you were told wrong, along with many others
You may have been told some wrong information, which is all too common concerning things about fish and fishing. While the Skagit had been the king of steelhead rivers, runs were already trending downward when treaty tribes began fishing after the 1974 Boldt Decision. My data show peak steelhead returns, hatchery and wild fish combined, and expressed as harvest occurred between 1968 and 1972. Sport fishing pressure increased significantly after the steelhead hatchery program began at Barnaby Slough around 1962. Catches were astounding, and much credit was given to the returning hatchery fish. In all likelihood the hatchery steelhead returns, while significant, were less than predicted, and more of the harvest consisted of wild steelhead than might have been expected. Of course when all this happened, no distiction was made between hatchery and wild steelhead, and hatchery steelhead were not marked.
The treaty tribes took a large steelhead catch one season, the winter of 1974-75, with the combined treaty and recreational catch comparable to some of the previous high year sport catches. After that, total combined catches collapsed. You can point to the treaty net catches of 74-75 if you know nothing about steelhead life history and biology. But the runs from 76 to 79 occurred on fish whose brood years had not been netted by the tribes. It would be ignorant, if not racist, to blame the reduced run sizes and catches of those years on treaty Indian netting.
While I cannot prove it, I can reasonably infer that the very high sport catches of the late 1960s through 1974 unknowingly over-harvested wild steelhead runs while everyone was caught up in the mania over the Barnaby Slough hatchery returns. That over-harvest led to low spawning escapements through the early 1980s. Ending late season steelhead fishing by treaty tribes and sportsmen beginning in 1977 allowed escapements to increase, and resilient as steelhead are, the runs rebounded very well due in large part to good ocean survival of smolts.
This led to the heyday of CNR fishing for late season wild Skagit steelhead beginning in 1981 through the 1990s and until the bottom sort of fell out as marine survival declined. No matter what the escapement, most years the spawners have produced only one recruit (subsequent adult fish 4 or 5 years later) or even less. The freshwater habitat remains much the same, although like everywhere it continues to suffer the slow death of a thousand small cuts. Harvest is all but non-existant. For all the blame heaped on the treaty tribes, in part from posts like yours, it likely would surprise you to know that sportsfishermen have caught many times more wild steelhead in the last 50 years than have the treaty Indians. Not that they wouldn't like to harvest them, but they cannot catch fish that are not there. And they did not target wild steelhead from 1976 until they began some limited fishing on the rebounded stock in the 1990s.
Regarding some of your other remarks, a hay bale dropped into a river set net will remove the gear, but usually it then gets lost and is never recovered. Some of that lost gear becomes ghost nets, pieces of which continue to fish unseen, unknown, and unaccounted for whatever they do catch.
The length limit on tribal drift or set nets has nothing to do with the width of the river. The length limit is 35 fathoms, or 210 feet. Most set nets are significantly shorter because the effective length is determined by the characteristics of the specific set net site. Fishermen check their nets at least daily if they are intent on earning any money. Poachers, treaty and non-treaty, may not check their nets or retrieve them at all if they think the gear has been spotted, and they might get caught.
You did get it right that the state Game Dept. or WDFW these days can't do anything about it. Right or wrong, the state effectively prohibited treaty Indians from exercising their federally protected fishing rights from 1935 until 1974, effectively reserving about 96 to 98% of the salmon and steelhead for us non-treaty folks. In hind sight, was it worth it? Since 1974, through numerous federal court decisions, the tribes have become self-regulating co-managers of the state's fishery resources. The good side is that a higher degree of transparency and accountability has accrued to all parties. The downside IMO is that maximum sustained yield has become institutionalized as the core value of fishery management at a time when social and ecological circumstances are least served by it.
WDFW can't shut the tribes down. But they don't need to. There is no fishery that targets the harvest of wild steelhead today. WDFW cannot will early marine survival to increase so that steelhead will return in greater numbers. What WDFW can do and is doing, is closing most of the sport fishing opportunity that had remained on the much diminished return of wild steelhead.
I guess the one message I would like you to take home from this post is that the treaty Indian tribes do not now, nor have they ever, been the limiting factor of the Skagit River wild steelhead run. For at least the past three decades, harvest by any party has not been the limiting factor for the steelhead return. And the only time in history that harvest has limited the wild Skagit steelhead return, it was due to the unknowing over-harvest by white sportfishermen. Pretty amazing, eh?