62
R.H. Charlier and Th. Lonhienne
Coastal urbanization by engendering eutrophication has contributed
to primary production and to increased chances of summer distrophies.
Other causes are biological, meteorological, oceanographic and geomorphological. Though not the only culprits, sport fishing and black tides
(oil spills) have brought about a reduction of the grazers' population.
Weather has undergone changes reflected in modification of water
temperature, insolation, amount and distribution of precipitation and
direction of predominant winds. The path of marine currents and
the shape of the coastline play a significant role in "green tide"
occurrence.
Concentrations, in aquaculture basins, of feces and pseudofeces
(undigested food) also contribute to the problems, as in the case of
culture of mussels. In addition, the nitrogen-rich food provided for
salmon also contributes to the eutrophication of fjords. Additional
factors are intensification of fishing and the decimation of marine
mammals.
Algae, foreign to European waters, have added to the nuisance caused
by native species. The Japanese Sargassum muticum invaded Atlantic
and Mediterranean littorals, apparently when Japanese oysters were imported (Crassostrea gigas) because the "Portuguese" oyster could no
longer cope with rising pollution. In some instances small pleasure craft
are hampered by the sometimes massive Sargassum accumulations.
The danger of an accidental introduction of a foreign species is not
illusory. In the case of Caulerpa taxifolia, not less than two ministries
(Ministries of the Sea and of the Environment), one governmental agency
(Maritime Affairs), four scientific and research organizations (IFREMER,
SRETIE, DRAE PACA and CEV A) and the University of Nice-Sophia
Antipolis are involved in the search for a solution to the blooms of this
alga. In 1984, the tropical Caulerpa taxifolia (Vahl) C. Agardh, normally
displayed in the aquarium of the Musee Oceanographique de Monaco,
was accidentally introduced into the sea where it soon thrived in the
waters at the foot of the museum. Unexpectedly it resisted the low
temperatures prevailing there and colonized a wide variety of substrates
(rock, sand, mud). By 1990, it had spread not only to Cap Martin which
is only 3 km from Monaco, but also to Toulon at some 150 km. It is
found as deep as 30 m. Sexual and efficient vegetative reproduction
permit us to expect further spreading. Its toxin (caulerpenyn) is
dangerous for grazers, epiphytes and competitors. Furthermore it is
eaten only by Sarpa salpa (Mediterranean bream); consumption of the
fish is then poisonous to humans (Cigautera poisoning symptoms).
Aquaria, but also mariculture installations thus pose a threat of
pollution, under specific circumstances, of the native waters (Meinesz
R.H. Charlier and Th. Lonhienne
Coastal urbanization by engendering eutrophication has contributed
to primary production and to increased chances of summer distrophies.
Other causes are biological, meteorological, oceanographic and geomorphological. Though not the only culprits, sport fishing and black tides
(oil spills) have brought about a reduction of the grazers' population.
Weather has undergone changes reflected in modification of water
temperature, insolation, amount and distribution of precipitation and
direction of predominant winds. The path of marine currents and
the shape of the coastline play a significant role in "green tide"
occurrence.
Concentrations, in aquaculture basins, of feces and pseudofeces
(undigested food) also contribute to the problems, as in the case of
culture of mussels. In addition, the nitrogen-rich food provided for
salmon also contributes to the eutrophication of fjords. Additional
factors are intensification of fishing and the decimation of marine
mammals.
Algae, foreign to European waters, have added to the nuisance caused
by native species. The Japanese Sargassum muticum invaded Atlantic
and Mediterranean littorals, apparently when Japanese oysters were imported (Crassostrea gigas) because the "Portuguese" oyster could no
longer cope with rising pollution. In some instances small pleasure craft
are hampered by the sometimes massive Sargassum accumulations.
The danger of an accidental introduction of a foreign species is not
illusory. In the case of Caulerpa taxifolia, not less than two ministries
(Ministries of the Sea and of the Environment), one governmental agency
(Maritime Affairs), four scientific and research organizations (IFREMER,
SRETIE, DRAE PACA and CEV A) and the University of Nice-Sophia
Antipolis are involved in the search for a solution to the blooms of this
alga. In 1984, the tropical Caulerpa taxifolia (Vahl) C. Agardh, normally
displayed in the aquarium of the Musee Oceanographique de Monaco,
was accidentally introduced into the sea where it soon thrived in the
waters at the foot of the museum. Unexpectedly it resisted the low
temperatures prevailing there and colonized a wide variety of substrates
(rock, sand, mud). By 1990, it had spread not only to Cap Martin which
is only 3 km from Monaco, but also to Toulon at some 150 km. It is
found as deep as 30 m. Sexual and efficient vegetative reproduction
permit us to expect further spreading. Its toxin (caulerpenyn) is
dangerous for grazers, epiphytes and competitors. Furthermore it is
eaten only by Sarpa salpa (Mediterranean bream); consumption of the
fish is then poisonous to humans (Cigautera poisoning symptoms).
Aquaria, but also mariculture installations thus pose a threat of
pollution, under specific circumstances, of the native waters (Meinesz