Pacific Ocean Threats & Impacts: Overfishing and Exploitation

Overfishing from overexploitation of fisheries by subsistence, artisanal, recreational and commercial fishing can result in the mortality of target and non-target species (including top predators, reproductively immature juveniles, marine mammals, sea birds and sea turtles). This mortality, in turn, impacts the economy, impacts other species in the ocean, as well as further threatens endangered species.

Quick Facts

  • Since the early 1990s, total catches in the Okhotsk Sea have been reduced by 2 to 2.5 times due to overfishing; this portion of the Pacific contains some of the world’s richest fishery resources.
  • 55% of Pacific island countries unsustainably manage their coral reef fisheries.
  • A study published in the journal Nature shows that 90 percent of all large fishes have disappeared from the world's oceans in the past half century, a result of overfishing.


Among all of the threats facing the Pacific Ocean, overfishing exerts one of the most severe impacts on both the environment and society. Many of the commercially important fisheries throughout the Pacific, from the Okhotsk Sea to the Humboldt Current, have collapsed or shown severe declines. International tuna fleets often fish unsustainably in waters controlled by small countries, strip stocks to low levels and move on. Fishing on the high seas for top predators such as sharks has made these creatures rare across the Pacific. By-catch further reduces fish stocks when large numbers of non-target species with low economic return are discarded as waste back into the ocean. Artisanal, recreational and subsistence fishing can be just as destructive as commercial fishing, especially if destructive techniques such as blast or poison fishing are used.

Environmental & Socioeconomic Impacts

Overfishing and exploitation can devastate an entire marine ecosystem. Unsustainable resource use reduces fish stocks throughout the Pacific. When highly-fished top predators disappear, altered recruitment trends affect the food web. Overhunting of herbivores results in uncontrolled growth of algae and seaweeds, which can smother corals and other bottom-dwelling organisms. Overall, the mortality of target fish from the ocean, as well as by-catch and the increased discards of fish that enter the ocean as food, can change food web dynamics and cause ecological shifts that further reduce biodiversity and productivity.

Besides impairing the marine ecosystem, overfishing and exploitation can also devastate human livelihood and sustainability. Many Pacific societies, particularly those in Southeast Asia, Central America and the South Pacific islands, depend on commercial or artisanal fishing for daily survival. These communities suffer when local needs outstrip local supply. What may result is displacement of fishing activity, reduced income and an insecure food supply. Habitat destruction exacerbates overfishing by reducing fishable area and productivity. Overfishing and exploitation also affect tourism.  For example damaged coral reefs can deter popular recreational activities such as snorkeling.

Click here for key readings about overfishing and exploitation's threat to and impact on the Pacific Ocean.