Fishing for money is a very dangerous job, because people can die or be badly hurt. Fishing gives a lot of food to many countries around the world, but those who take it as a job must often go far into the ocean under bad conditions. Commercial fishermen get many kinds of sea animals. This includes fish such as tuna, cod, and salmon, as well as invertebrates such as shrimp, lobster, clams, and squid. Alaskan king crab fishing is a famous example. Ways to fish for money have become very simple, using large nets and machines to catch the animals. Many countries have made rules limiting how much fish people can catch, because some kinds have become scarce.