Discussion in 'General Open Forum' started by agentaqua, Aug 28, 2017.
Welcome to the Salish Sea hydrophone network
Evaluating anthropogenic threats to endangered killer whales to inform effective recovery plans
Robert C. Lacy, Rob Williams, Erin Ashe, Kenneth C. Balcomb III, Lauren J. N. Brent, Christopher W. Clark, Darren P. Croft, Deborah A. Giles, Misty MacDuffee & Paul C. Paquet
Port of Vancouver’s ECHO Program dedicated to protecting marine life
ECHO Program works with scientists, environmental groups, First Nations individuals and industry to protect marine life.
Published on: November 20, 2017
Study finds U.S. regulations to protect killer whales near B.C. coast effective
Linda Givetash / The Canadian PressJanuary 1, 2018
Andrew Trites, a professor at UBC’s Institute for the Oceans and Fisheries, noted it’s quite possible that southern residents never had a large population, raising the question as to what the goal of a recovery program should ultimately be given the challenges the whales face in a heavily populated area.
Through our annual monitoring of the population, we have been able to track the changes in population size, which has fluctuated considerably over the last four decades (Krahn et al. 2002; Olesiuk et al. 2005; Balcomb et al. 1982.). From a starting point of just 68 identified individuals in 1976 following the live captures (Balcomb et al. 1982.), the population showed signs of recovery and grew to a peak size of 98 individuals by 1995. The population then went into a steep decline with only 78 individuals remaining in the population by July 2000. This decline was followed by a further period of moderate growth to 89 individuals in the population in July 2006. Since then the population has declined once again and as of Sept 2017 there are only 76 individuals remaining in the population, which is getting very close to the population size following the depletion of the population by the live captures. The population is not recovering.
I believe US/CA research shows 3 main things affecting the southern pods 1) Food: like chinook populations but also loss of habitat such as declining eel grass and kelp areas which support the lower food chain which support chinook. 2) Human activities and noise. 3) Toxic pollutants like PCB's, PBDE's and DDT which don't break down in the environment but get passed up the food chain and get concentrated in the top predator species like the killer whale. Research seems to point to toxicity affecting their general health and ability to reproduce and raise offspring. Seems like toxicity accumulates in their fatty tissues and when they can't find enough food their bodies start using their fat reserves releasing the toxins into their bloodstreams making them sick.
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