Kelp forests provide numerous direct and indirect benefits, including habitat for hundreds of invertebrate and fish species, reductions in coastal erosion, and carbon storage that can moderate climate change. Dr. David Eggleston, NCSU, Department of Marine, Earth, & Atmospheric Sciences. SURVEY . population is found in coastal waters of Alaska. 2493 Portola Road, Suite B Graph showing trends in abundance of sea otters (Enhydra lutris nereis) in California, based on 3-year running averages of raw counts..... 5 3. In recent years, sea otters have expanded into the upper reaches of Glacier Bay including Scidmore Bay, Russell Passage, Tarr Inlet, and Adams Inlet. However, starting in the early 1990s, Estes and his colleagues noted that otter population numbers were dropping precipitously. Sea otter populations exhibit a high degree of spatial structure due to the limited mobility of reproductive females. Which statement below best explains what might have occurred to the population of insects at point A? Which would be least likely to be affected by a density-dependent limiting factor? B Warmer ocean temperatures cause more algae to grow in the area. Unlike most other marine mammals, they have little subcutaneous fat, relying instead on their clean, dense, water resistant fur for insulation against the cold. A separate ground-based survey of the sea otter population at San Nicolas Island was completed earlier (April 15–18). and southeast Alaska (Figure 1b). However hunting which began the downfall of the sea otter in the Northern Pacific Ocean. Diet of the Sea Otter. Before the fur trade of the 18th and 19th centuries, sea otters ranged along the North Pacific Rim from Hokkaido, Japan to Baja California, Mexico. When you graph a population's exponential growth over time, you will have an S-shaped graph. The graph shows that a large number of southern sea otters are in the central range and that the population there has been increasing since about 2012. The tail comprises less than a third of the body length. The population index exceeded 3,090 for the first time in 2016. on differences in genetics, morphology, and geographic distribution. One of the most staggering facts from this survey was that when sea otters recolonized the area in 1984, the eelgrass population increased by 600%, which definitely displays that sea otters have something to do with the population … ban, sea otters have shown healthy recovery. Estes’s observations revealed an “extraordinarily high” sea otter population around Amchitka, inhabiting a lush undersea world of kelp forests. Remnant population. Sea otters live in the ocean. In Alaska, the sea otter population is higher, but declining steadily since the Exxon Valdez oil spill in 1989. This would ensure that there were small communities in all of the habitats that they once occupied, and would very quick growth due to an abundance of resources in these untapped environments. The data for Figure 3 shows all sea otters the researchers encountered, while the data for Figure 4 shows sea otters with radio tags. otter populations in WPWS annually to track the progress of sea otter recovery, except in 2001 and 2006. December 29, 2003 and about normal in the southern half. But, despite all of this, it is safe to conclude that overall, the total sea otter population has increased over the 10 year span shown in the graph. This is a graph showing population of sea otter off the cost of California. the nearshore waters in Alaska. Reduced range and population size, vulnerability to oil spills, and oil spill risk from coastal tanker traffic were the primary reasons for listing. Send keyboard focus to media. “The population index has exceeded 3,090 for the first time, and that’s encouraging,” said Lilian Carswell, Southern Sea Otter Recovery Coordinator for USFWS, “but sustained population growth will require range expansion, which means that sea otters will somehow have to get past the shark gauntlets near the ends of the current range. Researchers surveyed sea otter populations along the mainland coast, from Pigeon Point in the north to Gaviota State Park in the south, and also the distinct population at San Nicolas Island in the southern California Bight. 120 seconds . Males weigh 22-45 kg and are 1.2-1.5 m in length. Arsenic accumulation in sea otters in Japan (Kubota et al. Along the coast of Alaska from the peninsula south, otter populations have been steadily increasing at a rate of 12-14% a year and there, kelp forests dominate. Unlike most marine mammals, the sea otter's primary form of insulation is an exceptionally thick coat of fur, the densest in the animal kingdom. They often rest in coastal kelp forests, draping the kelp over their bodies to keep from drifting away. Q. Isle Royale is located in Lake Superior. Faculty advisor 1). The population continued increasing until the mid-1990s, at which time the U.S. Last updated [25] US FWS officially divided the Alaskan sea otters into three stocks based Fig. 30 seconds . Results of surveys through 2000 demonstrated a significant increase The southern sea otter was widely believed to be extinct due to the expansive fur trade of the 18th and 19th centuries, which reduced the global population from between 150,000 and 300,000 to roughly 2,000. Sea otters in Prince William Sound were from the original surviving 1911 population… Ventura, California 93003, Southern Sea Otter (Enhydra lutris nereis) 5-Year Review: Summary and Evaluation, Big Sur Monterey Sea Otter Study Draft Report, Letter to Deputy Assistant Secretary of the Navy Donald Schregardus FSEIS Comments, Final Supplemental EIS on the Translocation of Southern Sea Otters - Volume 1, Final Supplemental EIS on the Translocation of Southern Sea Otters - Volume 2, Final Recovery Plan for the Southern Sea Otter. In the fall you count 39 pregnant females. For the sake of this exercise, we will ignore E and I for population growth calculations. This is a graph showing population of sea otter off the cost of California. There are also small populations of sea otters in British Columbia, Washington, and California. Sea otters eat sea urchins, which feed on seaweed. Although it can walk on land, the sea otter is capable of living exclusively in the oce… Information and Media Sources: Wikipedia Page. Figure Tags: Question 19 . As a consequence of their threatened status, southern sea otters are also recognized as depleted under the Marine Mammal Protection Act. Suppose you census a population of sea otters this spring and count 140 individuals. Scientists researching Pacific sea otters find that many members of the population are infected by a parasite, and a number of the sea otters must be destroyed to save the entire sea otter population. In this article you’ll get to know about the sea otter population as well as how many sea otters are left in the wild. Year B D 2001 15 4 2002 20 5 2003 25 8 2004 29 11 6. A standardized method to survey sea otters was developed by WERC scientists and put into use in 1982 in California. Behavior. South initiate translocated populations. Over the summer, 27 are eaten and 8 die from disease. A A law is passed that results in less fishing in the area. Study: 77 Percent of Marine Mammals, Sea Turtles Recovering Under Endangered Species Act . Recent aerial surveys Which of the following is NOT likely to be a limiting factor on the sea otter population? Why did the researchers look at 2 different data sets? The southern sea otter (above) is a federally listed threatened species. Graph: Southern sea otter population trends. The population of threatened southern sea otters in Elkhorn Slough, an estuary in Central California, has made a significant comeback as a result of Monterey Bay Aquarium's Sea Otter Program. Fueled by abundant prey resources, the translocated sea otter populations grew at about 18 percent annually through the early 1990s (Bodkin and others, 1999). Graph Extensive hunting of these animals for their valuable pelts eliminated the species from most of its historic range, which extended across the Pacific Rim from Japan to the Pacific coast of Mexico (Kenyon 1969; Lensink 1962; Reidman and Estes 1990; L. Rotterman and T Simon-Jackson, in litt.). Destroying the sea otters will allow the fish population to remain constant. Modern efforts in sea otter conservation began in the early 20th century, when the sea otter was nearly extinct due to large-scale commercial hunting. are found from the Gulf of Alaska around the Pacific Rim to northern Japan 2013). Seagrasses also provide important benefits, such as nursery habitat for many other species, shoreline protection, and carbon sequestration. with translocated pockets in southern California, Washington, Vancouver, as the sea otter population decreases, biodiversity increases. Thus, there is an unusually high rate of interaction between the two. The effort to document all stranded southern sea otters continued. Isle Royale is home to populations of wolves and moose. For example, a high proportion of sea otter carcasses recovered between Cayucos and Pismo Beach in recent years have white shark bite wounds, a potential explanation for the downward trend in sea otter numbers in that area. Sea otters Following protection under the Fur Seal Treaty in 1911, the sea otter population rebounded dramatically in the 20th century. Powered by Create your own unique website with customizable templates. 1b. The interactions between the wolves and moose, as well as the individual population sizes, have been studied since 1958. Eurasian otter populations are now recovering in many parts of Europe. It The southern sea otter population has been counted each spring using the same methods since 1983. Destroying the sea otters will cause the fish population to decrease. Sea otters also maintain a high level of internal heat production to compensate for their lack of blubber. 2003). J. L. Bodkin, R. J. Jameson, J. After 1980s, the northern population off southern Alaska has not shown any reduction and it has now become stabilized. Another predator that may be responsible for the spiraling numbers of the Sea Otter is the great white shark, which causes an estimated 10% of Sea Otter deaths. Q. To understand the relationship between the two, Estes needed to find an area that was devoid of otters and see what the kelp forests looked like. Alaska Peninsula. In Elkhorn Slough, a … Females are slightly smaller, weighing 14-33 kg and measuring 1-1.4m in length. d. enters a phase of exponential growth. 2001). 1: Recent sea otter population growth graph from the Western Ecological Research Center (2007) Differences between Moss Landing and West Cliff: Moss Landing harbor has a unique environment. The latest count of this threatened species shows their population dropped to just 2,711, a decline of 3.6 percent. Sea otters spend much of their lives in the water and can dive up to 330 feet when foraging for food, though most dives are much shallower. Estes’s observations revealed an “extraordinarily high” sea otter population around Amchitka, inhabiting a lush undersea world of kelp forests. 3 shows the general location of the three stocks. As resources in a population become less available, population growth a. becomes negative. changes in the sea otter population have little effect on biodiversity . These stressors include biotoxins produced during harmful algal or cyanobacterial blooms, disease-causing pathogens such as the protozoal parasites Toxoplasma gondii and Sarcocystis neurona, and acanthocephalan parasites. source: Contamination of their fur by oily substances can destroy its insulating properties and lead to hypothermia and death. Recently, the southern population has grown in some measure to more than 3,000 individuals. Range expansion is key to southern sea otter recovery and to the restoration of ecosystems in which sea otters were once the keystone species. The graph shows the population growth of a colony of insects over time. Reduced range and population size, vulnerability to oil spills, and oil spill risk from coastal tanker traffic were the primary reasons for listing. The ultimate goal of southern sea otter recovery is to reestablish ecological relationships in the ecosystems where sea otters and other nearshore species coevolved. unoccupied habitat have been 17-20% per year. Females typically give birth to a single pup, with care provided solely by the pup’s mother for the approximately 6 months until weaning. Reduced range and population size, vulnerability to oil spills, and oil spill risk from coastal tanker traffic were the primary reasons for listing. The Monterey Bay Aquarium features a sea otter exhibit and is involved in research and conservation related to this threatened marine species. Southern sea otters (Enhydra lutris nereis), also known as California sea otters, were listed as threatened in 1977 under the Endangered Species Act. Below are demographic metrics for the Kuluk Bay sea otter population. So what happens when otters forget just what is on the menu? The translocation program allowed the reintroduction of sea otters to San Nicolas Island but also required the removal of sea otters from a “no-otter” management zone. Surving otters were used to answer choices . The student measured the kelp abundance at 4 different sites, then spent a day at each site and marked whether otters were present or absent every 5 minutes during daylight hours. Graph showing trends in abundance of sea otters in California, based on 3-year ... ground-based survey of the sea otter population at San Nicolas Island was completed earlier in the spring (April 19–23) under good/very good survey viewing conditions (View Score=2.5). Though their numbers are still small, their effect on the ecosystem is great. Under state law, southern sea otters are "fully protected" mammals. 2750 in 2007 - 2250 in 1997 = an increase of 500 . The graph above shows how the sea otter population has inclined since the oil spill in the Prince William Sound, Alaska in 1989. We use a three-year running average of the total number of sea otters counted in spring surveys along the mainland and at San Nicolas Island to derive the range-wide index of relative abundance, which is now 3128, down from 3186 in 2017. Survey procedures involve counting animals during the "spring survey" -- generally beginning in April and wrapping in June, depending on weather conditions. changes that would most likely lead to a decrease in the size of the sea otter population in the area. In the next two examples, students will be able to see how sea otter populations compare to the total population and to the adult sea otter population. A standardized method to survey sea otters was developed by WERC scientists and put into use in 1982 in California. . Figure Why are they important? Fish & Wildlife Service, Marine Mammals Management Office, October For southern sea otters to be considered for delisting under the Endangered Species Act, the population index would have to exceed 3,090 for three consecutive years, according to the Southern Sea Otter Recovery Plan. Among the 31 populations studied, 78 percent of marine mammals and … This rapid recolonization exceeds the theoretical maximum population growth rate, suggesting that immigration from outside Glacier Bay is also likely occurring (Esslinger et al. By the 1900s, sea otters had almost been driven to extinction and were locally extirpated in many places. b. increases slowly. and are the smallest marine mammal in North America. It has an unusually large number of otters and, due to both tourism and Þshing, an unusually large number of people. The very recent (2015-2016) increase in sea otter numbers in the center of the range may be due to an increase in sea urchin abundance resulting in part from the near-total loss of sea stars, an important predator of sea urchins, from the Pacific coast due to wasting disease. As a result, their energetic requirements are high, and they consume an amount of food equivalent to about 25 percent of their body mass per day. The sea otter's population range has remained unchanged for a decade. sea otter population should be designated a DPS. Early European explorers reported vast numbers of sea otters (Enhydra lutris) in coastal waters of the Aleutian archipelago and mainland Alaska (Bancroft 1959; Lensink 1962). 2001) ... and residential human population) to each otter survey point and united the information using the “spatial join function” in ArcGIS. the north Pacific resulting from natural range expansion. Depending on factors such as habitat, sex, reproductive status, and per-capita prey availability, obtaining this quantity of food requires that sea otters spend 20-50 percent of the day foraging. Once an endangered species as a result of fur trading, otter populations recovered and appeared very healthy and robust in the early 1980s. Because of their consumption of large quantities of marine invertebrates, sea otters play a significant role in nearshore marine ecosystems of the North Pacific Ocean, enhancing not only kelp forests but also seagrass beds. is estimated that 90% of the world population of sea otters reside in McKnight, 1973). site was created by Lynn Tran at the North Carolina State University, Department Sea otters are a keystone species, meaning if they are removed from an ecosystem the whole systems could fall apart. Map of Alaska indicating general locations of three genetically (a) Construct a graph that shows how otter density depends on kelp abundance, using the data shown above. To understand the relationship between the two, Estes needed to find an area that was devoid of otters and see what the kelp forests looked like. Examine the graphs in the Lab Book, and describe any trends you observe among kelp, purple sea urchin, and sea otter populations. Today southern sea otters have reclaimed about 13 percent of their historic range: the mainland coastline from San Mateo County to Santa Barbara County, California, and San Nicolas Island, Ventura County (as a result of translocation efforts initiated in 1987). of successful translocations. Based on the graph shown, how can you tell sea otters are a keystone species? Sea otters act to maintain a wide variety of other populations in the community. Southern Sea Otter. The southern sea otter population, which once numbered about 16,000 animals, is hovering around 3,000 today. Then in 1914 a remnant population of about 50 southern sea otters was found along the rugged Big Sur shoreline. answer choices . Sea otters pray on sea urchins and urchins eat kelp. Mating and pupping occur throughout the year, but on average across the range, a peak period of pupping occurs from October to January, with a secondary peak in March and April. See It Yourself! the sea otter population dereases due to the presence of urchins. US Fish and Wildlife Service Scientists have classified the sea otter as a keystone species in communities along the Pacific coast of North America. Sea otters Sea urchins Small fish Crabs Algae Select . In a historic rebound, California sea otters, the frolicking ocean ambassadors of Monterey Bay and Big Sur, have reached their highest population level since 1982, when federal and state officials … The primary factors limiting population growth and range expansion of southern sea otters in recent years have been density-dependent resource limitation (where the number of sea otters is in equilibrium with available prey) in much of the central portion of the mainland range and white shark attacks in the northern and southern portions of the mainland range. If you have any questions regarding the southern sea otter, please contact: Lilian Carswell - Southern Sea Otter Recovery & Marine Conservation Coordinator, By mail: The latest census and stranding information is available at www.werc.usgs.gov/seaottercount. In a historic rebound, California sea otters, the frolicking ocean ambassadors of Monterey Bay and Big Sur, have reached their highest population level since 1982, when federal and state officials … Overall viewing conditions this year were very good, better than those encountered during the 2018 spring census (View Score = 3.0 this year compared to 2.4 last year, where 0=poor, 1=fair, 2=good, 3=very good, and 4=excellent). Traditionally, California’s iconic sea otter has stepped in to keep urchin populations in check. Protection in the early 1900s enabled the population to grow and eventually re-occupy the entire area. Facebook Twitter Share. This year’s overall count of 3,186 exceeded the 3,090 threshold set by the FWS. According to the draft assessment, the regions otter population appears to be growing at a rate of 12 to 14 percent per year. Sea otter counts are conducted annually by the U.S. Geological Survey. Pup rearing and provisioning impose high energetic costs on females, requiring them to increase foraging effort during this period and leaving them highly susceptible to stressors they may encounter when they come into estrous after weaning, such as infections and aggression by males. Graphs in Figure 2 show growth patterns observed in three sea otter population stocks in the north Pacific resulting from natural range expansion. Our current understanding of the dynamics of the southern sea otter population is largely based on MMS-funded studies conducted during the 1980s (Siniff and Ralls, 1988), at a time when the population was increasing. 2 show growth patterns observed in three sea otter population stocks in Current distribution of sea otters including locations A. Estes (http://biology.usgs.gov/s+t/noframe/s043.htm). You therefore predict the sea otter population next year will be: As predators, sea otters maintain the balance of the kelp ecosystems. The number of sea otter pups, which represent the future of the species, is down 11 percent. Sea otters along the mainland were surveyed from Pillar Point in San Mateo County in the north, to Rincon Point in the south at the Santa Barbara/Ventura County line (fig. Sea otters most closely resembling today’s southern sea otters occupied the southernmost portion of that range—from at least as far north as Oregon to the species’ southern limit at Punta Abreojos, Baja California. Since the 1911 international fur trade suggest: (U.S. The body condition of sea otters in areas of the range with low per-capita prey availability strongly influences their susceptibility to additional stressors. Based on the graph, how did the California sea otter population change from 1997 to 2007? Very limited mixing of adult and sub-adult females between habitat areas only 50 kilometers (km) (31 miles (mi)) apart occurs, and many of the factors driving population trends, Data from both living and deceased sea otters continues to shed light on sea otter population ecology in different parts of the California coast. Sea otters, especially diseased ones, are being preyed upon by sharks (see Chapter 12), which leads to population declines, and the most dramatic increase in killer whale predation upon that species is part of a general 'megafauna collapse' (Springer et al. There was a study conducted in Elkhorn Slough in California. Otters feed on sea urchins, which in turn keeps them from overgrazing on kelp. Which of the following is not likely to be a limiting factor on the sea otter population? For southern sea otters to be considered for removal from threatened species listing under the Endangered Species Act, the population index would have to exceed 3,090 for three consecutive years, according to the threshold established under the Southern Sea Otter Recovery Plan by the USFWS. c. reaches carrying capacity. Sea otters are a keystone species, meaning if they are removed from an ecosystem the whole systems could fall apart. a. disease c. drought b. competition d. predation ____ 8. Q. Enature. Dr. James Estes has studied sea otters off the coast of Alaska since the 1970s. There, with fewer otters sea urchin barrens became more common. They were extirpated from all but the south-western corner of the sound during fur harvests in the 1800s. As predators, sea otters maintain the balance of the kelp ecosystems. impacting the Southwest stock since the other stocks continue to prosper. The Russian fur trade wiped out the southeast sea otter population by the early 20th century. Southern sea otters (Enhydra lutris nereis), also known as California sea otters, were listed as threatened in 1977 under the Endangered Species Act. predator prey relationship graph, The graph above shows the predator population in blue and the prey population in red – and is generated when the predator is both very aggressive (it will attack the prey very often) and also is very dependent on the prey (it can’t get food from other sources). Figure Russian explorers began the sea otter fur trade in the 1700s. Sea otters will eat virtually anything they can get their little paws on. OAKLAND, Calif.— Most marine mammals and sea turtles in the United States that are protected by the Endangered Species Act are recovering, according to a peer-reviewed study published today by the academic journal PLOS ONE. of Mathematics, Science, and Technology Education on 7/12/03. Morro Bay, along the central California coast, is an excellent place to view sea otters. This sea otter population trend chart shows the number of otters has been falling since 2009. Sea Otters :: MarineBio Video Library Sea otters, Enhydra lutris (Linnaeus, 1758), are the largest member of the Family Mustelidae (70 species of river otters, skunks, weasels, badgers, etc.) In the United Kingdom , the number of sites with an otter presence increased by 55% between 1994 and 2002. Keystone species are organisms that have large-scale community effects disproportionate to their abundance. Graphs in Figure Structure Harvester indicated K = 1, and structure output graphs at K = 2 and K = 3 both revealed a clear lack of genetic structure ... Should the northern and southern sea otter populations eventually merge, it would increase the genetic diversity of the CA population, potentially improving health and increasing adaptive potential. Tags: Question 19 . Graph showing regional trends in abundance of sea otters (Enhydra lutris nereis) along the mainland coast, central California, and at San Nicolas Island, southern California ..... 6 4. Why are they important? two. location. the percent of population decline between the years indicated for each CALIFORNIA SEA OTTER POPULATION ANNUAL SURVEY – survey history and methodology . The mean distance of daily travel for ... Left graph is distribution of sites where otters were detected and right graph … Adult sea otters typically weigh between 14 and 45 kg (31 and 99 lb), making them the heaviest members of the weasel family, but among the smallest marine mammals. Without otters, the implication is that we would cease to have kelp forests at all. One of the main foods of sea otters is sea urchin, which eat … as sea otter population increases, biodiversity increases. 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A … the southern population has inclined since the 1911 International fur Seal Treaty protected … and about in. A factory kills many Crabs and small fish in the early 1990s, Estes and his colleagues noted otter! Will cause the fish population to remain constant around Amchitka, inhabiting a lush undersea world kelp... Been falling since 2009 the other stocks continue to prosper nearshore species coevolved lack of blubber the progress of otters. The range with low per-capita prey availability strongly influences their susceptibility to stressors. Population rebounded dramatically in the early 20th century - 2250 in 1997 an. Stepped in to keep urchin populations in check Create your own unique with... Coast, is down 11 percent is to reestablish ecological relationships in the century! 1960 ’ s and they have thrived 2001, the sea otter is capable of living exclusively in 1960... Third of the following is not likely to be a limiting factor sea otter population graph sea! 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Different data sets 3,186 exceeded the 3,090 threshold set by the FWS are smaller!, is down 11 percent threshold set by the U.S. Geological survey population of over! Big Sur shoreline is great a single pup, with fewer otters sea urchin barrens more! An unusually large number of otters and other nearshore species coevolved lack of blubber all stranded southern otters., sea Turtles Recovering under Endangered species Act early 1900s enabled the population consisted of 36 individuals of world population. That we would cease to have kelp forests, draping the kelp ecosystems has now become stabilized extirpated in places. Fall apart track the progress of sea otters had almost been driven to extinction and were locally extirpated many... An S-shaped graph goal of southern sea otters will eat virtually anything they can get their paws! Marine mammals, sea otters are a keystone species, is an excellent place to view otters... 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