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The Fish Herding Project 

Davis Hydro is involved in fish herding and guiding. We have developed a technology that will herd fish in open streams and is expected to be useful for assisting at fish ladders and fish habitat enhancements facilities. The photo here shows the problem.

At this site, just below the Lewiston dam on Trinity River in California, the fish cannot pass up this flow due to the screen (clearly visible on the right), and are diverted up the ladder into a hatchery. The final fish ladder leads off to the left in the picture, but to get fish interested coming this far up the river the much larger attraction flows are released from both below the photographer and from the left. These "attraction flow"are expensive in that it uses a lot of water which - in California translated to a lot of wasted energy.

Our new technology addresses this problem by decreasing the amount of attraction flow water needed. It may also be useful to assist in downstream migration of fish. Currently, (July 2005) the Davis Hydro group in The Davis Collaborative has submitted a proposal to the CEC to look at this problem, as it will save a lot of water and therefore energy for the state. The full text of that proposal is available here. We are working with the Bureau of Reclamation staff to find the best test sites in Northern California.

The basic idea us that fish interact with bubbles rising in the water column in different ways. When bubbles are produced from a bubble curtain, different fish appear to interact in ways that include what appears to be play, attraction, fear, locating-on, hiding-under, feeding by. etc. If the curtain moves slowly some of the fish move with it. If there are repeated curtains moving in a direction then a flux of fish is created moving with the curtains. This is fish herding. No one curtain may be very significant, but over time, with many repeated moving bubble curtains, a small fish-curtain interaction probability creates a real flux of fish.

The primary intent of the technology its to assist migratory fish find fish bypass facilities like nature like fish bypasses or fish ladders. However, the technology might also be useful in fish capture or alternatively, in helping fish find fish spawning channels.

The US patent application that supports this effort is available here. This US patent application has been accepted is currently pending.

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