Base your answers to questions 16 through 18 on the passage below and on your knowledge of biology.
Fish Farming
Approximately 44% of the world’s fish produced for human consumption comes from aquaculture, which is the farming of fish and other aquatic organisms. This practice has increased the food supply and has also allowed over-fished wild populations to increase. As a result of genetic modifications, farm-raised fish usually grow faster and are typically larger than those in the wild.
However, there are some negative environmental effects associated with fish farming. Sea lice, a parasite of salmon, have spread quickly through some farms and have also been found in waters around the farms. Farm-raised fish sometimes escape through breaks in the sea cages. There is a concern that these escaped fish could negatively affect ocean ecosystems.
Researchers are studying methods that can be used to reduce the possible negative effects of fish farming. Improvements in engineering could make the sea cages where the farmed fish are raised more secure. Another suggestion involves raising farmed fish that have extra chromosomes. This would prevent them from reproducing with wild fish that have the normal number of chromosomes.
