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1.
Brianna M. Wright Volker B. Deecke Graeme M. Ellis Andrew W. Trites John K. B. Ford 《Marine Mammal Science》2021,37(4):1428-1453
Availability of preferred salmonid prey and a sufficiently quiet acoustic environment in which to forage are critical to the survival of resident killer whales (Orcinus orca) in the northeastern Pacific. Although piscivorous killer whales rely on echolocation to locate and track prey, the relationship between echolocation, movement, and prey capture during foraging by wild individuals is poorly understood. We used acoustic biologging tags to relate echolocation behavior to prey pursuit and capture during successful feeding dives by fish-eating killer whales in coastal British Columbia, Canada. The significantly higher incidence and rate of echolocation prior to fish captures compared to afterward confirms its importance in prey detection and tracking. Extremely rapid click sequences (buzzes) were produced before or concurrent with captures of salmon at depths typically exceeding 50 m, and were likely used by killer whales for close-range prey targeting, as in other odontocetes. Distinctive crunching and tearing sounds indicative of prey-handling behavior occurred at relatively shallow depths following fish captures, matching concurrent observations that whales surfaced with fish prior to consumption and often shared prey. Buzzes and prey-handling sounds are potentially useful acoustic signals for estimating foraging efficiency and determining if resident killer whales are meeting their energetic requirements. 相似文献
2.
Thirteen Weddell seals ( Leptonychotes weddellii ) were collected at Vestkapp, eastern Weddell Sea coast, in austral spring 1986. All stomachs contained partially digested food. The mean wet weight of stomach contents was 7.5 kg, 3.3% of the. mean body weight of the collected seals. Twelve fish species and three cephalopod species were identified from 372 left otoliths and 25 lower beaks, representing 58.4% of 679 total prey items obtained. Composition by number of total prey was: Chionodraco myersi (15.8%), Trematomus eulepidotus (10.0%), Pagetopsis maculatus (9.7%), Racovitzia glacialis (9.6%) and Cryodraco antarcticus (4.1%). Otoliths of the seven other fish species and beaks of the three cephalopod species together represented 9.1% of total prey numbers. The pooled wet weights calculated from 13 prey species (regressions for two octopod species were not available) amounted to 43.5 kg food mass and represented 44.7% of the combined food mass in all stomachs. Composition by mass was: C. myersi (44.5%), T. eulepidotus (19.8%), squid Psychroteuthis glacialis (8.5%), P. maculates (7.9%), C. antarcticus (7.1%) and R. glacialis (6.2%). The remaining 7 fish species together represented 5.8% by mass. Temporal variation in food availability was apparent. Midwater fish Pleuragramma antarcticum was the staple food of Weddell seals from the same area during the 1985 summer, whereas it was absent in the samples taken in spring 1986. Estimates of fish biomass from net hauls demonstrate a highly variable availability of pelagic food resources for top predators in the Vestkapp area. 相似文献
3.
Kym T. Collins John M. Terhune † Tracey L. Rogers ‡ Kathryn E. Wheatley § Robert G. Harcourt ¶ 《Marine Mammal Science》2006,22(4):933-951
As a result of selective pressures faced during lactation, vocal recognition may play a crucial role in maintaining the phocid mother–pup bond during the period of dependence. To investigate this possibility, we examined whether Weddell seal ( Leptonychotes weddellii ) pups produce individually distinctive \"primary\" calls. One temporal, nine fundamental frequency features, and two spectral characteristics were measured. A discriminant function analysis (DFA) of 15 Vestfold Hills pups correctly classified 52% of calls, while the cross-validation procedure classified 29% of calls to the correct pup. A second DFA of 10 known-age McMurdo Sound pups correctly classified 44% of \"test\" calls. For novel calls, the probabilities of attaining such classification rates by chance are low. The relationship between age and call stereotypy indicated that pups 2 wk and older may be more vocally distinctive. Overall, findings suggest that Weddell seal pup \"primary\" calls are moderately distinctive and only exhibit sufficient stereotypy to aid maternal recognition by approximately two weeks of age. 相似文献
4.
Methods for estimating tag loss and sightability of tags are presented. Rates of tag loss were estimated for metal and several varieties of plastic cattle ear tags in a long-term population study of Weddell seals. Tags were lost at a higher rate in the first year after application than in subsequent years, and pups lost tags at a higher rate than older seals given the same tag types. Medium-sized plastic tags (Dalton, Allflex and Fearing) were retained at higher rates and were overlooked less frequently than metal tags on adult seals. Dalton Jumbo Rototags showed the lowest loss rates on pups in comparison to larger, flexible plastic tags, but were harder to read in the field. 相似文献
5.
Robert L. Pitman John W. Durban Trevor Joyce Holly Fearnbach Simone Panigada Giancarlo Lauriano 《Marine Mammal Science》2020,36(2):565-594
Long-distance migration in whales has historically been described as an annual, round-trip movement between high-latitude, summer feeding grounds, and low-latitude, winter breeding areas, but there is no consensus about why whales travel to the tropics to breed. Between January 2009 and February 2016, we satellite-tagged 62 antarctic killer whales (Orcinus orca) of four different ecotypes, of which at least three made short-term (6–8 weeks), long-distance (maximum 11,000 km, round trip), essentially nonstop, migrations to warm waters (SST 20°C–24°C), and back. We previously suggested that antarctic killer whales could conserve body heat in subfreezing (to −1.9°C) waters by reducing blood flow to their skin, but that this might preclude normal (i.e., continuous) epidermal molt, and necessitate periodic trips to warm waters for routine skin maintenance (“skin molt migration,” SMM). In contrast to the century-old “feeding/breeding” migration paradigm, but consistent with a “feeding/molting” hypothesis, the current study provides additional evidence that deferred skin molt could be the main driver of long-distance migration for antarctic killer whales. Furthermore, we argue that for all whales that forage in polar latitudes and migrate to tropical waters, SMM might also allow them to exploit rich prey resources in a physiologically challenging environment and maintain healthy skin. 相似文献
6.
Dawn P. Noren 《Marine Mammal Science》2011,27(1):60-77
Killer whales are large animals that often feed in groups and thus have the potential to deplete prey populations. Determining predator energy requirements is essential to assessing whether prey availability is sufficient. This is important because one risk factor facing the endangered Southern Resident killer whale distinct population segment is limited prey availability. Body mass, field metabolic rate (FMR), and daily prey energy requirements (DPERs) were estimated for each individual in the population. FMRs were calculated from body mass, assuming they range from five to six times Kleiber‐predicted basal metabolic rates. FMRs of adults were also calculated from resident killer whale activity budgets and the metabolic cost of swimming at speeds associated with daily activities. These two methods yielded similar results. Total FMRs varied by age and sex, which is partly due to the long developmental period and sexual dimorphism in killer whales. FMRs for males (465–4,434 kg) ranged from 35,048 to 228,216 kcal/d while FMRs for females (465–3,338 kg) ranged from 35,048 to 184,444 kcal/d. DPERs were calculated from FMRs assuming a standard digestive efficiency. Corresponding DPERs ranged from 41,376 to 269,458 kcal/d and 41,376 to 217,775 kcal/d, respectively. 相似文献
7.
Ecological,morphological and genetic divergence of sympatric North Atlantic killer whale populations
ANDREW D. FOOTE JASON NEWTON STUART B. PIERTNEY ESKE WILLERSLEV M. THOMAS P. GILBERT 《Molecular ecology》2009,18(24):5207-5217
Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro‐evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche‐width in the generalist type is more strongly influenced by between‐individual variation rather than within‐individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation. 相似文献
8.
Robert L. Pitman Lisa T. Ballance Sarah I. Mesnick Susan J. Chivers 《Marine Mammal Science》2001,17(3):494-507
In October 1997 we observed a herd of approximately 35 killer whales ( Orcinus orca ) attack a pod of nine sperm whales ( Physeter macrocephalus ) 130 km off the coast of central California. During the four hours we watched, adult female killer whales, including some with calves, attacked in waves of four to five animals in what was apparently a \"wound and withdraw\" strategy. Adult male killer whales stood by until the very end when one charged in and quickly killed a seriously wounded sperm whale that had been separated from the group. The sperm whales appeared largely helpless: their main defensive behavior was the formation of a rosette (\"marguerite\"-heads together, tails out). When the killer whales were successful in pulling an individual out of the rosette, one or two sperm whales exposed themselves to increased attack by leaving the rosette, flanking the isolated individual, and leading it back into the formation. Despite these efforts, one sperm whale was killed and eaten and the rest were seriously, perhaps mortally, wounded. We also present details of two other encounters between sperm whales and killer whales that we observed. Although sperm whales, because of various behavioral and morphological adaptations, were previously thought to be immune to predation, our observations clearly establish their vulnerability to killer whales. We suggest that killer whale predation has potentially been an important, and underrated, selective factor in the evolution of sperm whale ecology, influencing perhaps the development of their complex social behavior and at-sea distribution patterns. 相似文献
9.
The minisatellite DNA profiles from four captive killer whales (two adult males, a female and her calf) were compared to determine paternity between two potential fathers. One of the males was clearly excluded, while the other shared all paternal bands with the calf. The background of this technique, and its potential applications in captive breeding programs and field studies are discussed. 相似文献
10.
Margaret M. Krahn Robert L. Pitman † Douglas G. Burrows ‡ David P. Herman ‡ Ronald W. Pearce ‡ 《Marine Mammal Science》2008,24(3):643-663
Measuring chemical tracers in tissues of marine predators provides insight into the prey consumed and the predator's contaminant exposure. In this study, samples from Type C killer whales ( Orcinus orca ) biopsied in Antarctica were analyzed for chemical tracers ( i.e. , stable isotopes of carbon and nitrogen, fatty acids, and persistent organic pollutants [POPs]). Profiles of these individual tracers were very different from those of killer whale populations that have been studied in the eastern North and eastern Tropical Pacific. For example, δ13 C and δ15 N stable isotope values and most POP concentrations were significantly lower in the Antarctic population. In addition, multivariate statistical analyses of both fatty acid and POP profiles found distinctly different patterns for Antarctic Type C whales compared to those from whales in the other populations. Similar assays were conducted on four species of Antarctic marine fish considered potential prey for Type C killer whales. Results were consistent with a diet of fish for Type C whales, but other species ( e.g. , low trophic-level marine mammals or penguins) could not be eliminated as supplemental prey. 相似文献
11.
Olga A. Filatova Ivan D. Fedutin Alexander M. Burdin Erich Hoyt 《Marine Mammal Science》2011,27(2):E26-E42
Killer whales produce repertoires of stereotyped call types that are primarily transmitted vertically through social learning, leading to dialects between sympatric pods. The potential function of these call repertoires remains untested. In this study, we compared the reaction of Kamchatkan fish‐eating killer whales to the playbacks of calls from the same and different pods. After the playback of recordings from a different pod, in three cases whales changed the direction of their movement toward the boat, and in three cases no changes in direction were observed. After the playback of recordings from the same pod (either from the same or a different unit within the pod), in seven cases whales changed the direction of their movement toward the boat, and in only one case no change in direction was observed. Whales remained silent after all six playbacks of recordings from a different pod, even when they changed direction toward the boat. After the playback of recordings from the same pod, however, in all eight cases whales started calling in response. Our playback study shows that killer whales may react to playbacks of conspecific sounds and that reactions are dependent on the type of playback stimuli. 相似文献
12.
Anna Selbmann Volker B. Deecke Ivan D. Fedutin Olga A. Filatova Patrick J. O. Miller Jörundur Svavarsson Filipa I. P. Samarra 《Marine Mammal Science》2021,37(1):268-289
Killer whale call repertoires can provide information on social connections among groups and populations. Killer whales in Iceland and Norway exhibit similar ecology and behavior, are genetically related, and are presumed to have been in contact before the collapse of the Atlanto-Scandian herring stock in the 1960s. However, photo-identification suggests no recent movements between Iceland and Norway but regular movement between Iceland and Shetland. Acoustic recordings collected between 2005 and 2016 in Iceland, Norway, and Shetland were used to undertake a comprehensive comparison of call repertoires of Northeast Atlantic killer whales. Measurements of time and frequency parameters of calls from Iceland (n = 4,037) and Norway (n = 1,715) largely overlapped in distribution, and a discriminant function analysis had low correct classification rate. No call type matches were confirmed between Iceland and Norway or Shetland and Norway. Three call types matched between Iceland and Shetland. Therefore, this study suggests overall similarities in time and frequency parameters but some divergence in call type repertoires. This argues against presumed past contact between Icelandic and Norwegian killer whales and suggests that they may not have been one completely mixed population. 相似文献
13.
14.
Traci L. Ness W. Guy Bradley John E. Reynolds III William B. Roess 《Marine Mammal Science》1998,14(3):531-543
Complementary DNA encoding interleukin-2 (IL-2) was isolated, cloned, and sequenced from the killer whale, Orcinus orca . The sequence of the killer whale IL-2 coding region consists of 455 nucleotides which translate into a polypeptide containing 151 amino acids. Killer whale IL-2 displays 88%, 88%, 87%, 87%, 85%, 84%, 80%, and 71% nucleotide sequence homology and 76%, 76%, 76%, 73%, 68%, 73%, 64%, and 56% amino acid homology with the cow, sheep, pig, red deer, horse, human, manatee, and mouse, respectively. High levels of killer whale recombinant IL-2 were generated by transiently transfecting killer whale IL-2/pCMV Blue plasmid DNA into cultured monkey kidney cells (Cos-1). Generation of this recombinant IL-2 will allow the development of assays useful for assessing IL-2 levels in the serum and from isolated lymphocytes of killer whales and possibly other species of cetaceans. A major contribution and significance of the in vitro expression of killer whale IL-2 exists in its potential to be used as a therapeutic agent. 相似文献
15.
Darren Ireland Robert A. Garrott Jay Rotella Jeff Banfield † 《Marine Mammal Science》2006,22(2):361-378
Traditional methods of acquiring mass data limit the ability to collect large samples from across populations of some pinnipeds, or to sample without great disturbance to the animals. In order to collect substantial samples of mass data from the Weddell seal (Leptonychotes weddellii) population in Erebus Bay, Antarctica, we developed the equipment and methods for estimating the mass of Weddell seals using digital photographs. Resulting regression models predict the mass of adult female seals to within ±13.8% of estimated mass, and ±25.9% of estimated mass for pups. We show the protocols developed are repeatable and efficient enough to be applied to a large number of animals in a relatively short period of time and may be useful for studies of other marine mammals. We caution that prediction intervals exist around mass estimates and must be accounted for when estimates are applied to biological questions. In a limited application of the method, differences in mass transfer between experienced and inexperienced maternal females and their pups were detected when prediction error variance around mass estimates was explicitly included. Similar mass‐estimation methods may therefore be useful in consideration of biological questions requiring large samples of mass previously unattainable. 相似文献
16.
Male–male contest behavior can contribute to spatial distributions of male pinnipeds during breeding seasons. To maximize breeding opportunities, the most competitive males would be expected to be surrounded by the highest numbers of reproductive-age females. As information regarding fine-scale spatial ecology of Weddell seals is lacking, we performed an exploratory study using kernel density analyses to evaluate age-specific habitat use of male Weddell seals in Erebus Bay, Antarctica. Additionally, we investigated the relationship between age and number of surrounding reproductive-age females using a competing set of regression models in a Bayesian framework that considered different functional forms of age while incorporating individual heterogeneity. As male adult Weddell seals aged, to at least 20 years, they were more likely to be found in areas associated with the greatest densities of reproductive-age females, but individual heterogeneity also influenced the number of reproductive-age female neighbors. The youngest males tended to haul out in offshore areas associated with better hunting, and older males tended to settle in more nearshore areas associated with more pup production. Our findings from this preliminary investigation indicate that male Weddell seal spatial behavior during the breeding season varies with age and individual and might be related to reproductive activity. 相似文献
17.
18.
Kelly M. Proffitt Robert A. Garrott Jay J. Rotella Subhash Lele † 《Marine Mammal Science》2008,24(1):147-158
Numerical characterization of animal body forms using elliptical Fourier decomposition may be a useful analytic technique in a variety of marine mammal investigations. Using data collected from the Weddell seal (Leptonychotes weddellii), we describe the method of body form characterization using elliptical Fourier analysis and demonstrated usefulness of the technique in photogrammetric mass‐estimation modeling. We compared photogrammetric mass‐estimation models developed from (1) standard morphometric measurement covariates, (2) elliptical Fourier coefficient covariates, and (3) a combination of morphometric and Fourier coefficient covariates and found that mass‐estimation models employing a combination of morphometric measurements and Fourier coefficients outperformed models containing only one covariate type. Inclusion of Fourier coefficients in photogrammetric mass‐estimation models employing standard morphometric measurements reduced the width of the prediction interval by 24.4%. Increased precision of photogrammetric mass‐estimation models employing Fourier coefficients as model covariates may expand the range of ecological questions that can be addressed with estimated mass measurements. 相似文献
19.
Daniel W. Olsen Craig O. Matkin Franz J. Mueter Shannon Atkinson 《Marine Mammal Science》2020,36(4):1150-1159
Killer whales (Orcinus orca) are highly social and occasionally gather in large aggregations that reach 150 individuals. During 338 encounters with Southern Alaska resident killer whales, we collected 1,352 hr of behavioral data to assess the probability of various behaviors based on season, number of pods present, presence of rarely sighted pods, and number of mitochondrial DNA haplotypes present. A binomial generalized linear model was used to estimate the role of these factors in the probability of four behaviors, foraging, resting, socializing, and traveling. The presence of “rarely sighted” pods (sighted in <5% of encounters) significantly increased probability of social behavior, and significantly decreased probability of resting. The number of pods present also significantly increased probability of increased social behavior. The presence of rarely sighted pods and the number of pods present did not have a significant interaction. Ordinal day and number of mitochondrial DNA haplotypes appears to not have changed the probability of any behavior. Foraging remained the predominant behavior throughout all factors. The concurrent increase in social behavior and decrease in resting behavior with rarely sighted pods present implies an unusually high importance of social behavior in the lives of resident killer whales. 相似文献
20.
Eve Jourdain Richard Karoliussen Jacques de Vos Stanislav E. Zakharov Christelle Tougard 《Marine Mammal Science》2020,36(1):89-102
Killer whales (Orcinus orca) in Norwegian waters have long been known to rely on Atlantic herring (Clupea harengus) as a main prey resource. However, research almost exclusively conducted at seasonal herring grounds may have biased studies away from detecting other potentially significant prey species. Since 2013, dedicated research efforts have focused on monitoring killer whale occurrence and foraging ecology throughout the year in northern Norway. This study presents results on site-fidelity of photographically identified individuals, predation records and behavioral patterns from five spring seasons (March–April) in 2014–2018 in Andfjord, northern Norway. A minimum number of 75 adult and subadult killer whales (out of a catalog of 971 individuals) returned seasonally to the study area for foraging and residency for up to six weeks. Lumpfish (or lumpsucker, Cyclopterus lumpus) was the only type of prey identified (based on molecular or visual identification) on 22 predation events from 2016 (n = 4), 2017 (n = 2) and 2018 (n = 16). Spatial group cohesion observed when foraging was a potential adaptation for efficiently hunting this prey species. These whales were also encountered at herring wintering grounds the same years, but with different group sizes. Such behavioral adaptations suggested intraannual switching between prey resources and foraging strategies. 相似文献