Monday, October 30, 2017

COTW: The End of Chinook Salmon?

US Person posted previously about the "king of salmon", the chinook, and their alarming decline in numbers. {28.08.17} Federal scientists have been sampling the waters off Oregon and Washington for twenty years to get an accurate idea of the changes in the size of runs up the Columbia River. This years count was the lowest ever with some nets coming up completely empty. Bad news not only for anglers but other species like orca that feed on salmon. Instead of juvenile salmon the researchers came up with jack mackerel and Pacific pompano, not usually found off the coasts of Oregon and Washington; Pampano is usually associated with tropical seas. Mackerel feed on young salmon. Look at this chart, if you can:

These indications according to the surveyors may mark a fundamental ecosystem shift that is not beneficial to salmon, a cold water species. The "Blob" is gone {16.08.17}, but warm water species that came with it have remained. Other changes in the North Pacific ecosystem also do not bode well for salmon and their predators. Fatty zooplankton and copepods, which young salmon need to survive, are less abundant.  Chlorophyll, the first link in the marine food chain, is also at its lowest recorded level in twenty years. Marine birds who normally feed on other small fish may be turning to juvenile salmon as a replacement because forage fish like herring, anchovies and smelt, are severely depleted.

All of this is very bad news for resident orcas, who have an ingrained culture of eating just salmon and nothing else. They seem unable to switch to other sources of protein in the ocean like seals that are the prey of transient orcas.  Resident orcas would rather starve to death than change their diet.  A resident 2½ year-old calf, J-52, was observed to die of starvation off the coast of Port Renfew, BC on September 19th.