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Future survival of southern resident killer whales

By November 14, 2016 No Comments

southern-resident-killer-whale_noaaWith the southern resident killer whale population consisting of around 80 animals, the death of each female is a lost opportunity to help increase their number. Colleague Ken Balcomb, senior scientist for the Centre for Whale Research said the recently deceased orca, known as J28, follows a trend of females dying either late in pregnancy or not long after giving birth. In October last year, J28 gave birth to a male calf  and approximately 4 months later, researchers noticed she was suffering weight loss – 10 months later she was dead.  Although her body was never recovered, Balcomb  suspects an inadequate food supply and toxins are to blame.  In recent years chinook salmon and other fish stocks have been very poor, forcing the orcas to metabolize their blubber which releases stored toxins into their bloodstream and organs, suppressing their immune system and making them more susceptible to diseases. Hunger is particularly problematic for pregnant orcas that need extra food to carry their babies to full term.  Just this summer another female orca died and more than 50% of pregnancies end in miscarriage.  Not all southern resident killer whales are showing signs of starving however and some appear to be in generally good condition – but for how long?  This population is comprised of three individual pods known as J, K, and L with several matrilines within each pod – the world’s oldest known killer whale is Granny or J2.

Photo Credit: NOAA
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