347
have been made. These outbreaks occurred from
time to time when the coral cover of the reefs is
optimum but without any defi ned cycle. Such was
the case on the Great Barrier Reef in the 1970s
and 1980s or in French Polynesia in 1978–1982
and 2006–2007 (Salvat et al. 2008 ; Adjeroud et al.
2009 ), and recently, they provoked 42 % of coral
mortality (De’ath et al. 2012 ).
The phenomena of coral bleaching correspond
to the break of the association between the coral
and its symbiotic algae. This is generally a
response to heat stress especially at positive
temperature anomaly of ocean waters in the summer. These phenomena may lead to colony mortality if stress is too important depending upon
the temperature differential and the duration of
the anomaly. These bleaching events affecting
mortality of large coral reef areas have increased
over the last 50 years with the warming of ocean
waters. The 1980s saw the development of this
bleaching mortality to several large areas of the
Indo-Pacifi c and Caribbean (Brown 1997 ;
Wilkinson and Souter 2008 ; Eakin et al. 2010 ;
Salvat et al. 2008 ; Burge et al. 2014 ). These
events are consistent with the IPCC report in
2013 indicating that the surface ocean temperature has risen by 0.85 °C since 1880 and a tenth
of a degree per decade since 1971, 0.4 °.
Diseases and epidemics affecting reef animals
over large geographic regions are also the cause
of major degradations whose causes are not
clearly elucidated (Sutherland et al. 2004 ). These
disturbances have been very important in the
Caribbean and have changed the structure of reef
communities (Gardner et al. 2003 ; Weil and
Cróquer 2009 .) such as loss of Acropora or mortality of the sea urchin Diadema . These deceases
are often linked to bleaching coral mortality
(Willis et al. 2004 ) or other factors such as wastewater (Sutherland et al. 2011 ) or abundance of
macro-algae (Nugues et al. 2004 ).
Anthropogenic disturbances have developed
since the mid-twentieth century (Salvat 1987 ).
Most anthropogenic coral reef degradations
occurred in the early 1960s with the destruction
of corals or annihilation by sedimentation caused
by land mismanagement of the watershed or the
massive releases of untreated wastewater with
their nutrients: smothering reefs, fi ll or excavation
on fringing reef areas for construction of airports
or ports, expansion of urban areas and hotel complexes, organic pollution profi ting to algae to the
detriment of corals, etc. (Ryther and Dunstan
1971 ; Banner 1974 ; Endean 1976 ; Salvat 1978 ,
1987 to name but precursors papers).
The pesticide pollution of reef communities
seems general but in varying concentrations
according to region and their uses in urban and
agricultural areas (Ramade and Roche 2006 ). It
has a few drawbacks to public health through the
consumption of fi sh or invertebrates. The presence of several organochlorine insecticides
(HCH, aldrin, DDT) was reported in organisms
of the Great Barrier Reef in Australia (Shaw et al.
2010 ) and even in the centre of the Pacifi c, French
Polynesia, with chlordecone or kepone (Roche
et al. 2011 ; Salvat et al. 2012 ). The presence of
the herbicides, group of triazine and substituted
urea (diuron) and chloroacetic acid derivatives
both in Australia (Lewis et al. 2009 ) and in
French Polynesia (Salvat et al. 2012 ) is a concern
for coral reef health given the concentrations
found and considering the considerable sensitivity of symbiotic algae of corals to these molecules that inhibit photosynthesis (Ramade and
Roche 2006 ).
Overfi shing is responsible for a very signifi -
cant degradation of reef communities not only
by the plunder of resources by a population
more and more numerous, especially in
Southeast Asia and in areas where the subsistence economy is still valid, but also because of
the progress of technology in place for fi shermen since the 1970s: aluminium boats, engines
and net-nylon diving equipment. Moreover, the
development of the economy, often related to
tourism, induces a local commercial fi shery
which requires more exploitation. Fisheries are
threatened by a scarcity of resources in some
regions (Newton et al. 2007 ), and more than half
of fi sheries in the South Pacifi c are considered
unsustainable (Bell et al. 2009 ). Such a situation
is the same in the Indian Ocean (McClanahan
et al. 2011 ) and in the Caribbean (Paddack et al.
2009 ). Many species of fi sh reproduce by
spawning aggregations at certain times of the
Health and Degradation of Coral Reefs: Assessment and Future
have been made. These outbreaks occurred from
time to time when the coral cover of the reefs is
optimum but without any defi ned cycle. Such was
the case on the Great Barrier Reef in the 1970s
and 1980s or in French Polynesia in 1978–1982
and 2006–2007 (Salvat et al. 2008 ; Adjeroud et al.
2009 ), and recently, they provoked 42 % of coral
mortality (De’ath et al. 2012 ).
The phenomena of coral bleaching correspond
to the break of the association between the coral
and its symbiotic algae. This is generally a
response to heat stress especially at positive
temperature anomaly of ocean waters in the summer. These phenomena may lead to colony mortality if stress is too important depending upon
the temperature differential and the duration of
the anomaly. These bleaching events affecting
mortality of large coral reef areas have increased
over the last 50 years with the warming of ocean
waters. The 1980s saw the development of this
bleaching mortality to several large areas of the
Indo-Pacifi c and Caribbean (Brown 1997 ;
Wilkinson and Souter 2008 ; Eakin et al. 2010 ;
Salvat et al. 2008 ; Burge et al. 2014 ). These
events are consistent with the IPCC report in
2013 indicating that the surface ocean temperature has risen by 0.85 °C since 1880 and a tenth
of a degree per decade since 1971, 0.4 °.
Diseases and epidemics affecting reef animals
over large geographic regions are also the cause
of major degradations whose causes are not
clearly elucidated (Sutherland et al. 2004 ). These
disturbances have been very important in the
Caribbean and have changed the structure of reef
communities (Gardner et al. 2003 ; Weil and
Cróquer 2009 .) such as loss of Acropora or mortality of the sea urchin Diadema . These deceases
are often linked to bleaching coral mortality
(Willis et al. 2004 ) or other factors such as wastewater (Sutherland et al. 2011 ) or abundance of
macro-algae (Nugues et al. 2004 ).
Anthropogenic disturbances have developed
since the mid-twentieth century (Salvat 1987 ).
Most anthropogenic coral reef degradations
occurred in the early 1960s with the destruction
of corals or annihilation by sedimentation caused
by land mismanagement of the watershed or the
massive releases of untreated wastewater with
their nutrients: smothering reefs, fi ll or excavation
on fringing reef areas for construction of airports
or ports, expansion of urban areas and hotel complexes, organic pollution profi ting to algae to the
detriment of corals, etc. (Ryther and Dunstan
1971 ; Banner 1974 ; Endean 1976 ; Salvat 1978 ,
1987 to name but precursors papers).
The pesticide pollution of reef communities
seems general but in varying concentrations
according to region and their uses in urban and
agricultural areas (Ramade and Roche 2006 ). It
has a few drawbacks to public health through the
consumption of fi sh or invertebrates. The presence of several organochlorine insecticides
(HCH, aldrin, DDT) was reported in organisms
of the Great Barrier Reef in Australia (Shaw et al.
2010 ) and even in the centre of the Pacifi c, French
Polynesia, with chlordecone or kepone (Roche
et al. 2011 ; Salvat et al. 2012 ). The presence of
the herbicides, group of triazine and substituted
urea (diuron) and chloroacetic acid derivatives
both in Australia (Lewis et al. 2009 ) and in
French Polynesia (Salvat et al. 2012 ) is a concern
for coral reef health given the concentrations
found and considering the considerable sensitivity of symbiotic algae of corals to these molecules that inhibit photosynthesis (Ramade and
Roche 2006 ).
Overfi shing is responsible for a very signifi -
cant degradation of reef communities not only
by the plunder of resources by a population
more and more numerous, especially in
Southeast Asia and in areas where the subsistence economy is still valid, but also because of
the progress of technology in place for fi shermen since the 1970s: aluminium boats, engines
and net-nylon diving equipment. Moreover, the
development of the economy, often related to
tourism, induces a local commercial fi shery
which requires more exploitation. Fisheries are
threatened by a scarcity of resources in some
regions (Newton et al. 2007 ), and more than half
of fi sheries in the South Pacifi c are considered
unsustainable (Bell et al. 2009 ). Such a situation
is the same in the Indian Ocean (McClanahan
et al. 2011 ) and in the Caribbean (Paddack et al.
2009 ). Many species of fi sh reproduce by
spawning aggregations at certain times of the
Health and Degradation of Coral Reefs: Assessment and Future