threat

Threats to Horseshoe Crabs

Adult horseshoe crabs do not have many natural predators, only sharks and loggerhead turtles. However, there are other different kinds of threats to the horseshoe crabs that live in the Delaware Bay. One of the bigger threats is overharvesting. People are taking too many crabs to be sold and used as conch and eel bait. People can get as much as $1 for just one female with eggs.
Another big problem is horseshoe crabs sometimes get stranded on the beach.

They get flipped over by big waves, and they can't get back up. If they stay on their backs too long, the sun will dry out their gills, and the crabs will weaken and die. Then gulls, raccoons, or other beach predators come along and eat them.
     Pollution also is a possible threat to horseshoe crabs. People are using more pesticides on their lawns and farmland, and New Jersey and Delaware are spraying more for mosquito control. As a result, you get more chemicals washing into the water from the urban and agricultural runoff. Junk in the water causes problems, too. Sewage, factory waste, rainwater carrying pollutants from parking lots, yards and streams can kill clams and other animals that crabs use for food. Water pollution may weaken or kill horseshoe eggs and larvae.
     A very large oil refinery is located on the Delaware coast, and a lot of oil tankers use the bay. There is always the threat of a big oil spill.
     There recently has been a loss of beaches where the crabs could lay their eggs. There has been an increase in development along some beaches. When people build thick walls to protect their homes from waves, these same walls keep out the crabs looking for places to spawn . Other people toss tires, bricks, broken cinder blocks, and rocks on the beach to help prevent erosion. This junk doesn’t stop the crabs, but when they try to nest on a littered beach, they often get trapped and die.
     Recreational vehicle traffic on beaches can crush the crabs as well as destroy their habitat.

Horseshoe crabs in Massachusetts have a different kind of problem. Many people in Massachusetts are concerned about the amount of shellfish that horseshoe crabs eat. So, since Massachusetts has a home rule law which gives the authority to regulate shellfishing to the individual coastal community, each town develops its own rules and regulations, including control of predators such as the horseshoe crab. In the past while most towns put bounties on horseshoe crabs, not all did. The bounties were in existence for as long as anyone can remember, probably a hundred years or more. Some of the older fishermen have said that the bounty (three cents/tail) ended in the mid to late sixties when towns began their own predator control programs. However, at least eight of the fifty five coastal towns still have regulations requiring fishermen to destroy horseshoe crabs.
Horseshoe crabs remain a heated issue in Massachusetts. One group feels that the crabs are endangered, and any harvest will threaten the crabs and the food supply for shorebirds. Another group feels that the crabs are quite abundant and are a major shellfish predator and need to be controlled.

Information about the situation in Massachusetts came from Frank Germano, Senior Marine Biologist for the State of Masachusetts

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