5.3 Impact of Exploitation of the Oceans

📖 Main Content

1. What is a Fishery?

A fishery is an area of the ocean (or another body of water) where fish and other sea creatures are caught in large numbers for food or trade. Fisheries are incredibly important — billions of people around the world rely on fish as their main source of protein (a nutrient that keeps our bodies strong and healthy).

However, when humans catch too many fish, or catch them in harmful ways, serious problems begin to develop. This is called exploitation of fisheries — meaning we are using the ocean's resources in a way that damages them.

2. What is Overfishing?

Overfishing happens when fish are caught faster than they can reproduce (breed and have young). Think of it like spending money faster than you earn it — eventually, you run out.

Fish populations naturally replenish themselves (grow back) over time, but only if enough adult fish are left in the ocean to breed. When too many fish are removed, the population crashes — it falls so low that it cannot recover easily.

Why does overfishing happen?

• There is huge global demand for fish as food
• Modern fishing technology makes it very easy to catch enormous numbers of fish quickly (e.g. large trawler ships, sonar to find fish, enormous nets)
• Some fishing areas have weak rules and regulations, making it hard to control how many fish are caught
• Illegal, unreported, and unregulated (IUU) fishing is widespread in many parts of the ocean

3. Impact of Exploitation of Fisheries

3a. Impact on Target Species

A target species is the specific type of fish or seafood that fishermen are deliberately trying to catch — for example, cod, tuna, or prawns.

When a target species is overfished, the following impacts occur:

• Population decline: The number of fish in the population drops rapidly. This means future catches become smaller and smaller.
• Disruption of the food chain: Fish are part of complex food webs. If one species declines sharply, the animals that eat that species (predators) lose their food source and their populations can also fall. Meanwhile, the prey of the target species (the creatures the fish normally eat) may increase uncontrollably.
• Economic losses: Fishing communities and fishing businesses lose their income as catches shrink. Entire coastal towns that depend on fishing can suffer serious poverty.
• Food insecurity: Many communities — especially in developing countries — rely on fish as their primary source of protein. When fish stocks collapse, people can go hungry.
• Loss of biodiversity: If a species is fished to the point of extinction (dying out completely), that species is lost forever, reducing the variety of life in the ocean.

A well-known example is the Atlantic cod. Cod were once so plentiful off the coast of Newfoundland, Canada, that fishermen described walking on them. By the early 1990s, the population had collapsed due to overfishing, and the fishery was completely shut down. Tens of thousands of people lost their jobs, and cod numbers have been very slow to recover.