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Killer whales

J K O'Brien, K J Steinman, G A Fetter, T R Robeck
Circulating concentrations of testosterone and its precursor androstenedione, as well as dehydroepiandrosterone (DHEA) and the adrenal hormones cortisol and corticosterone were measured at monthly intervals in 14 male killer whales (Orcinus orca) aged 0.8-38 years. Analyses were performed for examination of the relationships of age, sexual maturation status (STATUS), season, and environmental temperature (monthly air ambient temperature, A-TEMP) with hormone production using a mixed effects linear regression model with animal ID as the random variable...
September 16, 2016: Andrology
Melissa P Galicia, Gregory W Thiemann, Markus G Dyck, Steven H Ferguson, Jeff W Higdon
Polar bear (Ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. In the Foxe Basin region of Nunavut, Canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. We used fatty acid analysis to examine polar bear feeding habits in Foxe Basin and thus potentially identify ecological factors contributing to population stability...
August 2016: Ecology and Evolution
Masoume Vakili Azghandi, Mohammadreza Nasiri, Ali Shamsa, Mohsen Jalali, Mohammad Mahdi Shariati
BACKGROUND: The SRY gene (SRY) provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences. METHODS: Nucleotide sequences of SRY were retrieved from the NCBI databank...
April 2016: Reports of Biochemistry & Molecular Biology
A D Foote, P A Morin
Three ecotypes of killer whale occur in partial sympatry in the North Pacific. Individuals assortatively mate within the same ecotype, resulting in correlated ecological and genetic differentiation. A key question is whether this pattern of evolutionary divergence is an example of incipient sympatric speciation from a single panmictic ancestral population, or whether sympatry could have resulted from multiple colonisations of the North Pacific and secondary contact between ecotypes. Here, we infer multilocus coalescent trees from >1000 nuclear single-nucleotide polymorphisms (SNPs) and find evidence of incomplete lineage sorting so that the genealogies of SNPs do not all conform to a single topology...
November 2016: Heredity
Todd R Robeck, Karen J Steinman, Justine K O'Brien
The secretory patterns of progestagens and estrogens were characterized throughout 28 normal pregnancies until two month post-partum in eleven killer whales. HPLC analysis of serum from different reproductive stages (luteal phase, EARLY, MID, and LATE pregnancy) identified three major immunoreactive progestagen peaks; progesterone (P4), 5α-pregnane-3,20-dione (5α-DHP) and pregnanediol, with 5α-DHP approximately half of that for P4 in the luteal phase, and EARLY, but approximately 2/3 of P4 during MID and LATE pregnancy...
September 15, 2016: General and Comparative Endocrinology
Marjoleine M H Roos, Gi-Mick Wu, Patrick J O Miller
Respiration rate has been used as an indicator of metabolic rate and associated cost of transport (COT) of free-ranging cetaceans, discounting potential respiration-by-respiration variation in O2 uptake. To investigate the influence of respiration timing on O2 uptake, we developed a dynamic model of O2 exchange and storage. Individual respiration events were revealed from kinematic data from 10 adult Norwegian herring-feeding killer whales (Orcinus orca) recorded with high-resolution tags (DTAGs). We compared fixed O2 uptake per respiration models with O2 uptake per respiration estimated through a simple 'broken-stick' O2-uptake function, in which O2 uptake was assumed to be the maximum possible O2 uptake when stores are depleted or maximum total body O2 store minus existing O2 store when stores are close to saturated...
July 1, 2016: Journal of Experimental Biology
Fleur Visser, Charlotte Curé, Petter H Kvadsheim, Frans-Peter A Lam, Peter L Tyack, Patrick J O Miller
Social interactions among animals can influence their response to disturbance. We investigated responses of long-finned pilot whales to killer whale sound playbacks and two anthropogenic sources of disturbance: tagging effort and naval sonar exposure. The acoustic scene and diving behaviour of tagged individuals were recorded along with the social behaviour of their groups. All three disturbance types resulted in larger group sizes, increasing social cohesion during disturbance. However, the nature and magnitude of other responses differed between disturbance types...
2016: Scientific Reports
Mirkka Lahdenperä, Khyne U Mar, Virpi Lummaa
Usually animals reproduce into old age, but a few species such as humans and killer whales can live decades after their last reproduction. The grandmother hypothesis proposes that such life-history evolved through older females switching to invest in their existing (grand)offspring, thereby increasing their inclusive fitness and selection for post-reproductive lifespan. However, positive grandmother effects are also found in non-menopausal taxa, but evidence of their associated fitness effects is rare and only a few tests of the hypothesis in such species exist...
2016: Scientific Reports
Tatjana Sitt, Lizabeth Bowen, Chia-Shan Lee, Myra T Blanchard, James McBain, Christopher Dold, Jeffrey L Stott
Early identification of illness and/or presence of environmental and/or social stressors in free-ranging and domestic cetaceans is a priority for marine mammal health care professionals. Incorporation of leukocyte gene transcript analysis into the diagnostic tool kit has the potential to augment classical diagnostics based upon ease of sample storage and shipment, inducible nature and well-defined roles of transcription and associated downstream actions. Development of biomarkers that could serve to identify "insults" and potentially differentiate disease etiology would be of great diagnostic value...
July 2016: Veterinary Immunology and Immunopathology
Andrew D Foote, Nagarjun Vijay, María C Ávila-Arcos, Robin W Baird, John W Durban, Matteo Fumagalli, Richard A Gibbs, M Bradley Hanson, Thorfinn S Korneliussen, Michael D Martin, Kelly M Robertson, Vitor C Sousa, Filipe G Vieira, Tomáš Vinař, Paul Wade, Kim C Worley, Laurent Excoffier, Phillip A Morin, M Thomas P Gilbert, Jochen B W Wolf
Analysing population genomic data from killer whale ecotypes, which we estimate have globally radiated within less than 250,000 years, we show that genetic structuring including the segregation of potentially functional alleles is associated with socially inherited ecological niche. Reconstruction of ancestral demographic history revealed bottlenecks during founder events, likely promoting ecological divergence and genetic drift resulting in a wide range of genome-wide differentiation between pairs of allopatric and sympatric ecotypes...
2016: Nature Communications
Alexander M von Benda-Beckmann, Paul J Wensveen, Filipa I P Samarra, S Peter Beerens, Patrick J O Miller
Sound-recording acoustic tags attached to marine animals are commonly used in behavioural studies. Measuring ambient noise is of interest to efforts to understand responses of marine mammals to anthropogenic underwater sound, or to assess their communication space. Noise of water flowing around the tag reflects the speed of the animal, but hinders ambient noise measurement. Here, we describe a correlation-based method for stereo acoustic tags to separate the relative contributions of flow and ambient noise...
August 1, 2016: Journal of Experimental Biology
Jessica I Lundin, Gina M Ylitalo, Rebecca K Booth, Bernadita Anulacion, Jennifer A Hempelmann, Kim M Parsons, Deborah A Giles, Elizabeth A Seely, M Bradley Hanson, Candice K Emmons, Samuel K Wasser
Persistent organic pollutants (POPs), specifically PCBs, PBDEs, and DDTs, in the marine environment are well documented, however accumulation and mobilization patterns at the top of the food-web are poorly understood. This study broadens the understanding of POPs in the endangered Southern Resident killer whale population by addressing modulation by prey availability and reproductive status, along with endocrine disrupting effects. A total of 140 killer whale scat samples collected from 54 unique whales across a 4 year sampling period (2010-2013) were analyzed for concentrations of POPs...
June 21, 2016: Environmental Science & Technology
Alexandra Wright, Miriam Scadeng, Dominik Stec, Rebecca Dubowitz, Sam Ridgway, Judy St Leger
The evolutionary process of adaptation to an obligatory aquatic existence dramatically modified cetacean brain structure and function. The brain of the killer whale (Orcinus orca) may be the largest of all taxa supporting a panoply of cognitive, sensory, and sensorimotor abilities. Despite this, examination of the O. orca brain has been limited in scope resulting in significant deficits in knowledge concerning its structure and function. The present study aims to describe the neural organization and potential function of the O...
April 27, 2016: Brain Structure & Function
Saana Isojunno, Charlotte Cure, Petter Helgevold Kvadsheim, Frans-Peter Alexander Lam, Peter Lloyd Tyack, Paul Jacobus Wensveen, Patrick James O'Malley Miller
The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records)...
January 2016: Ecological Applications: a Publication of the Ecological Society of America
Filipa I P Samarra, Volker B Deecke, Patrick J O Miller
Killer whale acoustic behavior has been extensively investigated; however, most studies have focused on pulsed calls and whistles. This study reports the production of low-frequency signals by killer whales at frequencies below 300 Hz. Recordings were made in Iceland and Norway when killer whales were observed feeding on herring and no other marine mammal species were nearby. Low-frequency sounds were identified in Iceland and ranged in duration between 0.14 and 2.77 s and in frequency between 50 and 270 Hz, well below the previously reported lower limit for killer whale tonal sounds of 500 Hz...
March 2016: Journal of the Acoustical Society of America
Ewen Callaway
No abstract text is available yet for this article.
March 24, 2016: Nature
Scott Veirs, Val Veirs, Jason D Wood
Combining calibrated hydrophone measurements with vessel location data from the Automatic Identification System, we estimate underwater sound pressure levels for 1,582 unique ships that transited the core critical habitat of the endangered Southern Resident killer whales during 28 months between March, 2011, and October, 2013. Median received spectrum levels of noise from 2,809 isolated transits are elevated relative to median background levels not only at low frequencies (20-30 dB re 1 µPa(2)/Hz from 100 to 1,000 Hz), but also at high frequencies (5-13 dB from 10,000 to 96,000 Hz)...
2016: PeerJ
Todd R Robeck, Kevin Willis, Michael R Scarpuzzi, Justine K O'Brien
Data collected on life-history parameters of known-age animals from the northern (NR) and southern resident (SR) killer whales (Orcinus orca) of the eastern North Pacific were compared with life-history traits of killer whales located at SeaWorld (SEA) facilities. For captive-born SEA animals, mean age and body length at 1st estrus was 7.5 years and 483.7cm, respectively. Estimated mean age at 1st conception was different (P < 0.001) for the combined data from both northern and southern resident (NSR) free-ranging populations (12...
September 29, 2015: Journal of Mammalogy
Adam B Smith, Laura N Kloepper, Wei-Cheng Yang, Wan-Hsiu Huang, I-Fan Jen, Brendan P Rideout, Paul E Nachtigall
The echolocation system of the Risso's dolphin (Grampus griseus) remains poorly studied compared to other odontocete species. In this study, echolocation signals were recorded from a stationary Risso's dolphin with an array of 16 hydrophones and the two-dimensional beam shape was explored using frequency-dependent amplitude plots. Click source parameters were similar to those already described for this species. Centroid frequency of click signals increased with increasing sound pressure level, while the beamwidth decreased with increasing center frequency...
January 2016: Journal of the Acoustical Society of America
Paul D Jepson, Rob Deaville, Jonathan L Barber, Àlex Aguilar, Asunción Borrell, Sinéad Murphy, Jon Barry, Andrew Brownlow, James Barnett, Simon Berrow, Andrew A Cunningham, Nicholas J Davison, Mariel Ten Doeschate, Ruth Esteban, Marisa Ferreira, Andrew D Foote, Tilen Genov, Joan Giménez, Jan Loveridge, Ángela Llavona, Vidal Martin, David L Maxwell, Alexandra Papachlimitzou, Rod Penrose, Matthew W Perkins, Brian Smith, Renaud de Stephanis, Nick Tregenza, Philippe Verborgh, Antonio Fernandez, Robin J Law
Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds...
2016: Scientific Reports
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