Thursday, March 10, 2011



True Wild Life | Oyster | The oyster is a sessile (immobile) mollusc that is commonly found clinging onto shipwrecks, debris and harbour walls around the world. Oysters are bivalve molluscs meaning that they are closely related to other animals such as scallops, clams and mussels. Oysters are found in salt water environments all around the world but are more commonly found in more temperate regions where the shallows are richer in nutrients. Oysters are thought to be among the oldest animals on the planet although their exact evolutionary path remains unclear.

As with other molluscs, oysters filter water in and out of their protective shells so that their vulnerable bodies inside are never put in danger. The hard shell of the oyster is primarily made up from calcium. Despite there being numerous different species of oyster, oysters are generally split up into four distinct groups, which are true oysters (the ones eaten by humans), pearl oysters (produce pearls), thorny oysters (also known as spiny oysters) and saddle oysters (have very thin shells).

Oysters are filter-feeders so collect their nutrients by taking in water and their gills filter and collect food that the stomach then digests, dispersing the remaining water out of it's shell. Oysters are thought to be able to process up to 10 litres of water an hour so can vary in quality depending on the quality of the water. Due to their small size and the fact that they don't move once they are adults, oysters are preyed upon by numerous different predators both in the sea and on the land. Humans, birds, marine mammals, sea turtles and various species of fish all prey upon the oyster.

Oysters have varying methods of reproduction. as some oyster species are hermaphrodites and some have separate sexes. Female oysters release millions of eggs into the water, where fertilization occurs externally. The oyster larvae develop within a matter of hours, and spend their first few weeks swimming around until they finally settle and attach themselves to objects, where they remain for the rest of their lives. Today, although now commercially farmed, wild oysters are becoming rarer mainly due to increasing levels of pollution. Although many oysters have adapted to life in poor quality water, they are not as healthy as those oysters that are filtering water that is chemical-free.

No comments:


Albatross Alligator Amphibian Angelfish Ant Anteater Antelope Ape Armadillo Aves Avocet Axolotl Baboon Badger Bandicoot Barb Barracuda Bat Bear Beaver Bee Beetle Binturong Bird Birds Of Paradise Bison Boar Bongo Bonobo Booby Budgerigar Buffalo Butterfly Butterfly Fish Caiman Camel Capybara Caracal Carnivore Cassowary Cat Caterpillar Catfish Cattle Centipede Chameleon Chamois Cheetah Chicken Chimpanzee Chinchilla Cichlid Civet Clouded Leopard Clown Fish Coati Cockroach Collared Peccary Common Buzzard Coral Cougar Cow Coyote Crab Crane Critically Endangered Crocodile Crustacean Cuscus Damselfly Deer Dhole Discus Dodo Dog Dolphin Donkey Dormouse Dragon Dragonfly Duck Dugong Eagle Echidna Eel Elephant Emu Endangered Extinct Falcon Ferret Fish Flamingo Flatfish Flounder Fly Fossa Fox Frog Gar Gazelle Gecko Gerbil Gharial Gibbon Giraffe Goat Goose Gopher Gorilla Grasshopper Grouse Guinea Fowl Guinea Pig Guppy Hamster Hare Hedgehog Herbivore Heron Hippopotamus Horse Human Hummingbird Hyena Ibis Iguana Impala Insect Invertebrate Jackal Jaguar Jellyfish Kangaroo Kingfisher Kiwi Koala Kudu Ladybird Ladybug Larvae Least Concern Lemming Lemur Leopard Lion Lionfish Lizard Llama Lobster Lynx Macaque Mammal Mammoth Manatee Mandrill Manta Ray Marsupial Mayfly Meerkat Millipede Mole Mollusca Molly Mongoose Monkey Moorhen Moose Moth Mouse Mule Near Threatened Newt Nightingale Numbat Octopus Okapi Olm Omnivore Opossum Orang Utan Oriole Ostrich Otter Owl Oyster Pademelon Panda Panther Parrot Peacock Pelican Penguin Phanter Pheasant Pig Pika Pike Piranha Platypus Pond Skater Possum Prawn Primate Puffer Fish Puffin Puma Quail Quoll Rabbit Raccoon Raccoon Dog Rare Rat Reindeer Reptile Rhinoceros Robin Rodent Salamander Scorpion Scorpion Fish Sea Dragon Sea Lion Sea Slug Sea Squirt Sea Urchin Seahorse Seal Serval Shark Sheep Shrew Shrimp Skunk Sloth Snail Snake Spider Sponge Squid Squirrel Starfish Stoat Swan Tamarin Tapir Tarantula Threatened Tiger Toad Tortoise Toucan Turkey Turtle Vulnerable Vulture Walrus Weasel Whale Wildebeest Wolf Woodlouse Woodpecker Worm Zebra