Southwest Alaska Northern Sea Otter - Rebekah Fesmire

The Southwest Alaska Northern Sea Otter 

http://www.defenders.org/sea-otter/basic-facts

Description and Ecology of Otters

 Sea otters are mammals in the order Carnivora. Adult males can weigh up to 99 pounds and reach a length of 58 inches, and females can weigh up to 79 pounds and a length of 55 inches. This size can vary from population to population, however, potentially due to food resources. Unlike other carnivores who have teeth designed to shred their prey, sea otters have teeth used to crush prey. They are also unique in that they use tools such as rocks or shells to open their hard-shelled prey. Sea otters need to eat 20-33% of their total body weight every day to reach the energy they need for day-to-day activities. Otters must dive to the ocean floor in order to acquire food, so usually they only live out to depths of 100m. Additionally, sea otters don't tend migrate great distances. They tend to stay in a fairly small home range. Male sea otters tend to live to a maximum age of 15, while females can live to an age of 22.

https://summitcountyvoice.com/2013/09/08/feds-finalize-recovery-plan-for-alaska-sea-otters/

Sea otters consist of three different subspecies. The E. Lutris Lutris, which are found from Asia to the Commander Islands, the E.l. nereis, which can be found in California, and the E.l. Kenyoni, which are found in Alaska. Even more specifically, there are three groups of sea otters in Alaska: southeast, south-central, and southwest. This blog post will be focusing on the Southwest Alaska Northern Sea Otter.

Geographic and Population Changes

The Northern Sea Otter's populations have been steadily declining over the past several decades. In an eight year period alone, between 1992, and when the Norther Otters were surveyed in 2000, 70% of the population had decreased. In some areas, populations are currently just 10% what they were in 1990. In addition to the Sea Otter population declining, they have also shifted their habitat. When before the Northern Sea Otters tended to live further off-shore, they have begun to shift closer to shallow water and near-shore areas. This can cause more difficulty in helping the otter population to recover. 

https://secure.defenders.org/site/SPageServer?pagename=wagc_seaotter&s_src=3WEW1800XXXXX&s_subsrc=111017_adopt_body_sea-otter/how-you-can-help

Listing Type and Date

The U.S. Fish and Wildlife Service conducted a aerial survey of otters in 2000, and found that populations had declined by an estimation of 70% since 1992. Therefore otters became a candidate to be put in the US. Endangered Species Act. On August 9th, 2005, the Fish and Wildlife Service officially listed Sea Otters as threatened, meaning a high likelihood of otters becoming endangered. 

Cause of Listing and Major Threats   

While most threats to the Northern Sea Otter are of fairly low importance, there are several that effect the otter populations in some way. Some of the top threats are biotoxins, infectious diseases, oil spills, and predation.

Biotoxins

Every year a toxic algae blooms in the Pacific Ocean. This contaminates Sea Otter's prey such as shellfish, poisoning otters when they eat. In 2013 this toxic bloom lasted much longer than normal, which is thought to be caused by warmer than usual ocean temperatures in addition to a lot of freshwater run-off. With a continual contaminated food source, many Sea Otters died as a result.

Why Hundreds of Sea Otters Died in the Pacific | National Geographic 

Infectious diseases

The increase of infectious diseases in Norther Sea Otters may be a result of deficiency to their immune system. This may come from poor nutrition or lack of genetic diversity. While it is difficult to perform controlled experiments to see if lack of genetic diversity truly is a cause of infectious disease, the idea is backed up by multiple models.

Oil Spills

http://blog.nus.edu.sg/lucastange3246/2015/01/30/history-the-1989-exxon-valdez-oil-spill-part-1/

When an oil spill occurs, it can have both immediate and long-term effects. These spills can negatively effect otters in a number of ways. First, otters depend on their fur for insulation. When oil gets on their fur, however, they lose the water-repellent nature of their fur. Secondly, otters will ingest oil that has gotten on their fur when they groom themselves. Finally, oil tends to collect in kelp beds, which is a common resting place for otters.

The Exxon Valdez oil spill in 1989 resulted in the deaths of over 1,000 otters. After an oil tanker crashed 42 million liters of oil was spilled into the ocean majorly effecting otters along with other animals. Oil spills can effect wildlife several hundred miles away from the site at which it occurred. 

http://blog.nus.edu.sg/lucastange3246/2015/01/30/history-the-1989-exxon-valdez-oil-spill-part-1/

Predation

Predation is the biggest current threat to the Norther Sea Otter. While there are several animals that prey on otters, such as bald eagles, white sharks, and terrestrial carnivores, the biggest threat is the killer whale.

Recovery Plan Description

The goal of recovering the Northern Sea Otter Population is to control, reduce, and remove the treats this species faces so they no longer need protection. The recovery plan outlines the objectives to be to reach a self-sustaining population of Sea Otters, for otters to play a functional role in the ecosystem close to shore, and to reduce threats to otters so their populations can continue to carry on.

Northern Sea Otters have a number of criteria in order to be taken off the threatened species list. First, the demographic criteria is to have a low chance of becoming endangered in the near future. Next, threats-based criteria requires that threats to the population level be alleviated.

Some of the top prioritized recovery actions include monitoring Norther Sea Otter population, identify the important habitat needs and protections,  manage how human uses of otter's ecosystems impact the otters, and look into how disease could be a threat to the population recovery of otters.

What Can You Do?

Adopt a Sea Otter! Through the organization Defenders of Wildlife, you can give a symbolic adoption of a sea otter. With different adoption level kits ranging from $20-$50, all proceeds go towards educating people on the importance of protecting sea otters, as well as protecting otters and their habitats.

https://secure.defenders.org/site/SPageServer?pagename=wagc_seaotter&s_src=3WEW1800XXXXX&s_subsrc=111017_adopt_body_sea-otter/how-you-can-help

Other Resources

Visit these websites for more information. 

http://www.adfg.alaska.gov/index.cfm?adfg=seaotter.main
https://www.nationalgeographic.com/magazine/2016/09/warm-water-pacific-coast-algae-nino/
https://ecos.fws.gov/ecp0/profile/speciesProfile?sId=2884

Works Cited

dfg.webmaster@alaska.gov. “Northern Sea Otter (Enhydra Lutris Kenyoni) Species Profile.”Northern Sea Otter Species Profile, Alaska Department of Fish and Game, www.adfg.alaska.gov/index.cfm?adfg=seaotter.main.

Marine Mammals Management Office U.S. Fish and Wildlife Service. Southwest Alaska      Distinct Population Segment of the Northern Sea Otter Recovery Plan, Region 7 U.S. Fish and Wildlife Service Anchorage, Alaska, 2013.