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Entanglements in Fishing Gear and Strandings Reported to the Whale Release and Strandings Group in Newfoundland and Labrador and a Summary of the Whale Release and Strandings Program during 2020. A Report to the Department of Fisheries and Oceans, Canada - Newfoundland and Labrador Region.&nbsp

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.

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.

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.

Habitat characterization allows prediction of dolphin distributions in response to oceanographic processes and can be used to understand and predict effects of anthropogenic disturbances. Many habitat models focus on contemporary dolphin occurrence and environmental predictor data, but time-lagged oceanographic data may increase a model's predictive power due to ecological successional processes. Using hourly occurrence of Risso's dolphin Grampus griseus clicks and 2 types of Pacific white-sided dolphin Lagenorhynchus obliquidens clicks in autonomous passive acoustic recordings, we investigate the importance of time-lagged predictor variables with general- ized additive models. These models relate dolphin acoustic activity from recordings at 6 sites in the Southern California Bight between August 2005 and December 2007 to oceanographic variables including sea surface temperature (SST), SST coefficient of variation (CV), sea surface chlorophyll concentration (chl), chl CV, upwelling indices, and solar and lunar temporal indices. The most consis- tently selected variables among the trial models evaluated during cross-validation were SST (100% of models) and SST CV (80%) for Risso's dolphin clicks; solar indices (100%) and SST and SST CV (60% each) for Pacific white-sided type A (PWS A) clicks; and SST CV (100%), solar indices (100%) and SST (80%) for Pacific white-sided type B (PWS B) clicks. Best predictive models for Risso's dolphins and PWS A clicks included time-lagged variables, suggesting the importance of ecological succession between abiotic variables and dolphin occurrence, while best models of PWS B clicks were for current conditions, suggesting association with prey-aggregating features such as fronts and eddies.

Acoustic data collection is a cost-effective approach to evaluating activity patterns of otherwise challenging-to-study offshore cetaceans. However, manual analysis of acoustic data is time-consuming and impractical for large data sets. This study evaluates diel and seasonal patterns in Pacific white-sided dolphin communication through automated analysis of 20 months of continuous acoustic data collected from the Barkley Canyon node of Ocean Networks Canada’s NEPTUNE observatory, offshore of Vancouver Island, British Columbia, Canada. In this study, cetacean signals are manually annotated in a sub-set of the data, and 94 time and frequency features of these and other sounds are extracted and used to train random forest classifiers targeting Pacific white-sided dolphin pulsed calls. The performance of binary and multiclass models with various forest sizes, minimum leaf sizes, and confidence thresholds for Pacific white-sided dolphin classification are compared through nested 10-fold cross-validation to select the best model. Vocalizations are classified with the resultant classifier, manually verified, and examined for seasonal and diel patterns. Pacific white-sided dolphins are shown to be vocally active during dawn and day in spring and summer and at dusk and night year-round with reduced overall activity in fall and winter, suggesting both consistent nocturnal and migratory diurnal populations.

A comparison of temporal and geographical trends in different echolocation click types produced by Pacific white-sided dolphin Lagenorhynchus obliquidens can lead to insights into the significance of their usage by the dolphins. Using autonomous seafloor recording packages, the spa- tial, diel and seasonal patterns of Pacific white-sided dolphin echolocation click activity are described for 6 locations in the Southern California Bight. Click bouts of the 2 types of Pacific white-sided dol- phin echolocation clicks are identified based on their unique spectral characteristics in long-term spectral averages. Type A clicks were detected on 317 of 1959 recording days and were heard at all 6 sites, with the majority of detections occurring at San Clemente Island and Point Conception. Type B clicks were detected on 130 recording days and were only heard at the 2 southern inshore sites. Significant diel patterns were evident for both click types: Type A click bouts were detected during more hours and with higher click rates at night than during the day, while Type B click bouts exhib- ited the opposite behavior, with greater activity during the day. At the southern sites, both click types exhibited a fall-winter peak in seasonal occurrence. At Point Conception, where only Type A was detected, peak occurrence was during spring. The described spatial and seasonal patterns support the hypothesis that click types are population-specific, while diel patterns suggest differences in prey preferences.

Semen was collected from three captive odontocetes: a killer whale (Orcinus orca); a Pacific white-sided dolphin (Lagenorhynchus obliquidens) and a beluga (Delphinapterus leucas). Semen was collected from the killer whale and Pacific white-sided dolphin using behavioural commands, whereas semen from the beluga was collected postmortem. Ultrastructure of the spermatozoa was examined using scanning and transmission electron microscopy. Species differences were more pronounced in the head sections followed by the midpiece and finally, the tail sections. Spermatozoa from the killer whale and beluga were similar but differed from the Pacific white-sided dolphin spermatozoa.

Metallothioneins (MTs) were characterised in the kidneys of a white-sided dolphin Lagenorhynchus acutus stranded along the Belgian coast, displaying high levels of cadmium (Cd) and mercury (Hg) in liver and kidney. The protein has two isoforms: MT-1 and MT-2. MT-1 binds Cu, Zn, Hg and Cd, while MT-2 only binds Zn, Hg and Cd. This suggests different metabolic functions for the two isoforms: MT-1 is mainly involved in Cu homeostasis; MT-2, which was four-fold more abundant than MT-1, detoxifies most of the accumulated cadmium.

Diel patterns in marine mammal activity can be difficult to assess visually due to the cost of ship time and limitations of daylight and weather during expeditions that can bias analysis based on sightings. Acoustic data can be a cost-effective approach to evaluate activity patterns in marine mammals. However, manual analysis of acoustic data is time consuming, and impractical for large data sets. This study seeks to evaluate diel patterns in Pacific white-sided dolphin communication through automated analysis of one year of continuous acoustic data collected from the Barkley Canyon node of Ocean Networks Canada’s NEPTUNE observatory, offshore of Vancouver Island, British Columbia, Canada. In this study, marine mammal acoustic signals are manually annotated in a sub-set of the data, and used to train a random forest classifier targeting Pacific white-sided dolphin pulsed calls. Binary and multiclass classifiers are compared, and the effects of different data-balancing methods are evaluated. The results fr...

There have been few studies of brain growth in cetaceans despite their potential importance for understanding cetacean, and generally mammalian, brain-behavior relationships. Among terrestrial mammals, and notably primates, high encephalization levels and long juvenile periods of dependency are associated with a prolonged period of brain development. I examined brain-growth patterns in the harbor porpoise ( Phocoena phocoena ) and Pacific white-sided dolphin ( Lagenorhynchus obliquidens ). The brain of P. phocoena is substantially more mature throughout development than that of L. obliquidens , and brain-growth patterns are related generally to adult encephalization levels in these two species. Various factors, such as habitat type and body size, are likely to play an interrelated role in brain development in cetaceans.

Biological data were collected from 341 Pacific white-sided dolphins (Lagenorhynchus obliquidens; 171 males and 170 females) taken in high seas drift nets in the central North Pacific Ocean in June–September of 1990 and 1991. Age was determined for 149 dolphins (73 males and 76 females) by counting dentinal growth layer groups and measuring postnatal dentine thickness. Reproductive status was determined for 76 females and 71 males. Ten females were sexually mature (3 pregnant and 7 lactating), as were 11 males. The estimated average length at birth was 91.8 cm (SE = 0.4787 cm; n = 4). The estimated gestation period was 11 – 12 months. The sex ratio was not significantly different from 1:1. The youngest sexually mature male was 10 years of age and the oldest sexually immature male 11 years. The youngest sexually mature female was 8.3 years of age and the oldest sexually immature female 11 years. The average length at sexual maturation was 173.7 cm (SE = 0.8953 cm) for males and 177.5 cm (SE = 1.5 cm) for females. Males and females reached an estimated asymptotic length of 184 and 177 cm, respectively. Estimates of early postnatal growth rates were complicated by poor growth model fit; however, both sexes appeared to grow about 4.5 cm/month during the first half year. A calving period preceded sampling during late winter and spring.

Incidental Entanglements of Cetaceans and Leatherback Sea Turtles in Fishing Gear Reported During 2011-2012 and a Summary of the Whale Release and Strandings Group Activities. A Preliminary Report Submitted to the Department of Fisheries and Oceans, Canada.

Incidental Entanglements of Cetaceans and Leatherback Sea Turtles in Fishing Gear Reported During 2010-2011 and a Summary of the Whale Release and Strandings Group Activities. A Preliminary Report Submitted to the Department of Fisheries and Oceans, Canada

infection. VetParasitol 34: 159-163.7. Jeffrey M, O’Toole D, Smith T, Bridges AW: 1988, Immu-nocytochemistry of ovine sporozoan encephalitis and enceph-alomyelitis. J Comp Pathol 98:213-224.8. Jortner BS, Troutt HF, Collins T, Scarratt K: 1985, Lesions ofspinal cord parelaphostrongylosis in sheep. Sequential changesfollowing intramedullary larval migration, Vet Pathol 22:137-140.9. Leek RG, Fayer R: 1980, Amprolium for prophylaxis of ovine

Increasing water temperatures due to global warming mean that specific isotherms are shifting polewards. This may cause the poleward shifts in the range limits of species that are only found in specific thermal habitats. Such range shifts have been recorded in a number of plant and animal species. In the last 3 decades, we observed a decline in the presence of Pacific white-sided dolphin Lagenorhynchus obliquidens in the southwest Gulf of California (GOC), which is considered the southern boundary of their distribution. Considering that the thermal environment is physiologi- cally important to animals, we believe that this poleward shift in the usual geographic range of the Pacific white-sided dolphin is due to long-term changes in the local climate. To obtain the conceptual framework needed to discuss such a hypothesis, we summarize and analyze current knowledge about Pacific white-sided dolphins in the southwest GOC, and sea surface temperature variability at a regional scale.

International audience; Top predators from the northern sub-polar and polar areas exhibit high cadmium concentrations in their tissues. In the aim to reveal possible adverse effects, samples of five Atlantic white-sided dolphins Lagenorhyncus acutus have been collected on the occasion of the drive fishery in the Faroe Islands, for ultrastructural investigations and energy dispersive X-ray microanalyses. Cadmium concentrations were less than the limit of detection in both immature individuals and ranged from 22.7 to 31.1 µg g-1 wet weight in the mature individuals. Two individuals with the highest cadmium concentrations exhibited electron dense mineral concretions in the basal membranes of the proximal tubules. They are spherocrystals made up of numerous strata mineral deposit of calcium and phosphorus together with cadmium. Cadmium has been detected with a molar ratio of Ca:Cd of 10:1 in the middle of these concretions. To our knowledge, this is the first report of such granules in a wild vertebrate. The role of these granules in the detoxification of the metal and the possible pathological effects are considered.

The masked hearing threshold of a Pacific white‐sided dolphin (Lagenorhynchus obliquidens) was determined by measuring the animal’s auditory brainstem response (ABR). The dolphin was trained to wear surface‐contact electrodes embedded in suction cups and to swim into a hoop centered at 1 m below the water surface facing a sound projector 5 m away. Broadband transient signals with center frequencies of 8, 16, 32, 64, 80, and 100 kHz were used as the stimuli. ABR signals were measured by digitizing the electrode signals in 32 point blocks at a sampling rate of 20 kHz. Five hundred blocks were averaged in order to obtain an ABR. The response latency for suprathreshold threshold signals was approximately 1.9 ms with the highest peak‐to‐peak ABR amplitude of approximately 2.8 uV occurring for a signal frequency of 64 kHz. The spectrum of the ABR signal was similar to that of Tursiops truncatus, with a major peak at 1120 Hz and a secondary peak at 664 Hz. Threshold was determined by progressively reducing the amplitude of the stimulus until an evoked potential could not be detected. The energy signal‐to‐noise ratio within an integration window at threshold varied between 1 and 8 dB.

To investigate the ultrasonic receiving system of a dolphin’s sonar, three experiments were carried out using dead dolphins’ heads. The first experiment was an anatomical investigation by magnetic resonance imaging followed by dissection. The second experiment was measurements of the receiving sensitivity distribution on a dolphin’s head surface to locate receiving areas with high sensitivity. The third experiment was muscle excision to determine which organs contribute to the ultrasonic sound wave propagation from the highly sensitive areas to the tympanic bone. These experimental results show that the receiving sensitivity is highest at the middle points of both the left and right mandibula, at which points the left and right digastrici terminate, respectively. The highly sensitive areas lie along lines just inside of the lower mandibula, where both digastrici are located. Furthermore, not only are the highly sensitive areas along the right mandiblum connected acoustically to the right tympanic bone but those on the left side are also cross‐connected by muscles on the lower jaw and vice versa. Therefore, a dolphin’s ultrasonic receiving system may be modeled by a multi‐input/two‐output system in which each right or left ear, respectively, is a multi‐input/single‐output system.

According to anatomical investigations, measurements of the receiving sensitivity distribution and investigation of ultrasonic sound wave propagation paths, each ear may be constructed as a multi‐input/single‐output system in the head. These two multi‐input/single‐output systems may be considered to act together as one multi‐input/two‐output system. Here, the input points are highly sensitive areas lying just inside of the lower mandibula. The two output points are the tympanic bones in each mandibula. All input points are connected acoustically to both tympanic bones by the the digastrici, mylohyoidei and sternohyoid muscles. Mathematical simulations were carried out using this multi‐input/single‐output system, applying impulse response functions previously measured from the right tympanic bone to each of the measuring points on the dolphin’s head surface. From the results of these simulations, it is considered that the highly sensitive areas located in lines along both mandibula act as line arrays, so t...

Little is known about abilities of odontocetes to hear in a noisy environment. Using a descending staircase method and go/no‐go response, underwater hearing of a female, Pacific white‐sided dolphin masked by two levels of white noise (30 dB apart) was measured. The same dolphin had an unmasked audiogram [Tremel et al. (1998)]. Frequencies were tested in octaves between 500 Hz and 64 kHz, with 15 to 30 trials/frequency. Masked thresholds at maximum noise were similar to those on a bottlenose dolphin [Moore and Au (1982)], a beluga [Johnson et al. (1989)], and a false killer whale [Thomas et al. (1990)]. At 8 kHz, masked thresholds were more sensitive than unmasked thresholds, perhaps because masking and pool noise were similar levels. The highest critical ratio (43) was at 500 Hz and the lowest critical ratio (14) at 8 kHz. Critical ratios at 8 kHz or higher were comparable to other species. However, critical ratios at 500 Hz (43) and at 1 kHz (40) were higher than in the beluga (20 and 18, respectively). [The authors are grateful for support by the marine mammal staff at the Shedd Aquarium and financial support by ONR.]

Six species of helminths were collected from the gut of 37 Lagenorhynchus acutus. The following are new host–parasite records: Pholeter gastrophilus, Oschmarinella laevicaecum, Tetrabothrius forsteri, Anisakis sp., and Bolbosoma sp. Stenurus globicephalae was also found. Prevalence for O. laevicaecum was 49% and for T. forsteri 78%. Key words: Atlantic dolphins, digenea trematodes, cestodes, nematodes, acanthocephala, biological tags

Post-mortem examination of a stranded Atlantic white-sided dolphin (lagenorynchus acutus) revealed congested lungs, sanguinous fluid in the peritoneal cavity, and an oral wound. Histopathologic findings were acute necrotizing hepatitis and acute focal bronchopneumonia. Vibrio alginolyticus was isolated from the blood and other organs.

A young, male, free-ranging Pacific white-sided dolphin (Lagenorhynchus obliquidens) was found disoriented and died after being held in captivity for several months. Malacic lesions in several areas of the brain were associated with helminth eggs. The appearance and location of these eggs suggested they were of the genus Nasitrema.

Damage to Inshore Fishing Gear in Newfoundland and Labrador by Whales and Sharks During 1981. Annual Report