Beaked Whales

The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different methods to obtain a single density index for the region. A total of 594,996 km of survey effort and 507 sightings of Cuvier’s beaked whales, from 1990 to 2016, were pooled together from 24 different sources. Data were divided into twelve major groups according to platform height, speed and sea state. Both availability bias and effective strip width were calculated from the sightings with available perpendicular distance data. This was extrapolated to the rest of the sightings for each of the twelve groups. Habitat preference models were fitted into a GAM framework using counts of groups as a response variable with the effective searched area as an offset. Depth, coefficient of variation of depth, longitude and marine regions (as defined by the International Hydrographic Organization) were identified as important predictors. Predicted abundance of groups per grid cell were multiplied by mean group size to obtain a prediction of the abundance of animals. A total abundance of 5799 (CV = 24.0%) animals was estimated for the whole Mediterranean basin. The Alborán Sea, Ligurian Sea, Hellenic Trench, southern Adriatic Sea and eastern Ionian Sea were identified as being the main hot spots in the region. It is important to urge that the relevant stakeholders incorporate this information in the planning and execution of high risk activities in these high-risk areas.

True's Beaked Whales are found in cool temperate, deep oceanic waters. This species has a uniquely disjunct distribution, occurring in the northern North Atlantic Ocean, as well as the southern regions of the Atlantic, Indian and Pacific Oceans. Sightings of the species are very rare and it is mainly known from strandings. In the southern hemisphere a stranding hot spot is South Africa. Here we report two records from Mozambique, including the first stranding record for this country.

The first mid-Atlantic diet of Mesoplodon beaked whales is presented, from ten Sowerby’s Mesoplodon bidens stranded in the Azores region between 2002 and 2009. This doubles the worldwide number of stomachs sampled, and reveals new feeding habits for this species. the mean number of prey items per stomach was 85789 (range: 12–238), with fish accounting for 99.3% and cephalopods contributing less than 1% of total prey. Fish otoliths from 15 families and cephalopod lower mandibles from three families were identified, representing 22 taxa. The diet consisted mainly of small mid-water fish, the most numerous being Diaphus sp., Lampanyctus sp. and Melamphaidae species. Myctophids were present in all stranded individuals, followed by Diretmidae, Melamphaidae and Opisthoproctus soleatus, while the remaining fish species were scarce or single occurrences. Consistency of diet in four different years reveals a divergence from all previous records in continental areas, where mainly neritic and shelf-break benthopelagic fish species have been reported. Mid-Atlantic Sowerby’s beaked whales’ showed dietary plasticity, feeding on the most abundant mid-water groups occurring between 0 and750 m. Trophic level from prey numerical frequency was estimated at 4.470.46.

video summary: https://www.youtube.com/watch?v=r93I8ffgAoI
We analysed 3680 dives from 23 satellite-linked tags deployed on Cuvier's beaked whales to assess the relationship between long duration dives and inter-deep dive intervals and to estimate aerobic dive limit (ADL). The median duration of presumed foraging dives was 59 min and 5% of dives exceeded 77.7 min. We found no relationship between the longest 5% of dive durations and the following inter-deep dive interval nor any relationship with the ventilation period immediately prior to or following a long dive. We suggest that Cuvier's beaked whales have low metabolic rates, high oxygen storage capacities and a high acid-buffering capacity to deal with the by-products of both aerobic and anaerobic metabolism, which enables them to extend dive durations and exploit their bathypelagic foraging habitats.

Cuvier's beaked whales are found in all the oceans of the world except the polar regions of both hemispheres. This species is known from over 1800 strandings. In southeast Asia strandings have been reported in China, Indonesia (Java and Bali), Malaysia, in the Philippines, Taiwan and Thailand. We present a first stranding record of the species from Sulawesi, Indonesia.

The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different methods to obtain a single density index for the region. A total of 594,996 km of survey effort and 507 sightings of Cuvier’s beaked whales, from 1990 to 2016, were pooled together from 24 different sources. Data were divided into twelve major groups according to platform height, speed and sea state. Both availability bias and effective strip width were calculated from the sightings with available perpendicular d...

The first mid-Atlantic diet of Mesoplodon beaked whales is presented, from ten Sowerby's Mesoplodon bidens stranded in the Azores region between 2002 and 2009. This doubles the worldwide number of stomachs sampled, and reveals new feeding habits for this species. The mean number of prey items per stomach was 85±89 (range: 12–238), with fish accounting for 99.3% and cephalopods contributing less than 1% of total prey. Fish otoliths from 15 families and cephalopod lower mandibles from three families were identified, representing 22 taxa. The diet consisted mainly of small mid-water fish, the most numerous being Diaphus sp., Lampanyctus sp. and Melamphaidae species. Myctophids were present in all stranded individuals, followed by Diretmidae, Melamphaidae and Opisthoproctus soleatus, while the remaining fish species were scarce or single occurrences. Consistency of diet in four different years reveals a divergence from all previous records in continental areas, where mainly neritic and shelf-break benthopelagic fish species have been reported. Mid-Atlantic Sowerby's beaked whales' showed dietary plasticity, feeding on the most abundant mid-water groups occurring between 0 and750 m. Trophic level from prey numerical frequency was estimated at 4.4±0.46.► First insight on the diet of Mesoplodon beaked whales' from the mid-North Atlantic area. ► Ten M. bidens stranded in the Azores, doubles the number of records worldwide. ► The beaked whales M. bidens are piscivorous marine mammals, in accordance to all previous studies. ► Diet consisted on the most abundant mid-water groups between 0 and 750 m, no larger than 15 cm. ► A shift from benthopelagic fish on continental slopes and lower shelf areas, reveals dietary plasticity.

Cuvier's beaked whale is the most cosmopolitan of the beaked whales and is found in all oceans except in
the high polar waters. This species is known from over 1600 strandings. In the Caribbean strandings are
rare, and we present a first record from Antigua and Barbuda

The first mid-Atlantic diet of Mesoplodon beaked whales is presented, from ten Sowerby’s Mesoplodon bidens stranded in the Azores region between 2002 and 2009. This doubles the worldwide number of stomachs sampled, and reveals new feeding habits for this species. the mean number of prey items per stomach was 85789 (range: 12–238), with fish accounting for 99.3% and cephalopods contributing less than 1% of total prey. Fish otoliths from 15 families and cephalopod lower mandibles from three families were identified, representing 22 taxa. The diet consisted mainly of small mid-water fish, the most numerous being Diaphus sp., Lampanyctus sp. and Melamphaidae species. Myctophids were present in all stranded individuals, followed by Diretmidae, Melamphaidae and Opisthoproctus soleatus, while the remaining fish species were scarce or single occurrences. Consistency of diet in four different years reveals a divergence from all previous records in continental areas, where mainly neritic and ...

The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different methods to obtain a single density index for the region. A total of 594,996 km of survey effort and 507 sightings of Cuvier’s beaked whales, from 1990 to 2016, were pooled together from 24 different sources. Data were divided into twelve major groups according to platform height, speed and sea state. Both availability bias and effective strip width were calculated from the sightings with available perpendicular d...

On 10 and 1.5 March 1993, sightings of large ziphiids, probably the same group of animals, were made in the waters of Baja California Sur, Mexico. The first sighting was of seven individuals 24 km southeast of San Jose de1 Cabo (23 " 02'N, 109 " 18'W) where the depth is 1,100 m. This observation was made from an aircraft, Cessna-l 82, at an altitude of 100 m while conducting a humpback whale (Megaptera novaeangliae) survey. The seven whales were swimming in front of two adult humpback whales; after about two minutes they dove and were not spotted again. The average size of the ziphiids was estimated to be about half of the total length of the adult humpback whales, and their coloration and body shape were similar to those of the bottlenose dolphin (Tursiops truncatis). The second sighting occurred while we were studying humpback whales aboard a 7-m skiff. The animals were spotted because at least one of them was breaching (it was completely clear of the water and fell on its ventral side upon reentry); this behavior was observed five times. Once the skiff was within 50 m of the animals, they began to swim toward it, and the motor was turned off. While the animals were approaching the boat, three characteristics were noticed: (1) the blow was hardly visible, (2) the coloration was brown and no scars could be seen, and (3) the dorsal fin was falcate and located on the last third of the body. It was surprising that the animals approached the boat so closely (two animals came within 1 m of the skiff), allowing us to confirm the characteristics described above. The fact that the animals were so close made it impossible for us to bring them into focus with our telephoto lenses. However, important external characteristics were clearly observed because one of the two individuals spun slightly and raised its head out of the water, apparently to examine the boat visually for a few seconds. Four features were perfectly observed: (1) the dorsal surface of the neck was more lightly colored than the rest of the body; (2) the rostrum was short and the forehead was slightly steep, although the melon was well defined; (3) no teeth were seen and the eye was reddish in color; and (4) the total length was estimated to be between 6.3 and 7 m by comparing the animal with the skiffs length (the whales were similar in size). Finally, the individual that had shown its head swam around the skiff and dove with the rest of the group; at that moment a photograph was taken with an underwater camera (Fig. 1). The location of this sighting was 13 km southeast of San JO& de1 Cabo (23 " 04'N, 103 " 23'W) where depth reaches 800 m. The water temperature was 23°C which was about the same in comparison to other years. Two species of the genus Hyperoodon have been described: the northern bottlenose whale (Hyperoodon ampullatus) in the North Atlantic, and the southern bottlenose whale (Hyperoodon planifrons) in the Southern Hemisphere. Some