Over the last 20 years salmon recruitment, the number of returning adults, has taken several shocks. The late 1980s, 1990s, and 2000s have been marked by radically reduced runs for various salmon species. The United States Department of Commerce issued a Federal Disaster Declaration for the 2008 and 2009 Commercial Chinook Yukon River fisheries, calling for the complete closure of commercial fishing along with restrictions on subsistence fishing. The root cause of these poor returns remains debated, with questions about the effects of climate change on ocean food-supply & disease prevalence in returning adults, the methods of fishing used on the river, and the effects of the Bering Sea Pollock trawl fleet on food supply and salmon bycatch. In 2010, the Alaska Department of Fish & Game's Board of Fisheries issued the first-ever restriction for net mesh size on the Yukon, reducing it to .