San Francisco's Fisherman's Wharf typically bustles this time of year as workers prepare to haul millions of pounds of Dungeness crab that are a tradition at Thanksgiving and other holiday meals. A massive bloom of microscopic algae — which produced a natural toxin called domoic acid that is harmful to wildlife and fish — in the Pacific Ocean is threatening the crab industry during a time when many fishing outfits make their most money. Experts say the warm conditions that set up the toxic algae bloom — while not attributed to climate change — does offer a picture of what's to come as ocean temperatures are projected to warm. [...] warmer ocean temperatures off New England have shaken up fisheries there, contributing to the collapse of the region's cod fishery and the shift northward in the lobster population, studies have found. Matt Hunter, shellfish project leader with the Oregon Department of Fish and Wildlife, said crabbing is huge fishery in the state and any closure will have "trickle-down effect on the economy, not only on the coastal communities." Kris Ducker, who grew up in California, looks forward to her family's holiday tradition: eating crab served ice cold, cracked, with a side of sourdough bread. "Whether this warming itself is a direct function of climate change or not, we can't say," said Mark Wells, an oceanography professor in the School of Marine Sciences at the University of Maine.