Shrimp
Shrimp are characterized by a semitransparent body flattened from side to side and a flexible abdomen terminating in a fanlike tail. The appendages are modified for swimming, and the antennae are long and whiplike. Shrimp occur in all oceans—in shallow and deep water—and in freshwater lakes and streams.
The gills are reduced in size, and the bases of the appendages are modified into thin gills for the exchange of gases. Oxygen is dissolved in water by means of small extensions (lamellae) on the base of each leg. The shrimp's digestive gland filters out food particles from ingested sand or mud.
The nervous system has two longitudinal nerve cords and a number of smaller ventral nerve cords. The paired, dorsal ganglia usually work as one, controlling the dorsoventral muscles.
The shrimp's compound eye is composed of 16 or more minute lenses (ommatidia) on each side of the head. Each lens is associated with its own sensory cell in the retina, so each point of the external environment is viewed by only one lens. This arrangement, which gives excellent resolution, is found in most crustaceans.
Shrimp that inhabit freshwater but go to sea to breed (anadromous shrimp) include members of the families Atyidae and Palaemonidae, which swim back from saltwater for spawning. Some shrimp migrate many miles upstream; others make short downstream journeys. Usually, only a few eggs are laid in each stream, and these are attached to the adhering gravel on the bottom. The eggs are guarded by both parents until they hatch in 50 to 60 days.
Shrimp are valuable as food for humans and other animals, and they are also important in marine ecology. They are distributed over all the world's coastal waters in numbers that sometimes yield a catch of more than 4 million pounds (1.8 million kilograms) per hour.
Their importance in the commercial fishing industry is great. The United States is the second-largest shrimp producer in the world, next to China. According to U.S. government data cited by Reuters, the country's 2015 shrimp production amounted to 428,000 MT, with exports reaching 460,000 MT.
The U.S.'s aquaculture industry has greatly expanded in recent years due to strong demand. According to the U.S. Department of Agriculture, the country's shrimp production nearly doubled from 197,000 MT in 2010 to 397,000 MT in 2014.
Shrimp are classified in the phylum Arthropoda, subphylum Crustacea, class Malacostraca, order Decapoda. Shrimp have a semitransparent body flattened from side to side and a flexible abdomen terminating in a fanlike tail. The appendages are modified for swimming and the antennae are long and whiplike. Shrimp occur in all oceans—in shallow and deep water and in freshwater lakes and streams.
They have a semitransparent body flattened from side to side with a flexible abdomen terminating in a fanlike tail. Shrimp have a segmented body with a hard exoskeleton and compound eyes, and antennae that can detect smells and vibrations. The appendages are adapted for swimming and the antennae are long and whiplike. They occur in all oceans—in shallow and deep water—and in freshwater lakes and streams. They are mostly detritivores, that is they feed on dead or decaying organic matter (such as animal faeces). Some species are filter feeders; many deposit feed by extracting organic particles from the sediments; some scrape algae off rocks. Individual shrimp congregate in specific areas of the water column where food density is high, and these congregations are termed "bait balls".
They have segmented bodies with hard exoskeletons and compound eyes, their antennae can detect smells and vibrations. Shrimp have Appendages that are adapted for swimming and whiplike antennae. They occur in all oceans, in shallow and deep water, and freshwater lakes and streams. They are mostly detritivores, feeding on dead or decaying organic matter (such as animal faeces). Filter feeders extract organic particles from the sediments, scrape algae off rocks, and some deposit feed by extracting organic particles from the sediments. Shrimp congregate where food density is high in specific areas of the water column- these are called "bait balls."
They have a segmented body with hard exoskeleton and compound eyes, their antennae can detect smells and vibrations. Shrimp have adapted appendages for swimming that are modified into long whiplike antennae. They occur in all oceans- in shallow and deep water- freshwater lakes and streams. They are mostly detritivores, feeding on dead or decaying organic matter (such as animal faeces). Filter feeders extract organic particles from the sediments, scrape algae off rocks, and deposit feed by extracting organic particles from the sediments. Shrimp congregate where food density is high in specific areas of the water column- these are called "bait balls."