Zaeschmar J.R.,Massey University |
Visser I.N.,Orca Research Trust |
Fertl D.,Ziphius EcoServices |
Dwyer S.L.,Massey University |
And 5 more authors.
Marine Mammal Science | Year: 2014
On a global scale, false killer whales (Pseudorca crassidens) remain one of the lesser-known delphinids. The occurrence, site fidelity, association patterns, and presence/absence of foraging in waters off northeastern New Zealand are examined from records collected between 1995 and 2012. The species was rarely encountered; however, of the 61 distinctive, photo-identified individuals, 88.5% were resighted, with resightings up to 7 yr after initial identification, and movements as far as 650 km documented. Group sizes ranged from 20 to ca. 150. Results indicate that all individuals are linked in a single social network. Most observations were recorded in shallow (<100 m) nearshore waters. Occurrence in these continental shelf waters is likely seasonal, coinciding with the shoreward flooding of a warm current. During 91.5% of encounters, close interspecific associations with common bottlenose dolphins (Tursiops truncatus) were observed. Photo-identification reveals repeat inter- and intraspecific associations among individuals with 34.2% of common bottlenose dolphins resighted together with false killer whales over 1,832 d. While foraging was observed during 39.5% of mixed-species encounters, results suggest that social and antipredatory factors may also play a role in the formation of these mixed-species groups. © 2013 Society for Marine Mammalogy. Source
Visser I.N.,Orca Research Trust |
Zaeschmar J.,P.O. Box 91 |
Halliday J.,6 Kennedy Street |
Abraham A.,Care of Orca Research Trust |
And 13 more authors.
Aquatic Mammals | Year: 2010
The first record of killer whale (Orcinus orca) pre-dation on false killer whales (Pseudorca crassi-dens) is reported here. On 25 March 2010, a group of 50 to 60 false killer whales, including approximately 15 calves and accompanied by three to five bottlenose dolphins (Tursiops sp.), were sighted in the Bay of Islands, New Zealand. Within 30 min, they were approached by a group of approximately eight killer whales. Five false killer whales were attacked, with at least three rammed from below, forcing them out of the water. After 29 min, the killer whales were milling at the surface and feeding on the carcass of a false killer whale calf, possibly the only individual killed. The killer whales had prolific fresh and healed oval wounds, which were attributed to cookie cutter shark (Isistius sp.) bites. Source
Dwyer S.L.,Massey University |
Visser I.N.,Orca Research Trust
Aquatic Mammals | Year: 2011
Forty-nine species of cetaceans have been recorded in the literature with cookie cutter shark (Isistius sp.) bites. The first record of a cookie cutter shark bite mark on orca (Orcinus orca) was from New Zealand waters in 1955. We present 37 unpublished records of cookie cutter shark bite marks on orca in tropical to cold waters; a further six published records were collated, and additionally 35 individuals with bite marks were noted in photo-identification catalogues. A total of 120 individuals and 198 bite marks were recorded, with the northernmost at 70° 44' N and the southernmost at 77° 14' S. We provide the first heal-ing rate of a cookie cutter shark bite mark on an orca in New Zealand waters, with a maximum of 150 d between open wound and healed scar. Longevity of scars is considered, with one particular bite mark still visible as a dark grey oval/elliptic mark 1,158 d post photographing the open wound. Open cookie cutter shark bite marks were not observed on orca photo-graphed in Antarctic waters, despite the majority of bite marks being recorded on Antarctic orca. This sug-gests a high level of movement outside the Antarctic cold water regions as the known distribution of cookie cutter sharks is in warm temperate to tropical waters. Supporting evidence for these movements is given by records of Antarctic orca in New Zealand waters with open cookie cutter shark bite marks. Source
Morin P.A.,Southwest Fisheries Science Center |
Parsons K.M.,National Oceanic and Atmospheric Administration |
Archer F.I.,Southwest Fisheries Science Center |
Avila-Arcos M.C.,Copenhagen University |
And 21 more authors.
Molecular Ecology | Year: 2015
Global climate change during the Late Pleistocene periodically encroached and then released habitat during the glacial cycles, causing range expansions and contractions in some species. These dynamics have played a major role in geographic radiations, diversification and speciation. We investigate these dynamics in the most widely distributed of marine mammals, the killer whale (Orcinus orca), using a global data set of over 450 samples. This marine top predator inhabits coastal and pelagic ecosystems ranging from the ice edge to the tropics, often exhibiting ecological, behavioural and morphological variation suggestive of local adaptation accompanied by reproductive isolation. Results suggest a rapid global radiation occurred over the last 350 000 years. Based on habitat models, we estimated there was only a 15% global contraction of core suitable habitat during the last glacial maximum, and the resources appeared to sustain a constant global effective female population size throughout the Late Pleistocene. Reconstruction of the ancestral phylogeography highlighted the high mobility of this species, identifying 22 strongly supported long-range dispersal events including interoceanic and interhemispheric movement. Despite this propensity for geographic dispersal, the increased sampling of this study uncovered very few potential examples of ancestral dispersal among ecotypes. Concordance of nuclear and mitochondrial data further confirms genetic cohesiveness, with little or no current gene flow among sympatric ecotypes. Taken as a whole, our data suggest that the glacial cycles influenced local populations in different ways, with no clear global pattern, but with secondary contact among lineages following long-range dispersal as a potential mechanism driving ecological diversification. © 2015 John Wiley & Sons Ltd. Source
News Article | June 9, 2016
A viral video showing a killer whale beaching herself after a show in Tenerife has sparked outrage among animal rights activists. The video, which was posted by Ric O'Barry of the animal rights nonprofit group Dolphin Project, shows an orca named Morgan lying motionless beside a tank after a show in Loro Parque in Tenerife, Spain on May 16. The SeaWorld-owned killer whale was loaned from the company to Loro Parque. On June 8, a longer video of the incident was posted, revealing that Morgan stayed out of the Tenerife pool for at least 9 minutes, even after a trainer signaled her to return to the water. Morgan comes back to the pool, but after 42 seconds, she gets on the ledge again. Witnesses that day reported that Morgan was being body-slammed by other orcas in the pool. These orcas were allegedly not evaluated for social compatibility before being placed in the tank together. Some say Morgan was trying to commit suicide because she was "suffering a life in captivity." However, SeaWorld refuted the allegations, saying that Morgan was exhibiting "natural behavior" and was protecting herself from other orcas. Marine biologist Ingrid Visser from New Zealand's Orca Research Trust says it was highly unlikely that the animal jumped on the ledge to kill herself. It was possible that she was trying to escape other orcas that bullied her. "She's coming out to avoid antagonistic behavior from other orcas," says Visser. Former SeaWorld trainer and current orca-captivity activist Jeffrey Ventre says the actions of Morgan were typical "escape behavior." Ventre, who is also the star of the anti-SeaWorld documentary Blackfish, says Morgan was inserted into the social group with five other whales but she does not get along with them. "It looks like she jumped up on that stage area to get away from the other whales," says Ventre. "I think that that was a way for her to prevent from getting beat up further." Meanwhile, the Dolphin Project said in a statement that although it cannot explain the reason for Morgan's behavior, the incorporation of a previously wild orca against the backdrop of the park's show area is unsettling. Loro Parque has released its statement regarding the incident. "It is absolutely illogical and absurd to assume that the length and the quality of such video would be sufficient to make a conclusion and declaration of such nature," the park says. Loro Parque officials say that the orcas in the park are trained to leave the water when they want to. This behavior is useful especially when presenting the animals to the public, for inspecting the animals' blowholes, for performing corporal check-ups and for testing the animals' hearing abilities. Morgan the orca was rescued in the Netherlands when she was young. Unfortunately, she cannot be released into the wild because she is deaf and unequipped to survive there. Whales like Morgan occasionally beach themselves during hunting. However, if the marine animals remain on land for too long, their muscles and internal organs will be crushed by their own weight. In April, Morgan was caught on video banging her head in the Loro Parque medical pool. The park claims the video was an example of manipulation and exaggeration of a "completely normal situation" where there is no actual problem for the animals. At that time, the People for the Ethical Treatment of Animals (PETA) disagreed. "Morgan was captured from the sea six years ago and has been fighting hard against the trials of her captivity ever since," says Jared Goodman, PETA Foundation Director of Animal Law. "Her behavior shows that she is frantic to get back to the ocean home that she remembers and misses." © 2016 Tech Times, All rights reserved. Do not reproduce without permission.