Archive Number 20050331.0933
Published Date 31-MAR-2005
Subject PRO/AH> Undiagnosed die-off, herring – USA
UNDIAGNOSED DIE-OFF, HERRING – USA (WASHINGTON)(02)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 31 Mar 2005
From: Michael A. Jacobs <mikejac>
This case appears to be more likely a multifactorial problem than a real
mystery. Warmer water temperatures and periodic draw-down events from dams
have occurred in the early spring several times over the past decade. These
inputs can spark bacterial blooms and other toxic blooms, such as algae.
At the same time, industrial and agricultural expansion in the Skagit delta
(the largest riverine input to Puget sound) and the Fraser River delta
(under enormous pressure from growth of the Vancouver metropolitan area)
may add fertilizer, further exacerbating the bloom problem, and also may
increase the toxins mentioned in the original post to more lethal levels.
Devastating logging in the area over the past 30 years has also
dramatically altered runoff patterns in the spring.
In addition, while shoreline development is tightly regulated in this part
of the world, eelgrass beds (the shelter and habitat for herring) are
shrinking. Perhaps there is a threshold effect, in that a minimum area of
healthy eelgrass is needed to support a herring population.
The impact of herring extinction would indeed be devastating.
Unfortunately, the political trend in Washington and British Columbia is
toward loosening regulation. For example, a large gravel mining project
likely to be approved on the southern end of Vashon Island would likely
destroy major eelgrass beds located at a critical junction between the main
basin and southern part of the Puget Sound estuary.
Severely affected species would not be limited to salmon and sea birds,
but also the top predators in this system, which feed on those species,
such as the Bald Eagle and Orca.
Michael A. Jacobs PhD
Univ. of Washington Genome Center
Dept. of Medicine
225 Fluke Hall Box 352145
Seattle, WA 98198-2145