The “agitator”: an inexpensive device for culturing large numbers of fragile marine invertebrate larvae

The “agitator”, a device designed for culturing lecithotrophic echinoderm larvae, is described. The unit consists of an open system which is easily constructed and is made up of a base which holds the culturing baskets as well as a lid or manifold carrying a tube which transports fresh seawater into each culture, gently stirring it and eliminating any decaying embryos. The device is scalable and water flow can be adjusted for laminar flow or slow dripping. The method has been used to successfully rear large numbers of lecithotrophic larvae of the starfish Solaster stimpsoni. The agitator could be used to culture any fragile planktonic organisms that require an extended rearing time.