Aquaculture of brine shrimp
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Brine shrimp have the ability to produce dormant eggs, known as cysts. This has led to the extensive use of brine shrimp in aquaculture. The cysts may be stored for long periods and hatched on demand to provide a convenient form of live feed for larval fish and crustaceans.[1]
From cysts, brine shrimp nauplii can readily be used to feed to fish and crustacean larvae just after one-day incubation. Instar I (the nauplii that just hatched and with large yolk reserves in their body) and instar II nauplii (the nauplii after first moult and with functional digestive tracts) are more widely used in aquaculture, for the reasons they are easy for operation, nutrients rich, and of small size which makes them suitable for feeding fish and crustacean larvae live or after drying.
In their first stage of development, brine shrimp nauplii do not feed but consume their own energy reserves stored in the cyst.[2] Wild brine shrimp eat microscopic planktonic algae. Cultured brine shrimp can also be fed particulate foods including yeast, wheat flour, soybean powder or egg yolk.[3]
Reproduction
Adult female brine shrimp ovulate approximately every 140 hours. In favourable conditions, the female brine shrimp can produce eggs that almost immediately hatch. While in extreme conditions, such as low oxygen level or salinity above 150‰, female brine shrimp produce eggs with a chorion coating which has a brown colour. These eggs, also known as cysts, are metabolically inactive and can remain in total stasis for two years while in dry oxygen-free conditions, even at temperatures below freezing. This characteristic is called cryptobiosis, meaning "hidden life". While in cryptobiosis, brine shrimp eggs can survive temperatures of liquid air (−190 °C or −310.0 °F) and a small percentage can survive above boiling temperature (105 °C or 221 °F) for up to two hours.[4][5] Once placed in briny (salt) water (>5‰), the eggs hatch within a few hours. The nauplii, or larvae, are less than 0.4 mm in length when they first hatch. Brine shrimp have a biological life cycle of 1 to 3 months in a controlled environment.[6][7]
