Oddly enough, it was the red knot’s decline that made us pay attention to another species in decline. In the past decade, it’s been estimated that horseshoe crabs in the Delaware Bay have dropped by 75%.

It all began in the nineties … when a growing fishery discovered that horseshoe crabs made good bait.

They were easy to collect and free. With no regulations, anyone could scoop crabs right off the beach. At the height of the rush, 2 million crabs were harvested in one year.

No one seemed concerned… until red knot numbers began to drop. By the time we saw the connection, the red knot was in serious trouble.

Getting a handle on horseshoe crab populations has been tricky. One method is to tag crabs and ask the public to report sightings.

Dave Smith from the US Geological Survey has been a key player in tracking crab numbers.

Dave Smith: There’s a lot of demands on this animal and right now it’s up to us to find out if there’s room for all of those demands – if there’s room for using horseshoe crabs for bait, as well as biomedical and still meet the needs of the red knots.

Today, efforts are underway to restore a balance that’s been lost. To build up crab numbers, there’s now a two-year moratorium on harvesting horseshoe crabs in the Delaware Bay.

Dave Smith: The regulations that have been put in place for horseshoe crab seem to be working. There’s going to be a lag, and whether or not this success has occurred in time for the red knots, we just don’t know.

Narrator: A recovery of crabs in the Bay… will take time. Horseshoe crabs don’t mature till they’re 9 or 10. That’s nearly a decade before the next generation is ready to spawn.

In the short season, females lay over 80,000 eggs. Out of 80,000, only 10 might survive to adulthood.

The odds might seem low, but it’s been a successful breeding strategy for eons.

Protected beneath the sand, the eggs are nurtured by the warmth of the sun and the moisture from the tides.

By the fifth day, tiny legs become visible inside their watery nurseries.

The next day, they’ll molt for the first time.

They’ll shed their little shells four times while still inside the egg.

But their tails won’t grow until after they’ve hatched.

It’s a remarkable process the horseshoe crab has carried out for 350 million years… But will the population recover in time for the red knot? No one knows…

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