Keep in mind that the authority of the Oregon State Police does not end at the three mile territorial boundary.
Because the State of Oregon has entered into a cooperative agreement with NOAA Fisheries (formerly the National Marine Fisheries Service) many of the OSP game officers have been duly authorized to enforce the provisions of the Magnuson Act within the Exclusive Economic Zone (EEZ). In other words out to 200 miles for species that are managed by the Pacific Fishery Management Council, and that means most marine species including coho, chinook, lingcod, etc.
OSP game officers are regularly found boarding vessels at the deep water halibut holes in the all depths fisheries. They are probably more likely to be found within three miles simply because that is where the majority of the anglers are usually fishing for marine fish species.
Since we pounded this issue to death last fall, I won't go into all of the details, but suffice it to say that if you are on an Oregon licensed vessel at sea within 200 miles of shore, OSP has the authority to board and inspect your gear, catch, etc. You are also subject to all of Oregon's angling rules that are applicable to the fishery you are participating in. That includes only one rod or line per angler.
As Miss B Haven pointed out, there is a proposal to make some exceptions to the rules for "tuna anglers". These proposals will be considered by the Oregon Fish and Wildlife Commission at their August meeting in Astoria. A thread discussing these proposals can be viewed here:
Tuna Regulation Discussion
If you are interested in seeing these proposals being turned into regulations, I suggest that you plan on attending the Commission meeting and presenting testimony. These proposals are a big leap, and are sure to be controversial to some.