I work on Environmental Impact Assessment, especially with regards to fish ecology. I have never come across this before.
We work a lot on the hearing capabilities of fish and impacts of noise. Generally salmonids are not as sensitive to noise as Clupeids. If they are not normally disturbed by boat noise or other noise impacts, I doubt divers will be of any concern in that regard.
As for a visual impact I think that is covered by the previous response.
It sounds like someone is taking concerns on environmental impacts a little too far...
Dr Adam Payne
EPD Marine Oil & Gas
North Hinksey Lane
Oxford OX2 0QS
T: +44 1865 384 869 (Direct)
F: +44 1865 384 848
M: +44 7717 004 227
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From: Scientific forum on fish and fisheries [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: 11 March 2009 16:54
To: [log in to unmask]
Subject: Re: Impacts of divers
who raised the question and God bless their pointy head ------ I have drift
dived many streams and small rivers and have never observed any exceptional
behavior by salmonids except a careful cautionary gaze and a tendency to keep
their comfort distance ---- if your divers want to chase the sockeye that
would probably tire them some and waste air --- so don't do that
I am working on a project that will replace some anchor cables on the
two floating bridges that cross Lake Washington in Seattle, Washington.
The project will use a pair of divers to replace these cables in water
from 40 to 200 feet deep. Lake Washington is the largest lake in
Western Washington, and supports a number of salmonid species, including
anadromous sockeye. Adult sockeye are known to find thermal refuge at
50 to 90 feet deep during the warmest part of the summer, and this
season the population is expected to be 105,000.
A question has arisen on the potential impact that two divers would have
on these fish, and I am at a loss to find a source of information. Does
anyone know, or can anyone provide best professional judgment, on the
potential impact of a pair of divers moving vertically through the
thermal refuge layers where sockeye would be dispersed?
NW Region Biology Program Manager
Washington State Department of Transportation
Nelson Resources Consulting, Inc.
954 653 8295
561 449 9637
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