Alitta Succinea
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''Alitta succinea'' (known as the pile worm, clam worm or cinder worm) is a species of marine
annelid The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...
in the family Nereididae (commonly known as ragworms or sandworms). It has been recorded throughout the North West Atlantic, as well as in the
Gulf of Maine The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America. It is bounded by Cape Cod at the eastern tip of Massachusetts in the southwest and by Cape Sable Island at the southern tip of Nova Scotia in the northea ...
and
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
.


Description

''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 clam worm can reach up to in length, but most specimens are smaller than this. It is brown colored at the rear, and reddish-brown on the rest of its body. It has an identifiable head with four eyes, two sensory feelers or palps, and many
tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
s. The head consists of two segments: the anterior and posterior
prostomium The prostomium (From Ancient Greek, meaning "before the mouth"; : prostomia; sometimes also called the "acron") is the Cephalization, cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not in ...
. The last body segment is known as the pygidium. The jaws of the clam worm are partly composed of
zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
, making them lightweight compared to calcified jaws, whilst still maintaining strength.


Ecology and behavior

To feed, it uses a
proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...
, 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
crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s, 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 of 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.


Life cycle

''Alitta succinea'' is a freeswimming
polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...
, scavenging on the bottom of shallow marine waters. It feeds on other worms and algae. They can protect themselves by secreting a mucous substance that hardens to form a sheath around them. During
lunar phase A lunar phase or Moon phase is the apparent shape of the Moon's directly sunlit portion as viewed from the Earth. Because the Moon is tidally locked with the Earth, the same hemisphere is always facing the Earth. In common usage, the four maj ...
s in the spring and early summer, the clam worm undergoes epigamy. Their
parapodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; : parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed late ...
enlarge so they can swim. The clam worms are then capable of releasing eggs and sperm. Soon after they have released their eggs or sperm, they die.
Plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...
ic
larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
e develop, grow into adults and eventually sink to the bottom of the water.


Reproduction

Like most of its fellow polychaetes, ''Alitta succinea'' reproduces sexually. Fertilization normally occurs externally, and the sexes are separate. Epitoky is a process that occurs in polychaete, where a sexually immature worm (apitoke) is transformed into a sexual mature worm (epitoke). There are 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 an enhanced swimming ability (parapodia enlargement), body cavity filled with gametes, large eyes, and 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, and swarming increases chances of fertilization. Environmental factors can also trigger swarming, such as temperature, salinity, light levels, and the lunar cycle. Reproduction normally occurs around early spring, and may extend into the summer. Both sexes die after swarming 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 larvae, which later metamorphose into juveniles, which in turn develop into adults.


Economic importance

''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.


Dispersal

''A. succinea'' is dispersed outside of its native range in the course of
oyster farming Oyster farming is an aquaculture (or mariculture) practice in which oysters are bred and raised mainly for their pearls, shells and inner organ tissue, which is eaten. Oyster farming was practiced by the ancient Rome, ancient Romans as early as the ...
and
fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment (Freshwater ecosystem, freshwater or Marine ecosystem, marine), but may also be caught from Fish stocking, stocked Body of water, ...
, on the
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but no ...
s themselves, in ballast water, as hull fouling, on normal
ocean current An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...
s, and possibly in sport fishing bait.


References

{{Taxonbar, from=Q2465819 Phyllodocida Annelids of the Atlantic Ocean Fauna of the Black Sea Fauna of the Caspian Sea Animals described in 1847 Taxa named by Rudolf Leuckart