Conservation groups today filed a motion to intervene to help fight a lawsuit aimed at overturning a seasonal speed rule protecting North Atlantic right whales from deadly vessel strikes. The groups want to defend the rule against a lawsuit brought by a New York vessel owner fined for violating seasonal speed limits. The suit alleges that NOAA Fisheries lacked the statutory authority to issue the rule. “The speed limit rule is a slender thread protecting North Atlantic right whales from extinction, and if it’s ripped away these majestic animals could plunge into the abyss,” said Kristen Monsell, oceans legal director at the Center for Biological Diversity. “Sensible speed limits to keep pleasure craft and other ships from running over right whale calves and their mothers are absolutely crucial to ensuring these beautiful creatures aren’t wiped off the face of the Earth.…