Fishing technique known as trawling can sometimes be productive.

Trawling is a certain fishing method which is basically just an intense raking of the seabed. Usually, it is known to cause much damage to sea life but recently, scientists have studied and found that there are many potential benefits to it. Studies have shown that trawling can create better conditions for the fish. The trawling process usually catches the bigger fish but the smaller fish grow resistant to it and find their way around it which increases population for the smaller fish. Due to the larger population of smaller fish, the larger fish population also increases. Although this is a positive relation to trawling, this really occurs best when the trawling process isn't as intense.

http://www.insidescience.org/content/stirring-ocean-floor-can-boost-fish-populations/1385