Hatching devises recognized by AquaSearch
AquaSearch recognizes only three principal types of hatching devises, all characterized by the fact that water flow is forced upwelling trough the microenvironment surrounding the eggs. ‘Water is “lacy”, and if allowed to bypass the eggs, the counter pressure of the eggs will result in exactly this, and the eggs will suffocate. E.g., floating a mesh in a fry trough or simply pouring eggs into a trough with a certain water flow from one end to the other will not support survival and normal hatching.
The three principal types of recognized hatching devises are:
- Zuger jars
- California type trays and troughs
- Vertical stacked incubators of a certain minimum standard (MariGold®, MariSource®, or similar).
And to summarize, upwelling waterflow is a mandatory feature for any hatching devise to be recognized by AquaSearch.
“Zuger” is the Sir name of the inventor of this device. A Zuger jar is basically, an inverted open cylinder with a forced waterflow from the bottom and up and a mesh to support the eggs in the bottom of the device. Zuger jars are the safest way of hatching eggs. Waterflow can easily be controlled and adjusted and cannot flow in any wrong directions. Uniquely also to this solution, individual units typically have a parallel water supply, and all eggs will receive water of the same quality and oxygen content. Unfortunately, the method is also the most space consuming, and is not practical for larger quantities of eggs. For hatching purposes, the jars can only be stocked with limited layers and volume of eggs (8 – 10 layers, if waterflow is adjusted correctly).
California type trays and troughs
This hatching devise consist of individual serial trays with a tight fit inside a shallow trough. Trays are perforated in the bottom and the top of the one side turning away from the water inlet. In combination with a tight fit to the sides and the bottom of the trough and correct dimensions, this design result in an upwelling waterflow. A lot of examples are available in the Market, and it is recommended to use thoroughly tested versions only. The relation between bottom mesh area, egg density (counter pressure) and outlet mesh area does matter, and cannot be ignored e.g., by simply upscaling the size of the trays or changing the length to width dimensions. Most versions in the market will require min. 8 – 10 l / min waterflow and min. 8 mg / l oxygen saturation with an even distributed 3 – 5 egg thickness layers of eyed eggs for hatching.
Vertical stacked incubators
These devises are the more space efficient solution, but also the more technical, demanding, and risky solution. Although most vertical stacked incubators do work by upwelling principle, waterflow capacity is typically limited by pipes and tubing, and for the devises to secure water exchange in the microenvironment of the eggs, they must be 100 % level. Furthermore crooked or lopsided trays, out of level installation, or suboptimal oxygen levels cannot be compensated for, by increased waterflow, as it is often seen done with e.g. California type trays and troughs. Attention should be paid also to the quality of the devises. Some vertical stacked incubators are of such appalling quality, that waterflow will find its own alternative ways after short time use