Atlantic silverside
Encyclopedia
The Atlantic silverside, Menidia menidia, is one of the most common fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...

 and in the Barnegat Bay
Barnegat Bay
Barnegat Bay is a small brackish arm of the Atlantic Ocean, approximately 30 miles long, along the coast of Ocean County, New Jersey in the United States. It is a long barrier peninsula, as well as by the north end of Long Beach Island...

. It is a common subject of scientific research because has a sensitivity to environmental changes.

The fish is about 15 cm long, mostly silver and white. It eats smaller (biotic) animals and plants – small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, algae, annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...

 worms, shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...

, zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...

, copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...

s, amphipods, squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

, and insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s.

The Atlantic silverside’s predators are larger predatory fish – striped bass
Striped bass
The striped bass is the state fish of Maryland, Rhode Island, South Carolina, and the state saltwater fish of New York, Virginia, and New Hampshire...

, blue fish, Atlantic mackerel
Atlantic mackerel
The Atlantic mackerel , is a pelagic schooling species of mackerel found on both sides of the North Atlantic Ocean. The species is also called Boston mackerel, or just mackerel....

 – and many shore birds, including egrets, terns, cormorants, and gulls.

The abiotic factors the Atlantic silverside needs to survive varies for populations of fish based on their geographical location. A general rule-of-thumb for the species includes an average temperature of 70oF/21oC, a salt content of the water ranging from 0 to 37ppt (Tagatz and Dudley 1961), and a well-mixed body of water to prevent hypoxic
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...

 conditions.

The Atlantic silverside’s habitat is generally near the water’s edge. They are mostly found swimming in brackish waters, such as in the mouths of rivers and streams that connect to the ocean. These small schooling fish have been seen to gather in seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...

beds, which can harbor the nearly defenselss fish some form of shelter from predation as well as provide safe haven for spawning. During winter, most Atlantic silversides swim in deeper water to avoid cold/low temperature. During the summer, most are found in the shallows along the shoreline.

The Atlantic silverside’s defense is to hide in seagrass beds. They are also quick swimmers and their coloration of silver and a little white makes it confusing to predators to determine the direction the fish are heading. The silverside's strongest form of defense is the strength-in-numbers strategy, where fish will school in large numbers to diminish their chances of being the one picked off by a predator.

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