The study, undertaken by Norwegian researchers, evaluates the optimum weight at which to transfer juvenile salmon (smolts or post-smolts) under a variety of environmental conditions.
The researchers note that the study is inspired by the growing cost of dealing with sea lice, which cause higher mortality, lower harvest weights and a reduction in the quality of harvested salmon.
One of the ways salmon producers are tackling this, they explain, is by extending the land-based phase in the production: instead of releasing smolts of 100-150 g for on-growing in sea, the land-based phase is lengthened to produce post-smolts of up to 1,000 g before transfer.
A longer production period on land means that the sea water phase is correspondingly reduced, with less exposure to sea lice.
“Results indicate that, in the case of no lice, on-growing of 100 g smolts is most cost-efficient. However, as lice costs are considered, the results clearly show that on-growing of post-smolts on land is profitable,” they conclude.
The results are supported by developments in Norway’s salmon growing industry, where increased production of post-smolts is taking place.
The Health and Welfare of Atlantic Salmon course
It is vital that fish farm operatives who are responsible for farmed fish are trained in their health and
welfare. This will help to ensure that fish are free from disease and suffering whilst at the same time
promote good productivity and comply with legislation.
The results of the study were published in Aquaculture Economics & Management, under the title “Economic analysis of on-growing of salmon post-smolts”. The abstract can be accessed here.