292
the development of commercially exploited fi sh
species, these artifi cially enhanced areas are
intended to increase the levels of primary production and stock recruitment. Additionally, parts of
these zones are protected as no-take zones or
areas where bottom trawling is prohibited; measures were voluntarily implemented by local fi shers organizations. From the perspective of marine
ecosystem recovery, these sites have been created
to ensure sustainable marine communities, nurturing not only commercially valuable fi sh stocks
but also the larger surrounding environment in
this region. These efforts have been successful in
contributing to the enhanced harvest of fi sh
stocks and brought stability of marine ecosystem
in the areas.
Regarding the socio-ecological context of
those projects, it shall be noted that those projects are designed and managed on the basis of
the Satoumi concept, that is, “High productivity
and biodiversity in the coastal sea area with
human interaction” (Yanagi 2008 ). And both
implementations of marine ranching were not
simply the technological solution to aggregate
local productivity of stock but also facilitated by
local fi shers who are engaged with communitybased activities to restore nursery habitats, such
as sea grass beds. Thus, those projects contribute to the greater challenge that has been
amounted to arguing the continued relevance of
the “community” effort of coastal management.
We argue that the orchestrated attempt to recover
and recreate coastal ecosystem with strong initiative of fi shers communities is critical in the
face of increasing environmental challenges,
such as climate change and loss of biodiversity,
to recompose the unity and resilience of coastal
living and environment.
2
Okayama Coastal
Environment and Fisheries
The two marine ranching projects introduced
here are both deployed in Okayama Prefecture,
facing Japan’s largest enclosed body of ocean,
the Seto Inland Sea. The area has rich marine
heritage with 20 commercial fi shing towns where
fi shers are engaged with small-scale fi sheries and
low-impact aquaculture including seaweed and
oyster farming, whose total production covers
approximately 25 % of the entire fi sheries production in the Japanese coast.
Ecologically, this high productivity originated
from the unique oceanographic environment of
the inland sea. The sea has two distinctive hydrographic features, including numerous narrow
channels (seto) between more than 3,000
scattered islets and wider body of open sea with
gradual water circulation (nada). The sea accumulates micronutrients released from river
basins, while the channel itself conveys the water
slowly to resuspend the sediment and maintain
healthy turbulence.
However, there has been constant decline of
fi sh catch and little recovery of the stock due to
the rapid coastal development which initially
started in the 1950s (lost 60 % of costal natural
habitat by 1980) and the continuous fi shing
pressure, though moderate but constant for some
species. This has called for the urgent stock
recovery plan, which considered the use of
ecosystem- based approach and the involvement
of fi shing communities to be appropriate for the
unique biophysical characteristics of the area and
socioeconomic context, especially its role to
sustain the ownership and interest in the conservation of fi sh stock as well as marine ecosystem
among the stakeholders, especially the fi shing
communities.
3
Historical Degradation
of Marine Habitats
in Okayama
Up to the 1940s, 10 % of the marine area was
covered by mud fl at and sea grass bed, providing
spawning and nurturing habitat for various
marine species. After the 1980s the sea area was
changed by large-scale reclamation and landfi ll,
almost 90 % of those mud fl at and sea grass
bed have disappeared and were also polluted by
various land and sea activities, such as 35 years
of aggregate extraction, large-scale oil spill,
herbicide from inland agriculture, and mercury
T. Tanaka and Y. Ota
the development of commercially exploited fi sh
species, these artifi cially enhanced areas are
intended to increase the levels of primary production and stock recruitment. Additionally, parts of
these zones are protected as no-take zones or
areas where bottom trawling is prohibited; measures were voluntarily implemented by local fi shers organizations. From the perspective of marine
ecosystem recovery, these sites have been created
to ensure sustainable marine communities, nurturing not only commercially valuable fi sh stocks
but also the larger surrounding environment in
this region. These efforts have been successful in
contributing to the enhanced harvest of fi sh
stocks and brought stability of marine ecosystem
in the areas.
Regarding the socio-ecological context of
those projects, it shall be noted that those projects are designed and managed on the basis of
the Satoumi concept, that is, “High productivity
and biodiversity in the coastal sea area with
human interaction” (Yanagi 2008 ). And both
implementations of marine ranching were not
simply the technological solution to aggregate
local productivity of stock but also facilitated by
local fi shers who are engaged with communitybased activities to restore nursery habitats, such
as sea grass beds. Thus, those projects contribute to the greater challenge that has been
amounted to arguing the continued relevance of
the “community” effort of coastal management.
We argue that the orchestrated attempt to recover
and recreate coastal ecosystem with strong initiative of fi shers communities is critical in the
face of increasing environmental challenges,
such as climate change and loss of biodiversity,
to recompose the unity and resilience of coastal
living and environment.
2
Okayama Coastal
Environment and Fisheries
The two marine ranching projects introduced
here are both deployed in Okayama Prefecture,
facing Japan’s largest enclosed body of ocean,
the Seto Inland Sea. The area has rich marine
heritage with 20 commercial fi shing towns where
fi shers are engaged with small-scale fi sheries and
low-impact aquaculture including seaweed and
oyster farming, whose total production covers
approximately 25 % of the entire fi sheries production in the Japanese coast.
Ecologically, this high productivity originated
from the unique oceanographic environment of
the inland sea. The sea has two distinctive hydrographic features, including numerous narrow
channels (seto) between more than 3,000
scattered islets and wider body of open sea with
gradual water circulation (nada). The sea accumulates micronutrients released from river
basins, while the channel itself conveys the water
slowly to resuspend the sediment and maintain
healthy turbulence.
However, there has been constant decline of
fi sh catch and little recovery of the stock due to
the rapid coastal development which initially
started in the 1950s (lost 60 % of costal natural
habitat by 1980) and the continuous fi shing
pressure, though moderate but constant for some
species. This has called for the urgent stock
recovery plan, which considered the use of
ecosystem- based approach and the involvement
of fi shing communities to be appropriate for the
unique biophysical characteristics of the area and
socioeconomic context, especially its role to
sustain the ownership and interest in the conservation of fi sh stock as well as marine ecosystem
among the stakeholders, especially the fi shing
communities.
3
Historical Degradation
of Marine Habitats
in Okayama
Up to the 1940s, 10 % of the marine area was
covered by mud fl at and sea grass bed, providing
spawning and nurturing habitat for various
marine species. After the 1980s the sea area was
changed by large-scale reclamation and landfi ll,
almost 90 % of those mud fl at and sea grass
bed have disappeared and were also polluted by
various land and sea activities, such as 35 years
of aggregate extraction, large-scale oil spill,
herbicide from inland agriculture, and mercury
T. Tanaka and Y. Ota