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We have decided to use a system based on Passive Integrated Transponder tags to measure the effectivness of our final solution. PITs are small (~10mm diameter) glass cylinders that are injected into the fish. PITs are not electronic, giving them a near infinite lifespan. When the tags are read by the antenna, they report a unique ID, allowing us to know exactly which fish we are tracking.

The fish are tagged in a tagging survey (manned by scientists and/or out-of-season fihsermen and/or local harbor watch groups). The fish are caught either by a short, slow-speed bottom trawl (so that the fish are ALIVE when they get onboard) (to get info on the spectrum of fish in a given area) or more species specific techniques (such as handlines, more precise nets, etc) (to get more info on just a few species). As the fish are brought onboard, they are tagged (current automated machines can do 150 fish/minute) and their length/weight is recorded. This data is combined with the ships location (from GPS) and uploaded to a database. (Note: the fish are passed through an antenna first, if they are already tagged then their location/wieght/length is recorded, but they do not get a new tag). After the fish are tagged, they are released back into the water.

Because the range of antennas is severely limited (less than 2 meters), we cannot track the fish while they are at sea. We can, however, put the antennas on commercial fishing ships. As the fish are caught, they are dumped down a chute into a holding tank. The chute includes an antenna, so every tagged fish that is caught will be reported. The tag ID is combined with GPS data so that we can see where each fish is caught.

When the fish arrive at the processing facility (either onbaord for a factory ship or on land for smaller boats), the fish are checked for length and weight. We are not exactly sure how to do this yet, but we are thinking that an automated camera could be used to check the length, and an automatic scale would check the mass. Another antenna would relate the mass/length info to tag id. The weight and length measuring devices would be integrated into the processing equipment, so there would be no effect on the output of the facility.

The data from the processing facility and ship are uploaded to a central database where the info can be analyzed.

These devices currently cost about $4 per tag, but with mass production we expect prices to decline sharply. Note that once the fish are tagged there is no additional human effort to collect data; it is all automated.

1 Todd: October ?

Here is an outline/template for our solution.

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