Mechanized fishing boats are used for:

The correct answer is: a) Deep-sea fishing.

Mechanized fishing boats are used for deep-sea fishing because they are equipped with powerful engines and large nets that can catch fish in deep waters. Near-shore fishing can be done with smaller boats and hand-lines, and river fishing can be done with even smaller boats or even by wading in the river. Aquaculture is the farming of fish, and it is not done with mechanized fishing boats.

Here is a more detailed explanation of each option:

• Deep-sea fishing is done in waters that are more than 100 meters deep. Mechanized fishing boats are used for deep-sea fishing because they are equipped with powerful engines that can travel long distances and large nets that can catch fish in deep waters.
• Near-shore fishing is done in waters that are less than 100 meters deep. Near-shore fishing can be done with smaller boats and hand-lines.
• River fishing is done in rivers. River fishing can be done with even smaller boats or even by wading in the river.
• Aquaculture is the farming of fish. Aquaculture is not done with mechanized fishing boats.