Although these ecological discoveries are relatively recent, the relationships between sea otters and other organisms in the nearshore North Pacific, with whom they coevolved for millions of years, are ancient. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. Effects of predator depletion or recovery are frequently accompanied by time lags, which are often context-dependent. Sea otters are a shallow-water species, spending their lives within depths where they can reach the bottom for food, so the sea otters range tends to hug the coastline, visible to and easily within reach of hunters. Read about our approach to external linking. To communicate the science behind these concepts to a wide and diverse audience, I hosted a virtual Lightning Talk event with my employer, the Seattle Aquarium. Incorporating it would offer a clearer picture of what a warmer future holds in store. According to this explanation, by defending macroalgae (like kelp) from herbivores that attacked its living parts, sea otters allowed the macroalgae to relax its chemical defenses, making the pieces that drifted down to waiting herbivores higher quality food. However, copper rockfish fishable biomass was negatively correlated with canopy kelp stipe density, likely due to the successional transition as sea otters return to an area from the disturbance-tolerant annual kelp Nereocystis to the perennial kelp Macrocystis. When the sea otter returned and began to compete for these same shellfish, some saw the sea otter as an interloper, a destroyer of the oceans bounty. She delights in all things creeping, crawling and curious, and studies human-dog coevolution as an anthropology Ph.D. student at Washington State University. Comparing kelp density with otters and kelp density without otters, they found that "sea otters have a positive indirect effect on kelp biomass by preying on sea urchins, a kelp grazer." Thanks for reading Scientific American. R Soc Open Sci. Two of these populations disappeared by the end of the decade. They will remain accessible to anyone who wants to watch them in the future. The voracious echinoderms not only mowed down the kelp but are also tearing apart and devouring the massive, slow-forming limestone reefs on which this seaweed grows, Rasher and his colleagues recently reported in Science. The far-sightedness of the MMPA is only beginning to be realized. part may be reproduced without the written permission. They have mostly done so by exposing a single species to warmer temperatures and/or higher acidity and recording how it responds, however. Baby otters dont yet have the muscle mass to stay warm through these leaks, but their muscle cells generate heat at adult rates, the researchers found, showing that proton leak begins early. The southern sea otter has reclaimed only about 13% of its historical range, and its population size is far below its estimated historical population size in California, about 17,000 (though it could be as low as 10,000 or as high as 30,000), a number that does not include the historical populations in Oregon and Baja California. As sea otters declined (for reasons scientists are still trying to understand), their favorite preysea urchinsexploded in number. Otters' indirect effects on coastal ecosystems can also follow pathways other than the otter-urchin-kelp trophic cascade. CO2 concentration in the atmosphere has increased 40 percent since the beginning of the industrial revolution, causing global temperatures to rise, the authors write. A. Estes, C.A. But to understand the sea otters relationship with abalone, and with other organisms in the nearshore marine communities of the North Pacific Ocean, we need to go back in time. In determining these effects, it's important to recognize that sea otters alter ecosystems via both direct and indirect pathways. The main objectives of this project were to: In 2020, the Seattle Aquarium transitioned its Lightning Talk event to a virtual format. Wolf C, Betts MG, Levi T, Newsome TM, Ripple WJ. The emissions from travel it took to report this story were 0kg CO2. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. The return of these playful creatures doesn't just transform their ecosystems, it can turn them into a powerful carbon sink. disaster), and due to their own self reporting of knowledge, many were relatively well-versed in what climate change is. While the ESA focuses on preventing extinction and promoting species recovery, the MMPA has a more explicitly ecological aim: to maintain marine mammal stocks at levels where they are significant functioning elements of the ecosystems of which they are a part. In other words, marine mammal stocks must be restored to ecological relevance. Whereas urchin-dominated communities supported more diverse fish assemblages than kelp-dominated communities, this was not a simple effect of the otter-induced trophic cascade because all islands supported more diverse fish assemblages in 2000 than in the mid-1980s. But these perpetually hungry mammals don't only protect kelp ecosystems. The sea otter had been hunted almost to extinction for its fur by 1910. "If ecologists can get a better handle on what these impacts are, there might be opportunities for win-win conservation scenarios, whereby animal species are protected or enhanced, and carbon gets sequestered," he said. I think were all coming to realize that theres going to be a lot of synergies between species loss and climate change, says Hillary Young, an ecologist at the University of California, Santa Barbara, who was not involved in the new study. Some of these effects are perceived as beneficial to people, and others are perceived as negative. We used the overexploitation, recovery and subsequent collapse of sea otter (Enhydra lutris) populations in the Aleutian archipelago to explore if and how the abundance and diet of kelp forest fishes are influenced by a trophic cascade linking sea otters with sea urchins and fleshy macroalgae. Contrary to expectations, we found no evidence for an effect of sea otter occupation time or kelp metrics on the fishable biomass of kelp greenling. And it could lead to new insights into how the ancestors of these creatures first evolved to live and thrive in the seas. We measured the abundance of sea urchins (biomass density), kelp (numerical density) and fish (Catch per unit effort) at four islands in the mid-1980s (when otters were abundant at two of the islands and rare at the two others) and in 2000 (after otters had become rare at all four islands). Before the fur trade, the range of sea otters spanned the entire North Pacific rim, from the northern islands of Japan to midway down the Pacific Coast of Baja California, Mexico. Create your free account or Sign in to continue. Not only can a wider audience be reached, but speakers from throughout the world can participate. Even at a lower estimate, sea otter carbon sequestration can add up. Sea otters (Enhydra lutris) are a small mammal in the weasel family. Then, using a device called a respirometer, researchers measured otter muscle cells respiratory capacity in different states of oxygen flow compared with other animals including humans, Iditarod sled dogs and elephant seals. Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. "When we help restore missing keystone predators, we make things right in a lot of ways before we even recognise what some of those ways are," Lilian Carswell, the southern sea otter recovery coordinator for the US Fish and Wildlife Service, wrote in an email to the BBC. Sea otters were transferred from state management to federal management, and in 1977 the U.S. The thick lustrous coat is reddish to dark brown. When sea otters are absent, urchins decimate kelp, resulting in low net primary productivity. By using our site, you acknowledge that you have read and understand our Privacy Policy The author granted permission for the file to be printed and for the text to be copied and pasted. New methods of reintroduction using juvenile sea otters who stranded as pups and were raised by surrogate sea otter mothers also show great promise. Randall Davis (Image obtained under USFWS Marine MammalPermitNo. The sea otters keystone role in nearshore marine ecosystems was first recognized in 1974, initiating an extensive body of work on sea otters indirect effects, including increases in the abundance of kelp-associated finfish. However, it eventually began to grow more rapidly, numbering about 100 at the time of the most recent range-wide count in 2019. While scuba diving around the Aleutian Islands in 2014, marine ecologist Doug Rasher saw little sign of the curtains of lush green kelp forests he would have had to push through decades earlier. And similar situations likely hold true for other ecosystems across the globe. "Just in my own soul, it was an important thing," he says of his early observations of that stark difference. The Lightning Talks: Sea Otters event occurred on Earth Day, 4/22/2021 from 6-7pm PT on YouTube Live. The talks are catered to a wide range of ages and no science background is required. Epub 2014 Nov 22. In 1911, most Californians werent thinking about sea otters. amount of work on sea otter-sea urchin-macroalgal relationships, our study focuses on the indirect effects of this trophic cascade on kelp forest fishes. It inhabits coastal waters from the Kuril Islands to the Aleutian Islands southward to the coast of California. Your feedback is important to us. The site is secure. But when dead kelp sinks to the sea floor, it might not surface (and therefore decompose and produce carbon dioxide) for thousands of years. This puts them at a high potential for heat loss, especially because, unlike most marine mammals, sea otters do not have blubber to insulate them. eCollection 2018 Aug. These leaks account for a higher percentage of muscle cells total respiratory capacity in extremely small mice compared with otters. In temperate rocky reef ecosystems, sea otters (Enhydra lutris) trigger a cascade of direct and indirect effects driving transitions between kelp-depleted and . But otters extreme metabolism helps them stay cozy in the waves. The large hind feet are broad and flipperlike. The video link was shared 53 times. www.esajournals.org/doi/abs/10.1890/110176. Other Russians soon returned to obtain more furs, forcing skilled Aleutian hunters to join their hunting expeditions. The sea otter is the largest otter, reaching 100-160 cm (40 . Fifteen years ago Christopher Wilmers, a wildlife ecologist now at the University of California, Santa Cruz, published studies looking at how warmer winters in Yellowstone National Park meant fewer elk foundering in deep snow and dying. An adult male sea otter weighing 34 kg provides 61,540 kcal (34,000 gm 1.81 kcal gm -1 of wet weight); a 23-kg adult female otter provides 41,630 kcal. 2018 Jun 27;8(15):7346-7354. doi: 10.1002/ece3.4259. or, by Guy Lasnier, University of California - Santa Cruz. Learn more about structure and function of the surrounding ecosystem. This explanatory language, which accompanied the 2021 Appropriations Act, also instructed the Service to study the feasibility and cost of reestablishing sea otters on the Pacific Coast of the contiguous United States. That perspective is echoed in a soon to be published paper by University of Colorado Boulder ecologist Laura Dee, who points to the many indirect effects warmer temperatures can have on a species. We studied the diets, productivity, and density of breeding Bald Eagles on four islands during 1993-1994 and 2000-2002, when sea otters were abundant and scarce, respectively. 2006. Rocks are typically used to break open crabs and other shellfish, whereas sea urchins are crushed with the forefeet and teeth. Please select the most appropriate category to facilitate processing of your request. Registration occurred through the Seattle Aquarium website, and was advertised in multiple ways (facebook ads, Seattle Aquarium members, staff and volunteers, UW SMEA department listserv, UW PCC listserv, etc). Breen et al. With more hairs per square inch than those of any other mammal, the thick, lush furs fetched enormous sums. 2020 Feb;192(2):391-401. doi: 10.1007/s00442-019-04578-8. I believe the speakers did an amazing job at articulating climate change through an animal lens, and they highlighted multiple ways that climate change will impact the marine environment and how sea otters can help mitigate those changes. The survey itself showed that people learned something new that they had not known before. The content is provided for information purposes only. The result was less early-winter carrion for the parks many scavengers, such as grizzly bears and ravens, with dead elk bunching up at the end of relatively severe winters. To fuel this metabolism, sea otters need to consume about a quarter of their body weight in prey each day. The intent was to create a second population that could provide sea otters to replenish the mainland range in the event of a catastrophic oil spill. You can unsubscribe at any time and we'll never share your details to third parties. Skeletal muscle makes up 40 to 50 percent of most mammals body mass, so it affects the whole bodys metabolism. T. Wright (Image obtained under USFWS Marine MammalPermitNo. The presentations needed to be accessible, with no jargon and no assumptions that the audience has any background knowledge in what they are speaking about. Sea otters help ecosystems capture carbon from the atmosphere and store it as biomass and deep-sea detritus, preventing it from being converted back to carbon dioxide and contributing to climate change. Sea otters were hunted to the brink in the 19th Century fur trade, but their numbers have been slowly recovering since. Oecologia 146:623-631. When kelp dies, it tends to stay buoyant until those little floats break down. And a 2020 study found that the monetary benefit of sea otters due their restoration of kelp habitat and associated increase in fish stocks, carbon sequestration, and ecotourism value outweighs the losses to shellfish fisheries. Get weekly and/or daily updates delivered to your inbox. "But animals the world over, working in different ways to influence the carbon cycle, might actually have a large impact. who points to the many indirect effects warmer temperatures . As a nonprofit news organization, we cannot do it without you. The large hind feet are broad and flipperlike. We found no evidence that sea otter occupation time or any other factor tested affected rockfish or greenling density observed on underwater visual surveys. Unlike many other marine mammals, they lack blubber, so they keep themselves warm by eating a quarter of their body weight in food a day. They found that otters "undoubtedly have a strong influence" on the cycle of CO2 storage. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. Crabs eat animals that clean the estuary's sea grass of algae, which is caused by farm pollution. It could be that warmer conditions slow the larvaes metabolism, prompting the predators to eat less, Rudolf says. Although the indirect effects of sea otters are widely known, this example is unique because the food-web pathway transcended five species and several trophic levels in .

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