294
Y. Olsen et al.
The growth of the human population, forecasted to reach about 9 billion inhabitants along the 21st century, along with the increasing per capita consumption of
food and water is likely to be conducive to increasing difficulties to feed humanity.
Indeed the projected population is within present estimates of the carrying capacity
imposed by the availability of freshwater, estimated at 10–16 billion people using
conservative assumptions (Cohen 1995). Indeed, the average per capita water
consumption already exceeds by 50% that used in deriving the estimated carrying
capacity above (Cohen 1995), suggesting a smaller carrying capacity than anticipated. These estimates suggest that the availability of water to produce food will
become a bottleneck to the human population along the 21st century; a situation
that has already been reached in many densely populated regions of the world (e.g.
Asia and Africa) (Vörösmarty et al. 2000). The only source of food that does not
consume freshwater is the ocean as provided through wild harvesting or, increasingly, aquaculture. Enhancing food production from the ocean may, therefore, help
feed humanity by releasing pressures on freshwater resources.
The total fish supply and hence consumption has been growing at a rate of 3.6%
per year since 1961, while the world’s population has been expanding at 1.8% per
year (WHO 2003). The average apparent per capita consumption of fish products
has increased from about 9 kg per year in the early 1960s to 16 kg in 1997 (WHO
2003), close to the recommended intake of 50 g day
−1
, or about 2–3 servings per
week, of fish and seafood products for a healthy diet. Provided the rise in human
population to near 9 billion in the 21st century, the required fish production to satisfy
market demands and dietary requirements will be about 160 million tonnes year
−1
,
which is twice as high as the current fisheries catch, which has reached a plateau at
about 82 million tons (Fig. 10.1). Wild fish captures are unlikely to increase, as
most fish stocks are depleted (Myers and Worm 2003). Accordingly, aquaculture,
which already supplies one third of the fish production, must develop further to
produce the recommended dietary components.
These two considerations: (1) the likely exhaustion of the capacity of agriculture
to feed a growing human population, and (2) the need to increase fish production
beyond the ceiling of exploitation of wild fish stocks to meet market needs, are likely
to act as motors driving a continued expansion of aquaculture. Aquaculture technologies and practices must greatly improve relative to current practices to meet these
challenges. Here we examine present trends and driving forces of marine aquaculture
development and discuss possible projections and scenarios of aquaculture along the
next decades on the basis of possible scenarios and bottlenecks.
10.2 Current Trends of Development
A shift in paradigm for the development in global marine fisheries took place
around 1990. The change in trend towards a stagnation of capture from global
marine living resources was verified around one decade later. FAO statistics
Y. Olsen et al.
The growth of the human population, forecasted to reach about 9 billion inhabitants along the 21st century, along with the increasing per capita consumption of
food and water is likely to be conducive to increasing difficulties to feed humanity.
Indeed the projected population is within present estimates of the carrying capacity
imposed by the availability of freshwater, estimated at 10–16 billion people using
conservative assumptions (Cohen 1995). Indeed, the average per capita water
consumption already exceeds by 50% that used in deriving the estimated carrying
capacity above (Cohen 1995), suggesting a smaller carrying capacity than anticipated. These estimates suggest that the availability of water to produce food will
become a bottleneck to the human population along the 21st century; a situation
that has already been reached in many densely populated regions of the world (e.g.
Asia and Africa) (Vörösmarty et al. 2000). The only source of food that does not
consume freshwater is the ocean as provided through wild harvesting or, increasingly, aquaculture. Enhancing food production from the ocean may, therefore, help
feed humanity by releasing pressures on freshwater resources.
The total fish supply and hence consumption has been growing at a rate of 3.6%
per year since 1961, while the world’s population has been expanding at 1.8% per
year (WHO 2003). The average apparent per capita consumption of fish products
has increased from about 9 kg per year in the early 1960s to 16 kg in 1997 (WHO
2003), close to the recommended intake of 50 g day
−1
, or about 2–3 servings per
week, of fish and seafood products for a healthy diet. Provided the rise in human
population to near 9 billion in the 21st century, the required fish production to satisfy
market demands and dietary requirements will be about 160 million tonnes year
−1
,
which is twice as high as the current fisheries catch, which has reached a plateau at
about 82 million tons (Fig. 10.1). Wild fish captures are unlikely to increase, as
most fish stocks are depleted (Myers and Worm 2003). Accordingly, aquaculture,
which already supplies one third of the fish production, must develop further to
produce the recommended dietary components.
These two considerations: (1) the likely exhaustion of the capacity of agriculture
to feed a growing human population, and (2) the need to increase fish production
beyond the ceiling of exploitation of wild fish stocks to meet market needs, are likely
to act as motors driving a continued expansion of aquaculture. Aquaculture technologies and practices must greatly improve relative to current practices to meet these
challenges. Here we examine present trends and driving forces of marine aquaculture
development and discuss possible projections and scenarios of aquaculture along the
next decades on the basis of possible scenarios and bottlenecks.
10.2 Current Trends of Development
A shift in paradigm for the development in global marine fisheries took place
around 1990. The change in trend towards a stagnation of capture from global
marine living resources was verified around one decade later. FAO statistics