User:2cool4school99/Alitta succinea, geographic range

Description and Characteristics
The Alitta succinea has a long, elongated, cylindrical body divided into 160 segments, with four eyes, and two antennae on the front, resembling a pear shape with the posterior of its body being longer. The anterior of the Alitta succinea is a brownish color. At the same time, the rest of the body, prostomium, can vary in color ranging from green, greenish-yellow, or a pale reddish color with the appearance of white or dark dots. The anterior is divided into 2 branches, the dorsal lobe (notopodium) and the prechaetal lobe, which then branches into smaller lobes called ligules.

Geographic Range
They are able to live in a range of temperatures from 0.9°C- 36°C, as well as a range of salinities from 0.14-80 ppt. Because of their ability o live in such a large salinity range, they live in areas of brackish water as well as saltwater. This allows us to know that Alitta succinea has the ability to live in very different areas worldwide. Due to this ability Alitta succinea is known to be introduced to new areas due to fouling on ships, oyster transport or even in areas where they are used as bait. They will continue and thrive. Alitta succinea is usually found in and/or on soft substrates from the intertidal to the subtidal regains.

They are native to the Northern Atlantic waters. Alitta succinea have been introduced into the Caspian Sea by humans starting in the late 1930s. They were introduced in order to increase food recourses for the commercial fishing industry, they were used as bait.

Habitat Preferences
The species Alitta succinea has been known to tolerate a variety of different habitats, some which include soft sediment, mud/sand bottoms,  rocky reefs, and oyster beds. A. succinea can occur in habitats which are cold-temperate to tropical. Although Alitta succinea was first recognized in the North Sea in 1847 from the German island of Helgoland, it continues to be considered as cryptogenic on both sides of the North Atlantic''. A. succinea'' has a strong tolerance for variations in oxygen saturation, including hypoxic circumstances, and can thrive in both euryhaline and eurythermal environmental settings.

Ecology
To feed, it uses a proboscis, which has two hooks at the end, to grasp prey and draw it into its mouth. Clam worms are an important food source for bottom-feeding fish and crustaceans, though they also feed on different species of aquatic plants such as algae and diatoms. By feeding on organic matter and types of waste and debris that is in the surrounding water the worm is commonly classified as a deposit feeder, more specifically omnivorous. They are also commonly preyed upon and an important food source for many animals. Crab, fish, and shorebirds are the most common predators for the clam worm. Populations in the Caspian Sea are heavily influenced by the predation of fish. The species was brought over to the Caspian Sea to increase the fish populations for the use of commercial fishing.

Alitta succinea have been recorded to be indicators of imbalances in their habitats. Populations in the Black Sea have been shown to indicate changes in the water chemistry. Die-offs of the species can occur when there are hostile environmental changes in the habitats they live in. Shore bird populations commonly decline when populations of the clam worm dissipate.

Reproduction
Alitta succinea reproduce sexually like most of the class Polychaetea. Commonly known as the clam worm, fertilization normally occurs externally and the sexes are separate. (sexual reproduction). Epitoky is a process that occurs in polychaete, where a sexually immature worm (apitoke) is transformed into a sexual mature worm (epitoke) two methods of Epitoky (schizogamy and epigamy).
 * Schizogamy where atoke is formed from division of the organism into sexual and asexual parts. Asexual reproduction to produce buds from its posterior end. Each bud into an epitoke and once fully formed, will then break off from atoke and become free swimming.


 * Epigamy is the other method of morphological modifications. Typically, female and male worms undergo a metamorphosis to epitoke where they become even better swimmers and carry gametes.

When Sexual maturity is achieved individuals who metamorphose into a nektonic (free swimming) heternoneid form (free swimming di-morphic sexual individual). It is similar to the non reproductive form of the worm however, the parapodia are more apparent (larger) and can be lobal. Modifications of the heternoneid form may include a enhanced swimming ability (parapodia enlargement), body cavity filled with gametes, large eyes, incomplete gut formation. Females produce a pheromone attracting and signaling males to shed sperm which in turn stimulates the females to shed eggs, this feature is known as swarming. Both sexes swim to the surface to release gametes. It is Said that Alitta succinea  reproduction can be in sync with Lunar cycles. Normally occurs around early spring and may go into summer. Both sexes die after releasing gametes and after fertilization most eggs become planktonic, although some are retained in the worm tubes or burrow in jelly masses attached to the tubes (egg brooders). Eggs develop into trochophore Larva, then metamorphosis later into juvenile (body lengthen), and later develop into adults.

Economic Importance
The Alitta succinea was first introduced to bodies of water to enhance the salinity and bring in new hybrids of fish that could be sold for a larger quota. In the present day, Alitta succinea is used in different wildlife situations to determine the pollutants present, their levels, and how they affect the wildlife in that area. Additionally, Alitta succinea is used as bait for fishing, resulting in increased fish, crab, and oyster harvesting in newly restored reefs on the mainland.