Pacific Ocean Threats & Impacts: Habitat Destruction

Habitat Destruction along the coast and in the ocean results from harmful fishing practices such as trawling or dynamite fishing; poor land use practices in agricultural, coastal development and forestry sectors; and other human activities such as mining and anchoring. Destroyed habitats include sea grasses, marshes, corals and mangroves – all of which are important nurseries for fish and critical for buffering coasts from storm damage. Damaging habitat can lead to increased erosion and sedimentation, increased impact from storms, fewer nursery grounds and fewer places for animals and plants to live.

Quick Facts

  • Over 40% of the world's oceans and coasts are heavily affected by human activities and few, if any, areas remain untouched, as highlighted in a recent study from the National Center for Ecological Analysis and Synthesis (2008).
  • Loss of coastal habitat such as estuaries, mangroves and wetlands means loss of nurseries for important fish species and loss of coastal protection from storms.
  • Population growth, large-scale infrastructure developments and extensive land reclamation projects in eastern Asia have greatly altered the coastline.
  • Coastal wetland and peat swamp loss is estimated at 54.9% in Indonesia, 74.1% in Malaysia, 66.7% in the Philippines, 83.7% in Thailand and 36.9% in Vietnam.
  • For the last two decades, Indo-Pacific reefs have shrunk by 1 percent each year—a loss equivalent to nearly 600 square miles (1,553 square kilometers). That makes the rate of reef loss about twice the rate of tropical rain forest loss.

Threats

As human populations expand throughout the Pacific, habitat destruction from various sources—destructive fishing, land-based sedimentation, dredging, marine recreation, typhoons and storms, poor agricultural practices, and coastal development and land reclamation—increasingly impair and devastate productive marine habitats. Destructive fishing includes the use of bottom trawls, gillnets, longlines, dynamite or poisons like cyanide, and indiscriminate netting; a single blast fishing event can destroy thousands of years of coral growth. Land use practices such as deforestation or mining create erosion and sedimentation, which can smother corals. Intensifying pressures to modify and develop coastlines for industry, tourism, agriculture and aquaculture increase the rate and area of habitat destruction. Other poorly designed development projects for roads, housing and urban centers destroy coastal habitats across the Pacific and harm the communities that depend on ecosystem productivity.

Environmental & Socioeconomic Impacts

Habitat destruction can impair and destroy productive marine ecosystems. One major ecological impact derives from increased sediment loads in coastal waters from activities such as logging. Sedimentation, which produces turbidity and limits the penetration of sunlight, affects primary and secondary producers—thus altering food web dynamics. The smothering of coral reefs by sediment also reduces fish and produces ecosystem changes. Chemicals in sediments, such as DDT or heavy metals, may bioaccumulate in marine life as well. Another form of habitat destruction, destructive fishing, indiscriminately kills large numbers of fish and other nearby marine life. By removing target and non-target fish, crustaceans, and other marine organisms, destructive fishing leads to fish mortality, altered recruitment, and changes in food web dynamics.

Habitat loss not only has serious implications for marine species, but also for the viability of Pacific communities. Mangroves, for example, often serve as nursery and recruitment areas for important commercial fisheries, but are often removed for development purposes. Other activities such as the conversion of mangrove ecosystems to shrimp ponds may sacrifice long-term productivity for short-term profit. The destruction of large areas of mangrove forest can result in lower incomes from fishing, reduced local food production and extreme poverty; destructive fishing techniques produce the same impacts. Coastal modification, besides affecting livelihood, can alter natural drainage patterns and increase salinity, thereby threatening water supplies. It can also exacerbate flooding and storm damage, as well as increase inputs of pollutants and sediments into coastal waters. Finally, habitat destruction of all kinds, from mangroves to coral reefs, can impair tourism, recreation, aesthetics and human health.

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