Rotifera

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Taxonavigation

Kingdom: Animalia
Sub Kingdom: Eumetazoa
Super Phylum: Protostomia
Phylum: Rotifera
Class: Monogononta - Digononta - Bdelloidea - Seisonidea


Introduction

Commonly referred to as rotifers.

Represented world wide and predominantly found in freshwater environments. Species are also found in marine and terrestrial environments.

Characteristics

An elongated or saccate (sac or pouch like) multicellular organism found mostly in freshwater environments, however marine and even terrestrial species are known. Latin for "Wheel Bearer", Rotifera are so named due to a ciliated oral structure known as a corona, a common characteristic of the phylum. A very diverse group of animals ranging in size from 0.05 to 2mm [1], typically free swimming although attached and crawling species have been identified. Rotifers are a commercially important species due to their wide acceptance by many cultured organisms as a "first food", used extensively in aquaculture and fish breeding for nauplii and larvae development.

Captive Care

Easily cultured in small volume containers through to large intensive aquaculture systems and prefer low flow, high flow can inhibit feeding. Require little to no lighting. Voracious feeders, rotifers can quickly multiply and entirely consume cultured algae blooms in aquaculture ponds. Their diet primarily consists of algae, bacteria, diatoms and organic particulates. Rotifers can grow and reproduce at a phenomenal rate with doubling rates ranging from 5 days down to as little as 9 hours [2].

Culturing

Culturing rotifers requires a starter culture of rotifers, a food source (algae, yeast, etc), a container, water and air pump. Add rotifers to the water filled container with low, gentle aeration, feed regularly and consistently (cultures may crash if the food source is depleted). Feeding example: 1ml of algae concentrate per litre, per day. Harvest the rotifers regularly, from 1/3 to 1/2 of the culture per day, by draining the container by the harvested volume and refilling with new water and feed. Regular and consistent feeding and harvesting will allow the culture to reach an equilibrium point based upon the amount of feed input and organisms harvested. Containers should be kept reasonably clean to avoid a build up of ciliates, cultures should be strained, containers cleaned and refilled and cultures restarted with fresh feed. Lighting is not a requirement. Heating may be required to keep optimum metabolism and reproduction rates (~25C).

Classification

Gallery

Resources

References

  1. (Campbell 1992): Campbell, N., Biology, 3rd ed., The Benjamin/Cummings Publishing Company, 1992.
  2. (Landau 1992): Landau, M., Introduction to Aquaculture, John Wiley and Sons, 1992

Invertebrate Zoology, Edward Ruppert and Robert Barnes, Saunders College Publishing, 1994.