Farmed fish, taking advantage of extremes in tidal flow, leave the confines of their sea cage, and take to the open sea and rivers.

Documented big breaks:

Escapees may carry disease, such as ISA, or parasites, and spread them to wild populations. They also subject native populations to competition and genetic pollution.

Interesting tidbit: 5 million Atlantic salmon are being farmed off the coast of Maine, near wild rivers. If aquaculture farms prevent 99.99 percent of their salmon from escaping, that leaves 400-500 salmon escapees, which exceeds the total number of wild salmon returning to Maine's seven Downeast Rivers in recent years (under 200 salmon). The actual number escaping each year is unknown, as the State of Maine does not require documentation or reporting of escapees. Escapees have been found in Maine rivers since 1990.

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