One of my family members used to have a home out in a forested area, with access to a lake that had lots of fish in it. Not long after the fall of the soviet union, someone bought one of the nearby properties, and started fishing the lake with explosives. Within several years the lake had basically no fish left because of how indiscriminant the fishing method was. The family member and some of the other people who had access to the lake finally managed to drive out the dynamite-laden arsehole, but by then the damage was done. Even 20+ years later the fish population in the lake hasn't recovered.