Author
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Ludwig, Gerald |
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Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only Publication Acceptance Date: 10/15/2006 Publication Date: 2/26/2007 Citation: Ludwig, G.M. 2007. zooplankton succession in fingerling production ponds [abstract]. Book of Abstracts Aquaculture America. p. 553. Interpretive Summary: Technical Abstract: Many pond cultured species require a range of zooplankton species for consumption before they can be weaned onto manufactured feed. The widest variety of plankton species develops when empty ponds are filled and fertilized. Use of organic and inorganic fertilizers facilitates the development of bacteria and phytoplankton blooms which quickly turn a pond green. They are grazed upon by the protozoans and then rotifers which may appear in massive populations. Very tiny fry, such as those of sunshine bass, golden shiners or yellow perch, should be stocked just before the rotifer bloom. Within a short time copepod nauplii, instars, and then adults appear along with cladocerans and ostracods. Predation by some cyclopod copepods, grazing competition by calanoid copepods and cladocerans, and reduction of food resources decimates the rotifer bloom and replaces it with longer lived and larger species. If small fry are stocked at this time sufficient food may not be available and they may be preyed upon by cyclopoid copepods. Rotifers that appear later in succession are generally larger than those in the initial bloom. Rotifers in colonies up to 4 mm in diameter may also appear then. Larger fry that do not require rotifers can be successfully stocked after that bloom, however they should be in the pond well before large populations of predacious insects make their appearance. Species’ population changes in ponds in a particular geographical area are usually predictable each year. The speed at which succession within a pond occurs is mainly a factor of water temperature while pond nutrients may greatly affect the amount of zooplankton present. |
