Mediterranean
biodiversity and the ecosystems that support it are particularly
sensitive to
human impact, such as tourism,
agriculture, urbanisation, fire, fishing, pollution,
introduction of non-indigenous species...
Population
and mass tourism
The population
of the Mediterranean countries is about 450 million. The population
pressure is increasing because
of tourism. The mild climate and the natural and cultural heritage
attract about one third of world international
tourism, during the summer concentrated along the coastline.
Mass tourism caused enormous transformation of the Mediterranean
area, leading to soil erosion, increasing discharges into the
sea,
destroying
natural
habitat and threatening plants and animals.
Estimation of tourism
during summer season in the Mediterranean
Source: UNEP-RAC,
1995
Industrial
pollution
There are many heavy
industry complexes and large commercial harbours situated in the
north-west area of the Mediterranean.
These harbours are being affected by toxic and persistent pollutants.
Fishing
and mariculture
Fishing
has increased by about 12 % in the past years, with
high exploitation of species as tuna, swordfish, red
coral and many invertebrates.
The Mediterranean sea is one of the few marine areas of the
world with increase in landings of fisheries.
Illegal driftnets are still killing thousands of dolphins and other vulnerable
species every year in the Mediterranean.
A recent WWF report reveals that, with 177 boats, the Moroccan
driftnet fleet is the most lethal for Mediterranean marine
biodiversity.
Between 3000 and 4000 dolphins are estimated to be caught
every year in the Alboran Sea, southwestern Mediterranean,
alone.
This is more
than 10%
of
the area’s dolphin population.
About 23000 sharks are also caught annually by the Moroccan driftnet fleet.
Also mariculture
has expanded greatly.
Alien
species
More
than 500 species entered the Mediterranean between the opening
of the Suez Channel (1876) and 1978. The increase of alien
species has accelerated recently.
In addition to the species that have spontaneously entered
from the South through the Suez Channel, others have been
transported
by
ships and
others have been imported for aquaculture. Some of today's
fish and mollusc fauna consists of alien species introduced
after 1975. Between
these
there is the Red Sea barracuda, often sighted last summer
(2003) in the Tyrrhenian. Some imported species have established
dense
natural populations of commercial interest, e.g. the Red
Sea mullet.
The impact of the intruders on the natural environment is usually negative,
affecting activities such as fishing, aquaculture, shipping, public health
and tourism as well as the equilibrium of the ecosystem. In
fact the "new entries" are much more competitive
than the autocton ones and often replace them.
Some
intruders have had catastrophic effect.The
tropical alga Caulerpa
taxifolia contains a toxin
which may hinder the growth of other organisms. It was recorded for
the first time in the western Mediterranean in 1984 and now threatens
the eastern Mediterranean.
Besides
the alien species phenomenon, there is the increase of the
autocton thermofile fishes, that are migrating from the South
Mediterranean to the North, due to the climate change.
The
Barcelona Convention establishes to take all appropriate
measures to regulate
the introduction of non-indigenous
or genetic modified species and prohibit those
that may have harmful impacts on the ecosystems.
Eutrophication
One effect
of the industrial, agricultural and domestic pollution is
the eutrophication, resulting in massive
phytoplankton blooms. It occurs mainly in the Adriatic,
in the Gulf of Lion and in the northern Aegean.
Microbial contamination
The urban wastewater discharges cause microbial contamination
and represents a potential risk to humans, especially
through the consumption of poisoned
shellfish. The situation has only partly
been mitigated by building urban wastewater treatment
plants in the EU countries along the coast.
Greenhouse effect
The warming trend in Mediterranean deep
waters, that was recorded since 1990, represent one of the earliest
evidence of the greenhouse effect. It is causing negative consequences
on the biological equilibrium of the sea. An
effect is the increasing migration, from the South Mediterranean
to the North, of the thermofile fishes.
Oil
slick
The tanker sinking
sometimes cause ecological catastrophe. In November 2002 the Prestige
tanker toxic oil slick
affected Galician, Cantabric and French coasts. Also the tanker
washing pollutes the sea.
From
European Environment Agency
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