WAS meeting 2003F

Advances in Zebra Danio Spawning, Embryo Development and Larval Rearing Technology : 

Advances in Zebra Danio Spawning, Embryo Development and Larval Rearing Technology BY Dallas E. Weaver, Ph.D. Scientific Hatcheries Huntington Beach, Ca

Existing Technology: 

Existing Technology Remove fish from tanks to spawn Hold embryos in small container with static water supply Daily water changes Possible sex ratio problems Variable survival Grow larva in static tank with limited live feed availability and variable water quality

Existing Technology: 

Existing Technology High Labor Variable results -- fungal/bacterial problems Low Capital Cost If you don’t count facilities (building) cost Easy to observe and manipulate embryos Standard protocols -- SOP Low learning curve cost

New Technology: 

New Technology The Vision of a better system Simple to operate with simple procedures Handles highly variable numbers from a few to several hundred embryos per batch High and consistent survival and rapid growth Ability to go egg to egg in < 50 days Low labor cost Highly automated

New Technology: 

New Technology The Prototype System Scale down commercial aquaculture technology to lab scale system The “Devil is in the Details” Find and fix all the little problems Modifications of a normal Zebra fish rack system -- Aquaneering stand alone system with fluidized bed biofilter.

Spawning: 

Spawning Eliminate moving the fish Spawning traps that go into the tank Screen bottoms Course screen tops A little garland Mounted off the bottom and easy to remove and harvest the embryos

Embryo Development: 

Embryo Development Objectives: Low labor High resistance to fungus and bacterial problems Insensitivity to non-viable eggs in system High hatch rate with strong larva Handle 1 to 2,000 embryos at a time

Embryo Development: 

Embryo Development Fluidized Bed Hatcher (FBH) Offshoot of commercial technology used by Scientific Hatcheries Achieves all the objectives

Larval Rearing System: 

Larval Rearing System Objectives Low labor cost Easy to automate High survival of even “weak larva” Fast Growth Rates Capable of high density operation > 100 per liter densities

Larval Rearing System: 

Larval Rearing System Approach High performance biofiltration to achieve high density and high survival Live feeds in automatic system for continuous feeding (using rotifers) Use fine screens on tanks with air diffusion behind screens (400 µ) -- minimize tank turbulence. Hatch and grow in same tank. Controlled water flow to each tank and system water salinity and pH control

Maturation -- egg to egg time: 

Maturation -- egg to egg time The experiment Four clear tank, Four Black, Four density classes

ResultsEGG to EGG 49 days: 

Results EGG to EGG 49 days