160
described sounds produced by the calves of this species, which have a much broader
bandwidth than adults, allowing discrimination between calves and adults by means
of PAM. Another species that can be found in the RNE is the Bottlenose dolphin
which produces clicks and whistles with a lower frequency content than Franciscana
dolphins and thus can be easily differentiated in the acoustic recordings. Killer
whales can be found all along the waters of Argentinean shelf, including Patagonian
shelf, and during February–April/ September–October can be frequently seen in the
waters off Península Valdés in Chubut province. Here they use a unique technique
to forage sea lions and elephant seals pups. However, the available acoustic information on this species is scarce and only recently the very first recordings on this
species in the north part of the western Antarctic Peninsula were obtained (Table 6.1).
During summer months, Dusky dolphins can be found in the waters of Golfo Nuevo.
Moving to the south, Commerson’s dolphins inhabit the waters of Playa Unión in
Chubut province. This species is also distributed further south down to the Magellan
Strait. Peale’s dolphins and Commerson’s dolphins are sympatric which means that
can be found together in many areas of the Southern part of Argentina in Santa Cruz
and Tierra del Fuego provinces. Both species produce NBHF clicks with very similar characteristics, making it challenging to unambiguously tell them apart by just
conducting passive acoustic monitoring in those areas. A detailed characterization
of the acoustic repertoire of both species along with the available classification and
appropriate statistical tools may enable to accomplish this objective. Systematic
studies of Commerson’s dolphin’s in Santa Cruz province in the last years showed
that the acoustic repertoire of this species is broader than previously thought. BB
clicks, whistles and variable NBHF clicks were described for the population of
Bahía San Julián, Santa Cruz province (Reyes Reyes et al. 2015, 2016a).
At least five species of beaked whales are known to occur in the Southern Ocean
waters, including Arnoux’s beaked whales (Berardius arnuxii), Cuvier’s beaked
whales (Ziphius cavirostris), Gray’s beaked whales (Mesoplodon grayi), Southern
bottlenose whales (Hyperoodon planifrons), and strap-toothed whales (Mesoplodon
layardii) (MacLeod et al. 2006). Given the elusive and deep-diving behavior of
beaked whales, visual sightings are extremely difficult to obtain. However, the
unique features of their upswept FM clicks facilitate the study of these cryptic odontocetes by means of their acoustic signals. Using baseline information on species
distribution and the available knowledge on some sister species in the Northern
hemisphere, we can infer which species are the most probable candidates producing
certain sounds, as in the two examples shown in Table 6.1.
We have seen that the number of odontocetes that have been recorded at least
once in Argentinean waters is large but acoustic data is only available for a few species. This means that there is a big potential for studying the acoustic repertoire of
many odontocete species along all the coastal and platform waters of this country.
M.L. Melcón et al.
described sounds produced by the calves of this species, which have a much broader
bandwidth than adults, allowing discrimination between calves and adults by means
of PAM. Another species that can be found in the RNE is the Bottlenose dolphin
which produces clicks and whistles with a lower frequency content than Franciscana
dolphins and thus can be easily differentiated in the acoustic recordings. Killer
whales can be found all along the waters of Argentinean shelf, including Patagonian
shelf, and during February–April/ September–October can be frequently seen in the
waters off Península Valdés in Chubut province. Here they use a unique technique
to forage sea lions and elephant seals pups. However, the available acoustic information on this species is scarce and only recently the very first recordings on this
species in the north part of the western Antarctic Peninsula were obtained (Table 6.1).
During summer months, Dusky dolphins can be found in the waters of Golfo Nuevo.
Moving to the south, Commerson’s dolphins inhabit the waters of Playa Unión in
Chubut province. This species is also distributed further south down to the Magellan
Strait. Peale’s dolphins and Commerson’s dolphins are sympatric which means that
can be found together in many areas of the Southern part of Argentina in Santa Cruz
and Tierra del Fuego provinces. Both species produce NBHF clicks with very similar characteristics, making it challenging to unambiguously tell them apart by just
conducting passive acoustic monitoring in those areas. A detailed characterization
of the acoustic repertoire of both species along with the available classification and
appropriate statistical tools may enable to accomplish this objective. Systematic
studies of Commerson’s dolphin’s in Santa Cruz province in the last years showed
that the acoustic repertoire of this species is broader than previously thought. BB
clicks, whistles and variable NBHF clicks were described for the population of
Bahía San Julián, Santa Cruz province (Reyes Reyes et al. 2015, 2016a).
At least five species of beaked whales are known to occur in the Southern Ocean
waters, including Arnoux’s beaked whales (Berardius arnuxii), Cuvier’s beaked
whales (Ziphius cavirostris), Gray’s beaked whales (Mesoplodon grayi), Southern
bottlenose whales (Hyperoodon planifrons), and strap-toothed whales (Mesoplodon
layardii) (MacLeod et al. 2006). Given the elusive and deep-diving behavior of
beaked whales, visual sightings are extremely difficult to obtain. However, the
unique features of their upswept FM clicks facilitate the study of these cryptic odontocetes by means of their acoustic signals. Using baseline information on species
distribution and the available knowledge on some sister species in the Northern
hemisphere, we can infer which species are the most probable candidates producing
certain sounds, as in the two examples shown in Table 6.1.
We have seen that the number of odontocetes that have been recorded at least
once in Argentinean waters is large but acoustic data is only available for a few species. This means that there is a big potential for studying the acoustic repertoire of
many odontocete species along all the coastal and platform waters of this country.
M.L. Melcón et al.