Suggest one reason why two individual rainbow trout of the same body mass might produce different amounts of nitrogenous waste.
The table below shows the mass of nitrogenous waste released into the environment by four different types of fish farms:
| Type of fish | Nitrogenous waste released in kg per 1000 kg of fish produced |
|---|---|
| Rainbow trout | 52.4 |
| Sea bass | 61.8 |
| Salmon | 45.6 |
| Halibut | 68.5 |
Calculate the mass of nitrogenous waste released into the environment when 650 kg of sea bass are produced. Show your working.
High concentrations of nitrogenous waste released into aquatic ecosystems can lead to eutrophication.
Describe the sequence of events in eutrophication and explain how this leads to the death of fish.
To maximize yield, fish farmers use various methods to keep fish healthy and promote growth. One such method is vaccination.
Explain how vaccinating fish protects them against pathogens and thereby improves their growth.
17 exam-style questions on Edexcel IGCSE Biology Excretion. Each one has a worked solution and a mark scheme showing where the marks go.