Shellfish biological characteristics

The lifestyle of shellfish varies from species to species. The terrestrial species are gastropods, and they crawl on land with muscular feet.

The types of aquatic lifestyles include floating, swimming, crawling, fixation, perforation and parasitism. The types of floating life are all living a floating life in the water with the current. Generally, the individuals are small, with thin or no shells. Some species have specialized fins, such as Pteropoda and Heteropoda. Some species can secrete a floating sac and carry animals. Float on the surface of the ocean, like a sea snail (Janthina). The species of swimming life can migrate long distances in the ocean, such as cuttlefish, calamari, and Ommastrephes in the cephalopods. Their feet are specialized into wrists and funnels, with fins on both sides of the carcass, which are sprayed by the funnel. The swing of water and fins can swim quickly and smoothly. Certain bivalves such as scallops, Chlamys, Amussium, and Lima are not species for swimming life, but they can be relied on the sharp opening and closing of the shells and the tentacles of the mantle when necessary. The role of butterfly swimming in the sea. Most aquatic shellfish live in benthic camps, crawling, crawling on the bottom, or digging holes in the bottom to live in seclusion, or attach to other foreign objects. For example, jade snails and bullacta (Bullacta) crawl on the bottom of the mud, abalones, horseshoe snails (trochus), and turban snails (Turbo) crawl on the rocks. Some nudibranchs such as manatees (Doris) and radishes living in fresh water Radix, Planorbis, etc. all crawl on aquatic plants. 

Their feet are particularly muscular, and the plantar surface is wide and flat, suitable for crawling. Many benthic shellfish live in buried camps, and most of the bivalves belong to this type. Their feet are muscular and shaped like axe blades. They are suitable for digging in the mud beach and bury their bodies underneath. Such as Venus, Tellina, Solen, and Sea beetle ( Mya) Wait, they rely on well-developed inlet and outlet pipes to communicate with the bottom surface to feed and breathe. Some bottom-dwelling shellfish live in camps, such as mussels, scallops, and clams (Anomia), etc. The feet can secrete foot silk to attach to rocks, coral reefs, other shells or objects. Oysters, Chama (Chama), Spondylus (Spondylus), etc. live on external objects as a scallop shell, and these species generally do not move after being fixed. Some benthic shellfish live in burrows on foreign objects such as rocks, coral reefs, shells, bamboo and wood. 

They are also known as perforating creatures, such as Lithophaga, some species in the Pholadidae family, and Saxicava. , Teredo, Martesia, Xylo-phaga, etc., all rely on well-developed water pipes to communicate outside the cave, drawing sea water for breathing and ingesting tiny organisms and organic debris in the water Wait as food. There are also parasitic life in shellfish. The ectoparasites, such as Stilifer, parasitize in the gullet groove of the echinoderms wrist; the endoparasites, such as Entovalva, parasitize in the esophagus of the anchor sea cucumber.