WOOLWICH, Maine (AP) — Dan Harrington makes his living unearthing marine worms by hacking away at mudflats with a tool that resembles the business end of an old steel rake. A mysterious drop in the harvest of two of the most popular worms for sport fishermen is proving expensive for anglers, perilous for bait shop owners and a threat to a way of life in Maine. An October study in the journal Fish and Fisheries said bloodworms are the most valuable marine worm species on the retail bait market, and sandworms aren't far behind. Among the factors that could play a role in the decline are rising temperatures in the Gulf of Maine, changes in currents that distribute worm larvae and increased harvesting pressure, said William Ambrose, a Bates College professor and marine researcher. A committee of the Maine Legislature this year considered a bill that would've shut down worm digging for four months a year to help preserve the industry, but it didn't pass. The proposal generated skepticism from as far away as the suburbs of Sacramento, California, where Big Red Worm Co.