabitants of all tropical and warm temperate waters between 40ºN and 40ºS, possibly migrate to seawaters off Odisha coast, along north-western side of Bay of Bengal for feeding purposes. However, the stranding data alone could not ascertain the habitat use and hence the study calls for further investigations such as stomach content, stable isotopes analysis, and/ or visual observation of feeding activity of the whales in the region to confirm their purpose of congregation as feeding. The study further claims a thorough investigation to understand the reason behind instances of stranding and mortality of baleen whales along the Odisha coast.
... The estimated length at birth for this species is about 3.4-4 m [28], suggesting that the recorded calf was a very young individual, likely born at the start of the summer. However, contrary to other baleen whales species, births of Bryde's whale are known to occur throughout the year [32,61,62]. In Nicaragua, for example, a 4 m calf stranded in December 2020 [32]. ...
Article
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Cetacean strandings constitute one of the most important sources of information for studying cetacean diversity and obtaining basic biological data. The Guatemalan Pacific Ocean supports a high diversity of cetaceans, with at least 19 confirmed species records. However, little is known about cetacean strandings in Guatemala and their association with anthropogenic activities. We reviewed the occurrence of cetacean strandings on the Pacific coastline of Guatemala between 2007 and 2021. Stranding records were obtained from publications and citizen science such as sporadic reports from third parties, local and social media. In total, 39 stranding events from 12 species were recorded over the 15-year period examined. Stranded species belong to five families: Delphinidae, Kogiidae, Ziphiidae, Balaenopteridae and Eschrichtiidae. The striped dolphin (Stenella coeruleoalba, n = 6), bottlenose dolphin (Tursiops truncatus, n = 6), spinner dolphin (S. longirostris, n = 5), spotted dolphin (S. attenuata, n = 4), and humpback whale (Megaptera novaeangliae, n = 4) were the most frequently stranded species. For three of the stranded species, the melon-headed whale (Peponocephala electra), Blainville's beaked whale (Mesoplodon densirostris), and gray whale (Eschrichtius robustus), these stranding records represent the first confirmed report of the species in Guatemalan waters. Although we could not determine the cause of stranding in most cases, at least 15% of stranded individuals presented marks or injuries that could be associated with anthropogenic activities, such as fisheries or vessel strikes. This study highlights the importance of stranding data and the need to create a national network to allow timely response to stranding events and to enable improved data collection protocols. A well-curated cetacean stranding database is crucial for scientific research as well as to implement management and conservation measures to protect these species in the region.
... The most frequently sighted mysticete species (and the sixth most frequently sighted cetacean species) was Balaenoptera edeni. Despite being a migratory species, its presence in the Canary Islands is quite marked (Aguilar de Soto, 2006;Morales-Herrera, 2015;Lado-Pedreda, 2018); it is found not only in these waters but also in nearby Macaronesian archipelagos, such as in Madeira (Alves et al., 2010) and the Azores (Steiner et al., 2008). Although robust information on the spatial and temporal distribution regarding the family Balaenopteridae and its habitats and/or feeding preferences is scarce, it is observed that all Balaenopteridae species found in the North Atlantic pass through the Canary Islands during certain months of the year. ...
Article
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The waters of the Canary Islands are considered a hotspot for marine biodiversity, especially regarding cetacean species. Based on this fact, this study pays attention to the spatial distribution pattern of cetacean species and the conservation role of the Natura 2000 Network, a set of Special Areas of Conservation (SACs), which were defined mainly based on data compiled in 1996, under the framework of the European Habitats Directive. In recent years, the declaration of conservation areas for cetaceans between the Tenerife—La Gomera Islands by two global conservation programs, Mission Blue (“Hope Spots”) and Whale Heritage Site (“Whale Sanctuary”) sent clear signals of scientific and social interest to promote better protection of the cetacean species in the Canary Islands. The main aim of the designated SACs is the conservation of its biological and ecological diversity, ensuring the long-term survival of the target species in the waters around islands. In this case, the enactment of the SACs was based only on the sparse data available for the common bottlenose dolphin, Tursiops truncatus. This study shows that the spatial distribution of cetaceans in the Canary archipelago generated from a large database of cetacean sightings, from 2007 to 2018. The results obtained show the main marine areas where the different cetacean species are distributed around the different islands of the archipelago. The spatial distribution maps of the cetacean species, when compared with the existing SACs of the Natura 2000, show the need to extend these SACs into the open sea to include more cetacean species and a larger number of individuals for better conservation of the endangered marine mammals. As a consequence, some suggestions were proposed to improve and update the role of SACs in European Northeast Atlantic waters as a key environmental tool for cetacean conservation. The data supporting the recent declarations of these two new milestones the “Hope Spot” and the “Whale Sanctuary” enhance more keystone information to promote a large marine protected area in the Eastern Atlantic Ocean, such as the “Macaronesian Biodiversity and Ecological Migration Corridor for Cetaceans,” a conservation figure that has been already proposed in the scientific literature as a deserving candidate of governmental regulations and policies by Portugal and Spain; it would also require joint cross-border cooperation efforts for marine spatial planning.
... The same authors hypothesize that interannual climate oscillations and oceanographic indexes (such as the ENSO) could explain some of the variability observed, recognizing that other environmental variables rather than the SST might influence the whales' movements. Therefore, depending on general circulation patterns, the animals might move to Madeira, to northern latitudes, up to the Azores (Steiner et al., 2008), or could remain in southern latitudes. ...
Article
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Species distributional estimates are an essential tool to improve and implement effective conservation and management measures. Nevertheless, obtaining accurate distributional estimates remains a challenge in many cases, especially when looking at the marine environment, mainly due to the species mobility and habitat dynamism. Ecosystems surrounding oceanic islands are highly dynamic and constitute a key actor on pelagic habitats, congregating biodiversity in their vicinity. The main objective of this study was to obtain accurate fine-scale spatio-temporal distributional estimates of cetaceans in oceanic islands, such as the Madeira archipelago, using a long-term opportunistically collected dataset. Ecological Niche Models (ENM) were built using cetacean occurrence data collected on-board commercial whale watching activities and environmental data from 2003 to 2018 for 10 species with a diverse range of habitat associations. Models were built using two different datasets of environmental variables with different temporal and spatial resolutions for comparison purposes. State-of-the-art techniques were used to iterate, build and evaluate the MAXENT models constructed. Models built using the long-term opportunistic dataset successfully described distribution patterns throughout the study area for the species considered. Final models were used to produce spatial grids of species average and standard deviation suitability monthly estimates. Results provide the first fine-scale (both in the temporal and spatial dimension) cetacean distributional estimates for the Madeira archipelago and reveal seasonal/annual distributional patterns, thus providing novel insights on species ecology and quantitative data to implement better dynamic management actions.
... Bryde's whale, short-finned pilot whales and Bottlenose dolphin (Canary Islands unit) exhibited the highest exposure score of all units because their distribution overlaps with areas of high projected climate changes, when compared to the remaining units (S.M.2 Fig. 1). The first two species are known to have a tropical and warm-temperate distribution (Kato and Perrin, 2018;Olson, 2018), with their northern, central and eastern Atlantic limit at the latitude of Azores (Steiner et al., 2008;Alves et al., 2019). In Madeira, Bryde's whales were only first recorded in 2003 (Freitas et al., 2012) but since 2005 are amongst the most encountered species in the region (Alves et al., 2018). ...
Article
Over the last decades global warming has caused an increase in ocean temperature, acidification and oxygen loss which has led to changes in nutrient cycling and primary production affecting marine species at multiple trophic levels. While knowledge about the impacts of climate change in cetacean's species is still scarce, practitioners and policymakers need information about the species at risk to guide the implementation of conservation measures. To assess cetacean's vulnerability to climate change in the biogeographic region of Macaronesia, we adapted the Marine Mammal Climate Vulnerability Assessment (MMCVA) method and applied it to 21 species management units using an expert elicitation approach. Results showed that over half (62%) of the units assessed presented Very High (5 units) or High (8 units) vulnerability scores. Very High vulnerability scores were found in archipelago associated units of short-finned pilot whales (Globicephala macrorhynchus) and common bottlenose dolphins (Tursiops truncatus), namely in the Canary Islands and Madeira, as well as Risso's dolphins (Grampus griseus) in the Canary Islands. Overall, certainty scores ranged from Very High to Moderate for 67% of units. Over 50% of units showed a high potential for distribution, abundance and phenology changes as a response to climate change. With this study we target current and future information needs of conservation managers in the region, and guide research and monitoring efforts, while contributing to the improvement and validation of trait-based vulnerability approaches under a changing climate.
... Whales stranded in Brazil have also been genetically confirmed as B. e. brydei (Pastene et al., 2015). In the eastern Atlantic Ocean, Bryde's whales have been reported from the offshore islands of Cape Verde (Hazevoet & Wenzel, 2000), Madeira (Alves et al., 2010), and the Azores (Steiner et al., 2008). They also inhabit nearshore waters and offshore waters of the southwestern African coast (Best, 2001;Weir, 2010). ...
Article
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Bryde's‐like whales are a complex of medium‐sized baleen whales that occur in tropical waters of all three major ocean basins. Currently, a single species of Bryde's whale, Balaenoptera edeni Anderson, 1879, is recognized, with two subspecies, Eden's whale, B. edeni edeni and Bryde's whale, B. edeni brydei (Olsen, 1913), although some authors have recognized these as separate species. Recently, a new, evolutionarily divergent lineage of Bryde's‐like whale was identified based on genetic data and was found to be restricted primarily to the northern Gulf of Mexico (GOMx). Here, we provide the first morphological examination of a complete skull from these whales and identify diagnostic characters that distinguish it from the other medium‐sized baleen whale taxa. In addition, we have increased the number of genetic samples of these Bryde's‐like whales in the GOMx from 23 to 36 individuals, all of which matched the GOMx lineage. A review of Bryde's‐like whale records in the Caribbean and greater Atlantic supports an isolated distribution for this unique lineage, augmenting the genetic and morphological body of evidence supporting the existence of an undescribed species of Balaenoptera from the Gulf of Mexico.
Conference Paper
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The waters off La Gomera (Canary Islands) are known for an extraordinarily high number of cetacean species. With more than 20 species identified, the regularly surveyed area (roughly 100 nm2) represents the highest species diversity in Europe. However, these waters predominantly are a habitat for medium sized and small toothed whales, such as several species of delphinids, short-finned pilot whales, beaked whales and others. Large baleen whales are seen regularly, but not very frequent, and mostly during certain periods during the year. This was different in 2005, when Bryde's whales (Balaenoptera edeni) were constantly seen from springtime on. During some months, they belonged to the most frequently seen species of the cetacean community. The observation of feeding behaviours indicated that these whales spent the greater part of the year in this area because they found enough fish to feed on. Preliminary analyses of the photographs taken suggest that the number of whales was within the range of dozens of animals. Mother/calf pairs were seen regularly. The extraordinary occurrence of Bryde's whales, together with some other remarkable changes within the cetacean community off La Gomera suggests that 2005 was an unusual year in terms of oceanographic conditions and fish abundance.
Article
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Forty nine strandings of 13 species of cetaceans were recorded in the archipelago of the Azores from 1992 to 1996. The common dolphin (Delphinus delphis) was the most frequent stranded cetacean. For the first time in this region of the Atlantic, a stranded fin whale (balaenoptera physalus) was recorded. An unusual occurrence of a live stranding, apparently successfully rescued, of a dwarf sperm whale (Kogia simus) constitutes a new record for the Azores, increasing the number of cetacean species to 24. Most of the strandings (32 out of 38 animals) of 1996 were recorded from 7 February to 12 April. The majority of these strandings were of D. delphis and took place mainly on S. Miguel and Terceira islands. The calculation of a stranding índex (No. of annual strandings per 100 km of coastline) enabled us to compare the number of strandings in the Azores with those from nearby areas. The Azorean indices were found to be within the range of values calculated for these other áreas. Several circumstances that might have been partly responsible for the strandings are discussed. The results of the analyses done (necropsies, and chemical analyses: PSP, DSP, PCB's, DDT, zinc, cadmium, lead and mercury) were lower or within normal limits. It seems reasonable to believe that natural mortality was the main cause of the strandings.
Article
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Occurrence of Phocoena phocoena (Cetacea: Phocoenidae) in the Azores. On the 4th January 2004, a specimen of P. phocoena was found stranded on rocks exposed during low tide on the east coast of Terceira Island (38º42.520’N; 27º03.031’W). The adult female, with a length of 161cm, presented no external wounds apart from a shark bite which we believe to have been made after the porpoise’s death.
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Four sympatric species of whales in the genus Balaenoptera were studied May 1983-April 1986 in the Canal de Ballenas, Gulf of California, Mexico. Most data were collected on the two most abundant species, Bryde's whale (B. edeni), ca. 13,000 kg and fin whale (B. physalus), ca. 47,000 kg. Bryde's whales fed primarily on schooling fish and were most abundant in summer and autumn when schooling fish are concentrated in the study area. Fin whales were only observed feeding on euphausiids, and were most abundant in winter and spring when euphausiids are abundant throughout the Gulf of California. Bryde's whales fed more at dawn and dusk, whereas fin whales fed throughout the day. Bryde's whales were relatively resident to the study area, rarely traveled in groups, and frequently fed alone or in small aggregations. Fin whales, in contrast, were relatively transient, passing through the study area and lingering only to feed; they traveled in larger groups and fed in larger aggregations, within which there were coordinated groups of two to four individuals. These results, coupled with limited data on the blue whale (B. musculus), ca. 80,000 kg, and minke whale (B. acutorostrata), ca. 5,000 kg, are interpreted in light of theories that relate body size to diet, habitat use, and social behavior in better-studied terrestrial mammals.
Article
A review of available catch and biological data suggests that there are 3 populations of Bryde's whales in the southern African region. An inshore population (the South African Inshore Stock) occurs over the continental shelf of South Africa, south of about 30°S, and seems to be nonmigratory, although there is a movement up the west coast in winter. A pelagic population (the Southeast Atlantic Stock) occurs on the west coast of southern Africa, ranging from equatorial regions to about 34°S, and appears to migrate north in autumn and south in spring. Whales from the Southeast Atlantic Stock differ from the South African Inshore Stock in size, scarring, baleen shape, seasonality of reproduction, fecundity and prey types. Both occurred in the west coast whaling ground off Donkergat, but with differing seasonalities and distributions from the coast. Bryde's whales are rare on the east coast of southern Africa, but are found in summer in some numbers south of Madagascar. Whales from this population are clearly smaller than those from the Southeast Atlantic Stock, but are similar in size to, or even smaller than, those from the South African Inshore Stock. Their external appearance is unknown, but they differ in prey type from the South African Inshore Stock, and because of a clear discontinuity in distribution it is believed that they form a third (pelagic) population (the Southwest Indian Ocean Stock). This population may or may not move north as far as the Seychelles in winter, but seems to be separate from Bryde's whales in the Arabian Sea. From their size composition, length at sexual maturity and infrequent capture, Bryde's whales taken at Durban may have represented strays from either the South African Inshore Stock or the Southwest Indian Ocean Stock, and recorded stomach contents also indicate prey types common to either stock. The unusual degree of population differentiation shown by Bryde's whales may be a consequence of their limited seasonal migrations and apparent resource partitioning.