Tighter fishing limits are needed in the Gulf of Maine and Georges Bank fishing grounds in New England on everything from cod to winter flounder to meet new conservation goals set by Congress, according to a report released yesterday by a scientific panel that tracks the region’s stocks. Fishing stocks continue to decline despite efforts to boost them, and cod stocks are at a historic low in the Gulf of Maine, the report found. The report follows five years of ever-tightening fishing regulations and is sure to stir up controversy and pit scientists against the fishing community. The New England Fishery Management Council has the job of setting fishing limits for next year. Enviros are pushing for a crackdown in New England on fishing for horseshoe crabs, which has soared in recent years.