Horse shoe crab

horse shoe crab fisheries

1. Presentation on LIFE CYCLE OF Horseshoe crab BY -joy

2. TAXONOMICAL CLASSIFICATION KINGDOM-ANIMALIA PHYLUM-ARTHROPODA SUBPHYLUM-CHELICERATA ORDER - XIPHOSURA SUBORDER- XIPHOSURIDA FAMILY - LIMULIDAE GENUS – Limulus

3. HORSE SHOE CRAB Horseshoe crabs are marine and brackish water arthropods of the family Limulidae.their popular name is a misomer,for they are not true crabs. Horseshoe crabs are hard-shelled sea creature closely related to spiders and scorpions. They spend much of their lives out in the deep ocean, but they come back to the beach to lay their eggs.

4. HABIT AND HABITAT Horseshoe crabs live primarily in and around shallow coastal waters on soft sandy or muddy bottoms. They tend to spawn in the intertidal zone at spring high tides. During breeding sea­son, both male and female horse-shoe crabs come on land and dig holes at the upper limit of high tides to lay eggs. It can dig by the help of cephalothorax and may remain completely buried. The full-grown horse-shoe crabs usu­ally crawl by using the legs, while the young’s can swim invertedly with the help of ab­dominal appendages The species common name is –Atlantic horseshoe crab.

5. EXTERNAL FEATURES OF HORSESHOE CRAB

6. In recent years population declines have occurred as a consequence of coastal habitat destruction and overharvesting. . PRODUCTION TRENDS

7. DISTRIBUTION

8. REPRODUCTION Horshoe crabs are able to breed after they are 10 years old. And once they reach breeding age , they will come to shore every year to make nests. These creatures come to shore in huge groups, sometimes numbering in the hundreds of thousands.

9. The males comeup first. When the females arrive they release a pheromone, or chemical SCENT to let the males know they are there and ready to mate. Then the males grab onto the females with their small front claws, and the females tow them up onto the beach. There the females make a nest and lay their eggs, and the males fertilize the eggs by releasing sperm.

10. Horseshoe crabs lay huge numbers of eggs. In a single nest , there can be up to 4000 eggs, and each female will make more than one nest. In a single season, one female horshoe crab might lay 88,000 eggs. They have a good reason for doing so. Baby horseshoe crabs are eaten by manyt creatures, including birds, crabs, fish and even large shrimp. Even with these huge numbers of eggs, many horshoe crabs do not survive to adulthood.

11. Species Diversity

12. LIFE CYCLE EGG TO INFACY:- Horseshoe crab eggs stay buries in the sand for two to four weeks. They then hatch into larvae, the first, immature form of the life cycle. Horseshoe crab larvae closely resemble adult horseshoe crabs, except they are much smaller and they donot have tails. These larvae will swim in the open water for about six days before they settle onto the ocean floor. After those first few days, a horseshoe crab will spend the majority of its life on the sea floor.

13. JUVENILES:- Once they are around 20days old, the larval horseshoe crab molts, which means it sheds its upper layer of shell and skin to make room for a larger one growing underneath. This molting marks the next stage of a horseshoe crab’s life, the juvenile, or young stage. The juvenile stage is where the horseshoe crab grows its tail.

14. Horseshoe crabs remain in the juvenile stage for about two years. During this time they stay in shallow, protected water, usually close to where they were born. They continue to molt regularly throughout the whole two years. Horseshoe crab shells donot grow with them, so they have to molt as they get bigger.

15. LIFE CYCLE

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