More than half of the fish consumed in the Netherlands is farmed. However, many people are unaware of the fact that farmed fish is not always sustainable. On this page we describe the three biggest problems that play a role in aquaculture: The effects on the environment, the effects on fish farming and problems related to the use of fish feed.
Effects on the environment
We make a distinction between two types of rearing systems, namely an open rearing system and a closed rearing system. Open rearing systems are connected to the sea or to a river and can cause the following problems:
– Pollution of the water by manure, medicines, and chemicals
– Spread of diseases and parasites by infecting wild congeners
– Development of crossbreeding between escaped farmed fish and wild fish
Breeding of fish
Most species you find in aquaculture reproduce in captivity. Mussels, eel, and tuna are exceptions to this rule. These species are caught in the wild and then reared for consumption. Because they cannot reproduce in captivity, the problems of overfishing and harmful fishing techniques persist.
The use of fish food
The amount of fish feed, fish meal and fish oil needed to grow a kilo of fish varies greatly per species. Wild fish is needed to make fish oil and fishmeal. Species such as salmon, turbot, and eel eat a relatively large amount of fishmeal and fish oil. An average of two kilos of wild fish is needed to produce one kilo of salmon. The lower the amount of fishmeal and fish oil per kilo of farmed fish is, the more sustainable it is.