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jan 11

killer whales thinning otter population by npr

Approximately 2,500 killer whales live in the eastern North Pacific Ocean—home to the most well-studied killer whale populations. It's one of those moments that biologists live for. Ms. WILLIAMS: We all want to think they're smiling at us and happy and they'll eat a few dead fish, and we're out there saying, `Well, gosh, no. I can't even ... it was thrilling for all of us." Pitman says it must have looked like a fishing line with fish on it — it looked like breakfast. K Pod K pod is the smallest of the three pods in the Southern Resident killer whale community with only 17 members. "This study was really a decade-long look at what do killer whales die from, from California to Alaska all the way out to Hawaii," he sasy. ", Pitman picks up the story: "The sun came up in the morning at 5:50. A rare photo of "type D" killer whales off South Georgia island, located between South America and Antarctica, shows the whales' blunt heads and tiny white eye patches. This is due to the fact that killer whales are used to eating animals two to five times the size of otters, so they need to eat two to five times as many otters as seals or sea lions. Some researchers can distinguish individual pods, and even matrilines (the line of relationship that can be traced from one mother to her offspring), just by their calls. Although the population size and status of killer whales in the Aleutian Islands are unknown, these animals are commonly seen. This suggests that four killer whales, feeding exclusively on sea otters, could have driven the population into decline. NPR's Allison Aubrey reports on a new development among sea otter populations off the coast of Alaska. NIELSEN: But it's not just whale-huggers who hate the orca hypothesis. For Pitman, the hunt was on. Fig. He says the authors of the orca paper greatly overestimate the number of sea otters being eaten by the killer whales, partly because he's sure these killer whales are also eating lots of other things, like fish. "It's a big ocean, and it's a rough ocean. Washington’s sea otter population isn’t growing as fast as it once was. If there were more fish, they say, marine mammals and orcas would have plenty to eat. Orcas Gobbling Alaskan Otters / Change in Killer whale diet puts ecosystem on edge of ruin Carl T. Hall, Chronicle Science Writer Oct. 16, 1998 Updated: Feb. 3, 2012 4:14 a.m. New Type Of Killer Whale Found Swimming In Southern Ocean The notion that there might be some new kind of killer whale emerged in 1955, when photos from New Zealand showed a … The primary focus of CWR research is the Southern Resident population of killer whales (orcas). "This was a very different-looking group of killer whales," says Robert Pitman, a marine ecologist with the National Oceanic and Atmospheric Administration. Sea otters are still classified as endangered. Later, they realized why the whales swam up to them. Copyright © 2005 NPR. NIELSEN: Williams is part of a team that first observed these sneak attacks seven years ago when they were studying the otter die-off along the Aleutian Islands. Then, when seals became rare, the killer whales turned to sea lions. NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. In recent decades, several populations of killer whales have declined and some have become endangered. The killer whale (also known as the orca) generally did not consume sea otters in the past, but now consumes thousands of otters. Credit: Weiss et al., “Modelling cetacean morbillivirus outbreaks in an endangered killer whale population,” Biological Conservation, 2020. For the moment this debate is largely academic; nobody is seriously talking about killing orcas to protect otters, seals and sea lions. NPR’s John Nielsen reported that this caused up to an 80% decline in the otter population. They are easy to identify because of their distinctive white and black colouring. A new theory suggests a massive decline in seals, sea lions and sea otters in the North Pacific may have been triggered by over-fishing of great whales. Sea otter numbers were stable from 1993 through 1997 in Clam Lagoon, whereas in Kuluk Bay they declined by 76%. It's gone. Then she multiplies that number by 365 days. Killer whales, or Orcas (Orcinus orca) are toothed whales in the oceanic dolphin family. Then she multiplies five to seven by 170, which is the estimated number of mammal-eating orcas living near the Aleutians. The team had lowered an underwater microphone over the side on a long cable, with cameras attached. ", It was a slow start. Since 1990, otter populations off the Aleutian Islands have fallen by as much as 80 percent. . Second, we evaluated the impact of killer whales on sea otter populations at Adak Island by contrasting otter population trends and sur- vival rates between Clam Lagoon, an area uniquely inaccessible to killer whales, and ad- jacent Kuluk Bay, an open coastal environment (Fig. (B) Global overview of PCB concentrations in killer whale blubber (ppm, parts per million).Light and dark green circles represent males and females, respectively. Killer whales, just like their dolphin cousins, communicate through underwater sounds with one another. Since 1990, otter populations off the Aleutian islands have plummeted by as much as 80 percent. NIELSEN: Environmental groups say the orca paper does a disservice to the cause of conservation by diverting attention from what they say is the real problem in the Bering Sea: overfishing. Killer whales in the north Pacific switched to eating Harbor seals, Northern fur seals, Steller sea lions, and finally Sea otters, thinning each species’ populations out one-by-one. The photograph above was taken on July 7, 2010. They use these sounds to help travel underwater. When the big whales got hard to find, Williams says, the orcas switched to big, stellar sea lions and then to medium-sized seals. PCBs first came under scrutiny in the 1970s, when birds, seals, and otter populations began rapidly decreasing. When the sea lion population crashed, they started fishing sea otters. "But that was definitely the way to bring them to the boat.". (A) Conceptual model of PCB bioaccumulation and magnification, leading to elevated PCB concentrations in killer whale populations. Accuracy and availability may vary. "And most importantly," Pitman adds, "they had a little tiny eye patch," a white spot under each eye characteristic of killer whales. "From the beginning, I had referred to it as the needle in the haystack," she says. You know, they're killing cute, little, fuzzy sea otters.' There are fewer fish available for them to eat, more noise in the water affecting their ability to find the fish, and more pollution in the water that impacts their health when they are not well fed. First, Williams determines that the average orca needs to eat the equivalent of five to seven sea otters a day just to get by. Different populations of killer whales make different vocalizations, and different pods within these populations may even have their own dialect. And baby makes 75: newborn orca boosts endangered whale population. Populations of otters along the Alaskan and Canadian coast, which had recovered to a few hundred thousand, were driven back down to just a few thousand. ", "There they were," Ballance recalls, for a moment at a loss for words. These giant pectoral fins come up on either side of the sea otter. NOAA biologist Lisa Ballance, who's married to Pitman, was part of the team. What kinds of other animals share the sea otters’ habitat? NIELSEN: In the current issue of the journal Ecology, Williams and her colleagues show just how big the killer-whale bite out of the otter population is. Local fishers had been complaining that some kind of whale was stripping fish off their lines. Each pod has distinctive noises, so whales in one pod can sense if another whale is part of its group. (The sea otter is an endangered species). The mouth comes up, takes the sea otter, grabs it and gulps it down. Serious scientists, like Doug DeMaster, don't think much of it either. All rights reserved. (killer whales spouting water) I would see a killer whale on average of probably once every three or four years in the '70s and '80s. Scientists found extremely high PCB levels in the animals’ bodies. Before reading: Describe a sea otter. The killer whale is easy to identify by its size and its striking coloration: jet black on top and pure white below with a white patch behind each eye, another extending up each flank, and a variable “saddle patch” just behind the dorsal fin. Then in 2005, Pitman met a French biologist at a science conference who showed him a photo of an odd-looking killer whale swimming in the southern Indian Ocean. The authoritative record of NPR’s programming is the audio record. But Jim Hasties, a federal biologist and a major proponent of the orca theory, says there is one solution that almost everyone can agree on: continuing efforts to rebuild the region's stocks of great whales. People raised on movies like "Free Willy" tend to think of killer whales as well-meaning, fence-jumping giants who want nothing more than to live in perfect harmony with all the other creatures in the ocean. Marine scientists suggest the Southern Resident orcas face problems centered on their diet. They are found in all the world's oceans, from the cold of the Arctic to the tropical seas. Populations of mammal-eating transient orcas, gray whales and humpback whales are increasing. Lull for killer whales. Where do sea otters live? Some feed exclusively on fish, while others hunt marine mammals such as seals and other species of dolphin. 2). Whale researchers spotted a baby orca swimming energetically with its mother west of San Juan Island on Friday. Still others are investigating what to do about killer whales feeding on sea otters in Alaska. That's the New Zealand killer whale!' Their ship at Cape Horn was trapped at anchor for eight days by howling weather. "And I looked down, and there they were, the New Zealand killer whales," he recalls. The team was able to snip off small tissue samples from the whales by firing a harmless dart, attached to a line, into their skin. Orcas were eating otters because the really big whales they used to eat were nearly wiped out by commercial whalers back in the 1950s. "The idea is that, if we can figure that out, we might be able to find some ways that we can further help recover the endangered population, like Southern residents." 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. As they documented more attacks, they began wondering why a 10-ton orca would waste its energy on a 65-pound sea otter. NIELSEN: DeMaster is director of the federal government's Alaska Fisheries Science Center. He also says the original idea that these orcas once ate the great whales can't be proven. Courtesy of J.P. Sylvestre What might threaten sea otters? Photos from New Zealand showed a bunch of whales stranded on a beach. Scientists recently found that as many as half of the world’s killer whale populations may not survive the next 100 years because of PCB pollution. The Navy estimates the southern population of killer whales in the Puget Sound region could be subject to the non-lethal take two to 51 times a year during the seven years of Navy activity. It is estimated that there are around 50,000 killer whales globally. Ecologists say killer whales are eating the otters, but as NPR's John Nielsen reports, not everyone buys that theory. Terry Williams, a marine biologist at the University of California at Santa Cruz, says that's because the killer whales eat them. "And you can imagine them thinking, 'Hey, where's our fish?' hide caption. But sea otters living in the Bering Sea off Alaska probably think differently. Scientists are finding the same trend around the world. Ms. WILLIAMS: Followed lastly by sea otters, which, you know, still give you calories, but it's going to take you a bit to fill up on them. I should point out that killer whales around the world are doing fine, but this population is listed as endangered on both sides of the border of the U.S. and Canada. It lives in parts of the ocean near Antarctica — and it could be the largest animal to have remained unidentified by biologists. Williams says the answer turned out to be a simple one. But then they got a 12-hour quiet spell. It's still waiting to be tested. I'm Michele Norris. Question Sheet: Sea Otters, Kelp, and Killer Whales. And by the late 1990's, I'd see 'em three or four times a day. Mr. DeMASTER: The people who really know killer whales, who spend their lives following them around and studying them--they just don't find any evidence that large whales are an important part of their diet. Either way, the mystery killer whales of the Southern Ocean have been found. This text may not be in its final form and may be updated or revised in the future. 2). Killer whales have a diverse diet, although individual populations often specialize in particular types of prey. Visit our website terms of use and permissions pages at www.npr.org for further information. The killer whale, also known as an orca (Orcinus orca), is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. One killer whale would need to eat 1,825 otters a year to live. Ms. TERRY WILLIAMS (University of California at Santa Cruz): It's a bizarre way of hunting, where these killer whales have learned to swim upside down, below a sea otter that's resting on the water's surface. Mr. DOUG DeMASTER (Director, Alaska Fisheries Science Center): This hypothesis is too simplistic, and it's not ready for the textbooks yet. They are the largest dolphins. They live in pods. Last year, he assembled a team to go to Cape Horn, in Chile, to look for what's now technically called the "type D" killer whale. Although the future looks grim for the otters at the moment, there is some hope on the horizon. SCIENCE. 1 Global PCB concentrations in killer whales. Other researchers are studying why California’s sea otters seem to have become more vulnerable to disease and parasites. All three pods uniting is referred to as a s uper pod. " he says. Danita Delimont/Getty Images Reproduction and Offspring . The chemicals were affecting their ability to reproduce. And I said, 'That's it! Pitman adds: "It's like seeing a dinosaur or something. affected. Killer Whale Predation on Sea Otters Linking Oceanic and Nearshore Ecosystems J. Many people are trying to figure out why. The whales were smaller than other killer whales, and they had rounded heads and pointier fins. Ecologists say killer whales are eating the otters. An analysis of the DNA will determine if this is actually a completely new species or just an unusual subtype. NIELSEN: Williams says it's hard to overstate how much these findings upset people who all but worship killer whales. These patches were unusually small, in some cases almost nonexistent. December 9, 2011 at 4:12 pm . "We left that night," Ballance recalls, and "pounded into the seas so that we could get to our spot at first light the next morning. But not everyone is buying the theory. Ms. WILLIAMS: And you end up with a whopping 300,000 sea otters in a single year potentially eaten by these animals. Killer whale, (Orcinus orca), also called orca, largest member of the dolphin family (Delphinidae). The notion that there might be some unusual kind of killer whale emerged in 1955. And a lot of people don't like hearing that. Scientists say they've found a mysterious type of killer whale that they've been searching for for years. Since 1990, otter populations off the Aleutian Islands have fallen by as much as 80 percent. ", There was no mistaking its peculiar look, says Ballance. John Nielsen, NPR News, Washington. This is ALL THINGS CONSIDERED from NPR News. Lifestyle. We had type D killer whales swimming around our boat. A group of ecologists says it has solved the mystery of Alaska's missing sea otters. "Visibly," she says, "this form is the most unusual and distinct form of killer whale on the planet.". As a result, populations of sea otters in the Aleutian Islands have declined from an estimated 60,000 animals in the mid-1980s to under 10,000 by 2000. A rare photo of "type D" killer whales off South Georgia island, located between South America and Antarctica, shows the whales' blunt heads and tiny white eye patches. The domino effect reaches even farther. Increased killer whale predation is the likely cause of these declines. Share this: Facebook; Twitter; Reddit; Google Classroom; Email; Print; By Science News for Students. They can tell, even in the darkest parts of the sea, where items are by how quickly their noises bounce back. Orcas have mostly black skin with white patches. Second, we evaluated the impact of killer whales on sea otter populations at Adak Island by contrasting otter population trends and sur-vival rates between Clam Lagoon, an area uniquely inaccessible to killer whales, and ad-jacent Kuluk Bay, an open coastal environment (Fig. A group of ecologists says it solved the mystery of Alaska's missing sea otters. 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