This year was a good year for horseshoe crabs. The weather was cooperative and the restrictions on horseshoe crab harvesting on the east coast the past few years has helped the repopulation of the species.
This is why you are seeing more horseshoe crabs stranded on the beach than in previous years. Most do not wash up on the beach, but come ashore to spawn and the waves turn them over stranding them on the beach making them vulnerable to predators. (shore birds, raccoons etc.)
It seems that the horseshoe crab conservation efforts are starting to show signs of working. It’s still a little early in the migration to be definitive, but it’s looks good so far. Read “red knots gaining weight in 2009″
This year the horseshoe crab population has shown signs of improved numbers and the red knots that depend on their eggs to give them the energy to complete their journey to their breading grounds in the Artic are getting enought eggs to bring them up to optimum weight.
This is a story that makes me mad and yet fills me with hope.
The Johor Straits Singapore is one of the homes of the Carcinoscorpius rotundicauda species of horseshoe crabs that inhabit that part of the world.
Carcinoscorpius Rotundicauda are horseshoe crabs that can be found in the indo/west pacific waters and are getting dangerously close to extinction.
The part that makes me mad is that fishermen are using mono-filament nets on these shores and are leaving them unmanned. The horseshoe crabs and other wildlife get caught in the nets and when the tide goes out are stranded on land where the heat quickly kills them.
horseshoe crabs coming to shore to spawn
This is the time of year when the weather gets nice and love is in the air in Delaware. At least for the horseshoe crabs.
From now until about the middle of June the Delaware bay area beaches will be covered with horseshoe crabs as they come to spawn as they have done for thousands of years.
Delaware bay area beaches have more horseshoe crabs by far then any other place on the east coast. The horseshoe crabs love Delaware’s quiet protected beaches to lay their eggs by the millions.
I’ve had many people come up to me and ask why are there so many dead horseshoe crabs on the beaches and what is killing them.
Finding horseshoe crab shells in shallow water
What they are looking at are not dead horseshoe crabs but their molts that they need to shed at least once a year. In areas where Limulus is common, the shells, exoskeletons or exuviae (molted shells) of horseshoe crabs frequently wash up on beaches, either as whole shells, or as disarticulated pieces.
The shell of these animals consists of three parts.
Limulus Polyphemus has also been known as horsefoot, king crab, or saucepan. Some people call the horseshoe crab a “helmet crab”, but this common name is more frequently applied to a true crab, a malacostracan, of the species Telmessus cheiragonus. King crab is also more usually applied to a group of decapod crustaceans.
Limulus means “odd” and Polyphemus refers to the giant in Greek mythology. It is based on the misleading idea that the animal had a single eye.
Former scientific names include Limulus cyclops, Xiphosura americana and Polyphemus occidentalis.
The horseshoe crab or Atlantic horseshoe crab (Limulus polyphemus) is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs.
Horseshoe crabs are most commonly found in the Gulf of Mexico and along the northern Atlantic coast of North America. A main area of annual migration is Delaware Bay, although stray individuals are occasionally found in Europe.
The other three species in the family Limulidae are also called horseshoe crabs. The Japanese horseshoe crab (Tachypleus tridentatus) is found in the Seto Inland Sea, and is considered an endangered species because of loss of habitat. Two other species occur along the east coast of India: Tachypleus gigas and Carcinoscorpius rotundicauda. All four are quite similar in form and behavior.
There are 4 species of horseshoe crabs that still exists today. One, Limulus Polyphemus can be found on the east coast of North America and in the Golf of Mexico. The highest concentration of limulus polyphemus is the Delaware bay area although we have a strong population of them here on the space coast in Florida.
Another species, Tachypleus tridentatus which are found in the Seto Inland Sea. (This one is considered endangered, although with regulation it seems to be making a come back.)
The third species is Tachypleus gigas is found off the coast of India.