1. The horseshoe crab: a keystone species
Miss Robertson 7R

2. Horseshoe crab

3. habitat
The Horseshoe Crab can be found living in warm, shallow coastal waters
They prefer sandy or muddy ocean bottoms
Horseshoe Crabs can be mainly found on the Eastern seaboard of the United States; down the Gulf Coast, and along the east coast of Mexico
Other varieties can be found along the coasts of southeastern Asia
The emerge from the ocean floor to breed on the beaches during the late spring

4. Food web Sanderling Sea turtle Bass Red Knot Horseshoe Crab Clams
Worms
Plankton

5. Keystone species
The Horseshoe Crab is an organism that is depended upon by many other organisms, making it a keystone species
Over 30 species of shorebirds & migratory birds, such as the Red Knot, the Sanderling, the Ruddy Turnstone and the Semipalmated Sandpiper, use horseshoe crab eggs as an important part of their diet
The high protein content of the eggs provides fuel their long migratory journeys
Many species of fish, such as the bass, also depend on Horseshoe Crab eggs and newly hatched Horseshoe Crabs for their diet
Essential part of oceanic food web

6. Disappearance
Approximately 75% of the Horseshoe Crabs in Delaware Bay have disappeared since the early 1990s
They are used largely as bait for the Eel and Conk fishing industries
Horseshoe Crabs are also used by the biomedical industry as their blood contains a unique chemical that detects infection
Use the blood to test IV drugs and medications to ensure their safety in human patients
Horseshoe Crabs are losing their habitat to coastal development. This means they have no where to lay their eggs

7. consequences
Disappearance of shorebirds and migratory birds, such as the Red Knot
Red Knot populations have decreased by 70% in the last 5 years
They are now at a critical number – one disaster could cause their extinction
Change food webs in both Chile and the Arctic where the Red Knot serves a food for other predatory animals such as foxes
Loss of an important biomedical product
IV drugs will have to be tested in other, slower, less effective ways
Hurt human health
Loss of bait for fisherman
Loss of incomes and livelihoods

8. REFERENCES
Agricultural, Fisheries and Conservation Department. hor_draw9.jpg. Accessed Nov. 9, 2015
Galathea Accessed Nov. 9, 2015
Horseshoe Crab. Crab.aspx. Accessed Nov. 9, 2015
Integration and Application Network html. Accessed Nov. 9, 2015
View from the Cape. Accessed Nov. 9, 2015
The Horseshoe Crab as a Keystone Species. lesson13.html. Accessed Nov. 9, 2015
Crash: A Tale of Two Species. NATURE.