2 Monitoring of Marine Aquaculture
65
This is not surprising since it is well known that, in particular, Posidonia oceanica is a very sensitive endemic species in the Mediterranean that has been
shown to suffer population reductions due to anthropogenic stress (Marbà et al.
2005).
All the above indicate that there are many different ecological processes and
biotic communities affected by aquaculture. Some of these may be easily detected
and monitored, such as the effects on macrofauna, although these are usually confined to a small area beneath and around fish farms. Others, such as water quality
and plankton dynamics, need new protocols for assessing the degree of change
imposed by aquaculture and further research to increase our understanding of the
related processes. Monitoring of fish communities seems to be a promising tool
for integrating the effects at larger spatial scales although there is need for defining
exact protocols, while taking account of fisheries and habitat heterogeneity. In the
Mediterranean and the tropics, the effects on seagrasses are probably the most
important since they are related to key ecological species with prime importance
for biodiversity. However, there is a need to study further these impacts and to
gather long term monitoring data in order to have a conclusive picture of the processes and the risks involved. In any case, it should be emphasized that each one of
these groups of variables indicates processes operating on different spatiotemporal
scales and therefore monitoring focusing only on one group can hardly be a proxy
for the entire health of the ecosystem.
2.2 Monitoring Environmental Impact from Norwegian
Aquaculture
2.2.1 Introduction
During the last 30 years, Norway has developed an aquaculture industry based on
production of marine fish, mainly Atlantic salmon (Salmo salar L). In 2005
580,000 metric tonnes of salmon and approximately 60,000 metric tonnes of other
fish species and shellfish were produced. Norwegian aquaculture facilities are
located along 2,000 km of coastline with numerous fjords and archipelagos and a
temperature regime that is favourable for cultivation of cold-water species. More
than 1,800 sites are located in the fjords and archipelagos where they are protected
from the open sea but where water movement is sufficient to maintain production.
Initially, fish farm facilities were placed in shallow areas but today many sites are
located at a depth exceeding 100 m. Due to the natural conditions and a well-developed infrastructure, the coast is well suited for aquaculture. During the growth of
the aquaculture industry and in concert with the increase in production, a number
of environmental effects and problems have been encountered. Some of these have
been minimized or resolved whereas others have increased in importance and new
ones have emerged.
65
This is not surprising since it is well known that, in particular, Posidonia oceanica is a very sensitive endemic species in the Mediterranean that has been
shown to suffer population reductions due to anthropogenic stress (Marbà et al.
2005).
All the above indicate that there are many different ecological processes and
biotic communities affected by aquaculture. Some of these may be easily detected
and monitored, such as the effects on macrofauna, although these are usually confined to a small area beneath and around fish farms. Others, such as water quality
and plankton dynamics, need new protocols for assessing the degree of change
imposed by aquaculture and further research to increase our understanding of the
related processes. Monitoring of fish communities seems to be a promising tool
for integrating the effects at larger spatial scales although there is need for defining
exact protocols, while taking account of fisheries and habitat heterogeneity. In the
Mediterranean and the tropics, the effects on seagrasses are probably the most
important since they are related to key ecological species with prime importance
for biodiversity. However, there is a need to study further these impacts and to
gather long term monitoring data in order to have a conclusive picture of the processes and the risks involved. In any case, it should be emphasized that each one of
these groups of variables indicates processes operating on different spatiotemporal
scales and therefore monitoring focusing only on one group can hardly be a proxy
for the entire health of the ecosystem.
2.2 Monitoring Environmental Impact from Norwegian
Aquaculture
2.2.1 Introduction
During the last 30 years, Norway has developed an aquaculture industry based on
production of marine fish, mainly Atlantic salmon (Salmo salar L). In 2005
580,000 metric tonnes of salmon and approximately 60,000 metric tonnes of other
fish species and shellfish were produced. Norwegian aquaculture facilities are
located along 2,000 km of coastline with numerous fjords and archipelagos and a
temperature regime that is favourable for cultivation of cold-water species. More
than 1,800 sites are located in the fjords and archipelagos where they are protected
from the open sea but where water movement is sufficient to maintain production.
Initially, fish farm facilities were placed in shallow areas but today many sites are
located at a depth exceeding 100 m. Due to the natural conditions and a well-developed infrastructure, the coast is well suited for aquaculture. During the growth of
the aquaculture industry and in concert with the increase in production, a number
of environmental effects and problems have been encountered. Some of these have
been minimized or resolved whereas others have increased in importance and new
ones have emerged.