Peponocephala Research Articles

Comparison of odontocete populations of the Marquesas and Society Islands (French Polynesia)

Small boat surveys were organized to study cetaceans of the Marquesas (9°S and 140°W) and the Society Islands (17°S and 150°W) in French Polynesia. Prospecting took place from 12–15 m sailboats, between 1996 and 2001 with systematic visual searching. Boats moved according to sea conditions, at a mean speed of 10 km/h. Effective effort of 4856 km in the Marquesas and 10,127 km in the Societies were logged. Relative abundance indices were processed for odontocetes using data obtained with Beaufort 4 or less. In the Marquesas, 153 on-effort sightings were obtained on 10 delphinids species including the spotted dolphin, spinner dolphin, bottlenose dolphin, melon-headed whale and rough-toothed dolphin. In the Societies, 153 sightings of 12 odontocetes included delphinids (spinner, rough-toothed and bottlenose dolphins, short-finned pilot and melon-headed whales, Fraser's dolphin, Risso's dolphin and pygmy killer whale) and two species of beaked whales, the sperm whale and dwarf sperm whale. Relative abundance indices were higher in the Marquesas than in the Societies both inshore (0.93 ind/km2against 0.36 ind/km2) and offshore (0.28 ind/km2against 0.14 ind/km2). Differences in remote-sensed primary production were equally important, the Marquesas waters featuring an annual average of 409 mgC.m−2 · day−1and the Societies of only 171 mgC · m−2 · day−1. The presence of a narrow shelf around the Marquesas also accounted for differences in odontocete populations, in particular the delphinids.

Negative APCI-LC/MS/MS Method for Determination of Natural Persistent Halogenated Products in Marine Biota

A sensitive and selective method utilizing high performance liquid chromatography coupled to negative atmospheric pressure chemical ionization tandem mass spectrometry (APCI-LC/MS/MS) was developed to enable analysis of selected natural persistent organohalogens accumulated in marine biota. The analytes were three methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47, 2'-MeO-BDE68, and 2',6-diMeO-BDE68), a dimethoxylated tetrabromobiphenyl (2,2'-diMeO-BB80), and two halogenated methyl bipyrroles (Cl(7)-MBP and Br(4)Cl(2)-DBP). These products were well resolved on a 150 mm reversed-phase column with methanol as the mobile phase. The fragmentation pathways of the Cl(7)-MBP and Br(4)Cl(2)-DBP produced characteristic multiple reaction monitoring (MRM) transitions. Determination was performed in the MRM mode using phenoxide ion [M-Br+O](-) and product Br(-) ions for MeO-BDE analogues, or the precursor [M-Cl+O](-) to Br(-) ion for Br(4)Cl(2)-DBP, and to C(4)NCl(4)(-) ion for Cl(7)-MBP. The APCI-LC/MS/MS method is acceptable for calibration of the linearity and repeatability of all products studied in the low ng/g (lipid weight) level and with similar sensitivity to the electron ionization (EI)-GC/MS method. The proposed method was applied for quantification of natural organohalogens accumulated in melon-headed whale (Peponocephala electra) blubber (N = 15) in the Asia-Pacific Ocean. The concentration was positively correlated between different groups of compounds except for 2'-MeO-BDE68. The use of the analytical method based on negative ion APCI-LC/MS/MS would provide a new way for rapid monitoring of halogenated natural products from marine biota, such as sponges or algae.

Time Trends and Transplacental Transfer of Perfluorinated Compounds in Melon-Headed Whales Stranded Along the Japanese Coast in 1982, 2001/2002, and 2006

As a result of the phase-out of production of perfluorooctanesulfonyl-based compounds by a major producer, concentrations of perfluorooctanesulfonate (PFOS) in marine mammals from North American and European coastal waters have been declining since the early 2000s. Nevertheless, temporal trends in perfluorochemical (PFC) concentrations in marine mammals from Asian coastal waters have not been examined. In this study, PFCs were determined in livers of melon-headed whales (Peponocephala electra) collected along the coast of Japan, from three mass strandings that occurred during the past 25 years. Concentrations of nine PFCs were determined in livers of 48 melon-headed whales that were collected during strandings in 1982, 2001/2002, and 2006. In addition, concentrations in liver tissues obtained from two pregnant females and their fetuses were compared for determination of transplacental transfer rates of PFCs during gestation. PFOS and perfluorooctanesulfonamide (PFOSA) were the predominant PFCs found in livers of melon-headed whales collected in 1982 (n = 22). PFOS, PFOSA, perfluoroundecanoate (PFUnDA), perfluorododecanoate (PFDoDA), perfluorodecanoate (PFDA), and perfluorononanoate (PFNA) were found in whales collected in 2001/2002 (n = 21) and in 2006 (n = 5). Concentrations of PFOS and PFOSA were approximately 10-fold higher in 2001/2002 than in 1982. Whereas concentrations of PFOSA then declined by 2-fold from 2001/ 2002 to 2006, concentrations of PFOS and perfluorocarboxylates did not decline after 2001/2002. Conversely, concentrations of PFNA and PFDA increased significantly from 2001/2002 to 2006. The proportion of perfluoroalkylsulfonates in total PFC concentrations decreased from 75% in 1982 to 51% in 2006. Conversely, the contribution of perfluorocarboxylates to total PFC concentrations increased from 25% in 1982 to 49% in 2006. PFUnDA was the major perfluorocarboxylate found in whale livers collected after 2000. Analysis of paired samples of mother-fetus demonstrated that the transplacental transfer rates of PFCs were higher than those for PCBs and PBDEs.

Cetacean diversity off La Réunion Island (France)

The waters of La Réunion, a French island located in the south-western Indian Ocean, have never been investigated for cetacean diversity. Dedicated daily surveys were conducted in 2004–2007 to assess cetacean diversity off the western and southern coasts of the island. A total of ten species was observed during the survey period, including two baleen whales and eight odontocetes. Four additional species that had not been observed at sea were reported stranded. The most frequent delphinid species were the Indo-Pacific bottlenose, the spinner and the common bottlenose dolphins, which were observed year-round. Photo-identification data showed a high recapture rate ofTursiops aduncus, strongly suggesting a resident population. The humpback whale uses the coastal waters of La Réunion seasonally, during winter. The high proportion of mother–calf pairs indicated that La Réunion might represent a breeding area for this species. Pantropical spotted dolphin, melon-headed whale and Fraser's dolphin were sighted at a medium frequency, in offshore waters, and tended to favour the southern part of the island. Three coastal species were frequently using the newly created Marine Protected Area (MPA), supporting the view that cetacean conservation issues have to be included in the MPA management plan currently in progress.

Histological, Immunohistochemical and Pathological Features of the Pituitary Gland of Odontocete Cetaceans from the Western Gulf of Mexico

Pituitary glands were recovered from dolphins and small whales found stranded along the Texas coast of the Gulf of Mexico over a 15-year period (1991-2006). One hundred animals of 14 species were found to be suitable for inclusion in this study. Of these, 72 were Atlantic bottlenose dolphins (Tursiops truncatus). Other species included were the melon-headed whale (Peponocephala electra), spinner dolphin (Stenella longirostris), striped dolphin (Stenella coeruleoalba), pantropical spotted dolphin (Stenella attenuata), pygmy sperm whale (Kogia breviceps), dwarf sperm whale (Kogia sima), Risso's dolphin (Grampus griseus), the short finned pilot whale (Globicephala macrorhyncha), false killer whale (Pseudorca crassidens), Fraser's dolphin (Lagenorhynchus hosei), rough-tooth dolphin (Steno bredanensis), Gervais's beaked whale (Mesoplodon europaeus) and an infant sperm whale (Physeter catodon). The pituitary weights in T. truncatus ranged from 0.69 g in a 109-cm long neonate to 3.44 g in a large (277 cm) male. More typical weights were in the range of 0.95-2.35 g (mean=1.65+/-0.70 g) The cetacean pituitary consisted of two distinct parts, the adenohypophysis and the neurohypophysis, which were separated by a thin fibrous membrane in all species examined, in contrast to terrestrial mammals in which the parts are apposed and joined through a pars intermedia. Cell types were identified with conventional stains and immunohistochemistry. Cells positive for adrenocorticotropic hormone, follicle stimulating hormone, growth hormone, melanocyte stimulating hormone, luteinizing hormone and prolactin were identified with appropriate antibodies. Lesions, which were few, included one pituicytoma of the pars nervosa and a squamous cyst in T. truncatus, and colloid cysts in several species. Nodular aggregates of single cell types were common, probably representing a physiological variant.

Contamination levels of mercury and cadmium in melon-headed whales ( Peponocephala electra) from a mass stranding on the Japanese coast

Total mercury (T-Hg), methyl mercury (M-Hg), cadmium (Cd), selenium (Se), zinc (Zn) and copper (Cu) concentrations in the organs of melon-headed whales from a mass stranding on the Japanese coast were analyzed. The mean concentration of T-Hg in the liver (126 ± 97 μg/wet g, n = 13) was markedly higher than those in kidney (6.34 ± 2.36 μg/wet g, n = 12) and muscle (4.90 ± 2.33 μg/wet g, n = 15). In contrast, the mean concentration of M-Hg in the liver (9.08 ± 2.24 μg/wet g) was similar to those in the kidney (3.47 ± 0.91 μg/wet g) and muscle (3.78 ± 1.53 μg/wet g). The mean percentage of M-Hg in the T-Hg found in the liver (13.1 ± 10.3) was significantly lower than those in the kidney (58.3 ± 15.0) and muscle (78.9 ± 8.4). The molar ratio of T-Hg to Se in the liver was effectively 1.0, but those in the kidney and muscle were markedly lower. Conversely, the mean concentration of Cd was markedly higher in the kidney (24.4 ± 7.4 μg/wet g) than in the liver (7.24 ± 2.08 μg/wet g) and muscle (less than 0.05 μg/wet g). These results suggest that the formation of Hg–Se compounds mainly occurs in the liver after the demethylation of M-Hg, and Cd preferentially accumulates in the kidney of melon-headed whales.

Species identification and measurement of activity in odontocete species of Palmyra Atoll by acoustic monitoring

Acoustic monitoring has been used to study odontocete presence at Palmyra Atoll, a remote island in the Northern Line Islands chain. Long-term recordings of high-frequency, broadband acoustic data have become possible with recent technological advances. A High-frequency Autonomous Recording Package (HARP) has been developed which samples at 200 kHz with a duty cycle of 1/4 for up to seven months. This instrument has recorded since October 2006 at Palmyra Atoll. Visual and acoustic surveys were conducted around Palmyra Atoll using a four-element towed hydrophone array sampling real-time at 200 kHz to obtain species-specific acoustic data. These data are used as reference for automatic detection algorithms applied on the long-term recordings. To date, acoustically and visually detected odontocetes include bottlenose dolphins (Tursiops truncatus), spinner dolphins (Stenella longirostris), melon-headed whales (Peponocephala electra) and beaked whales of the genus Mesoplodon. The long-term HARP data reveal acoustic activity primarily at night time and predominantely odontocete clicks. Both the beaked as well as the melon-headed whales are present year round and show a distinct daily acoustic activity cycle.

Occurrence and conservation needs of cetaceans in and around the Bar Reef Marine Sanctuary, Sri Lanka

The Bar Reef Marine Sanctuary lies off the north-west coast of Sri Lanka. In the first dedicated cetacean survey of this area, monthly boat-based surveys were carried out over 1 year (April 2004 to March 2005) both within the Sanctuary and seawards in deeper offshore waters. The survey established that the Sanctuary has year-round abundance of cetaceans. Eight species were observed, including three species of large whales. Live sightings of Sousa chinensis in this area were documented for the first time in Sri Lanka, as were the first live sightings of Kogia sima and Peponocephala electra off the west coast of the island. This area appears to be an important habitat for Balaenoptera acutorostrata in Sri Lanka's waters. Several threats to marine mammals were also identified and some were found to be localized and specific to this area. The results of this study were used to produce a set of management recommendations.

Polybrominated diphenyl ethers (PBDEs) and organochlorines in melon-headed whales, Peponocephala electra, mass stranded along the Japanese coasts: Maternal transfer and temporal trend

Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber of 55 melon-headed whales (Peponocephala electra) mass stranded along the Japanese coasts since 1982. DDTs and PCBs were predominant in all the specimens investigated. In whales that died during the latest event in 2006, concentrations of PBDEs (190-510 ng/g lipid wt) were approximately two orders of magnitude lower than DDTs and PCBs, but comparable with HCHs and HCB. Maternal transfer of PBDEs to offspring through the whole reproductive process was estimated to be 85% of the mother's body burden, while that occurring during gestation was much lower (2.6-3.5%). Concentrations of PCBs, DDTs, and HCB were lower in melon-headed whales stranded after the year 2000 than those stranded in 1982, whereas PBDE and CHL levels showed a temporal increase during the past 20 years, suggesting that the peak of their usage and contamination occurred after the year 1982.

Functional anatomy of the ocular circulatory system: vascular corrosion casts of the cetacean eye

To examine the functional anatomy of the ocular circulation in four bottlenose dolphins (Tursiops truncatus) and five melon-headed whales (Peponocephala electra). Eyes were obtained postmortem from whales that died while in captivity and/or were found beached. Specimens from whales were investigated using scanning electron microscopy (SEM) of vascular corrosion casts and histology. The thermal characteristics of live dolphin eyes were measured using an infrared imaging system. The whale eye receives its primary blood supply from the ophthalmic rete, which extends just behind the eyeball. The ophthalmic rete diverges from the basilar rete and the cervical rete via the posterior thoracic artery. The iris and ciliary processes are supplied by iridic arteries via the major arterial circle that is located around the iris edge. The retinal vessels show the holangiotic type. Choroidal arteries run in parallel arrays so as to interdigitate the densely packed choroidal veins. The venules in the conjunctival fold and palpebral conjunctiva form a well-developed venous plexus. Thermographic examination revealed that the eye shows a substantially higher degree of thermal emission than adjacent skin areas. The cetacean eye is characterized by a unique vascular pattern and multivessel plexuses, which are quite different from those of terrestrial mammals. This suggests that the ocular vasculature might function as a thermoregulatory system so that the appropriate operating temperature for the photoreceptors can be maintained in a deep and cold aquatic environment. The distinctive plexuses in the orbit might also be for pooling blood in the eye to conserve oxygen during dives. The ophthalmic rete might play a role in a pressure-damping effect on cetacean ocular circulation as well.

Pathological Findings in a Rare Mass Stranding of Melon-Headed Whales (<I>Peponocephala electra</I>) in Florida

Pathological Findings in a Rare Mass Stranding of Melon-Headed Whales (<I>Peponocephala electra</I>) in Florida

Occurrence of hydroxylated polychlorinated biphenyls in the brain of cetaceans stranded along the Japanese coast

Levels of hydroxylated polychlorinated biphenyls (OH–PCBs) and PCBs were measured in the brain of melon-headed whales (MW: Peponocephala electra), striped dolphins (SD: Stenella coeruleoalba) and finless porpoises (FP: Neophocaena phocaenoides) stranded along the Japanese coast during 2002–2003. Levels of OH–PCBs (including identified and unknown OH–P 5CB, –H 6CB, –H 7CB and O 8CB congeners) in the brain of MW, SD and FP were in the range of 20–290, 21–330 and 170–240 pg/g wet wt., respectively. Observed OH–PCB levels were 2–3 orders of magnitude lower than PCBs in the same individuals. OH–PCBs/PCBs ratios in MW, SD and FP brain were lower than those in blood of humans and wildlife and in the brain of polar bears reported previously. OH–PCBs were also detected in maternal and fetal brain of SD (1 pair), suggesting transfer of OH–PCBs into the fetal brain of odontocete cetaceans. When fetus/dam concentration ratios of OH–PCB congeners detected in maternal and fetal brain were estimated, the values were higher than those of PCB congeners, implying that OH–PCBs in maternal blood could be more easily transferred into fetal brain via placenta than PCBs.

Notes on the pygmy killer whale Feresa attenuata Gray, 1874 (Cetacea: Delphinidae) in Venezuela, southeastern Caribbean

The pygmy killer whale Feresa attenuata Gray, 1874 is one of the species usually known as 'black fish', which is easily mistaken for the false killer whale, Pseudorca crassidens (Owen 1846) and the melon-head whale, Peponocephala electra (Gray, 1846), especially in the field. Prior to 2002, there were very few data on this species in Venezuela and the only reports were based on craneometric studies of stranded animals in the western region. Five new reports on this species have been recorded since in the northeastern zone of the country, based on sightings or assistance of live-stranded animals. Detailed comparisons were made on specimens observed in the field for their corrected identification. These sightings and strandings of F. attenuata are the first reported for the Venezuelan northeast basin, thus increasing the number of reports of pygmy killer whales to seven in the country and extending their known distribution through the southern Caribbean Sea.

Passive cambering and flexible propulsors: cetacean flukes

The flukes are the primary locomotor structure in cetaceans, which produce hydrodynamic thrust as the caudal vertebrae are oscillated dorso-ventrally. Effective thrust generation is a function of the kinematics of the flukes, the angle of attack between the flukes and the incident water flow, and the shape of the flukes. We investigated the effect of bending within the caudal region of odontocete cetaceans to determine how changes in angular displacement between caudal vertebrae could effect passive shape change of the flukes. The internal and external changes of bent flukes were examined with computer tomography. Flukes and tailstock were removed from deceased Delphinus delphis, Lagenorhynchus acutus, Peponocephala electra, Phocoena phocoena and Tursiops truncatus, and bent on an adjustable support at 0, 45 and 90°. At 0°, cross-sections of the flukes displayed a symmetrical profile. Cross-sections of bent flukes (45°, 90°) were asymmetrical and showed a cambered profile. Maximum cambering occurred close to the tailstock and decreased toward the fluke tip. Maximum angular displacement occurred at the ‘ball vertebra’, which was located posterior of the anterior insertion of the flukes on the tailstock. Bending at the ‘ball vertebra’ passively cambers the flexible flukes. Cambering could increase hydrodynamic force production during swimming, particularly during direction reversal in the oscillatory cycle.

Analysis of melon-headed whale aggregation in Hanalei Bay, July 2004

On 3 July 2004, an aggregation of ca. 150–200 melon-headed whales (Peponocephala electra) appeared in the shallow waters of Hanalei Bay, Kauai and congregated there for over 27 h. Preceding the whales’ appearance and partially coincident with their time in the Bay, midrange (3.5–5 kHz) tactical sonars were intermittently deployed during the Rim of the Pacific 2004 (RIMPAC) joint military exercises being conducted in waters near Kauai by the U.S., Japan, and Australia Navies. An NOAA report (Southall et al., 2006) attributed the active sonar usage as a plausible, if not likely, contributing factor. A detailed timeline and reconstruction of the RIMPAC activities is presented showing the worst-case estimates of the sonar sound levels in the waters surrounding Kauai. A re-examination of available evidence combined with a new report of a simultaneous and similar aggregation in Sasanhaya Bay, Rota, Commonwealth of the Northern Mariana Islands, brings the plausibility conclusion into question. [This work was sponsored by multiple sources. D. Fromm and S. Martin conducted acoustic analyses with funds provided by the U.S. Pacific Fleet. J. Mobley received funding from the U.S. Geological Survey. P. Nachtigall is sponsored by the Office of Naval Research for marine mammal audiometric studies.]

Compound‐specific stable carbon isotope ratios (δ13C values) of the halogenated natural product 2,3,3′,4,4′,5,5′‐heptachloro‐1′‐methyl‐1,2′‐bipyrrole (Q1)

Compound-specific isotope analysis using gas chromatography interfaced to isotope ratio mass spectrometry (GC/IRMS) was applied for the determination of delta13C values of the marine halogenated natural product 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1). The delta13C value of a lab-made Q1 standard (-34.20 +/- 0.27 per thousand) was depleted in 13C by more than 11 per thousand relative to the residues of Q1 in dolphin blubber from Australia and skua liver from Antarctica. This clarified that the synthesized Q1 was not the source for Q1 in the biota samples. However, two Australian marine mammals showed a large variation in the delta13C value, which, in our experience, was implausible. Since the GC/IRMS system was connected to a conventional ion trap mass spectrometer by a post-column splitter, we were able to closely inspect the peak purity of Q1 in the respective samples. While the mass spectra of Q1 did not indicate any impurity, a fronting peak of PCB 101 was identified in one sample. This interference falsified the delta13C value of the respective sample. Once this sample was excluded, we found that the delta13C values of the remaining samples, i.e. liver of Antarctic brown skua (-21.47 +/- 1.47 per thousand) and blubber of Australian melon-headed whale (-22.80 +/- 0.33 per thousand), were in the same order. The standard deviation for Q1 was larger in the skua samples than in the standard and the whale blubber sample. This was due to lower amounts of skua sample available. It remained unclear if the Q1 residues originate from the same producer and location.

CDNA-derived amino acid sequences of myoglobins from nine species of whales and dolphins

We determined the myoglobin (Mb) cDNA sequences of nine cetaceans, of which six are the first reports of Mb sequences: sei whale ( Balaenoptera borealis), Bryde's whale ( Balaenoptera edeni), pygmy sperm whale ( Kogia breviceps), Stejneger's beaked whale ( Mesoplodon stejnegeri), Longman's beaked whale ( Indopacetus pacificus), and melon-headed whale ( Peponocephala electra), and three confirm the previously determined chemical amino acid sequences: sperm whale ( Physeter macrocephalus), common minke whale ( Balaenoptera acutorostrata) and pantropical spotted dolphin ( Stenella attenuata) . We found two types of Mb in the skeletal muscle of pantropical spotted dolphin: Mb I with the same amino acid sequence as that deposited in the protein database, and Mb II, which differs at two amino acid residues compared with Mb I. Using an alignment of the amino acid or cDNA sequences of cetacean Mb, we constructed a phylogenetic tree by the NJ method. Clustering of cetacean Mb amino acid and cDNA sequences essentially follows the classical taxonomy of cetaceans, suggesting that Mb sequence data is valid for classification of cetaceans at least to the family level.

Whale Stranding: Sonar Cited

Submarine sonar was “a plausible, if not likely” cause of the harm suffered by whales during a 2004 incident that stranded more than 150 melon-headed whales off the shore of Kaua'i, Hawai'i, an investigation by the National Oceanic and Atmospheric Administration (NOAA) has concluded. The U.S. Navy says it's unknown what caused the incident, but they reject NOAA's interpretation. One calf died in the episode, despite local canoeists' efforts to herd the whales away from the beach. Using time-stamped maps of joint U.S. and Japanese submarine exercises under way during the nearby Rim of the Pacific Exercises (RIMPAC), NOAA determined that the whales could have been within hearing range, and the report ruled out algal blooms or other natural causes. Now NOAA is considering a Navy request to authorize this year's RIMPAC; NOAA official Brandon Southall said that the incident will be part of the “range of information” that the agency uses to make its decision. The Navy has promised new mitigation measures during the event, but activists want NOAA to force it to turn its sonar volume down, avoid islands, and switch sonar off while traveling between exercise sites.

Marine mammal strandings in the New Caledonia region, Southwest Pacific

Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale, Physeter macrocephalus (18 single strandings, 2 pair strandings), pygmy sperm whale, Kogia breviceps (5 single strandings), dwarf sperm whale, K. sima (2 single strandings, 1 triple stranding), Blainville's beaked whale, Mesoplodon densirostris (2 single strandings), short-finned pilot whale, Globicephala macrorhynchus (4 strandings, 56 individuals), melon-headed whale, Peponocephala electra (1 single stranding and 2 mass strandings totalling 231 individuals), common dolphin, Delphinus delphis (1 single stranding), spinner dolphin, Stenella longirostris (1 pair stranding and 2 mass strandings of groups of ∼30 individuals each), Indian Ocean bottlenose dolphin, Tursiops aduncus (2 single strandings), dugong, Dugong dugon (14 single strandings), and New Zealand fur seal, Arctocephalus forsteri (3 single strandings). A stranded rorqual identified as an Antarctic minke whale ( B. bonaerensis), with coloration patterns that did not match known descriptions, was also reported. Sei whale was recorded for the first time in the tropical Southwest Pacific region and Antarctic minke whale, melon-headed whale, and Indian Ocean bottlenose dolphin were recorded for the first time in New Caledonia. Strandings of sperm whales were most frequent in the spring, but also occurred in autumn months, suggesting a seasonal pattern of occurrence possibly related to seasonal migration. One stranded humpback whale bore the scars of a killer whale's attack and one dugong was injured by a shark. Scars left by propellers were noted on several stranded animals including one Antarctic minke whale, one pygmy sperm whale, one dwarf sperm whale, and four dugongs. Collisions with vessels were suspected to be a frequent cause of death for dugong. To cite this article: P. Borsa, C. R. Biologies 329 (2006).

Rescue, handling and release of a melon-headed whale, <i>Peponocephala electra</i>, stranded in Ceará, NE Brazil.

Rescue, handling and release of a melon-headed whale, <i>Peponocephala electra</i>, stranded in Ceará, NE Brazil.