It's a question that is starting to be asked.
Strict measures to restore horseshoe crabs were designed to increase the number of eggs they lay on Delaware Bay beaches each spring.
The goal was to provide food for red knots, a threatened migratory shorebird that times its trip from as far away as South America to Arctic breeding grounds with a stopover here to feast on the eggs.
For years, horseshoe crab harvesting has been blamed for declining numbers of red knots. But an 80 percent cut in harvests since 1998 on the Delaware Bay population, which includes the states of New Jersey, Delaware, Maryland and Virginia, has boosted numbers of the critter locals call "the king crab."
Surveys of red knots on the beaches here, at wintering grounds in South America and even aerial surveys - are not finding a corresponding increase.
"There's something going on with red knots, and they have to figure out what it is," said Eleanor Ann Bochenek, a member of the New Jersey Marine Fisheries Council.
The Atlantic States Marine Fisheries Commission, which regulates horseshoe crabs, reduced the crab harvest from 2,748,585 in 1998 to 660,794 in 2008. The ASMFC quota for New Jersey is 100,000 crabs per year, but, pushed by environmentalists - and over the objections of crab harvesters - the state instituted a complete harvest ban in 2008.
It may be working. Trawl surveys done to gather data for the ASMFC are showing rising numbers of horseshoe crabs, especially juveniles and males, although one survey by scientists at Virginia Tech estimated the female population has jumped from 3 to 9.6 million crabs from 2001 through 2007.
More crabs have not equaled more red knots. Scientists are hoping it's just a natural lag time to be expected when the life cycles of two intertwined species are involved.
Gregory Breese, coordinator of the Shorebird Technical Committee of the U.S. Fish and Wildlife Service, noted it takes a female horseshoe crab about 10 years to produce eggs compared to about two years for a female red knot. Breese said there were a lot of horseshoe crab eggs on the beaches this year so a lot of food was available.
"Our models show it could take awhile to see a change," Breese said.
Breese said about 25,000 red knots were counted in 2009 and there were similar numbers this year: between 20,000 and 30,000.
Eel and whelk fishermen use the crabs as bait and harvested about six million crabs in 1997 before heavy restrictions began. Surveys have showed steady population increases since the year 2000.
Some are starting to consider other potential reasons for the red knot decline.
Breese said there are many variables at the three places red knots go, which include: migration stopover grounds in Brazil, Argentina, and the Delaware Bay. They time their migration to food supplies; wintering grounds in South America, on the eastern Georgia coast and the west side of Florida, where Breese said the Gulf oil spill could endanger them and New Jersey's piping plover population later this year; and nesting grounds in the Arctic where global warming is changing conditions such as snow cover, predators and food supply.
"Climate change is something we need to start talking about. Red knots are using the two extremes of the hemisphere so wed expect them to see the effects first. There are other factors outside the Delaware Bay having a role," Breese said.
There is also very little known about how the birds fare in South America, Breese noted. He has heard they are hunted down there, as they were here along the bay in the 19th century when they were known as robin-breasted snipes and wooden decoys were carved to lure them.
The ASMFC is working on a new management plan for horseshoe crabs, using a method approved in February called ARM, or Adoptive Resource Management. The ARM framework uses computer modeling and allows managers to link crab levels with impacts on migratory shorebirds such as red knots. The ARM modeling may help determine just how important the bay is for red knots.
"If the model says the Delaware Bay has no effect on survival and production then maybe the Delaware Bay is not the weak link in the system," Breese said.
The ASMFC is hosting public hearings on the proposed management plan including one in New Jersey on July 1. There are five options on the table for the Delaware Bay population ranging from a full harvest moratorium for all states to an increase in the harvest. One option is to allow a harvest of 280,000 males and 140,000 females, about the same as the current quotas.
The ASMFC's Horseshoe Crab Management Board will select the option after the public hearings. The current plan expires on Oct. 31.
Robert Beal, director of the ASMFC's Interstate Fisheries Management Program, expects the board to give red knots more time to recover.
"I think the ASMFC will maintain a high level of crabs on the Delaware Bay even if the birds aren't reacting favorably," Beal said.
The ASMFC also is reporting that cuts in Delaware Bay harvests are leading to reduced crab numbers for New York and New England populations as eel and whelk potters here are buying out-of-state crabs for bait.
"New Jersey is closed and Delaware has cut back. The (Delaware Bay) harvest is down but demand is still there," Beal said.
