Threats: Overfishing

Publication - April 8, 2008
One of the biggest threats to marine ecosystems today is overfishing. Our appetite for fish and seafood is exceeding the oceans’ ecological limits with devastating consequences for marine ecosystems, food security and the livelihoods of the 200 million people working directly or indirectly in the global fisheries industry.

Overfishing is a self-destructive cycle fuelled by an increase in global demand for seafood. Demand coupled with technological advances that allow commercial fleets to track and catch unprecedented numbers of marine animals in the pursuit of maximum profit is leaving almost no safe havens for fish in our oceans.

The reality of modern fishing is that the industry is dominated by fishing vessels that far outmatch nature’s ability to replenish fish. Commercial fleets today are essentially giant floating factories equipped to vacuum up huge quantities of marine animals and process and package them before they even get back to shore. Sophisticated tracking devices, indiscriminate catch methods and the sheer volume of a single ship’s capacity mean the fish simply don’t stand a chance.

To make matters worse, fish population dynamics are often poorly understood and international waters are nearly impossible to effectively govern, allowing for potential problems such as pirate fishing, transshipments (offloading catch from one ship to another at sea), and under-reporting of catches. This combination often results in rapid stock declines and serious implications for marine species.

Large predators (such as tuna, marlin, cod and swordfish) are usually the most valuable species and as their stocks are depleted, commercial fisheries begin to ‘fish down the food chain,’ shifting their attention to smaller fish once the larger ones have been fished out. Eventually the entire ecosystem is shifted upsetting the delicate equilibrium that has been established over hundreds of thousands of years of evolution, leaving smaller organisms unchecked. For example, in parts of the Pacific sea urchins have completely denuded kelp forests because their predators have been fished out. As the fish on our plates get smaller, we must ask ourselves what will happen next: will our children be eating jellyfish n’ chips for dinner?

The social implications of overfishing where fishing forms the basis of the economy or livelihood have been felt in coastal communities around the world. For example, in West Africa, European fleets that have exhausted their own waters have moved in, making deals with state governments to fish their waters. While ships suck up fish offshore, low-tech traditional fishing communities for whom fish are often the most important source of protein are noticing sudden plunges in their catch. Once these waters are void of valuable fish, the commercial fleets will move on, leaving small communities with empty nets and hungry bellies.

Here in Canada, the collapse of Newfoundland’s cod fishery and the resulting moratorium has had devastating effects on local and provincial economies that were dependent on the cod fishery as not just a way to eat, but a way of life. The case of the cod fishery could become the norm if fisheries continue to be managed with only profits in mind.