Echolocation signals of free-ranging killer whales (Orcinus orca) and modeling of foraging for chinook salmon (Oncorhynchus tshawytscha)

2004 ◽  
Vol 115 (2) ◽  
pp. 901-909 ◽  
Author(s):  
Whitlow W. L. Au ◽  
John K. B. Ford ◽  
John K. Horne ◽  
Kelly A. Newman Allman
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Orcinus Orca ◽  
Killer Whales ◽  
Free Ranging

scholarly journals Southern resident killer whales encounter higher prey densities than northern resident killer whales during summer

2021 ◽  
pp. 1-12
Author(s):  
Mei Sato ◽  
Andrew W. Trites ◽  
Stéphane Gauthier
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Killer Whale ◽  
Orcinus Orca ◽  
Foraging Success ◽  
Killer Whales ◽  
Juan De Fuca ◽  
Abundance And Distribution ◽  
Juan De Fuca Strait ◽  
Growing Population

The decline of southern resident killer whales (Orcinus orca) may be due to a shortage of prey, but there is little data to test this hypothesis. We compared the availability of prey (Chinook salmon, Oncorhynchus tshawytscha) sought by southern residents in Juan de Fuca Strait during summer with the abundance and distribution of Chinook available to the much larger and growing population of northern resident killer whales feeding in Johnstone Strait. We used ship-based multifrequency echosounders to identify differences in prey fields that may explain the dynamics of these two killer whale populations. Contrary to expectations, we found that both killer whale habitats had patchy distributions of prey that did not differ in their frequencies of occurrence, nor in the size compositions of individual fish. However, the density of fish within each patch was 4–6 times higher in the southern resident killer whale habitat. These findings do not support the hypothesis that southern resident killer whales are experiencing a prey shortage in the Salish Sea during summer and suggest a combination of other factors is affecting overall foraging success.

scholarly journals Estimates of Chinook salmon consumption in Washington State inland waters by four marine mammal predators from 1970 to 2015

2017 ◽  
Vol 74 (8) ◽  
pp. 1173-1194 ◽  
Author(s):  
Brandon Chasco ◽  
Isaac C. Kaplan ◽  
Austen Thomas ◽  
Alejandro Acevedo-Gutiérrez ◽  
Dawn Noren ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Marine Mammal ◽  
Oncorhynchus Tshawytscha ◽  
Interspecific Interactions ◽  
Puget Sound ◽  
The United States ◽  
Washington State ◽  
Killer Whales ◽  
Protected Species ◽  
Annual Biomass

Conflicts can arise when the recovery of one protected species limits the recovery of another through competition or predation. The recovery of many marine mammal populations on the west coast of the United States has been viewed as a success; however, within Puget Sound in Washington State, the increased abundance of three protected pinniped species may be adversely affecting the recovery of threatened Chinook salmon (Oncorhynchus tshawytscha) and endangered killer whales (Orcinus orca) within the region. Between 1970 and 2015, we estimate that the annual biomass of Chinook salmon consumed by pinnipeds has increased from 68 to 625 metric tons. Converting juvenile Chinook salmon into adult equivalents, we found that by 2015, pinnipeds consumed double that of resident killer whales and six times greater than the combined commercial and recreational catches. We demonstrate the importance of interspecific interactions when evaluating species recovery. As more protected species respond positively to recovery efforts, managers should attempt to evaluate tradeoffs between these recovery efforts and the unintended ecosystem consequences of predation and competition on other protected species.

Usage of monophonic and biphonic calls by free-ranging resident killer whales (Orcinus orca) in Kamchatka, Russian Far East

2009 ◽  
Vol 12 (1) ◽  
pp. 37-44 ◽  
Author(s):  
O. A. Filatova ◽  
I. D. Fedutin ◽  
M. M. Nagaylik ◽  
A. M. Burdin ◽  
E. Hoyt
Keyword(s):  
Russian Far East ◽  
Far East ◽  
Orcinus Orca ◽  
Killer Whales ◽  
Free Ranging

Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters

1998 ◽  
Vol 76 (8) ◽  
pp. 1456-1471 ◽  
Author(s):  
John KB Ford ◽  
Graeme M Ellis ◽  
Lance G Barrett-Lennard ◽  
Alexandra B Morton ◽  
Rod S Palm ◽  
...  
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Stomach Contents ◽  
Orcinus Orca ◽  
Foraging Strategies ◽  
Field Observations ◽  
Killer Whales ◽  
Sympatric Populations ◽  
Mammal Species ◽  
Dietary Specialization

Two forms of killer whale (Orcinus orca), resident and transient, occur sympatrically in coastal waters of British Columbia, Washington State, and southeastern Alaska. The two forms do not mix, and differ in seasonal distribution, social structure, and behaviour. These distinctions have been attributed to apparent differences in diet, although no comprehensive comparative analysis of the diets of the two forms had been undertaken. Here we present such an analysis, based on field observations of predation and on the stomach contents of stranded killer whales collected over a 20-year period. In total, 22 species of fish and 1 species of squid were documented in the diet of resident-type killer whales; 12 of these are previously unrecorded as prey of O. orca. Despite the diversity of fish species taken, resident whales have a clear preference for salmon prey. In field observations of feeding, 96% of fish taken were salmonids. Six species of salmonids were identified from prey fragments, with chinook salmon (Oncorhynchus tshawytscha) being the most common. The stomach contents of stranded residents also indicated a preference for chinook salmon. On rare occasions, resident whales were seen to harass marine mammals, but no kills were confirmed and no mammalian remains were found in the stomachs of stranded residents. Transient killer whales were observed to prey only on pinnipeds, cetaceans, and seabirds. Six mammal species were taken, with over half of observed attacks involving harbour seals (Phoca vitulina). Seabirds do not appear to represent a significant prey resource. This study thus reveals the existence of strikingly divergent prey preferences of resident and transient killer whales, which are reflected in distinctive foraging strategies and related sociobiological traits of these sympatric populations.

PBDEs, PBBs, and PCNs in Three Communities of Free-Ranging Killer Whales (Orcinus orca) from the Northeastern Pacific Ocean

2004 ◽  
Vol 38 (16) ◽  
pp. 4293-4299 ◽  
Author(s):  
Sierra Rayne ◽  
Michael G. Ikonomou ◽  
Peter S. Ross ◽  
Graeme M. Ellis ◽  
Lance G. Barrett-Lennard
Keyword(s):  
Pacific Ocean ◽  
Orcinus Orca ◽  
Killer Whales ◽  
Northeastern Pacific ◽  
Free Ranging

Structural and temporal emission patterns of variable pulsed calls in free-ranging killer whales (Orcinus orca)

Behaviour ◽  
2007 ◽  
Vol 144 (3) ◽  
pp. 307-329 ◽  
Author(s):  
Frank Thomsen ◽  
Nicola Rehn ◽  
Stefanie Teichert
Keyword(s):  
Orcinus Orca ◽  
Killer Whales ◽  
Free Ranging

Call-type matching in vocal exchanges of free-ranging resident killer whales, Orcinus orca

2004 ◽  
Vol 67 (6) ◽  
pp. 1099-1107 ◽  
Author(s):  
P.J.O. Miller ◽  
A.D. Shapiro ◽  
P.L. Tyack ◽  
A.R. Solow
Keyword(s):  
Orcinus Orca ◽  
Killer Whales ◽  
Call Type ◽  
Free Ranging
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