The Impact of Shark Overfishing Essay Example



Overfishing is defined as the rate at which catching fish is substantially higher than the rate at which fish reproduce and restock in its population. Each species plays an important role in how they interact with the environment to sustain balance in the ecosystem. Overfishing is one of the biggest thrivers of the extinction of oceanic wildlife. An increase in overfishing can result in a cascade of effects that will negatively impact marine habitats and the living organisms dwelling in the marine ecosystem. One such species that has been increasingly overfished are sharks. According to Ocean Preservation Society, sharks are the prime targets of overfishing mainly in high demands of their fins. It is estimated that over 70 million sharks are killed in the process of providing the luxury dish of shark fin soup each year. 

There is limited research pertaining to the shark's ecological role in maintaining a healthy oceanic ecosystem. It was not until this past decade with the sudden decline in its population have researchers begun to become aware of the possible negative impacts on the ecosystem. It is concluded, however, that top predators play an important role in shaping the marine food web. Sharks are defined to be apex predators who do not have much competition in the food chain, therefore these predators feed on species that are below the shark's food web. This behavior regulates the populations of their prey which in return helps keep the marine ecosystem in balance. Studies have shown that the behavior of apex predators consuming animals lower in the food web has benefitted the survival of coral reefs. 

A further benefit in the conservation of coral reefs allows the promotion of the diversity of species. Algae and coral reefs maintain a mutual relationship between the two, allowing both to benefit, however, overgrowth of algae promotes the degradation of coral reefs. Removing apex predators such as sharks can affect the food web which promotes the overgrowth of algae. Sharks help maintain the population of their predators which contains both herbivores and carnivore fishes. The herbivorous fish feed on algae, allowing corals to thrive. Overfishing of sharks depletes the number of this apex predator causing a shift in the food web. In the absence of sharks, carnivorous fish such as groupers may overpopulate and consume more abundance of herbivorous fishes. Higher consumption of herbivorous fishes induces less consumption of algae. The imbalance in the food web results in the overgrowth of algae and degradation of coral reefs. The sudden shift of coral reef decrease in abundance will ultimately result in the decrease of species biodiversity in marine ecosystems. A brief study on the decline of sharks in Jamaica demonstrates the parallel connection with the decrease in coral reefs. Over the past 40 years, shark abundance in Africa has significantly decreased and been replaced with herbivorous fish. Although there are fewer predators of the herbivorous fishes, the herbivorous fishes were unable to repopulate enough to control the spreading of algae. With the abundant switch in the abundance of sharks, corals have decreased from 50% to an estimated 5% while algae cover more than 90% of the reefs. Jamaica is a direct example in which the marine ecosystem could be negatively impacted by the decline of sharks.