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Relative Contributions and Impacts of Aquaculture and
Capture Fisheries
James H. Tidwell, Ph.D.
Kentucky State University
And
Geoff Allan, Ph.D.
New South Wales Fisheries
Tidwell’s Theory of Fisheries Relativity
Fish is man’s most important source of animal protein (FAO 2000)
• Fish makes the greatest contribution where needed most.
Fish as % animal protein
North America 10%
Africa 17%
Asia 26%
China 22%
The Demand for Fish is Increasing
0
20
40
60
80
100
120
MMT
1970 1998 2010
Why?• Not really due to
increased rates of consumption
• (15-16 kg/person).
• Primarily due to population growth.
1.5 MMT additional product each year!
World Population Increase
3
3.5
4
4.5
5
5.5
6
6.5
1970 75 80 85 90 95 2000
Billions of people
Where does it come from?
Only Two Sources-Capture or Culture
• Historically – the oceans
• About 80% of our foodfish supply comes from ocean capture fisheries.
• If we needed more – we just fished harder – longer – or further away.
Today’s Reality
The ocean’s bounty is NOT limitless.
70% in need of urgent management. (FAO 1999).
50% of ocean fisheries fully exploited.
Invest in bigger, faster boats with longer ranges
•Invest in new technologies to locate and aggregate the fish
•Mace (1997) estimated that the “catching capacity” of the fleet has increased 4-8 X faster than actual catch rates.
•Increased outlays and decreasing returns create a financial inertia against reducing fishing pressures.
What We Have Done?
Why?
• Consumer demand drives the system
• Not only how much – but what species are targeted
Environmental Costs of Capture Fisheries• Major Issue – By-Catch
• Longline fisheries -billfishes – pressures on shark species – slow reproduction and recovery rates.
•
• Trawling technologies for ground fish like flounder-also catch large numbers of skates and rays.
Shrimp trawls may kill 10 kg of juvenile finfish for each kg of shrimp
By-Catch• Other high profile
examples– Shrimp and Sea
turtles
•Driven by consumer demand
–Tuna and shrimp are #1 and #2 in popularity
–Tuna and Dolphins
Current Situation69.4
84.5
97.2
114.8
0
20
40
60
80
100
120
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
year
mill
ion
met
ric
ton
s
aquaculture
capture fisheries
•The ocean can supply only 2/3 of current demand. Significant increases from capture appear biologically unsustainable.
•Population growth continues. Demands for fish increases over 1 million tons per year.
•Where will almost all future supply increases come from?
Aquaculture is the fastest growing food production activity in the world.
0
5
10
15
20
25
30
35
40
45
MMT
1984 1986 1990 1994 1998 1999
69.4
84.5
97.2
114.8
0
20
40
60
80
100
120
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
year
mill
ion
met
ric
ton
s
aquaculture
capture fisheries
Projected requirements for food grade fisheries
Growth of Aquaculture•With a growth rate of 11% per year – Aquaculture is on a pace to surpass beef production by 2010.
Not only how much but where.
While 80% of beef production is in industrialized nations
–Aquaculture is growing 6X faster in developing countries than in developed countries
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35
40
1984 1986 1988 1990 1992 1994 1996 1998 2000Year
mil
lion
met
ric
ton
s
Developed
Developing
Aquaculture Production: Developed vs Developing countries
91% omnivores or filter feeders
FAO States that:
• “As an inexpensive source of highly nutritious animal protein, aquaculture has become an important factor for improving food security, raising nutritional standards, and alleviating poverty, particularly in the world’s poorest countries.”
Food Security
• Production already increased 400% between 1984 and 1998.
–FAO 2001 predicts significant increases in small-scale aquaculture production in Africa.
There are not too few fish - there are too many people
If terrestrial agriculture had not developed, we could never support the current human population.
A similar juncture has been reached or passed in fish supplies.
Aquaculture Too Has Its Costs
• The very rapid growth of aquaculture has led, in some cases, to environmental impacts and conflicts over limited resources.
• You cannot produce 40 Billion kg of anything without leaving an “environmental footprint”.
• However, let us base our analyses on facts and fairly compare these impacts to other sources.
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5
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40
45
MMT
1984 1986 1990 1994 1998 1999
Painting with a broad brush. Don’t say aquaculture when discussing one species!!
“Aquaculture Industry a failure”, study claims
The Down Side of Fish Farming
Shrimp and Salmon = Aquaculture
0
5
10
15
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25
30
35
MMT
Shrimp Salmon Total Aqua
9%6%
/
Environmental Costs of Aquaculture
• Mangrove Destruction
• Fact: As much as 50-60% of the historic resource has been lost.
• The World Wildlife Fund reported < 5% of mangrove losses due to shrimp farms. Most to urbanization, fuel, pulp…
Issue: Fish Meal in Aquaculture Diets
• Naylor et al (2000) reported that aquaculture is “a contributing factor to the collapse of fish stocks worldwide”.
• “ever increasing amounts of small pelagic fish would be caught for use in aquaculture feeds”
• An analysis of these data indicates no statistical relationship between aquaculture production and pelagic fish landings or fish meal production (P values > 0.80)
0
5
10
15
20
25
30
35
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
Mil
lion
Met
ric
Ton
s
World Aquaculture Production
World Landings of Pelagic Fish
World Fishmeal Production
el nino
What has occurred is a market driven reallocation of how this fixed amount is used.
17
55
20
23
48
17
35
24
29
0%10%20%30%40%50%60%70%80%90%
100%
1988 1998 2000
OthersSwinePoultryAqua
30 MMT
0
50000
100000
150000
200000
250000
300000
350000
MMT
Fish Meal Live Wt. of fishmeal fish
CatfishProduced
Fish Meal Use vs. Total Production in U.S. Catfish
6.9X Return
• Naylor et al pointed out that certain species are “net consumers” of fish.
• Specifically salmon and shrimp requiring 3Kg of fish to produce 1Kg of fish on the farm. (actually less)
0.67 0.47 0.45 0.642.222.79 1.97 1.89 2.67
9.32
1.39 1.13 0.85
29.94
33.31
0
5
10
15
20
25
30
35
Salmons and Trouts Shrimps, Prawns Marine Fish Others Total
1999 Fishmeal consumption (MMT)
1999 Live weight of fish species used in making fishmeal (MMT)
1999 Aquaculture production volume (MMT)
>4X Return
OK- What if we get that same fish from the wild??
30-35% 100%
Kg of Forage Fish Required to Produce 1 Kg of Salmon or Shrimp
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2
4
6
8
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14
16
Aquaculture Wild Capture
By-Catch + Wastes
Trophic Conversion
KG
Nutrition Research• Just as other livestock
industries have reduced fish meal inclusion – so will aquaculture – as nutritional requirements of culture species are identified.
Poultry 2 species
Aquaculture 167 species
Fish Meal Use in Poultry
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2
4
6
8
10
12
14
16
18
MMT
1988 1998 2000
• Naylor et al. 1999 – “due to a reliance on fish meal, aquaculture of these species is being subsidized by the marine ecosystem.”
• If we source these same products from capture fisheries, they are ENTIRELY “subsidized” by the marine ecosystem.
• Species identified as net producers do not convert food to flesh with more metabolic efficiency – They are just subsidized by a different ecosystem – freshwater or terrestrial.
These have their own environmental costs
Why is Aquaculture More Efficient?
• Less waste – In capture fisheries as much as 40% of the total catch may be wasted or discarded (Howgate 1997).
• In aquaculture there is a shorter chain, with more control , from production to harvest to processing and distribution.
Today’s Reality• We need Capture Fisheries AND
Aquaculture working together to meet human demand.
Soon they must each supply half of the worlds fish supply.
Percentage of Total World Seafood Supplied by Aquaculture
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5
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30
35
40
1990 1992 1994 1996 1998 2000
%
• “The divisions between aquaculture and capture fisheries will rapidly fade, and in many regions, have already gone” (Coates 1996).
• In Alaska aquaculture is “outlawed” but “wild harvest” salmon and oyster industries rely heavily on aquacultured seedstock.
9/27/01 2
• Rational growth of aquaculture production is necessary to meet basically ALL future increases in the world’s fish supplies.
• Simplistic, unbalanced assessments of aquaculture - multiplied through the popular media - can impede responsible aquaculture development.
69.4
84.5
97.2
114.8
0
20
40
60
80
100
120
1980 1985 1990 1995 2000 2005 2010 2015 2020 2025
year
millio
n m
etric to
ns
aquaculture
capture fisheries
• This could negatively impact food security in regions where high quality protein is needed most.
It could actually increase pressures on marine stocks to supply the shortfall.
FAO (2001):• “ Irrespective of whether inaccurate
information is generated deliberately to promote a specific cause, or inadvertently through ignorance, it can have a major impact on public opinion and policy making that may not be in the best interest of either sustainable use of fisheries resources or the conservation of aquatic systems.”