Aquatic Dictionary is an online dictionary made from your definitions. The aquatic world defined!
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1 definition of Artemia nauplii.
The brine shrimp is a relatively primitive form of crustacean of the class Brachiopoda (so named for the gills on their legs). The lack of a true carapace places them in the suborder Anostraca, and further in the family Artemiidae. There is still disagreement as to the number of species listed in the genus Artemia. Brine shrimp are naturally found in lakes or pools having extremely high salinities. The fact that these bodies of water regularly dry out and then fill again is thought to be one of the selective pressures that charted the mode of reproduction (i.e., cyst production) characteristic of the Artemia currently exploited in the aquaculture industry. While the adult form is primarily used as a live, frozen, or freeze-dried food in the aquarium trade, the nauplius stage is used exclusively in fish hatchery operations. Adult stages of the brine shrimp exhibit both oviparity and ovoviviparity. With ovoviviparity, both fertilized and parthenogenic eggs can undergo full development within the adult until the free swimming nauplius stage. Oviparity in Artemia is characterized by fertilized eggs becoming arrested at the blastula stage of development. These are encased in a complex shell that is impermeable to most substances. Production of cysts is initiated by changes in environmental conditions such as an increase in salinity. The cysts are shed from the body and desiccated osmotically or dried on the shores of pools or lakes. The desiccation process is thought to be necessary for further development after the cysts are rehydrated. It was recognized long ago that freshly hatched Artemia nauplii are a high value feed for fish larvae and fry. Because of the size of the nauplius stage, Artemia also represent the only practical food source for the early stages of many fish and crustacean larvae (Bardach 1972), but using them as a larval food is not foolproof. For example, the dry weight and caloric content of nauplii can decrease as much as 25% within 24 h after hatching when kept at 25 C. This means the nauplii must be fed to the larvae as soon as possible after hatching or be stored at low temperatures to decrease their rate of metabolism. Another drawback is that they have been found to be nutritionally deficient, especially in the long chain polyunsaturated fatty acids (PUFAs). The later shortcoming, however, can be corrected by enrichment of the Artemia nauplii.
Source: Stephen Single, June 22, 2004
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