Marine Habitats and Sustainable Fisheries

Additional Pendants Representing Marine Habitats

Marine habitats include all saltwater regions on Earth, the seas and oceans. Approximately seventy percent of Earth’s surface area is covered with oceans and seas that range in depth from coastal tidal marshes to deep sea canyons several miles deep. Although our understanding of marine ecology has improved dramatically in the last century, much remains to be discovered about the diverse life forms that inhabit Earth’s seas, their complexities, and the impacts of human activities on their ecological balance.

Included within Earth’s marine zones are many types of ecosystem. Pelagic, or open water habitats, constitute the majority of Earths seas. These areas are relatively sparsely populated with fish, birds and large sea mammals. Nonetheless they do support adult populations of important commercial fish species.

Coral reefs are one of the seas most diverse and productive marine ecosystems. Their distribution is limited to relatively shallow coastal waters of tropical seas. The rich, colorful and abundant diversity of life found in reefs make them popular recreational destinations as well as ecologically important habitats where many species of fish live and reproduce. They are very important habitat for commercial fishing because they support a higher concentration of life than the deepwater habitat of the open seas. Coral reefs are fragile ecosystems that suffer declines due to sedimentation and pollution from coastal areas and damage from human contact.

Estuaries are also very productive and important saltwater habitats. These coastal ecosystems are where fresh water inputs from land mix with salt water, producing a range of salinities and a rich diversity of life that thrives in the nutrient rich waters of the transitional zone between upland and open sea. Like coral reefs, estuaries are suffering the impacts of pollution and over exploitation that their proximity to land brings. Some positive steps have been taken to protect and restore estuaries in places like the Chesapeake Bay.

The sea floor is one of the last great frontiers of exploration on Earth. In recent decades deep sea submersibles have enabled scientists to explore habitats never before accessible to humans, where they have discovered entire ecosystems which have evolved around the upwellings of warm waters and nutrients at undersea volcanic vents. Scientists speculate that these areas may actually be where life on Earth originated, and that places like them may support life on other planets.

The current status of marine ecosystems worldwide is variable, depending upon the location. Half of all marine productivity and nearly all of the worlds catch of marine fish comes from the coastal zones, which are increasingly degraded due to pollution and over harvesting. Creating sustainable patterns of fisheries management on a global scale will be of increasing importance as mankind’s efficiency of locating and harvesting food from the sea makes it more difficult for natural regenerative process to continue supporting Earth’s growing human population.

Of perhaps greatest concern with regards to the worlds fisheries is the unpredictable consequences of global warming trends on the patterns of ocean currents such as the Gulf Stream, which mix surface and deep sea waters and waters of different temperatures around the globe. These currents are of critical important because they circulate nutrients from deepwater regions to the surface where they provide the necessary nutrients to marine food webs.

CASE STUDY :

Marine Sanctuaries

The United States has more than ten marine sanctuaries located in waters of the Atlantic and Pacific oceans and the Gulf of Mexico. These sanctuaries protect a broad range of habitats including whale migration corridors, coral reefs, kelp forests and deep sea canyons. There are even important underwater archeological sites located within their boundaries. Additionally, sanctuaries provide important recreational and educational opportunities for visitors. To learn more about the US marine sanctuaries and to see a map of their locations, check out the NOAA website: http://www.sanctuaries.nos.noaa.gov