Longline fishing is when we put a very long fishing line in the water with many hooks attached to it. The line can be as long as many football fields put together! Fishermen put the longline out in the water and wait for fish to swim by and get caught on the hooks.
But this type of fishing can be a bit tricky, because sometimes animals that we don't want to catch, like sea turtles or dolphins, can also get caught on the hooks. This can hurt them and is not good for the environment. So, fishermen have to be very careful to only catch the animals they want and let go the ones they don't.
Longline fishing can also have a big impact on the ocean's population of fish. If we catch too many fish with longline fishing, it can be hard for their numbers to grow back because we are taking them out of the ocean too quickly. So, it's important to use longline fishing responsibly and not catch too many fish so that the ocean and its creatures stay healthy.