7 NGO Approaches to Aquaculture
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7.2 Key Concerns of NGOs Related to Aquaculture
There are hundreds of small, negative impacts that can be associated with aquaculture and they vary by species produced and production system. However, the major
impacts of aquaculture have been clearly documented and remain a relatively short
list, which can be broken down into environmental, social, and food safety impacts.
There is an extensive body of literature as well as significant ongoing research on
these impacts, which are briefly described here.
It is important to note that although a number of major impacts of aquaculture
have been clearly identified, there is much debate about the extent and frequency
of these impacts. There remain a number of issues where scientific consensus has
not yet been reached and where there is poor and often contradictory data.
7.2.1 Environment Impacts
Impacts of aquaculture on wild fauna and flora are the cause of many of the concerns about the industry. It is important to note that the bulk of the concerns relate
to the production of fish and shrimp, especially carnivorous species, rather than to
filter-feeding shellfish and seaweeds. Though not without potential negative impact,
production of filter-feeding bivalve molluscs and seaweeds result in a different suite
of positive and negative impacts than the production of other species because they
remove nutrients from the water column and do not require feed (Boyd et al. 2005;
Shumway et al. 2003). These species typically rank well in NGO evaluations of
culture at a broad species level, and are not an area of focus for NGOs concerned
with minimizing impacts of aquaculture.
Effluents from fish and shrimp farms alter the natural nutrient levels of local
waters and can lead to eutrophication (Chapter 1). Chemicals used in aquaculture
production, including antibiotics, are released into local waters along with effluents.
Effluents and chemicals can be released from both open systems in rivers, lakes, or
coastal sites as well as from closed ponds or raceways that exchange water or drain
at harvest. Sensitive benthic ecosystems below marine culture sites are impacted by
these chemicals, organic matter, and accompanying sedimentation. Impacts range
from increased benthic productivity in oligotrophic waters to changes in the benthic
communities and local losses of biodiversity to anoxic sediments and even anoxia
in the lower levels of the water column (Black et al. 2002).
Wild fish populations can be impacted by aquaculture production as a result of
escapes and disease introduction or transmission. Escaped farmed species can interbreed with wild populations, altering the genetic pool and lowering the fitness of
these populations, or they can become established and compete with wild species
for food and habitat (Chapter 4, Black et al. 2002; Boyd et al. 2005). In 2005, it was
estimated that one in four salmon found in Norwegian seas was of farmed origin
(Esmark et al. 2005). In the same year, an average of 13% of salmon found in rivers
during spawning season were escaped fish, which is as low as it has been since the
231
7.2 Key Concerns of NGOs Related to Aquaculture
There are hundreds of small, negative impacts that can be associated with aquaculture and they vary by species produced and production system. However, the major
impacts of aquaculture have been clearly documented and remain a relatively short
list, which can be broken down into environmental, social, and food safety impacts.
There is an extensive body of literature as well as significant ongoing research on
these impacts, which are briefly described here.
It is important to note that although a number of major impacts of aquaculture
have been clearly identified, there is much debate about the extent and frequency
of these impacts. There remain a number of issues where scientific consensus has
not yet been reached and where there is poor and often contradictory data.
7.2.1 Environment Impacts
Impacts of aquaculture on wild fauna and flora are the cause of many of the concerns about the industry. It is important to note that the bulk of the concerns relate
to the production of fish and shrimp, especially carnivorous species, rather than to
filter-feeding shellfish and seaweeds. Though not without potential negative impact,
production of filter-feeding bivalve molluscs and seaweeds result in a different suite
of positive and negative impacts than the production of other species because they
remove nutrients from the water column and do not require feed (Boyd et al. 2005;
Shumway et al. 2003). These species typically rank well in NGO evaluations of
culture at a broad species level, and are not an area of focus for NGOs concerned
with minimizing impacts of aquaculture.
Effluents from fish and shrimp farms alter the natural nutrient levels of local
waters and can lead to eutrophication (Chapter 1). Chemicals used in aquaculture
production, including antibiotics, are released into local waters along with effluents.
Effluents and chemicals can be released from both open systems in rivers, lakes, or
coastal sites as well as from closed ponds or raceways that exchange water or drain
at harvest. Sensitive benthic ecosystems below marine culture sites are impacted by
these chemicals, organic matter, and accompanying sedimentation. Impacts range
from increased benthic productivity in oligotrophic waters to changes in the benthic
communities and local losses of biodiversity to anoxic sediments and even anoxia
in the lower levels of the water column (Black et al. 2002).
Wild fish populations can be impacted by aquaculture production as a result of
escapes and disease introduction or transmission. Escaped farmed species can interbreed with wild populations, altering the genetic pool and lowering the fitness of
these populations, or they can become established and compete with wild species
for food and habitat (Chapter 4, Black et al. 2002; Boyd et al. 2005). In 2005, it was
estimated that one in four salmon found in Norwegian seas was of farmed origin
(Esmark et al. 2005). In the same year, an average of 13% of salmon found in rivers
during spawning season were escaped fish, which is as low as it has been since the