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

0

5

10

15

20

25

30

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.

0

5

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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

20

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

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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

0

2

4

6

8

10

12

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

0

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

0

5

10

15

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25

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

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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.”