Sockeye salmon over Bonneville Dam on the Columbia River. Lower temperatures in 2008 North Pacific waters brought in fatter plankton, which, along with greater outflows of Columbia River water, fed the resurgent populations. Proposed legislative efforts, such as the Northern Rockies Ecosystem Protection Act, are attempting to protect the headwaters of the sockeye salmon by preventing industrial development in roadless areas. Record numbers of a once-waning population of sockeye salmon have been returning to the Northwest's Columbia Basin (as of June 2012), with thousands more crossing the river's dams in a single day than the total numbers seen in some previous years.
Fish disease and parasites mid-1980s, in particular, an overview report which states that "the fish that have the longest fresh water residence time as juveniles have the most noticeable infections. Hence in order of prevalence coho are most infected followed by sockeye, chinook, chum and pink." As well, the report says that, at the time the studies were conducted, stocks from the middle and upper reaches of large river systems in British Columbia such as Fraser, Skeena, Nass and from mainland coastal streams in the southern half of B.C. "are more likely to have a low prevalence of infection." The report also states "It