It may be difficult to know the exact number of fish in the oceans, but their significant importance in achieving ecological balance cannot be overlooked. Fish come in all shapes and sizes, from small sardines, guppies, and blennies that you might see on coral reefs to large tuna and whale fish found in the open ocean. Fish play crucial roles as both predators and prey within ocean ecosystems. Thousands of species throughout the oceans and terrestrial ecosystems rely on fish for food, including humans.
In coral reef ecosystems, larger fish and other marine animals eat smaller fish. This means that small fish form the base of the food web, providing energy for larger fish and other creatures. On land, many birds, mammals, and reptiles eat fish and depend on them as a primary protein source. Even terrestrial plants can benefit from the presence of fish. On the U.S. West Coast, salmon returning to streams after spending several years at sea act as a conveyor belt for nutrients. Salmon not only feed on the animals that catch them, such as bears, but also on the plants that border waterways.
Humans also rely on fish as a food source. Fish and other seafood products are an important source of protein for about 3 billion people. When fish hunt for food, they can create and maintain vital habitats for other living organisms. In coral reef ecosystems, fish that eat plants control algae growth by continuously grazing on it. Without the help of plant-eating fish, algae would rapidly grow, suffocating corals and effectively killing them.
Although many fish species are confined to the ocean, their presence can be felt in many habitats. They can directly and indirectly affect the lives of organisms that depend on them for food and shelter. Without fish, the Earth would gradually lose its beautiful white sandy beaches, coral reef ecosystems would become choked with algae, many people would struggle to find food to eat, and we would lose some of the most magnificent creatures on this planet.
