scampbell, finding a used seine net the size you're wanting is gonna be tough. The 300'X4.5' size is just not something a regular hatchery uses either. There's always going to be vertical and lateral bows on seine nets when being pulled, and that has to be allowed for when figuring the size of the net you'll need. Esshup knows the percentages, and maybe he'll see this, but you may be looking at a 350'X6'to 8'net to properly seine the fish. Nets are sold by running foot, and you could expect to pay $3 to $4 a foot, and that's a starting point. For a net that size, and remember this will have to be a commercial quality net, you might need a double bottom with extra weights. That helps with abrasion, and helps keep the net hugging the bottom. Also, extra floats at the top would almost be a necessity. If there's not enough buoyancy when pulling the net, the top can be pulled below the surface. You don't want that. IIRC, my big seine came out to around $7 a running foot once I added the options I needed.
Probably the best option is to call a net company and let them tell you what they recommend. Some of the bigger ones are Delta Net and Twine, Miller Nets, and Memphis Nets. I use Miller nets, but Delta's actual netting is used by several other net suppliers.
