Killer Whales: The World's Largest Dolphin

By: Laura Meert

 Southern Residents Killer Whales (Orcinus orca)

Dates:

2005 Endangered Listing

2006 Critical Habitat

2008 Recovery Plan

Description: 

Killer whales are the world's largest dolphin belonging to the Delphinidae family. They are easily identified by their black and white markings. Male killer whales can reach 32 feet long and weigh up to 22,000 pounds. Female killer whales are slightly smaller and are easily distinguishable from males based on their markings. Killer whales are one of the most geographically disbursed mammals on earth and are found in all seven oceans. Southern Residents killer whales population consists of three pods labeled J, K and L pods. While killer whales are found in all of the oceans around the world this population resides in the coastal waterways of Washington, Oregon, and California. There are three critical elements that are essential to the conservation of this population:

1. water quality to support growth and development

2. prey species of sufficient quantity, quality and availability 

3.  passage conditions to allow for migration, resting, and foraging

Population:

There is little information of the population trends of Southern Residence killer whales before the 1970s. However it is estimated that the population was greater than 200 whales in the 1800s. 

1975: 71

1985: 77

1995: 98

2005: 88

2012: 85

  

Threats to population:

Researchers have been unable to identify the biggest threat to killer whale extinction so it remains a combination of the following factors:

1. Environmental degradation
2. Changes in food availability due to overfishing and habitat degradation
3. Increased exposure to pollutants (oil spills)
4. Human disturbance including noise disturbance, boat collisions, and some whale watching activities

Recovery Plan:

The recovery plan for Southern Residence killer whales addresses all of the threats listed above. The ultimate goal of the recovery plan is to increase the population by 2.3% annually for 28 years. The  key elements in the plan include:

1. Increased Prey availability (salmon habitat restoration and hatcheries) 

2. Pollution/ contamination (cleanup of existing contaminated sites and monitor of future                       contamination levels that are harmful to whales), 

3. Vessel Effects (minimize the harmful effects of vessels with necessary regulations) 

4. Prevent oil spills and prepare for improved response if one were to occur.

5. Minimize potential impacts from acoustic effects 

References:

NNOA Fishers (2015). Killer Whale (Orcinus orca). Retrieved: http://www.nmfs.noaa.gov/pr/species/mammals/whales/killer-whale.html

US Fish and Wildlife Service (n.d.). Killer Whale (Orcinus orca). Retrieved: http://ecos.fws.gov/speciesProfile/profile/speciesProfile?spcode=A0IL

http://ecos.fws.gov/docs/recovery_plan/whale_killer.pdf