Nursery rearing of mussel spat up to seed

In Fig. 11.12, each down-welling unit consists of a plastic or PVC cylinder with an initial 150 pm nylon screen mesh fitted to it by covering one of their 

Another method involves rearing the spat, previously settled on different types of collector ropes, in circular or rectangular flowthrough tanks into which the collector ropes are either directly hung or introduced in down-welling units (Fig. 11.13). 

In the three types of approach, spat culture tanks were supplied with a flowthrough circulation of filtered sea water. Size of filter used can vary, depending on the specific environmental conditions of each culture situation the amount of seston or the presence of wild fertilised mussel eggs, embryos or even larvae in the incoming sea water, for example. Thus, while 

Estimation of the rearing density is a more complex process and depends upon the type of substrate used for rearing the spat ropes or screens. 

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