May 31, 1999
The first involves re-engineering our hatcheries to more closely mimic natural conditions, and the second involves dam modifications that would decrease smelt losses while traversing the dam and substantially lower subsequent predation.
The primary conclusion that can be reached from the dismal return rates of our hatchery fish is that our efforts have only provided the feeding for large numbers of other fish. The first step in saving the salmon is to abandon our linear, anthropocentric thinking and attempt to experience the world as a fish does.
For example, all bony fish possess a sense labeled the lateral line. This sense allows the fish to perceive motion from all sides and enables large schools to seemingly turn as one. It is critical for predator evasion in dark or turbid waters. Yet our hatcheries have been constructed in such a manner as to almost completely obliterate this sense via the insensate pounding of adjacent pumps.
We release smelt that have never known silence. How hard would it be to dampen or, better yet, completely eliminate the constant roar? Not only have our hatchery fish been "blinded" since birth, but the schools have also gotten a bad education.
The fish have been fed, historically, by periodically hand broadcasting pellets on the surface. This conditions the fingerlings to wait in the most dangerous of possible places, out in the open, near the surface. Their stupidity is reinforced every time they are fed. The featureless concrete raceways provide no incentive to be anywhere else.
Rearing tanks should be lined with boulders, rocks, gravel, and vegetation. Give the fish a reason to learn to hide. A few sterilized, naturally occurring predators should be introduced into the tanks, as well. The loss of a few now would go a long ways toward preventing the destruction of all later.
Introduce the food randomly, with the currents. Instead of simply raising deaf and naive food for other fishes, we need to start producing fry that are frightened, paranoid and fast--"stream smart."
The underwater pounding of a hatchery's pumps is a gentle lullaby, when contrasted with the unnatural thunder of a dam's turbines. Stunned by the sudden, tremendous wall of noise, fish lucky enough to escape the dicing find themselves confused, disoriented, and easy prey for the hungry hordes waiting in the wash.
A single squawfish has been demonstrated to consume ten smelts every day. Having fished below the dams, I can personally attest to the localized, high concentration of these predators. Yet "off-the-shelf" technology currently exists that would greatly alleviate the awesome noise pollution accompanying all existing dams.
Computers can record, analyze, and almost simultaneously generate sound waves which have the same amplitude as the offending source, but with exactly opposite effect. They can create a white noise that can almost completely dampen the noise pollution. This technology has been applied at airports, traffic situations, etc. It works best when the sound is re-occurring and predictable--precisely what is found at dams.
I believe a system of strategically-placed underwater speakers, so powered, would channel the fish away from sucking turbine inlets (the Army Corps of Engineers' $100 million goal for the six-month monstrosity at the Lower Granite). The emerging fish would better retain their natural lateral line sense, and as such, they would be more strongly equipped to escape the ensuing gauntlet.
Fish transiting dams need a quiet zone to guide and protect them. It is past the time to stop pointing fingers and to start taking serious actions.
Michael J. Harrington