The real reason for salmon depopulation is relatively straightforward for unbiased thinkers. It is habitat degradation in all of its various forms: from dam building, water pollution, to road culverts [photo]. Culverts are a pervasive problem that is often overlooked when discussing salmon conservation. In the state of Washington alone, almost two thousand fish-blocking culverts have been identified. By creating barriers too steep, or too angular, adult salmon are prevented from spawning upstream and juvenile salmon prevented from returning to the sea. Culverts were identified in a 1997 report to the Washington legislature as one of the most "recurrent and correctable" obstacles to healthy salmon stocks. In 2013 the state Department of Transportation was ordered to prioritize their replacement with fish-friendly crossings. So far in twenty-five years, the state has replaced 319 with fish passages.If the native peoples win their lawsuit in the US Supreme Court and lower court decisions recognizing their sovereignty are upheld, the state will be faced with a potential bill of $2.4 billion to replace 900 culverts with high priority by 2030. Understandably the state's attorneys have adopted an extreme interpretation of Indian fishing rights in their court arguments. One knowledgeable observer called the arguments a, "Wild West attitude" that was previously rejected by the courts. One Indian leader stated that the right to harvest salmon was one of the few things Indians retained in return for all the land they gave up in western Washington. But the Boldt decision did not expressly decide how far a state must go to protect habitat to insure healthy salmon stocks for Indians to fish. Montana and Idaho have sided with Washington in the case. Other states in the northwest with stream culverts are watching the litigation closely.