TRENTON - The Senate yesterday approved a ban on horseshoe-crab harvesting.

The moratorium, approved by a 39-0 vote, is designed to help the red knot, a migratory shorebird that feeds on the crabs' eggs along the shore of the Delaware Bay in May.

The red knot population has plummeted as the eggs have become more scarce. Environmental groups and agencies say the species could be extinct by 2010. Under the bill, harvesting of horseshoe crabs will be banned until the red knot population reaches 240,000 or until a fisheries plan satisfies the state Department of Environmental Protection that the population of both the crab and the red knot can be stabilized at viable levels. The latest count of red knots overwintering at Terra del Fuego, Chile, at the tip of South America, is 14,800.

The ban is opposed by fishermen who harvest horseshoe crabs to use as bait. They say global warming and habitat destruction may be to blame for the birds' diminishing numbers.

Yesterday's action was the latest in a back-and-forth between fishing and birding interests since a two-year ban expired.

In December, the DEP proposed to replace that ban with an open-ended moratorium.

The New Jersey Marine Fisheries Council vetoed that proposal in February.

Birders and conservationists reacted quickly to the veto, lobbying lawmakers in both houses to introduce bills that were similar to what DEP had wanted.

The Assembly approved its bill last week, 70-6. The Senate yesterday sent it to Gov. Corzine.

This article includes information from Inquirer staff.