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Imaging System to Sort Fish

US - Northwest Marine Technology with the Washington Department of Fish and Wildlife, Bonneville Power Administration, and the US Fish and Wildlife Service has developed a new series of machines to automatically inject Decimal Coded Wire Tags (CWTs) and excise the adipose fin on salmon and steelhead.

The research and development created the AutoFish System, which uses advanced technology to sort and process Pacific salmon and steelhead in a hatchery or fish farm.

The AutoFish System is a method of handling juvenile fish rapidly without the use of anaesthetic or human contact.

This system can be customised to perform any combination of sorting (to within 1-mm accuracy), clipping of adipose fins (marks), and injecting CWT in snouts (tagging).

The natural instinct of fish to move in water currents guides them through the AutoFish System with minimal stress and trauma. This has resulted in the AutoFish System changing the way fish are handled at hatcheries throughout the Pacific Northwest.

An integral component of AutoFish System is the AutoFish Sorter. The sorter uses video imaging and fish behavior to accurately measure fish in a stress-free environment.

The sorter measures the fish within 1 mm of total length and distributes them into size categories. Touch-screen software allows operators to view and change the system configuration. A screen shot of the AutoFish Sorter touch screen shows a fish being processed and histogram of the current size distribution.

Operators can observe individual fish, their lengths, and destinations. A graph shows the current size distribution, allowing the operator to fine-tune the system. Tabular data compare the current distribution with the previous day's processing and show the number of fish distributed into each size category. Once a fish is measured, the software selects the appropriate size category described by the user. The sorter instructs the diverter to open the appropriate port and the fish is routed to the lines for further processing.

Since its implementation, the AutoFish System has been used at hatcheries in California, Idaho, Oregon, and Washington. By 2005, more than 100 million fish had been coded wire tagged or fin clipped with the AutoFish System.

Ellen Hardy

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