Surface and underwater observations of cooperatively feeding killer whales in northern Norway

1993 ◽  
Vol 71 (8) ◽  
pp. 1494-1499 ◽  
Author(s):  
Tiu Similä ◽  
Fernando Ugarte
Keyword(s):  
Clupea Harengus ◽  
Orcinus Orca ◽  
Defence Mechanism ◽  
Killer Whales ◽  
Northern Norway ◽  
Schooling Fish ◽  
Feeding Techniques

Killer whales (Orcinus orca) feeding on herring (Clupea harengus) were observed both from the surface and underwater. We refer to one of the feeding techniques used by killer whales as the carousel method, whereby whales cooperatively herded herring into a tight ball close to the surface. During herding and feeding, whales swam around and under a school of herring, performing much lobtailing and porpoising. When the herring were gathered into a tight ball whales often swam with the white underside of their body towards the fish and emitted large bubbles close to the surface. While feeding, whales spent more time circling around the ball of fish than eating. Ball formation is a known defence mechanism used by schooling fish, and the effort by killer whales appeared to be directed towards keeping the ball very dense and close to the surface. The whales stunned their prey by slapping the edge of the school with the underside of their flukes and then ate the stunned fish one by one. The tail slaps created a loud banging sound which could have been either a by-product or an aid to stunning the prey.

Migratory and diurnal activity of North Atlantic killer whales (Orcinus orca) off northern Norway

2020 ◽  
Vol 533 ◽  
pp. 151456
Author(s):  
Rune Dietz ◽  
Audun H. Rikardsen ◽  
Martin Biuw ◽  
Lars Kleivane ◽  
Christina Lehmkuhl Noer ◽  
...  
Keyword(s):  
North Atlantic ◽  
Orcinus Orca ◽  
Diurnal Activity ◽  
Killer Whales ◽  
Northern Norway

Herring schooling manoeuvres in response to killer whale attacks

1999 ◽  
Vol 77 (10) ◽  
pp. 1540-1546 ◽  
Author(s):  
Leif Nøttestad ◽  
Bjørn Erik Axelsen
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Killer Whale ◽  
Clupea Harengus ◽  
Orcinus Orca ◽  
Antipredator Behaviour ◽  
Killer Whales ◽  
Predator Prey ◽  
Antipredator Responses ◽  
Different Types

The antipredator behaviour of overwintering Norwegian spring-spawning herring (Clupea harengus L.) was investigated during repeated attacks by killer whales (Orcinus orca L.) in Tysfjord in northwestern Norway. The observations were made using a high-resolution (455 kHz) multibeam sonar. Ten different types of predator-prey interactions were recorded during 54 observed events (an average of one antipredator event every 3.9 min). Antipredator responses included "split," "hourglass," "vacuole," "bend," "dive," "herd," and "fountain." Large attacked schools demonstrated a different repertoire of antipredator manoeuvres than small ones and were less likely to be attacked. Despite being located in the vicinity of the whales, herring schools with a cross section exceeding 460 m2 were not attacked by killer whales. Attacked schools were significantly more circular (p < 0.0001) and had higher relative densities (p < 0.05) than schools that were not attacked.

scholarly journals Isotopic niche differs between seal and fish‐eating killer whales ( Orcinus orca ) in northern Norway

2020 ◽  
Vol 10 (9) ◽  
pp. 4115-4127 ◽  
Author(s):  
Eve Jourdain ◽  
Clare Andvik ◽  
Richard Karoliussen ◽  
Anders Ruus ◽  
Dag Vongraven ◽  
...  
Keyword(s):  
Orcinus Orca ◽  
Isotopic Niche ◽  
Killer Whales ◽  
Northern Norway

Killer whales (Orcinus orca) feeding on schooling herring (Clupea harengus) using underwater tail-slaps: kinematic analyses of field observations

2000 ◽  
Vol 203 (2) ◽  
pp. 283-294 ◽  
Author(s):  
P. Domenici ◽  
R.S. Batty ◽  
T. Simila ◽  
E. Ogam
Keyword(s):  
High Performance ◽  
Prey Capture ◽  
Clupea Harengus ◽  
Physical Contact ◽  
Orcinus Orca ◽  
Whole Body ◽  
Maximum Speed ◽  
Killer Whales ◽  
Maximum Acceleration ◽  
Maximum Angle

Killer whales (Orcinus orca) feeding on herring (Clupea harengus) in a fjord in northern Norway were observed using underwater video. The whales cooperatively herded herring into tight schools close to the surface. During herding and feeding, killer whales swam around and under a school of herring, periodically lunging at it and stunning the herring by slapping them with the underside of their flukes while completely submerged. The kinematics of tail-slapping were analysed in detail. Tail-slaps were made up of a biphasic behaviour consisting of two phases with opposite angles of attack, a preparatory phase (negative angles of attack) and a slap phase (positive angles of attack). During the slap phase, the mean maximum angle of attack of the flukes was 47 degrees. The maximum speed of the flukes, measured at the notch, increased with whale length (L(w)) and was 2.2 L(w)s(−)(1), while the maximum acceleration of the flukes was size-independent and was 48 m s(−)(2). When killer whales slapped the herring successfully, disoriented herring appeared on the video at approximately the time of maximum fluke velocity, in synchrony with a loud noise. This noise was not heard when the tail-slaps ‘missed’ the target, suggesting that the herring were stunned by physical contact. Killer whales then ate the stunned herring one by one. Of the tail-slaps observed, 61 % were preceded by lunges into the school. We suggest that lunging was aimed at directing the school rather than at capturing the herring, since it occurred at a relatively low speed and there were no observations of the killer whales attempting to capture the herring during lunging behaviour. Given the high performance of the tail-slaps in terms of speed and acceleration, we suggest that tail-slapping by killer whales is a more efficient strategy of prey capture than whole-body attacks, since acceleration and manoeuvrability are likely to be poor in such large vertebrates.

scholarly journals Movements and site fidelity of killer whales (Orcinus orca) relative to seasonal and long-term shifts in herring (Clupea harengus) distribution

2017 ◽  
Vol 164 (8) ◽  
Author(s):  
Filipa I. P. Samarra ◽  
S. B. Tavares ◽  
J. Béesau ◽  
V. B. Deecke ◽  
A. Fennell ◽  
...  
Keyword(s):  
Site Fidelity ◽  
Clupea Harengus ◽  
Orcinus Orca ◽  
Killer Whales

Population size, survival and reproductive rates of northern Norwegian killer whales (Orcinus orca) in 1986–2003

2013 ◽  
Vol 94 (6) ◽  
pp. 1277-1291 ◽  
Author(s):  
Sanna Kuningas ◽  
Tiu Similä ◽  
Philip S. Hammond
Keyword(s):  
Population Size ◽  
Killer Whale ◽  
Survival Rates ◽  
Clupea Harengus ◽  
Orcinus Orca ◽  
Adult Males ◽  
Killer Whales ◽  
Apparent Survival ◽  
Photo Identification ◽  
Reproductive Rates

A long-term photo-identification study of killer whales (Orcinus orca) in northern Norway was initiated in 1986, when their prey the Norwegian spring-spawning herring (Clupea harengus) started to winter in a complex fjord system. The aim of this work was to estimate population size and apparent survival rates in this killer whale population using photo-identification and mark–recapture techniques with data collected during October–December 1986–2003. Total population size was estimated to be highest in 2003: 731 individuals (SE = 139, 95% CI = 505–1059) using a model taking heterogeneity of capture probabilities into account. Apparent survival of adult males and adult females was estimated using the Cormack–Jolly–Seber model as 0.971 (SE = 0.008) and 0.977 (SE = 0.009), respectively. Calving intervals ranged from 3 to 14 years (mean = 5.06, SE = 0.722). These are the first estimates of northern Norwegian killer whale population parameters, allowing their dynamics to be investigated and comparisons to be made with killer whale populations globally.

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