Of the more than 70 species of rockfish living off the United States' west coast, the bocaccio rockfish is one of the most endangered. While this 3-foot fish reaches reproductive age sooner than many overfished species -- as early as four to five years -- its larvae have a very low survival rate. Changes in ocean currents and temperature since the 1970s mean that large numbers of bocaccio larvae live to become juveniles only once every 20 years. In response to their dwindling numbers, the United States closed several fisheries along the West Coast in 2002. But even without trawling in these areas, scientists believe it could take 100 years for bocaccio populations to recover. With such significant challenges to recovery, the IUCN has listed the species as critically endangered.