Self-contained Upwelling System for Rearing Larval Fishes in the Laboratory

Abstract

The design and operation of a rearing and salinity conversion system is described. This system was developed and successfully used to rear snook (Centropomus undecimalis) from artificially fertilized eggs for the first time. The system consists of a 300-L glass aquarium with a biological filter and four 8-L flow-through rearing chambers. The rearing chambers consist of acrylic tubing 20 cm in diameter, friction-fitted into vacuum-formed styrene funnels. Each chamber is individually plumbed to produce an up welling current by introducing water at the bottom and discharging it near the top. Eight screened openings cut into the acrylic tubing assure an even, gentle flow through the chambers. Snook were reared through the early larval stages in salt water and then converted to fresh water. As many as 35 snook per chamber were reared through the conversion process and stocked in earthen freshwater ponds. Use of this system enabled the evaluation of the foods, feeding behavior, and growth of larval snook under laboratory conditions; investigations of the freshwater tolerance of young snook; and the preservation of a larval series from which the early development of snook could be described.