The Southern Sea Otter- Jennifer Marinov

The Southern Sea Otter

By: Jennifer Marinov

Summarize Description and Ecology of Organism:

The southern sea otter is in the Mustelidae family and is the smallest species of marine mammal in North America. Males weigh about 65 pounds, whereas females weigh around 45 pounds. On average, they are about 4 feet long. Insulation from the cold water is not from blubber like whales or from fat like seals, but rather from air trapped in their fur. In terms of food, sea otters consume numerous species of intervertebrates and even fishes. Studies have shown that sea otters give birth to one baby each year. And after 3 years they become sexually mature.

Evidence has shown that sea otters are a keystone species and have some important interactions with their environment. They will reduce prey populations including herbivorous intervertebrates. The otters will feed on sea urchins and other animals that graze on kelp, which allows for the kelp to maintain the habitat for other small plants and animals. The Southern Sea otter, specifically, ranges along the coast of California from San Mateo County southward through Monterey County and all the way down to Santa Barbara County.

Geographic and Population Changes:

Currently, the southern sea otter has 2,150 animals and ranges from between Half Moon Bay and Point Conception along the coast of central and Southern California. Across the whole range, the population declined at a rate of 5 percent per year between the years 1995 and 1999; although, these trends have not been so bad in recent years.

The moved colony in San Nicolas Island contains about 27 animals, including the babies. Even though more than 70 births have been reported at this newly populated island, the population remains small and the future is unknown. Oddly enough, the reasons for the death of many of these southern sea otters are not affecting sea otter populations in Washington, Canada, and Alaska. It is believed that the geographic ranges of the southern sea otter have increased since 1938. However, the number of the southern sea otters continued to expand through the mid 1990s, their range expansion slowed soon after.

 

Listing Date and Type of Listing:

The Southern Sea Otters were listed in 1977 after a massive oil spill. They are currently listed as threatened.

There is presently a delisting criterion of 3,090 individuals. Since there has not been an increase in populations recently, otters will most likely not be removed from the list anytime soon.

Cause of Listing and Main Threats to its Continued Existence:

     The otters were greatly reduced in the 18^th and 19^th centuries because of the fur trade. In 1911, the Fur Seal Treaty was put in place to stop the fur pelt trade.  But they were eventually listed in 1977 as threatened because of their small size and limited distribution. The remaining habitat was destroyed by a wide oil spill that took place in January of 1977. Furthermore, during the mid-1970s and early 1980s, there was a dip in the population because of entanglement in nets. Historically, oil spills from tankers have been considered the most serious potential threat. However, as of late, pollution and accidental catch from fisherman have become more dangerous. The sea otter’s population originally started out at around 16,000 animals and currently stays at about 2,150.

     The main threats to the otter’s existence are habitat degradation, specifically oil spills and other environmental pollutants, and human disruption, which include shooting, entanglement in nets/ fishing gear, and harassment. Oil spills are the most harmful because they occur often and at any point in time. It is unclear as to why there has been a recent decline in the otter population, but it is thought that infectious disease, commercial fishing, and resource depletion has greatly affected the animals. 

Description of Recovery Plan:

The recovery objective is to manage human activities that may harm the continued existence of the sea otters or that may damage/destroy their habitat that is critical to survival. The total cost of recovery is approximately 10 million dollars over the course of 20 years. If the population immediately reached an annual growth rate of 5 percent, it could reach the delisting requirements in 10 years. Unfortunately, that is not the case.

There are four main actions that are required to save the species. First, it is crucial that scientists monitor southern sea otter demographics and life history parameters to establish population size, rate of change, distributions, and changes in carrying capacities. Second, we must protect the population by managing petroleum exploration, and tankering to prevent the likelihood of an oil spill across the California coast. We must minimize the contaminant loading and infectious disease. As well as, manage fishery interactions to reduce sea otter deaths from commercial fishing. Next, scientists need to conduct research to understand the factors limiting the current growth rate and refine recovery goals from which management can be recognized and enforced. Lastly, it is important to evaluate why the translocation program at San Nicolas did not work out smoothly. Overall, the goal is to determine the reason for increased deaths, to fix that cause, and to allow the range and size of the population to increase.

What You Can Do:

The easiest way to contribute to conservation efforts is to donate money to advocacy groups. Next, it is important to limit the pollution that we dump in the sea. So be sure to clean up all trash after a day at the beach! Lastly, reducing the damage of nets from fishermen will help greatly increase otter populations. Spread the word about these adorable, furry animals, so that future generations can enjoy them as much as we do.

Other Resources:

There are a few other resources that can be helpful in learning more about these precious animals:

1.      Learn more about the research behind otters: https://www.wildlife.ca.gov/OSPR/Science/MWVCRC

2.      Supporting an advocacy group:

http://www.seaotters.org/

3.      Sea Otter Surveys:

https://www.usgs.gov/centers/werc/science/california-sea-otter-surveys-and-research?qt-science_center_objects=0#qt-science_center_objects

 

Works Cited:

Service, U.S. Fish and Wildlife. “Southern Sea Otter.” U.S. Fish and Wildlife Headquarters, U.S. Fish and Wildlife Service, 28 Aug. 2017, www.fws.gov/ventura/endangered/species/info/sso.html.

“Southern Sea Otter.” Southern Sea Otter, Kelp Forest, Marine Mammals, Enhydra Lutris Nereis at the Monterey Bay Aquarium, Monterey Bay Aquarium Foundation, 2017, www.montereybayaquarium.org/animal-guide/marine-mammals/southern-sea-otter.

“MWVCRC.” California Department of Fish and Wildlife, State of California, 19 Oct. 2017, www.wildlife.ca.gov/OSPR/Science/MWVCRC.

“Home || Friends of the Sea Otter || Sea Otter.” Friends of the Sea Otter, Friends of the Sea Otter, 19 Jan. 2016, www.seaotters.org/.

“CALIFORNIA SEA OTTER POPULATION ANNUAL SURVEY – Survey History and Methodology.” California Sea Otter Surveys and Research, US Department of the Interior, 2017, www.usgs.gov/centers/werc/science/california-sea-otter-surveys-and-research?qt-science_center_objects=0#qt-science_center_objects.

Pictures:

https://www.montereybayaquarium.org/-/m/images/animal-guide/marine-mammals/sea-otter-mom-pup.jpg?mh=916&mw=1222&usecustomfunctions=1&centercrop=1

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiOq8XRp7XXAhUKrFQKHdVRDW4QjRwIBw&url=https%3A%2F%2Fwww.montereybayaquarium.org%2Fanimal-guide%2Fmarine-mammals%2Fsouthern-sea-otter&psig=AOvVaw2PeQiQrfHQvWOUuWxcl9bO&ust=1510447920905000

http://www.seaotters.org/otterspot/World-Range.gif

https://voices.nationalgeographic.org/files/2014/06/sea-otter-mothers-s2048x1366-p.jpg

https://baynature.org/wp-content/uploads/2013/05/4611900487_5d6c8bb157_o.jpg

https://blog.nus.edu.sg/lucastange3246/files/2015/02/986-25web-Valdez-otters.standalone.prod_affiliate.91-2gd6jay.jpg

https://seaotters.com/wp-content/uploads/2013/05/640x360-no-otters-no-kelp1.jpg

https://futureoftheocean.files.wordpress.com/2015/08/otter_urchins_610.png