Salmon are farmed in large net cages in a sea loch.
Explain one way in which fish farming can help to protect biodiversity in the sea.
The salmon in the cages are kept very close together.
Explain why diseases can spread from the farmed salmon to wild fish living in the loch.
Uneaten food and faeces from the cages fall into the water.
Explain how this waste can reduce biodiversity in the loch.
Fish farmers sometimes add pesticides to the water to kill sea lice.
Suggest one way this could harm the ecosystem in the loch.
38 exam-style questions on Edexcel GCSE Biology 9.2 Energy transfer and biodiversity, covering 9.2.1 Energy transfer between trophic levels, 9.2.2 Efficiency of energy transfers, 9.2.3 Human interactions and biodiversity, 9.2.4 Benefits of maintaining biodiversity, and 9.2.5 Biological factors affecting food security. Each one has a worked solution and a mark scheme showing where the marks go.