Okay, imagine there is a big part of the ocean where fish live and swim around. This part of the ocean is like their home. We call this place a fish stock.
Now, just like how we have houses for humans, fish also have their own homes in the ocean. They live in something called habitats, which are areas where they can find food, shelter, and stay safe from bigger fish that might want to eat them.
Fish stocks are like big communities of fish living together in a specific area of the ocean. Each fish stock has different types of fish living in it. Some fish stocks might have lots of different kinds of fish, like salmon, tuna, and cod, while others might have mostly just one type.
People like to catch fish for food because they're delicious and healthy. But if we catch too many fish from a fish stock, it can be a problem. Just like if you ate all the cookies in the cookie jar and didn't leave any for later. If we don't leave enough fish in the fish stock to grow and have babies, then the fish stock can become smaller and smaller. This is called overfishing.
When a fish stock gets overfished, it means there might not be enough fish left for everyone who wants to catch or eat them. This can be a big problem for fishermen, because if there are fewer fish, they won't be able to catch as much. It can also cause problems for the fish themselves, because they need to have enough fish buddies around to make new baby fish.
To make sure we don't overfish a fish stock, scientists and governments help keep track of how many fish are being caught and make rules about fishing. They might say things like "You can only catch a certain number of fish each day" or "You can only catch fish of a certain size." These rules are called fishing regulations.
The governments also sometimes create areas in the ocean called marine protected areas. These protected areas are like fish nurseries or safe havens where fish can grow and breed without getting caught. It's a bit like a special room in your house where you keep all your toys safe, and nobody is allowed to take them away from you.
By following these rules and creating protected areas, we are making sure that there are always enough fish in the fish stocks. This way, fishermen can keep catching fish for food, and the fish stocks can stay healthy and continue to provide homes for the fish.