Bob,
If you can get the opportunity to read the book "NET LOSS" (The Salmon Netcage Industry in British Columbia) please do so. It should give you many of the answers that you may be looking for. The book (or Report) was published by David W. Ellis and Associates With Recommendations by David Suzuki Foundation that was published in 1996. It is a report of some 196 pages about net pens and the many problems that go along with them.

I Hope that this will help you out.
_________________________
Cowlitzfisherman

Is the taste of the bait worth the sting of the hook????