Housing system
Aquaculture Sea Cage
Confining farmed fish at sea
What it is
Floating rings hold large nets in coastal or offshore water, confining thousands of fish in a single pen. Water passes through the mesh; the fish cannot.
Where it sits in the system
The cage concentrates feeding, growth, treatment, and harvest into one enclosure in open water. A whole crop is handled as a single unit.
Welfare concern
Fish are held at densities they cannot escape, and when parasites, disease or poor water quality take hold in a pen there is nowhere inside it to go. Handling, crowding for treatment or harvest, and predators at the net add to it.
Worth being precise about
Density, site, species, monitoring, and regulation vary between farms, and so do the conditions inside the net. Open water does not by itself mean space or health, and fish that escape reach wild populations.
