STUN & MAINTENCANCE TUBES [page]:
The stun tube renders the fish unconscious within 1 second. The maintenance tube maintains the fish in the electric field to ensure the fish remain unconscious. The length of the stun and maintenance tubes will be determined by the speed of stunning, the species of fish, and the quantity of fish.
Typically, for 12 tonnes per hour the size of tubing is:
Salmon, cod, yellowtail 8 -12m at 12” diameter
trout, tilapia, bass and bream 6-8m at 8” diameter
tilapia and halibut see HSU