california
Well-Known Member
The inevitable extinction of this group is due to 3 things.
a. The captures took mostly large males out of the population and limited the genetic diversity of the group. The balance of male to females of breeding age is grossly out of whack and has led to a significant imbalance.
b. Lack of Chinook and change in size. The southern residents prefer chinook, but they also eat chum and probably sockeye. The inconsistent returns and the gradual decrease in size of chinook ,due to over fishing and poor management in California , Oregon, Washington state , Alaska and BC.
c. Pollution, The main culprit is PBDE's a fire retardant found mostly in children's clothing. When you wash juniors clothes the fire retardant attaches itself to molecules of water and is flushed out into the strait where it enters the food chain , shrimp-salmon-whales. When a new born killer whale is breast feeding the milk is produced by the mothers fat where the PBDE's hide. If the mother is malnourished she feeds her calf a toxic milk soup and the calf invariably dies. The survival rate of newborns in this group is less than 50%.
While the removals by Bob Wright no doubt were detrimental, the population did recover after captures were stopped and peaked at 100 in the mid 1990s and have dropped since then, so it seems they were able to breed successfully post capture era. points "b" and "c" may be more the issue, and yes unfortunately extinction may be inevitable even if point "b" were to now improve.