Fears over the number of fish left in our seas are making the government change rules about how fishermen net their daily catch.
Because fish like cod, mackerel and tuna are really popular in Europe, everyone wants to catch them.
It's thought around 80% of fish caught is thrown back into the sea - most of it dead - because it's not the right type of fish.
It looks like this practice could be banned if new rules are introduced.
Lots of people, including famous chef Jamie Oliver, are worried that unless we stop catching so many fish, the most popular types will die out soon.
But some fishermen aren't happy about the changes - they say it could lead to them losing their jobs.