Estes had seen what is now known as an urchin barren, the result of a trophic cascade. Burt and her colleagues also carry a panoply of marine science tools: a foldable, two-dimensional box for sampling called a quadrat; sealable bags for collecting everything from kelp to invertebrates; a writing slate with data sheets, pencil and built-in ruler; and meter tapes for measuring survey areas, known as transects. Now, a ne… Dr. Estes found that the presence of sea otters had a dramatic effect on coastal habitats (see case study below). Fur traders in the 18th and 19th centuries hunted the animals to the brink of extinction, allowing sea urchin numbers to skyrocket, Dr. Rasher said. However, these smaller urchins are a favourite food of sunflower stars. One of the results of Dr. Estes’ research was to designate sea otters as a “keystone species”. Sea Otters Are Walled in by Hungry Sharks Outside the safety of the kelp forest, California sea otters are being picked off by sharks. Sea urchins are like vacuum cleaners of the ocean floor. Image courtesy Grant Callegari/Hakai Institute. The sea otter’s diet includes about 40 marine species, including urchins, crabs, clams, abalones, mussels, and snails. In the 1970s, a scientist named Dr. James Estes recognized that he could study the influence of sea otters on other species in their environment by comparing the coastal habitats in Alaska’s Aleutian Islands where sea otters had recovered to similar places where sea otters were absent. Seals are frequent visitors to kelp forests, and grey whales will feed on the crab larvae they find there — as well as use the kelp to hide their calves from killer whales. Juvenile salmon, herring and rockfish all use kelp beds for habitat, as do crabs, sea stars, abalone and other snails. Sea urchins are voracious grazers of kelp. Researchers from British Columbia to California have seen large swaths of kelp forest disappear off the coastline in recent years, a troubling development that appears connected both to rising ocean temperatures and SSWD. The abundance of food now known to be generated by kelp forests has influenced the rise of the kelp highway hypothesis: the idea that the first ice-age human populations to expand southward from Beringia did so by exploiting the rich marine resources of ice-free coastal regions, rather than migrating via an inland corridor between ice sheets. Sea otters eat about 25% of their weight every day, and is arguably the number one cause in sea otter deaths, when they cannot forage enough food to feed themselves. “By the time you clip all the gear onto yourself so that you have everything and it doesn’t float away,” Burt says with a laugh, “it can look like a real gong show.”. They can be as small as a human blood cell or reach lengths of over 45 metres. The waters around the Hakai Institute on Calvert Island are at the leading edge of this expansion, and like the Aleutian Islands, are well suited to this sort of study. There are areas with and without sea otters where researchers can compare the differences in kelp abundance, urchin populations and other aspects of undersea habitat. The organisms sea otters had evolved alongside suddenly lost the main predator that kept them in check. Sea otters dive to rocky reefs, where they collect invertebrates and also a large rock. The Sea Otters eat Sea Urchins, which harm the kelp. What Burt noticed on underwater surveys after the disease event was that there were more small and medium-size urchins everywhere Burt and her colleagues looked. He will tuck himself beneath the prickly protection of the purple sea urchin, finding a safe haven in a dangerous ocean. Using a dataset collected over four years, Burt and her colleagues learned that sea otters are not the only predators that have a significant effect on urchins, and thus not the only creature that can help ensure the health and abundance of kelp forests: the less cute but nonetheless impressive sunflower star also plays a major role. Enduring the challenges of underwater experimentation and monitoring, however, can lead to groundbreaking insights. The relationships between predators and prey vary among communities. Kelp produce their own food through photosynthesis, absorbing sunlight and organic carbon from the environment. By wiping out huge numbers of sea stars, including those in nearshore kelp-producing zones, SSWD had created a new set of research conditions. Even the smallest donation may fund a “Respect the Nap” sticker for a child or a pair of binoculars for one of our community science researchers. Burt has years of experience exploring the ocean floor off British Columbia’s Central Coast, but scuba diving still fills her with wonder. Part of a recovering North Pacific population and expanding across the Central Coast over the past three decades, sea otters are a keystone species that indirectly influence the abundance of kelp forest habitat. They leave behind desolate areas called urchin barrens. “When you remove an organism from the system, it’s then you realize that its impact was actually quite substantial.”. And the Kelp provides an anchor for the Sea Otter when they sleep. “Sunflower stars mop up the little sea urchins,” says Anne Salomon. This type of relationship between a predator (sea otter), herbivore (urchin), and plant (kelp) is known as a trophic cascade. Enhydra lutris has a very close relationship with kelp. Sea otters do an excellent job of eating large sea urchins over eight centimetres in diameter, but they tend to leave behind smaller urchins. In 1970, an ecologist named James A. Estes traveled to Amchitka Island in Alaska’s Aleutian archipelago to study sea otters. Perhaps the biggest challenge is that the waters of the Central Coast are rarely still. “Sea star wasting disease came and did the experiment for us, and research on the Central Coast with Jenn Burt provided evidence of the important role that sunflower stars have,” says Salomon. The Atomic Energy Commission had sponsored his research there ahead of a contentious nuclear test on the island. Sea otters were hunted to near extinction during the maritime fur trade of the 1700 and 1800s. The Sea Otters have a Symbiotic Relationship with Kelp. When they did, says Burt, the insights came not only from her, but from “looking at the system with some clever modellers, from having coffees with Jim Estes and from talking with people who had seen similar things in other areas with green urchins.”. This was my 'aha moment,' a profound realization that would set a path for the remainder of my life.". Because the otter food source is easier to excavate from rocky-bottom habitats, as opposed to soft-bottom habitats, more otters tend to live in waters with rocky bottoms with access to shallow-burrowing prey. The disease outbreak created what is known to researchers as a natural experiment — a unique condition that appears without artificial or planned intervention. Urchins eat kelp, and sea otters eat sea urchins. In places where sea otters have disappeared, sea urchins will eat the kelp forest until it’s gone. For Hakai Institute scientists, undersea surveys bring other challenges. They are sensitive to temperature, ripped up by storms and affected by currents and waves. Watch this great short film to understand more about keystone species: While scuba diving in the Aleutian Islands, Dr. Estes noticed places where the seafloor was covered with sea urchins and no kelp remained. Kelp is a type of marine algae. Sea otters, by eating sea urchins, help kelp to flourish. That’s the bigger narrative around this research that I think is really neat.”. Sea otter resting on the ocean surface, grasping a purple sea urchin it has just pulled up off the ocean floor. The sea otter also has an ongoing relationship with brown algae (aka kelp) which is mutualistic (Costa, 2011). Sea urchins are related to starfish and look like small, purple hedgehogs. The growing sea otter population in B.C. One of them is cute and fuzzy — the other one, less so. herbivores. Since sea otters feed on sea urchins, they help to keep the sea urchin populations in balance and in return help to maintain a healthy kelp forest ecosystem. Interspecific Interactions (Predators and relationships): The purple sea urchin is the prey to many other species, such as: - Sea Otters (Left) - Sunflower Starfish (Below) - Horn Sharks (Below) Although they have spines for protection, animals such as the sea otter can break them open and feed on the insides of the urchin. Sea otters are known to carry rocks when they dive, to increase their weight when diving, as well as to … These furry creatures are closely intertwined with the life cycle and recovery of kelp forests from urchin predation. “This is the important element of surprise in science,” says Burt. Sea urchins are voracious grazers of kelp. The stipes and fronds of a kelp forest create a three-dimensional lattice that benefits everything from invertebrates like snails and anemones to marine mammals like seals and whales — providing food, hiding places and shelter. Symbiotic Relationships Natural Selection Works Cited QuIz. They feed primarily on algae but also eat slow-moving or sessile animals. Also known as seaweed, there are red, green and brown varieties of marine algae, among others. Researchers have also discovered that kelp forests in the northeast Pacific can be dramatically impacted by the presence of two predators. “Planet Earth,” says marine ecologist Jenn Burt, “is actually Planet Ocean.”. But Estes didn’t understand the real meaning of what he’d seen until a meeting with veteran … The complexity of trophic cascades can vary extensively from place to place, but this basic pattern is the foundation for understanding how sea otters fit into a healthy coastal environment. But Estes didn’t understand the real meaning of what he’d seen until a meeting with veteran ecologist Bob Paine. What is the Apex Predator? When SSWD struck the region during the winter of 2015, it suddenly brought a new dimension to the research: a rare opportunity to also look at how predatory sea stars influence coastal rocky reef ecosystems.  What would happen to the ecosystem if the Octopus go extinct? Salomon notes that although many ecologists had suspected that sunflower stars played a role in the resilience of kelp forests, that role had not yet been measured or acknowledged. Fortunately, sea otters have an appetite for sea urchins and they help to keep sea urchins in check, allowing the kelp to flourish and capture CO 2. Their beautiful fur is a main target for many hunters. Upon returning to the surface, they float on their backs, with the rock on the stomachs. Burt’s graduate studies undertaken with the Hakai Institute in British Columbia were focused on the ecological and social impacts of sea otter recovery — including the effects that growing sea otter populations have on coastal Indigenous communities. Islands with sea otters had healthy kelp forests while otter-less islands had barren sea floors littered with sea urchins but no kelp. * Sea Otter Seaweed Kelp Octopus. 's coastal ecology, glaciology and archaeology done in partnership with the Hakai Institute. COVID-19 has been the source of both obstacles and innovations to our plans and strategies for outreach and research, but it is due to the shock of the pandemic on our grants and funding sources that Sea Otter Savvy is facing our most serious threat to survival. Traditionally, California’s iconic sea otter has stepped in to keep urchin populations in check. The sea otters help the kelp by eating the sea urchins because if there is too big of a population of sea urchins the kelp is endangered. In this relationship, the sea otter eats sea urchins, as discussed above. Copyright © 2021 Sea Otter Savvy. Observing sea otters and kelp beds on Amchitka — both onshore and during scuba dives — led Estes to question the links between them. Sloan Wangel APES Woods Case Study TB p.101-102 Sea Otters Sea otters are well known as a keystone species because of their ability to transform sea urchin-dominated communities into kelp-dominated communities by preying on sea urchins and thus reducing the intensity of herbivory. As he tells in Serendipity, what he saw when he put on his scuba gear and entered the waters off Shemya shocked him: "When I looked down at the seafloor, I was stunned by the vast numbers of urchins and the absence of kelp… Every place I looked was the same—large and abundant sea urchins over a seafloor of crustose coralline algae with little or no kelp… In the absence of sea otter predation, sea urchins had increased in size and number, and the larger and more abundant urchins had eaten the kelp. Sea otters, in turn, are equally voracious predators of sea urchins. 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