Credit: Gabriel Salvo (Chile)
These two photos illustrate models of off-shore cages. Such cages could be square with approximate dimension of 15-30 meter per side and circular cages with diameters that range from 15-30 meters. Depth of cages ranges from 10-30 meters.
The principal species farmed in these cages are Atlantic salmon, Salmo salar, Coho salmon, Oncorhynchus kisutch and rainbow trout, Oncorhynchus mykiss. The growing season starts during winter-spring and lasts for 14-16 months for the first species and 8-12 months for the two other species. Average weight upon harvest is largely determined by market demand and ranges from 4-5 kg for Atlntic salmon and 2.8-3.2 kg for the other two species.
Depending on farmed species and cage size as well as stocking density and length of growing season, harvested weight of about 240-280 tons of Salmo salar per cage is a good estimate. Cage productivity may range from 140-190 tons for coho salmon and 140-320 tons for rainbow trout.