You "Otter" Help the Southwest Alaska Distinct Population Segment of the Norther Sea Otter

Lane Province

BIO 227

Description & Ecology
The Northern Sea Otter or Alaskan Sea Otter (Enhydra lutris kenyoni) is the one of three sea otter subspecies that inhabits the “Ring of Fire” coasts. Sea otters are known for being the largest member of the weasel family and the only ones that live almost entirely in the water. On average the Northern Sea Otter’s age will range from 10 to 12 years, but has been known to live up to 25 years of age. While sea otters are known as the smallest marine mammal, they average 4 ½ feet long and 65lbs in their adulthood. Sea otters are social animals that spend their leisure time floating in groups, called rafts, which range from 10 to more than 100 in size. These rafts are usually separated into two groups: females and pups, and males. The color of Northern Sea Otters range from brown to almost black, with guard hairs that can be silver, to light brown, to black. However, as they age their fur around their hands and necks will lighten to almost white. Sea otters in general have long flat tails, webbed hind feet, and retractable front claws. The Northern Sea Otter’s diet mostly consists of benthic invertebrates: clams, mussels, urchins, crabs, fish, etc. They mostly hunt during the mornings and afternoons, and must dive to capture their prey underwater, at depths that reach up to 250 feet below sea level. Predators of these sea mammals consists of humans, sharks, bears, eagles (mostly on young sea otters), and killer whales.

Geographic and Population Changes
The Southwest Alaska Distinct Population Segment (DPS) of the Northern Sea Otter resides on the southern peninsula and archipelago of Alaska from the Cook Inlet in the east, through the Aleutian Islands in the west. This region is highlighted in red in the figure below. Prior to their population decline in the 1980’s, the Northern Sea Otter in the Southwest Alaska DPS were estimated to be between 94,050 and 128,650 in 1976. This number has significantly declined to an estimate of 53,674 otters in the Southwest Alaska DPS based on surveys conducted in 2000-2008. Unfortunately, it is also estimated that this population is inflated, and was indeed lower during the development of the recovery plan in 2008-2010.

Listing Date & Type
The Southwest Alaska DPS of the Northern Sea Otter was listed as a threatened species under the Endangered Species Act (ESA) in 2005.

Cause of Listing & Main Threats
There are many threats to the Southwest Alaska DPS of the Northern Sea Otter, but the main threat, labeled with the highest importance, is predation. More specifically the predation by killer whales. Other threats, of low to moderate importance, include: oil spills (the potential and past spills), infectious diseases (mainly valvular endocarditis), hunting for the harvest of meat, and illegal take (from local human populations). The combination of these factors and others that ranked as low importance have all contributed to the steep decline in Northern Sea Otter populations in the Northwest Alaska DPS, thus leading to their listing under the ESA.

Description of Recovery Plan 
The recovery plan for the Southwest Alaska DPS of the Northern Sea Otter has three main objectives:

1. Achieve and maintain a self-sustaining population of sea otters in each MU. 
2. Maintain enough sea otters to ensure that they are playing a functional role in their nearshore ecosystem.
3. Mitigate threats sufficiently to ensure persistence of sea otters. 

The obvious goal of the recovery plan is the delisting of this DPS within the “foreseeable future” (25 years as defined by the PVA model). To be considered delisted as threatened, the DPS must meet all of the delisting criteria in three of the five Management areas of MUs. The chart below demonstrates how each MU must do to meet the delisting in demographics, ecosystem-based, and threats-based criteria

Personal Action
There are several ways how you can support the preservation of the Southwest Alaska DPS of the Northern Sea Otter. Below is a list of organizations that you can join or donate to learn more about this DPSs threatened population, and get involved.

• Friends of the Sea Otter
• The Alaska Sea Otter and Stellar Sea Lion Commission

SOURCES:

• http://ecos.fws.gov/docs/recovery_plan/Recovery%20Plan%20SW%20AK%20DPS%20Sea%20Otter%20Aug13.pdf
• http://www.seaotter-sealion.org/seaotter/factsseaotter.html
• https://alaskafisheries.noaa.gov/protectedresources/seaotters.htm
• http://www.seaotters.org/alaska-program/