killer whale predation on sea otters
"Killer Whale Predation on Sea Otters Linking Oceanic and Nearshore Ecosystems" Estes, Tinker, Williams, Doak General Hypothesis *Reduced Fertility *Increased morality *Redistribution CORRECT? Rejected "reduced fertility" and "redistribution" after testing (radiotagging) Survival Adak and Amchitka Islands, Torch and Surge Bay Semichi Islands and Attu Island The paradigm hold that where sea otters occur herbivores are rare and plants are abundant, whereas when sea otters are absent herbivores are relatively common and plants are rare Concepts to Understand Hey guys, bill here. Killer whale predation on sea otters: how predation can cause major changes in an ecosystem ... Killer whale prey in the Aleutians. The data are presented in Table 1. One killer whale is more than a hundred times heavier than a sea otter. A. Estes,* M. T. Tinker, T. M. Williams, D. F. Doak After nearly a century of recovery from overhunting, sea otter populations are in abrupt decline over large areas of western Alaska. The decline of sea otters followed a decline in harbour seal and Steller sea lion populations, the killer whale's preferred prey, [a] [126] which in ⦠JA Estes, MT Tinker, TM Williams, and DF Doak, Killer whale predation on sea otters linking oceanic and nearshore ecosystems: ⦠Killer Whales. 5. Killer whales presumably shifted their diet to include sea otters after populations of their preferred prey, harbor seals (Phoca vitulina) and Steiler sea lions (Eumetopias jubatus), declined. Increased killer whale predation is the likely cause of these declines. The killer whale predation hypothesis is based on three lines of evidence: (i) there was an increase in the number of observed killer whale attacks on sea otters during the 1990s, coincident with a decline in sea otters, (ii) sea otter ⦠Abstract. Killer whale predation estimates for western Alaska. A. Estes, M. T. Tinker, T. M. Williams and D. F. Doak. One reason for his doubt was that in several decades of going to sea and observing otters, he had never actually seen a killer whale eat a sea otter. This was an unusual idea, since killer whales and sea otters had been observed together in Alaska for decades with no obvious interactions occurring between them. 1998). Sea lions and seals are now not as abundant as they once were, especially in the North Pacific, forcing the whales to turn to sea otters ⦠Estes and his group hypothesized that increased predation by killer whales was the cause of the sea otter decline. It was speculated that these interactions reflected an increase in killer whale predation as a result of âtransientâ (mammal-eating) killer whales adjusting their diet to include sea otters, possibly in response to declines in other marine mammal prey, including harbor seals and Steller sea lions (Estes et al., 1998, ⦠Increased killer whale predation is the likely cause of these ⦠Killer whales have caused death of many sea otters . This crash began in the early 1990s, in the same year as one of the first confirmed sightings of a killer whale attacking a sea otter. Elevated sea urchin density and the consequent deforestation of kelp beds in the nearshore community demonstrate that the otter⦠Sea otter being chased by a killer whale leaps to safety on a boat with just seconds to spare. The first re-evaluate the evidence for killer whale predation and to review evidence for alternative causes. The uniform density suggested a common geographical cause in the region. But hungry killer whales arenât finding enough of their preferred prey: seals and sea lions. Kelp and sea urchin data from two Alaskan islands in 1988 Adak Alaid Island Island 0.23 6.56 Understory Kelp Density (Number -0.25m) Sea Urchin Biomass 80.25m) 336.4 38.4 In 1991, researchers at Adak Island observed the first attack by a killer whale on a sea otter in historical ⦠Increased killer whale predation is the likely cause of these declines. Their favorite prey has always been sea lions and seals. I don't know about you but lately I have been seeing lots of stories about Animals being more intelligent than we give them credit for. Members of all marine mammal families, except the river dolphins and manatees, have been recorded as prey of Killer Whales; attacks have been observed on 20 species of cetaceans, 14 species of pinnipeds, the Sea Otter⦠Killer Whale Predation on Sea Otters Linking Oceanic and . A report by J. Estes et al. 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