We packed 4 delivery packs with duplicate stocking densities with the aim to check for survival and water quality at 24 and 48 hours.
The stocking densities were 2 by 10,000 yolk-sack larvae and 2 by 40,000 yolk-sack larvae, each in 20 litres of water. There were a range of chemicals added but due to pending trials their information is not listed here.
Each box was a polystyrene foam transport box. The larvae was double bagged and the 20 litres of water was saturated with oxygen with each bag filled with a small quantity of oxygen gas. Each box was also given a small volume of ice to lower the temperature.
These boxes are to be moved and unsettled every time we go past them to try and replicate shipping conditions.
Tonight's egg collection was just under one million eggs, and with an approximate estimation based on tank surface and collection net size we have surmised that the nightly spawning is actually somewhere between 8 and 10 million eggs.
The tank, referred to as Tank 4, which was holding the larvae from the initial trials that had shown phenomenal growth rates, seems to have suffered a catastrophic loss from causes unknown. We relocated the larvae from two tanks to one, and also had not probably initiated artemia feed within a suitable time frame. However, this is just speculation by the group as to the cause of this devastating mortality rate.
Further Reading
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