I think I may have not been exactly clear. I didn't mean to imply that anything short of considering total eradication is indicative of wanting carp to be established. Not at all. I was just trying to think out all of the "what if" scenarios. It would be great if a fishery could put a huge dent in the population.
Clearly, fisheries management and regulation isn't always successful (the too little, too late problem). I'm just concerned that there is the potential for pressure to manage for a carp fishery. True, some trout populations are maintained by stocking; others aren't. That isn't quite my point. The entire trout fishery, stocked or not, is regulated in part to help support the fishing/vacation industries. These industries can be particulary important to small towns near national parks, say. The trout fishery supports not only guides and angling shops, but hotels, restaurants, car rental agencies, and all of the industries that support those (in a manner, even down to subcontractors who do road repair, etc.)
The reason cited for not closing the Chicago Canal was economic. Too much money depends on the canal. The potential for the same reasoning could exist for a carp fishery in the future. There will be people who's livlihoods will be based on the carp fishery, both from an industrial/commercial standpoint and a recreational/retail standpoint.
Anyway, I'm not saying I'm against a commercial fishery. Just trying to think out all of the potential issues that could go along with any management strategy.
Do you mean like protections for bluefin tune, striped bass and cod? Regulations there; too little, too late.
I think the carp stocks would be suppressed by harvesting activity, even if take is regulated. Hopefully carp stocks would be suppressed enough to limit ecological damage.
The trout populations are a bit different, in that some stocks must be maintained by stocking. At some point in future, political winds might change causing a lack of support for stocking / regulations and the trout stocks could be allowed to fail or at least drop to levels of minimal impact on the rest of the system.
I must state I am not a proponent of establishing bighead and/or silver carps into the Great Lakes basin. It appears any discussion not considering only eradication efforts or complete denial of carps becoming established is indicative of wanting to have the carps become established.