Marine salmon farming in open-net cages is a major method of food production globally, providing a significant source of protein.
An aquaculture manager operating sea cages in a coastal fjord notices several challenges affecting their salmon stock.
Suggest the cause of each problem and a solution for the manager:
(i) An increase in marine mammalian predators, such as harbor seals, attacking the cages.
(ii) A severe drop in dissolved oxygen levels within the cages.
(iii) A rapid spread of sea lice (parasitic copepods) among the salmon.
Suggest two advantages of farming salmon in controlled sea cages compared to harvesting wild salmon.
