1.Pond fish can make use of naturally occurring food, while cage grown fish only have a limited access natural food since they cannot forage on their own.Cage grown fish therefore needs to be fed by the farmer to a much higher extent. The food that is given to the cage grown fish also has to be nutritionally complete, e.g. contain proper amounts of all necessary vitamins and minerals.

2.When fish grown in cages instead of ponds, most farmers opt for a high stocking density. A high stocking density creates a stressful environment for the fish and stress damages the immune system. The risk of disease is therefore high. The risks will be increased further if the farmer fails to provide the fish with optimal water conditions and a satisfactory diet. Cage culture can introduce or disrupt disease and parasite cycles,change the aquatic flora and fauna and alter the behaviour and distribution of local fauna.

3. If proper water exchange is not there, the uneaten feed and metabolic waste released from cages will lead to eutrophication of the site.

4.Predators can be attracted to the cages and for that additional protection has to be provided such as
predator nets

5.Poaching is easy because fish are confined in a small area

6.Marine cages face problems like fouling and is more expensive

7.Storms can damage the cages.

8.When cages are installed indiscriminately, its impact on environment and biodiversity is adverse and it will have influence on current flow and increase local  sedimentation

9.Since cages occupy open water sources, it may affect navigation in the area, or reduce landscape value of that area and are vulnerable to pollution from any source.

In short disadvantages can be stated as follow---

  • Feed must be nutritionally complete and kept fresh.
  • Low Dissolved Oxygen Syndrome (LODOS) is an ever present problem and may require mechanical aeration.
  • The incidence of disease can be high and diseases may spread rapidly.
  • vandalism and poaching is potential problem.
  • Starting up a fish farm can be expensive, particularly in saltwater environments.
  • Fish farming requires more initial investment than some other traditional fishing methods

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