If we count 800 spat per slot * 25 slots, we are looking at approximately 20,000 oysters per spat catcher. If we want to produce 100 tons of grown oysters, that would mean we need approximately 50 spat catchers.
Estimating yearly yields
So lets give it a go based on Zapco’s common knowledge, if I’m correct the oyster from start to finish would take you around 3 years to grow out due to the cold climate conditions.
So lets start with a 75 – 85mm market size pacific oyster with a weight of 60g to 70g each = Approximately 15 – 16 oysters per 1KG, 10 tons = 155,000 oysters.
You will have to add a mortality rate of minimum 40% yes this is high but it is necessary due to the long period to produce the Oysters. This will bring the require oysters you need to 217,000 oysters per year to enable you to produce 10 tons of oysters each year.
The required volume of Spat traps you will need is 30 Based on a Minimum catch of 300 per Spat Catcher.
You have to keep in mind, each year spawning will vary, some years there is huge amount of Spat spawned compared to other years. It is always better to have too much than not enough. (PLEASE REMEMBER THIS IS BASED ON MARKET SIZE OYSTERS 75mm to 85mm).
