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Most cetaceans are born with vibrissae but they can be lost or reduced in adulthood, especially in odontocetes. Despite this, some species of odontocetes have been found to have functioning vibrissal follicles (including the follicle itself and any remaining vibrissal hair shaft) that play a role in mechanoreception, proprioception and electroreception. This reveals a greater diversity of vibrissal function in odontocetes than in any other mammalian group. However, we know very little about vibrissal follicle form and function across the Cetacea. Here, we qualitatively describe the gross vibrissal follicle anatomy of fetuses of three species of cetaceans, including two odontocetes: Atlantic white-sided dolphin (Lagenorhynchus acutus), harbour porpoise (Phocoena phocoena), and one mysticete: minke whale (Balaenoptera acutorostrata), and compared our findings to previous anatomical descriptions. All three species had few, short vibrissae contained within a relatively simple, single-part follicle, lacking in muscles. However, we observed differences in vibrissal number, follicle size and shape, and innervation distribution between the species. While all three species had nerve fibers around the follicles, the vibrissal follicles of Balaenoptera acutorostrata were innervated by a deep vibrissal nerve, and the nerve fibers of the odontocetes studied were looser and more branched. For example, in Lagenorhynchus acutus, branches of nerve fibers travelled parallel to the follicle, and innervated more superficial areas, rather than just the base. Our anatomical descriptions lend support to the observation that vibrissal morphology is diverse in cetaceans, and is worth further investigation to fully explore links between form and function.

Summary Fatal meningoencephalitis due to Brucella ceti infection has been described in striped dolphins (Stenella coeruleoalba), Atlantic white-sided dolphins (Lagenorhynchus acutus), short-beaked common dolphins (Delphinus delphis) and long-finned pilot whales (Globicephala melas), which are all within the family Delphinidae. We report B. ceti-associated neurobrucellosis in three juvenile male Sowerby's beaked whales (Mesoplodon bidens) that all had typical lesions of lymphocytic meningoencephalitis, which increased in severity from rostral to caudal regions of the brain. In two cases there was loss of ependymal cells lining the cerebral ventricular system, with large numbers of lymphocytes in the underlying neuropil. This finding suggests that B. ceti gains access to, and multiplies in, the cerebrospinal fluid, and confirms that this is the sample of choice for bacteriological recovery of the causative organism. These findings expand the increasing range of cetaceans susceptible to neurobrucellosis to members of the family Ziphiidae.

The North Atlantic Oscillation (NAO) is a dominant climatic driver that influences hydrographic and ecological parameters at multiple spatial scales and several trophic levels. To date, linkages between NAO variability and dolphin strandings on a regional scale have not been investigated. Stranding records of short-beaked common dolphins (Delphinus delphis) and Atlantic white-sided dolphins (Lagenorhynchus acutus) during 1990–2014 between Maine and New York were correlated against the winter NAO index at several time lags in order to explore the link between stranding variability and NAO. The stranding frequencies of the two species were positively correlated to one another. When analyzed against the winter NAO index, the stranding time-series for both species yielded statistically significant inverse correlations at time lags of one and/or two years. Dolphin strandings were lower during the two years after winters when the NAO was positive and were higher during the two years after a negative NAO. Linear regression modeling confirmed a significant relationship between strandings and winter NAO at both 1and 2-year lags for common dolphins, but not for white-sided dolphins. The hypothesized mechanism underlying the relationship is that NAOlinked hydrographic changes during winter in outer shelf and slope waters affect the abundance and/or availability of prey, leading to changes in the inshoreoffshore distribution patterns of the dolphins. Increased occurrence and foraging closer to shore increases the dolphin’s susceptibility to stranding caused by other localized or short-term factors. This study represents the first attempt at linking NAO variability to dolphin mortality within New England waters.

In the North Sea, white-beaked dolphins (Lagenorhynchus albirostris) occur regularly and are the second most common cetacean in the area, while their close relative, the Atlantic white-sided dolphin (Lagenorhynchus acutus), prefers the deeper waters of the northern North Sea and adjacent Atlantic Ocean. Though strandings of both species have occurred regularly in the past three decades, they have decreased in the southern North Sea during the last years. Studies describing necropsy findings in stranded Lagenorhynchus spp. are, to date, still scarce, while information gained through post-mortem examinations may reveal valuable information about underlying causes of this decline, including age structure and the reproduction status. Therefore, we retrospectively assessed and compared the necropsy results from fresh Lagenorhynchus spp. stranded along the southeastern North Sea between 1990 and 2019. A full necropsy was performed on 24 white-beaked dolphins and three Atlantic white-sided dolphins from the German and Dutch coast. Samples of selected organs were taken for histopathological, bacteriological, mycological, parasitological and virological examinations. The most common post-mortem findings were emaciation, gastritis and pneumonia. Gastritis and ulceration of the stomach was often associated with an anisakid nematode infection. Pneumonia was most likely caused by bacterial infections. Encephalitis was observed in three animals and morbillivirus antigen was detected immunohistochemically in one case. Although the animal also showed pneumonic lesions, virus antigen was only found in the brain. Parasitic infections mainly affected the gastro-intestinal tract. Lungworm infections were only detected in two cases and no associations with pathological alterations were observed. Stenurus spp. were identified in two of three cases of parasitic infections of the ears. Twelve of the 26 white-beaked dolphins stranded in Germany were found between 1993 and 1994, but there was no evidence of epizootic disease events or mass strandings during the monitored period.

The basal forebrain (BFB) cholinergic neurotransmitter system is important in a number of brain functions including attention, memory, and the sleep-wake cycle. The size of this region has been linked to the increase in encephalization of the brain in a number of species. Cetaceans, particularly those belonging to the family Delphinidae, have a relatively large brain compared to its body size and it is expected that the cholinergic BFB in the dolphin would be a prominent feature. However, this has not yet been explored in detail. This study examines and maps the neuroanatomy and cholinergic chemoarchitecture of the BFB in the Atlantic white-sided dolphin (Lagenorhynchus acutus). As in some other mammals, the BFB in this species is a prominent structure along the medioventral surface of the brain. The parcellation and distribution of cholinergic neural elements of the dolphin BFB was comparable to that observed in other mammals in that it has a medial septal nucleus, a nucleus of the vertical limb of the diagonal band of Broca, a nucleus of the horizontal limb of the diagonal band of Broca, and a nucleus basalis of Meynert. The observed BFB cholinergic system of this dolphin is consistent with evolutionarily conserved and important functions for survival.

Úrtak: Síðan 1872 siga veiðihagtølini frá, at uml. 9.435 skjórutir springarar hava lagt beinini í 158 grindum, og tað gevur eitt árligt miðaltal á 68.4 hvalir og 1.1 flokkur. Fyri tey árini, har ið dráp var, er talið 168 hvalir og 2.8 flokkar. Tað, ið árliga hevur verið dripið, hevur ligið um 0-774 hvalir á 1-10 flokkar. Støddin á flokkunum hevur ligið um 1-544 (í miðal 60 hvalir) við 74% < 50 hvalir/flokk. Flestir skjórutir springarar vórðu sæddir sunnan fyri Suðuroynna, og 37% av springarunum úr 20 flokkum eru hildnir til í Vági og Hvalba. Raksturin er í hæddini í september, og eingin hevur verið í mars og desember. Úti á havinum hava hvalir verið sæddir alt árið. Ein mislittur hvalur kom fyri í tveimum drápum.Abstract: Since 1872, the catch data informs about 9,435 white- sided dolphins taken in 158 drives, an annual average of 68.4 whales and 1.1 pod, and 168 whales and 2.8 pods for only the years containing a catch. The annual catch has ranged 0-774 whales in 1-10 pods. The pod size has ranged 1-544 (avg. 60 whales) with 74% < 50 whales/pod. Most white-sided dolphins were observed south off Suðuroy and 37% dolphins from 20 pods has been killed in Vágur and Hvalba. The drives peak in September and none has occurred in March and December. Offshore the whale has been reported all year round. A discoloured whale occurred in two catches.

The present study is the first record of twinning inLagenorhynchus acutusand indeed anyLagenorhynchussp. Both foetuses were male and located in the left uterine horn, had distinct grossly normal placentas and amniotic sacs, and were therefore likely dizygotic twins. The twins were an incidental finding in an animal that died of a systemicBrucella cetiinfection.

Cobbold (1858) established Diphyllobothrium Cobbold, 1858 with the description of Diphyllobothrium stemmacephalum Cobbold, 1858 from the common harbor porpoise, Phocoena phocoena (Linnaeus) (Phocoenidae), from the North Sea off Scotland. Diphyllobothrium stemmacephalum typically has been reported from a number of Phocoenidae and Delphinidae hosts from a variety of localities: common harbor porpoise from the northern Atlantic Ocean, Baltic Sea and Black sea (e.g. Cobbold, 1858; Delyamure 1955; Delyamure 1968; Delyamure 1971; Delyamure et al. 1985; Anderson, 1987); bottlenose dolphin, Tursiops truncatus (Montagu), from the Gulf of Mexico (Ward & Collins 1959), the Black sea (Delyamure et al. 1985); common harbor porpoise off Newfoundland (Brattey & Stenson 1995), the Black Sea (Krivokhizin & Birkun 1994 [see Yera et al. 2008]), off Denmark (Herreras et al. 1997); long-finned pilot whale, Globicephala melas [Traill], North Atlantic off Faroe Island (Balbuena & Raga 1993); Atlantic white-sided dolphin, Lagenorhynchus acutus [Gray], off Massachusetts (Olson & Caira 1999).

Publisher Summary This chapter describes the Atlantic white-sided dolphins that are robust and powerful, impressively patterned, and more colorful than most dolphins. A narrow, bright white patch on the side extends back from below the dorsal fin and continues toward the flukes as a yellow brown blaze above a thin dark stripe. The back and dorsal fin are black or very dark gray, as are the flippers and flukes, while the belly and lower jaw are white, and the sides of the body a lighter gray. A black eye ring extends in a thin line to the upper jaw, and a very thin stripe extends backward from the eye ring to the external ear. A faint gray stripe may connect the leading edge of the flipper with the rear margin of the lower jaw. The beak is short and grades smoothly into the “melon” (forehead). The upper jaw contains 29–40 and the lower jaw 31–38 small, conical teeth. Molecular analysis has recently been used to examine the evolutionary relationships of Lagenorhynchus acutus and the five other currently recognized members of the genus Lagenorhynchus. Although formal taxonomic revision awaits a comprehensive review of morphological and molecular characters, the molecular evidence suggests that some of the five are actually more closely related to the right whale dolphins (genus Lissodelphis) and some Southern Hemisphere dolphins (genus Cephalorhynchus) than they are to L. acutus.

Fatal Brucella ceti infection with histological lesions specific to the central nervous system has been described in only 3 species of cetaceans: striped dolphins Stenella coeruleoalba, Atlantic white-sided dolphins Lagenorhynchus acutus and short-beaked common dolphins Delphinus delphis. This paper describes the first report of a B. ceti-associated meningoencephalitis in a long-finned pilot whale Globicephala melas, showing the increasing range of species susceptibility. Brucella was recovered in larger numbers from cerebrospinal fluid than from brain tissue and is the sample of choice for isolation.

Perfluorinated alkyl acids (PFAAs) have been used for 50 + years in materials such as stain-resistant treatments for paper and clothing, lubricants, and foam fire extinguishers. PFAAs are characterized by a fully fluorinated alkyl chain with a terminal acid group. Their long half-lives and ubiquitous environmental distribution create considerable concern for wildlife and human exposure. There is interest in examining temporal trends of PFAAs using the National Marine Mammal Tissue Bank (NMMTB), but NMMTB tissues are frozen and cryohomogenized in polytetrafluoroethylene (PTFE)-based materials. Because PTFE supplies may leach PFAAs into samples, this study mimicked collection, processing and storage steps of NMMTB samples and measured PFAA leaching to determine the feasibility of using this sample archive for PFAA temporal trends. We also explored concentrations in Atlantic white-sided dolphin (Lagenorhynchus acutus, WSDs) and rough-toothed dolphin (Steno bredanensis, RTDs) blubber (n = 3 and 0) and liver (n = 48 and 12, respectively). The materials used in NMMTB protocols may add up to 0.968 ng/g perfluorooctanoic acid (PFOA), 0.090 ng/g perfluorononanoic acid (PNFA), and 0.221 ng/g perfluorooctane sulfonate (PFOS) to each archived sample. Leaching of PFNA and PFOS from supplies compared to dolphin levels was negligible, but PFOA contributions were substantially higher than levels found in most dolphin liver samples. Therefore, monitoring PFOA temporal trends from the NMMTB would require careful consideration. RTDs had significantly higher levels of PFOS and PFNA than WSDs. Both species have similar life history, trophic status, and foraging behaviors in deep pelagic waters, so differences could be from latitudinal variation in contamination. RTDs stranded in Florida; WSDs stranded farther north mostly in Massachusetts. Juveniles had significantly higher levels of PFOS and PFNA than adults in both species, suggesting growth dilution as they approach maturity. PFOS significantly decreased after 2001 in both species as expected based on changes in production.

Helicobacter infection in cetaceans was first reported from the US in 2000 when the isolation of a novel Helicobacter species was described from two Atlantic white-sided dolphins (Lagenorhynchus acutus). Since then, Helicobacter species have been demonstrated in cetaceans and pinnipeds from around the world. Since 1990, the Animal Health and Veterinary Laboratories Agency Polwhele, Truro, has been involved in the UK Cetacean Strandings Investigation Programme to establish the cause of death of cetacean species stranded along the coast of Cornwall, England. We describe the isolation of Helicobacter cetorum in a striped dolphin (Stenella coeruleoalba) and evidence of H. cetorum infection in cetaceans from European waters.

Apex predators such as Pacific white-sided dolphins (Lagenorhynchus obliquidens) have the potential to impact prey populations and to be affected by changes in prey abundance. As abundant predators that range widely across the North Pacific Ocean, their interactions with prey populations may have conservation implications. The energy required by individual Pacific white-sided dolphins was estimated using a bioenergetic model that accounted for different age classes and reproductive stages (calf, juvenile, adult, pregnant, and lactating). Monte Carlo simulations incorporating variability in model parameters (i.e., body mass, growth rate, costs of gestation and lactation, metabolic rate, cost of activity, and assimilation efficiencies) were used to predict ranges in energetic requirements of this species. Mean (± SD) total energy requirements in MJ/day were 40.3 ± 6.2 for calves, 70.8 ± 8.2 for juveniles, 69.0 ± 3.6 for adults, 70.3 ± 3.6 for pregnant females, and 98.4 ± 20.0 for lactating females....

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The health, postrelease movements, and behavior of mass stranded Atlantic white-sided dolphins (Lagenorhynchus acutus) and short-beaked common dolphins (Delphinus delphis) from Cape Cod, Massachusetts, were evaluated. Health was assessed through physical examination and blood analysis. Eleven dolphins (eight white-sided dolphins and three common dolphins) were relocated, outfitted with satellite transmitters, and released during seven mass stranding events. Five transmitters recorded only location, and six also included a time-depth recorder. Transmission duration ranged from 8 h to 218 d, with a mean of 117 d (median = 118 d, SD = 82 d), after release. All dolphins demonstrated extensive movement throughout the Gulf of Maine. The distribution of tagged dolphins was considered normal based on comparisons with published data for these species. Excluding the dolphin that transmitted for only 8 h, mean minimum speeds for individual dolphins ranged from 3.4 to 6.6 km/h; overall mean for all dolphins was 5.4 km/h (SD = 0.9 km/h). The five dolphins with time-depth recorders had mean dive depths of 8.6–40.3 m and mean dive durations of 46–296 s. Hematologic and biochemical data revealed only minor abnormalities. Data suggest that at least 10 of the 11 dolphins were likely successfully reintroduced into the wild.

Stenson, G. B., Benjamins, S., and Reddin, D. G. 2011. Using bycatch data to understand habitat use of small cetaceans: lessons from an experimental driftnet fishery. – ICES Journal of Marine Science, 68: 937–946. Many marine mammals inhabit offshore areas where it is difficult to determine distribution and abundance. Historical bycatch data of marine mammals in the Northwest Atlantic obtained from the Canadian experimental Atlantic salmon (Salmo salar) driftnet fishery were examined to obtain information on seasonal distribution and relative abundance. From 1965 to 2001, 47 cruises were undertaken totalling 12 566.5 km-h of fishing effort; four species of small cetacean and two species of pinniped were caught. Harbour porpoises (Phocoena phocoena) were the most frequently caught species in all areas except the Labrador Sea, where Atlantic white-sided dolphins (Lagenorhynchus acutus) were more common. Long-finned pilot whales (Globicephala melas), common dolphins (Delphinus delphis), harp seals (Pagophilus groenlandicus), and harbour seals (Phoca vitulina) were also taken occasionally. Although typically considered an inshore species, harbour porpoises were regularly reported in deep water (>2000 m), in the Newfoundland Basin and Labrador Sea. Atlantic white-sided dolphins were often caught along the edge of the continental shelf and appeared to prefer relatively warm water. Finally, catch records indicate that waters of the Newfoundland Basin and Southern Grand Banks may contain important winter habitat for several small species of cetacean.

The analysis of stranding events and the application of molecular markers can be powerful tools to study cryptic biological aspects of delphinid species that occur mainly in open ocean habitat. In the present study, we investigated nuclear and mitochondrial genetic variability of Atlantic white-sided dolphins that stranded from 1990 to 2006 (n = 42) along the west coast of Ireland, using 8 microsatellite loci and 599 bp of the mitochondrial DNA control region. Results from both classes of markers are concordant with the hypothesis of a large random-mating population of white-sided dolphins along the west coast of Ireland. In addition, the analyses of 2 live mass stranding events (19 and 5 individuals, respectively) revealed that dolphins within each group were mainly unrelated to each other, suggesting dispersal of both sexes from the natal group (i.e., no natal phylopatry). Parentage analyses allowed the identification of mother-offspring pairs but ruled out all adult males as possible fathers. In combination with data on age of individuals, these results confirmed previous knowledge on life-history parameters, with sexually mature females ranging between 11 and 15 years of age and an interbirth interval of at least 2 years. The present study provides novel information on population and group composition of Atlantic white-sided dolphins along the west coast of Ireland, where population and social structure of the species are still poorly understood.

Hexabromocyclododecane (HBCD) is a brominated flame retardant used primarily in expanded polystyrene foams and other styrene resins. Samples of blubber (n = 57) and liver (n = 16) from Atlantic white-sided dolphins, Lagenorhynchus acutus, that stranded on the eastern coast of United States between 1993 and 2004 were obtained from the National Marine Mammal Tissue Bank (NMMTB). Blubber samples from most of these animals (n = 47) were previously analyzed for polybrominated diphenyl ethers (PBDE), polychlorinated biphenyls (PCB), and several toxaphene congeners. The three most abundant diastereomers in the technical HBCD mixture (alpha-HBCD, beta-HBCD, and gamma-HBCD) and their enantiomers were determined using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). alpha-HBCD was found in all blubber and liver samples while beta-HBCD and gamma-HBCD were not detected in any samples. The alpha-HBCD concentration in blubber and liver ranged from 14 ng/g wet mass (19 ng/g lipid) to 280 ng/g wet mass (380 ng/g lipid) and 0.051 ng/g wet mass (2.9 ng/g lipid) to 3.6 ng/g wet mass (140 ng/g lipid), respectively. Concentrations of alpha-HBCD were 2 to 3 orders of magnitude lower than previously reported PBDE, PCB, and toxaphene concentrations in these same animals. There was not a significant temporal trend for these compounds in white-sided dolphin blubber. The enantiomeric fractions (EF) measured in blubber and liver were not statistically different and ranged from 0.34 to 0.53. Blubber EFs were significantly correlated with both alpha-HBCD concentrations and white-sided dolphin body length. In general, concentrations of HBCDs were lower in these white-sided dolphins than in cetaceans from Western Europe.

During Leg 1 of the MAR-ECO expedition on the R.V. G.O. Sars in June 2004 four main species of dolphins were observed along the Mid-Atlantic Ridge from Iceland to the Azores: pilot whale ( Globicephala melas ) ( n =326), short-beaked common dolphin ( Delphinus delphis ) ( n =273), white-sided dolphin ( Lagenorhynchus acutus ) ( n =103), and striped dolphin ( Stenella coeruleoalba ) ( n =86). Pilot whales and white-sided dolphins were found in cold (5–16 °C) and less-saline (34.6–35.8‰) water masses in the northern part of the study area, whereas common and striped dolphins inhabited warmer (12–22 °C) and more-saline (34.8–36.7‰) waters in the south. Dolphins tended to aggregate in areas of steep slopes, but actual bottom depth appeared to be less important. Based on spatial correlations between dolphin occurrence and candidate prey organisms recorded acoustically and by midwater trawling, mesopelagic fishes and squids were assumed to be important prey items, with Benthosema glaciale probably being the most important prey for pilot whales and white-sided dolphins, while Lampanyctus macdonaldi , Stomias boa ferox and Chauliodus sloani were probably of particular importance for common dolphins. Cephalopods, especially Gonatus sp. and Teuthowenia megalops were the most likely prey species of pilot whales and striped dolphins, respectively. The difference in physical habitat north and south of the Sub-polar Frontal Zone seemed to have important effects on prey distribution, in turn influencing dolphin distribution.

The structure and development of the brain are extremely difficult to study in free-ranging marine mammals. Here, we report measurements of total white matter (WM), total gray matter (GM), cerebellum (WM and GM), hippocampus, and corpus callosum made from magnetic resonance (MR) images of fresh, postmortem brains of the Atlantic white-sided dolphin (Lagenorhynchus acutus) imaged in situ (i.e., the brain intact within the skull, with the head still attached to the body). WM:GM volume ratios of the entire brain increased from fetus to adult, illustrating the increase in myelination during ontogeny. The cerebellum (WM and GM combined) of subadult and adult dolphins ranged from 13.8 to 15.0% of total brain size, much larger than that of primates. The corpus callosum mid-sagittal area to brain mass ratios (CCA/BM) ranged from 0.088 to 0.137, smaller than in most mammals. Dolphin hippocampal volumes were smaller than those of carnivores, ungulates, and humans, consistent with previous qualitative results assessed from histological studies of the bottlenose dolphin brain. These quantitative measurements of white matter, gray matter, corpus callosum, and hippocampus are the first to be determined from MR images for any cetacean species. We establish here an approach for accurately determining the size of brain structures from in situ MR images of stranded, dead dolphins. This approach can be used not only for comparative and developmental studies of marine mammal brains but also for investigation of the potential impacts of natural and anthropogenic chemicals on neurodevelopment and neuroanatomy in exposed marine mammal populations. Anat Rec, 291:263–282, 2008. 2008 Wiley-Liss, Inc.

The testes of 31 Atlantic white-sided dolphins, Lagenorhynchus acutus bycaught in the northeastern Atlantic were studied by histological and morphometric techniques. Twenty specimens were classified as mature, nine as immature and two as pubescent. Between immature and mature specimens there were overlappings in body length and body weight, but clear differences in the diameter of seminiferous tubules ( 480 μm) and the proportion of seminiferous tubules to interstitial tissue (ST:INT-ratio). Also relative testes weight differed clearly. The pubescent specimens showed intermediate characteristics. Spermatogenetic activity of mature dolphins ranged from quiescent to different degrees of activity and varied even in animals from the same site and capture date. The fact that we found mature males with quiescent testes suggests a seasonal rather than a continuous spermatogenesis. We assume that sexual activity in L. acutus begins at an age of 7-8 GLGs and that the reproductive season of this species in the northeastern Atlantic starts in February. Further, the ultrastructure of the spermatozoon is similar to that of the related Lagenorhynchus obliquidens.

Using a large passenger cruise-ship (MV ‘Discovery’) as a platform, a cetacean survey was conducted between 1 August and 3 September 2005 across the northern North Atlantic Ocean and back, covering waters between the UK, Iceland, Greenland and Canada. The objective was to collect sightings data for all cetacean species encountered to begin to collate information for a large-scale sightings database. Two observers employed standard-distance sampling techniques and visual observations (naked eye) to scan for cetaceans during daylight hours and favourable weather conditions. Approximately 112 h were spent surveying over 23 d. A total of 13 cetacean species were encountered, with 173 separate sightings recorded, totalling over 2000 animals. The most commonly sighted species were minke whales (Balaenoptera acutorostrata: N=44), Atlantic white-sided dolphins (Lagenorhynchus acutus: N=34, with group sizes of up to 600), and humpback whales (Megaptera novaeangliae: N=31). The distribution of minke whales, Atlantic white-sided dolphins and fin whales was linked to underlying oceanographic variables. Overall patterns of distribution were consistent with our understanding of the summer distributions for the species encountered. The survey highlighted the cetacean diversity of the northern North Atlantic region. Repeat work using this methodology will allow an examination of species' distributions and estimation of their relative abundance.

Three novel halogenated organic compounds (HOCs) have been identified in the blubber of marine mammals from coastal New England with the molecular formulae C 9 H 3 N 2 Br 6 Cl, C 9 H 3 N 2 Br 7 , and C 9 H 4 N 2 Br 5 Cl. They were identified using high and low resolution gas chromatography mass spectrometry (GCMS) and appear to be highly brominated analogues of Q1, a heptachlorinated HOC suspected to be naturally produced. These compounds were found in Atlantic white sided dolphin ( Lagenorhynchus acutus ), bottlenose dolphin ( Tursiops truncatus ), common dolphin ( Delphinus delphis ), Risso's dolphin ( Grampus griseus ), harbor porpoise ( Phocoena phocoena ), beluga whale ( Delphinapterus leucas ), fin whale ( Balaenoptera physalus ), grey seal ( Halichoerus grypus ), harp seal ( Phoca groenlandica ) and a potential food source ( Loligo pealei ) with concentrations as high as 2.7 μg/g (lipid weight). The regiospecificity of C 9 H 3 N 2 Br 6 Cl is suggestive of a biogenic origin. Debromination of C 9 H 3 N 2 Br 6 Cl may be significant in the formation of C 9 H 4 N 2 Br 5 Cl.

From May to September 2004 a survey of cetacean distribution and relative abundance was conducted on board a ‘ship of opportunity’ * a vessel used as a survey platform but not chartered for this purpose * off the west coast of Ireland. In total, 508 hours of survey effort were completed, with 304.2 hours in Beaufort sea-state 3 or less. Two hundred and thirty one sightings of eight species* common dolphin Delphinus delphis (L.), Atlantic white-sided dolphin Lagenorhynchus acutus (Gray), bottlenose dolphin Tursiops truncatus (Montagu), harbour porpoise Phocoena phocoena (L.), Risso’s dolphin Grampus griseus (Cuvier), pilot whale Globicephala melas (Traill), minke whale Balaenoptera acutorostrata (Lacepede) and fin whale Balaenoptera physalus (L.) * were recorded, totalling 2,933 individuals. The greatest diversity and relative abundance were recorded on the Rockall Bank where Atlantic white-sided dolphin was the most abundant species. The common dolphin was the most abundant species recorded on the continental shelf to the south-west of Ireland, while the relative abundance of cetaceans off the north coast was very low. The data suggest that cetacean species composition and relative abundance can vary greatly between adjacent marine habitat types and over relatively small geographical distances.

The vertebral column of the Atlantic white-sided dolphin, Lagenorhynchus acutus, reflects the radical reorganization of the cetacean column for locomotion in water. Both posterior thoracic and anterior caudal vertebrae have been ‘‘lumbarized,’’ and discontinuities occur within the caudal series at the synclinal point and fluke base. Morphology changes subtly as body size increases. Neural process height increases more rapidly, and centrum length more variably, than other vertebral parameters. As a result, large animals have disproportionately tall neural processes, short necks, long mid-body regions, and short flukes. Vertebral columns of large animals also show greater complexity (range, irregularity, and polarization) of centrum length than do those of smaller animals. Comparisons among dolphins reveal that complexity trends with respect to differentiation of parts run counter to the trend with respect to number of parts, a relationship predicted by Williston in 1914.