By Dr M. Sommer
The oceans, which contain 90 percent of the world's living biomass and are the primary source of food for more than 3.5 billion people, are currently severely degraded due to pollution, overfishing and excessive urban growth. coastal.
There are times when the hardest decision is to admit the obvious. It is obvious that throughout the world national economies are based on goods and services derived from ecosystems, as well as that human life depends on the capacity of these ecosystems to continue to provide their multiple benefits. Yet in rich and poor countries alike, development priorities have long focused on what we can extract from ecosystems, without taking too much account of the impact of our actions.
About 40 percent of the world's population lives within 100 km of the coastline, an area that barely represents 20 percent of the land mass. Coastal populations are increasing, and as they increase, the pressure on coastal ecosystems also grows.
Four out of 10 people live 100 km from the coast. Tourism is the fastest growing sector of the world economy; in 1999 its value was estimated at US $ 3.5 billion. Although it is known that there are areas that have been degraded by tourist activity - particularly coral reefs - the inverse effect that coastal degradation has on this sector of the economy is still unknown.
We are currently in the midst of a global marine crisis. Coastal and marine resources, and the ecosystems on which they depend, are showing signs of collapse.
· Approximately 50 percent of the world's coastal ecosystems (eg, including coral reefs, mangroves, and seagrasses, etc.) have already been altered or destroyed, by increasing demand from cities, industries, aquaculture, tourism etc. The modification of the coastline as a consequence of human activity has altered currents and sediment deposits to the benefit of some beaches but to the detriment of others. Coastal habitats that have a natural buffering and adaptive capacity are being modified by urbanization and replaced by artificial structures.
This is how the impact of waves during storms has increased, which has intensified coastal erosion, loss of habitat, and the growth of salinity in freshwater aquifers.
Even more serious, a rise in sea level is projected as a consequence of global warming, which may threaten several coastal settlements and some island states. Climate change and rising temperatures could lead to rising sea levels by as much as 95 centimeters by the end of this century. The Atlantic, Pacific and Indian Oceans have been warming slowly by an average of 0.06 degrees Celsius since 1955 due to the greenhouse effect.
· Half of the world's wetlands were lost in the 20th century. In the last 50 years, about 85 percent of the mangroves in Thailand, the Philippines, Pakistan, Panama and Mexico have been lost.
· Indiscriminate logging and conversion have halved the world's forests with the consequence of increased erosion and cloudiness of rivers.
· Fishing fleets are 40% larger than the oceans can support.
· About 95 percent of the world's marine fish harvest lives in coastal waters.
Fish and shellfish provide almost one sixth of the animal protein consumed by people around the world. About 1 billion people, mostly in developing countries, depend on fish as their main source of protein.
Production from marine fisheries has increased six times since 1950, but the annual rate of increase in marine capture fisheries decreased from 6 percent in the 1950s and 1960s to 0.6 percent in 1995-96. Fishing for low-value species has increased as the removal of high-value species has stabilized or decreased, thus masking some of the effects of overfishing. Almost 75 percent of the major marine fish stocks are either overfished or being taken to their biological limit. Trawling techniques are harmful and destroy habitats for reproduction.
· Since 1980, the size of the global economy has tripled, while the population has increased by 30% to 6 billion people. Population increases and conversion for urbanization, agriculture and aquaculture purposes are leading to the reduction of mangroves, coastal wetlands, seagrass areas and coral reefs at an alarming rate.
· Two thirds of aquaculture depends on the coastal ecosystem (mangroves, grasslands, coral reefs etc). As mangroves, coastal wetlands and seagrasses decrease in size, coastal habitats lose their ability to act as filters for pollutants and organisms.
The indicators of habitat loss, disease, invasive species and coral bleaching (greenhouse effect) all show that biodiversity is declining. Sedimentation and pollution from the land are suffocating some coastal ecosystems, while in certain areas trawling is reducing diversity. Some commercial species such as Atlantic cod, five kinds of tuna and pollock are threatened worldwide, along with several species of whales, seals and sea turtles.
· Of the total freshwater fish species, 20% are extinct, threatened or endangered.
· About half of the world's coastal ecosystems (eg, including coral reefs, mangroves, and seagrasses, etc.) are currently at risk of being fully degraded.
· It is estimated that more than 70 thousand synthetic chemicals have been discharged into the world's oceans. Only a small percentage of them have been monitored, and this corresponds to those related to human health and not to ecological impact. The increase in pollution levels is linked to the increasing use of synthetic chemicals and fertilizers.
· The explosive increase in harmful algae off the US coasts has involved, since 1991, nearly $ 300 million in losses due to massive fish kills, public health problems, and decreased tourism. In fact, the increasing frequency of algal blooms and hypoxia indicates that some coastal ecosystems have lost their ability to absorb polluting nutrients. Invasive species cause the interruption of the food chain, causing the elimination of native species.
· The increase in pollution from inland and the loss of habitats capable of filtering pollution have caused the expansion of hypoxic zones. These correspond to areas lacking oxygen and, therefore, with little marine life.
· The increase of foreign species in the coastal zones, produce the interruption of the food chains by eliminating the native species.
In recent years, 480 invasive species have been identified in the Mediterranean, 89 in the Baltic Sea and 124 in Australian waters. In the Black Sea the introduction of the Atlantic jellyfish has caused the collapse of the fishery. It is estimated that 3000 different species are transported in the ballast of ships.
Human dependence on marine resources and the massive migration of humans to coastal areas are increasing around the world. With the increase in global population, poverty, and hunger, human confidence is placed in the fishing industry to be able to face the livelihood of humanity in the coming years.
Fish represent at least one fifth of the total animal protein consumed on earth.
Fishing provides in developing countries between 40 and 100 percent of the total animal protein needed by the population.
Of the estimated 51 million fishermen in the world, 95 percent of them are in developing countries. 98 percent of these 51 million fishers are small-scale operators. To prevent further overexploitation and degradation of coastal and marine resources, we rely on them.
COASTAL MANAGEMENT. CHALLENGE FOR BETTER MARINE PROTECTION BY POLITICIANS AND CITIZENS:
* Work in cooperation with other groups, with local governments, as well as with industrialists and traders in order to find alternatives to eradicate the placement in the ocean of dirty sludge sediments and municipal garbage (sewage collectors), often dangerous.
* Support actions for the removal of debris that float in the waters or that reached the shores of the beaches. The coast guard or military can get involved in these tasks, alongside local groups of citizens who campaign on weekends.
* Control urban drainage waters, an important source of ocean pollution. Everything that appears thrown into the streets, into sinkholes or ravines and in vacant lots is possible that reaches the sea, rivers or lakes of the area. Rain washes waste into local sewers and contributes large amounts of sediment, food, bacteria, and toxic chemicals (organics, heavy metals, oil, and grease).
* Support initiatives by international authorities and organizations to prohibit the use of large-scale haulage nets, as well as other destructive techniques on the high seas anywhere in the world.
* Work with state and federal authorities to protect a habitat where a critical situation exists, whether by establishing protected areas or marine sanctuaries. All major coral reefs should be included in this definition. Each citizen can encourage his government to establish economic incentives in order to protect threatened ecosystems and to deactivate the tendency to destroy them, requesting to suspend economic investment initiatives that promote developments in vulnerable coastal areas.
* Locate marine pollution and its source. Oceans and coastal areas need to be protected from harmful waste, including industrial toxic waste, radioactive waste and dirty sludge.
The experts in Coastal Management increasingly recognize the need to change the focus from the pure research of biological and physical science, to a more comprehensive study of social, economic, institutional and political situations.
A crucial step towards caring for marine ecosystems is to make an inventory of their conditions and capacities to continue meeting our needs. However, such a global assessment of the state of marine and coastal ecosystems has yet to be done.
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