The measure is aimed at protecting the red knot, a small shorebird that migrates between the southern tip of South America and the Arctic. Red knots make a pit stop on the Delaware Bay during their northward migration to fatten up on horseshoe crab eggs.

In a statement, Corzine said the moratorium on taking horseshoe crabs will remain until both species are at self-sustaining numbers. Horseshoe crabs are used for bait.

"The effects of human behavior often have widespread, unintended consequences that reverberate across the animal kingdom for generations, like the ripple effect in a pond that started out as one small disturbance," Corzine said in a statement.

Horseshoe crabs, which are more closely related to scorpions and spiders than to crabs, have become important to medical research as well. In some states, crab fishermen now catch crabs for milking and then return them to the water, a procedure most survive.