The Road to Recovery: Southern Resident Killer Whale (Nick Fiore)

Southern Resident Killer Whale (Orcinus Orca)

By, Nick Fiore

http://www.daserste.de/information/wissen-kultur/w-wie-wissen/sendung/orcas-102.html

Description

              The southern resident killer whales are part of the dolphin family Delphinidae.  They are the largest dolphins in the world and are surprisingly not actually whales.  The name “killer whale” is from early whalers who hunted these mammals.  Many people today prefer the name “orca”. The term “southern resident” refers to three pods (about 80 individuals) of orcas that move between the Queen Charlotte Islands in Canada to Central California.  Males grow up to 9 meters long and weigh up to 5,568 kg while females grow up to 7.7 meters long and weigh up to 3,810 kg.  This size difference between the sexes is known as dimorphism.  Killer whales are black and white in color with unique dorsal fins which are used to distinguish some individual whales from others.

http://whaleopedia.org/oceanic-dolphins/killer-whale/

Ecology

            Southern resident killer whales stay close to the western coast of North America.  The map below displays their territory in relation to the northern resident pods.  Orcas in general prefer near-shore environments, usually at higher latitudes, with high marine productivity.  Southern resident killer whales’ diets are made up of 97% salmon and 3% other fish.  This heavy preference and reliance on salmon is unique to northern pacific orcas and earned them the nickname of “fish-eating orcas”. 

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

Geographic and Population Changes

            While the geography of the southern resident killer whales has remained constant in the area discussed in the section above, the population has fluctuated.  The killer whale recovery plan displays the following graph.  Here you can see the changes in killer whale populations from 1960 to 2007.  This graph is important because it displays the dip in orca population from 1996 to 2001 was about 20 whales or 20% of the population.

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

Listing Date and Type of Listing

In the previous section I noted that killer whales dropped in population by 20% from 1996 to 2001.  Not-so-coincidentally, in 2001 a petition for listing under the Endangered Species Act for the southern resident killer whales was issued.  However, it wasn’t until November 18^th, 2005 when the Killer whale was officially placed upon the Endangered Species List. 

http://www.oocities.org/orcasforever3/OrcaFood.html

Cause of listing and Main threats to its existence

            The 20% drop in population is the cause of listing for this Killer whale.  There is no singular factor that caused this population drop but rather an accumulation of issues.  The recovery plan lists decreases in prey availability and increases in pollution, vessel effects and acoustic effects as potential reasons for the population drop.  Since the Southern Resident Killer whales rely almost exclusively on salmon diet, a drop in salmon population in the Pacific Northwest could be devastating.  Another threat to the Killer whale’s existence is its k-selected reproduction and low population numbers.  When the population size is so low, the survival of every member is important to keep a healthy population. 

http://www.kayakingtours.com/orca-tours/kayaking-killer-whales.htm

Recovery Plan

            The recovery plan for killer whales is to target threats to their existence and reduce the chances of those threats taking any toll on the orca populations.  By working with salmon restoration projects in the Pacific Northwest, salmon populations can remain adequate for the killer whales.  Environmental clean ups of contaminated sites will curb the potential hazards of pollution.  Increasing the need for regulations of vessel activity around orcas will reduce noise pollution and the disturbance and stress boats can put upon them if they follow them around.  Another step in the recovery program is education and outreach.  This section intends to increase public awareness to the endangered state of the killer whales.  

            The end goal for the Southern Resident Killer whales is to restore the population to the point that they don’t need ESA protection and they can be delisted.  This end goal will be reached “when the Southern Resident killer whales have sustained an average growth of 2.3% per year for 28 years”.  This process is estimated to cost nearly $50 million over the course of 28 years.  The road to recovery and stabilization for the Southern Resident killer whale is underway and hopefully leading towards a successful delisting of a unique and majestic animal.  

http://www.sheknows.com/pets-and-animals/articles/969897/shouka-the-killer-whale-10-years-without-another-orca

References

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

http://www.iucnredlist.org/details/15421/0