Southern Resident Killer Whales

Ryan Milligan

Bio 227

Lisa Needles

Southern Resident Killer Whales

Killer whales are apart of the dolphin family, where they are the largest species in size and sit atop the food chain. For males, length can reach up to 30 feet long and weigh up to 12, 250 pounds, whereas females can reach a maximum length of 25 feet and weight up to 8,400 pounds.  The killer whale possesses a dual- coat color of black and white, that varies only in small features between male and female.  Males and females have numerous slight differentiations in pattern color that are distinguishable only above the eyes, on the belly, or behind the dorsal fin.  Each whale also contains their own uniquely shaped and scarred dorsal fin.  The southern killer resident whale is found mostly in the greater upper pacific region, around the the Puget sound area in Washington state and up as well in British Columbia.  These orcas generally stay in coastal waters of higher latitudes; the farthest south it has been documented that a southern resident killer whale has traveled is the central coast of California.  Southern residents are classified as living in three pods, the second hierarchical stage of the killer whale family.  Pods stem from the first and most closely connected group of whales, maternity; which make pods a bigger extension of family- all related whales.  Killer whales are a K-selected group with a maximum age of 80-90 years old for females, and 60-70 for males.  Pregnancy is a 17- month process, and 37-50% of newborn whales cannot survive past the first six months.  The diet of a southern resident killer whale consists of fish only.  Salmon is the overwhelming favorite, as 97% of all food consumed by a killer whale is apart of of the salmon family.  With this, 77% of all salmon consumption is particularly the chinook salmon- and the other three percent of all food intake consists of many different types of fish. Each day, a resident killer whale consumes anywhere from 3.6-4% of its body weight, and it does so through sound techniques.  Three different sounds are produced by killer whales are used in different scenarios.  Echolocation clicks are used for navigation and for hunting, tonal whistles are far longer range communications, and pulsed calls are used when traveling to keep contact with those out of physical range.  The sounds are a universal way of communication for all killer whales.   

After an ongoing disagreement whether southern resident killer were its own species, it was finally concluded on and added to the Endangered Species Act in November of 2005.  Factors that prompted the 80 or fewer whales onto the ESA include an issue of food as the forefront.  Both reduced quality and quantity of prey for Southern Residents stimulated a food dilemma.  Additionally, chemicals in the water were intolerably high and only growing larger.  Organochlorine originated as the primary contaminant source, and fire retardant succeeded as another potential chemical risk that endangered whales immune and reproductive systems.  While chemicals are a dangerous threat, the same goes for oil; as the Puget sound area holds five oil refineries. These have had four major oil spills in the last 34 years, each giving off high levels of petroleum into the habitat. Lastly, increased boat and vessel traffic hurt southern residents in their sound techniques and water movement.  Vessels put the killer whales in a constant state of movement and produce a number of collisions while whale watching- proving harmful for the species.  The high volume of the vessels put the whales out of their sound element- their key to many functions underwater.

Recovery action is to take the conflicts Southern Resident killer whales face and manage them.  The first action is rebuilding a stable population of salmon for an adequate food source. This is done through salmon restoration efforts in the local area and habitat and hatchery management.  Action plans to reduce pollution and contaminants in the waters of southern residents begin with first cleaning up polluted sites, then minimizing any further perpetuations into the habitat.  Further action is taken to “protect Southern Resident killer whales from additional threats that may cause disturbance,” according to the recovery action plan. In this contains the actions to decrease disturbance of Southern Residents with vessels, and diminish the risk of oil spills.  These are carried out through monitoring vessel activities around the whales, and to first prevent oil spills all together, but to have a response team in the event of an oil leakage that will protect the killer whales. 

Today, the number of Southern Resident killer whales is at 81 whales, right around where it began in 2005.  With this, it is unclear whether the recovery acts have been successful or not.  To help, individuals can become involved by participating in programs to become educated on Southern Residents.  These programs engage people with the behaviors, threats, and conservation measures of the killer whale.  Upon completion of the course, individuals are to take a pledge promising to partake in helping conserve the Southern Resident killer whales.  These whales are correctly placed under the ESA, but with the correct assistance, will hopefully recover to its own way of living one day soon. 

Works Cited

"Document." Family Planning Perspectives 22.1 (1990): 36-39. Web.

"Center for Whale Research - Study of Southern Resident Killer Whales." Center for Whale Research - Study of Southern Resident Killer Whales. N.p., n.d. Web. 23 Nov. 2015.

"Southern Resident Killer Whale Recovery." Endangered Species Program. N.p., n.d. Web. 23 Nov. 2015.