Aquaculture and Biodiversity Conservation

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Aquaculture and Biodiversity Conservation

• James S. Diana
• University of Michigan
• Aquaculture CRSP

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Plans for today

• Overview aquaculture and capture fisheries
• Review some issues about aquatic biodiversity
  conservation in the U.S.
• Examine the positive and negative aspects of
  aquaculture related to conserving biodiversity
• Propose a couple of systems that are able to
  produce aquatic crops without major threats to
  biodiversity

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Overview fisheries and aquaculture
Why should we promote aquaculture?

• Fastest growing food production system globally
  at about 7.42 increase per year since 1995 (9
  1985 to 1995)
• Can either exacerbate or reduce pressure on wild
  fisheries
• Increasing number of new species produced by
  aquaculture as other stocks decline (cod, hake,
  halibut, cobia, tuna)
• New industry with significant potential for
  innovation
• FAO forecasted global increase in seafood
  consumption of 1.5 kg/person, while catches
  remain static
• In US, a 1.5-2 billion kg increase in seafood
  consumption is anticipated by 2020, all from
  aquaculture
• Seafood exports generate twice as many for LDCs
  as coffee, tea, rubber, bananas, rice, meat
  combined35 from aquaculture

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What is aquaculture?

• Controlled growing of some aquatic crop, mainly
  for food
• Control can vary from complete life cycle to just
  placing appropriate medium for settlement
• Level of inputs (intensity) varies
• Extensive just raise in appropriate place
• Semi-intensive add fertilizer and control water
  quality
• Intensive provide full feed, water exchange,
  aeration, other chemicals

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Recent Trends in Aquaculture and Fisheries
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12.5
FAO 2005
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Future Trends in Aquaculture and Fisheries
202573
2011 50
FAO data and Diana projection
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Top 24 Species Produced Globally
Portion of wild fishery used for aquaculture feeds
From Aaron McNevin (WWF)
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Trends in cod and anchoveta (MMT)
FAO 2005
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Tuna yields (TMT)
FAO 2005
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Proportional culture of species in 2000
FAO 2005
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Changes in culture yields (MMT)
FAO 2005
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Trends in 3 cultured species (TMT)
FAO 2005
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Global Significance of U.S. Freshwater Species
Trends in aquatic biodiversity in the U.S.
Master et al. 1998 (TNC)
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Why worry about aquatic biodiversity

• Among vertebrates, fish species outnumber all
  other vertebrates combined
• Aquatic invertebrates are often sensitive
  indicators of pollution problems
• Very high rates of endemism in several aquatic
  systems (caves, African great lakes, some
  isolated streams)

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Proportion of U.S. Species at Risk
Master et al. 1998 (TNC)
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Number of species and endangered species by state
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Known Causes of Animal Extinctions
Cox 1993
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Distributions of exotic fishes
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Changes in shared species among pairs of
statesHOMOGENIZATION
Rahel 2000
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Number of events changing species in a state
Rahel 2000
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Relative Importance of Aquaculture Impacts
Positive and negative aspects of aquaculture
Boyd et al. 2005
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Impacts that Affect Biodiversity (my ranking)

• Escapement and invasive species
• Effluents and water pollution
• Land use change
• Use of fish meal in feeds
• Predator controls
• Genetic alteration from escaped organisms
• Antibiotic and hormone use

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Positive Impacts on Biodiversity

• Production reduces pressure on wild stocks
• Stocking organisms to enhance depleted stocks
• Effluents and wastes increase production,
  abundance, and diversity of species in local area
• Income generation replaces less sustainable
  income generating systems

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Negative Impacts Invasive species
Virtually all of these traits are ones favored
for species used in aquaculture!
Ricciardi Rasmussen 1998
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Negative Impacts Invasive species

• Tilapia is poster child
• More than half of documented introductions were
  not result of aquaculture but natural stocking
  (Canonico et al. 2005)
• Many species also spread by aquarium trade and
  dumping

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Negative Impacts Invasive species

• Factors limiting escapee impacts
• Most fish have been little domesticated that is,
  they are essentially wild fish

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Negative Impacts Invasive species

• Escapement is inevitable with aquaculture species
  in almost any system
• Best avoidance is not culturing outside of native
  or common current range

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Negative Impacts Effluents and Pollution

• Common concern in cages/pens
• In oligotrophic waters, actually seems to
  increase biodiversity
• Probably a major issue in eutrophic waters
• We rely on the assimilative capacity of waters as
  an important ecosystem service

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Negative Impacts Effluents and Pollution

• Oligotrophic studies
• 43 Chilean farms, only negative effects on
  benthic invertebrates in fallout zone, much
  increase in pelagic diversity and production
• Soto and Norambuena 2004
• Aegean farms showed increases in pelagic and
  benthic fish diversity and production in farmed
  zones
• Machias et al. 2004, 2005

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Effluents and pollution

• Clear that impact depends greatly on the density
  of fish in cages and of cages in area
• We need to know more about the assimilative
  capacity of waters and the resultant limits to
  cage culture
• Some pen facilities have the combined loading of
  phosphorus and nitrogen equivalent to domestic
  discharge of a fairly large city

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Effluent discharge, nutrient loss and pollution

• Effluents can also be a concern in ponds,
  especially for intensive culture
• May be remediated by plant co-culture or by
  draining and harvesting techniques

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Negative impacts - land use change

• Poster child is loss of coastal mangroves to
  shrimp culture

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Mangroves and shrimp culture
FAO 2005
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Abandoned shrimp ponds

• Cycle of intensity, disease, pond failure, and
  abandonment
• Results in altered land
• Causes salinization of soils
• Often land taken from other productive use

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Mangrove losses

• Important nursery and storm buffering area
• Coastal development has caused large losses (33)
  from many sources, including pond shrimp culture
  (Alongi 2002)
• Many specific studies show aquaculture and others
  are responsible for mangrove loss

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Abandoned shrimp ponds and society

• Thai ponds not abandoned but cycle of use
• Most local people perceive that they have a
  better life as a result of shrimp culture
• Obvious economic benefits as well as development
  of an industry for rural areas
• Disease and abandonment has been a major problem
  in some countries Taiwan, China

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The Fishmeal Issue

• 20-30 MMT of biomass currently harvested to
  produce 6-7 MMT of fish meal
• Aquaculture uses approximately 50 of all
  fishmeal and 80 of global fish oil (80 95
  respectively by 2020)
• Salmon aquaculture uses 2-3 of all fish caught
  for feed
• Shrimp aquaculture uses 3-4 of all fish caught
  for feed
• Antarctic krill biomass estimated at 62-137 MMT
  in 2000 but only 1.5 MMT of krill can be
  harvested without impacting krill predators

From Aaron McNevin (WWF)
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Fishmeal Species Produced Globally
Portion of wild fishery used for aquaculture feeds
From Aaron McNevin (WWF)
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Aquacultures Share of Small Pelagics
From Aaron McNevin (WWF)
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Trends in anchoveta (MMT)
FAO 2005
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Atlantic Salmon case

• Mainly commercial fishery
• Important and popular sport fish as well
• Aquaculture began in 1960s
• As aquaculture grew, pressure on wild fish
  declined
• Now some rejuvenation of wild stocks as well

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Changes in Atlantic salmon yields
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Environmentally friendly aquaculture systems
Intensive pond culture system
Liquids
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Catfish tilapia co-culture
Only works where both species are native or very
common!
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Tilapia-tilapia co-culture

• Can also work with other local combinations of
  species, with fed fish in cages, best when not
  using fish meal feed, and filter feeding fish in
  ponds
• Climbing perch rohu in Bangladesh

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Fish and plant culture

• Many ponds are grown with multiple use in mind
• Can even use in restoring communities
• Value added by second crop can make the operation
  successful

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Added revenue from new plant crop
Parameter Open system Closed system Recycle system
Gross revenue
Prawn 3.880.84a 7.200.66b 7.071.67b
Tilapia - - 0.370.06
Mimosa - - 0.700.32
Total Revenue 3.880.84a 7.200.66b 8.141.29b
Mean revenue per tank 3.880.84a 7.200.66b 2.710.43a
Operation Cost
Prawn juveniles 2.010.02 1.980.01 1.960.01
Tilapia fingerlings 0.250.00
Mimosa seedlings 0.250.00
Feeds 2.070.01a 2.370.03b 2.360.09b
Urea 0.010.00 0.010.00 0.010.00
TSP 0.010.00 0.010.00 0.010.00
Electricity 0.240.00a 1.450.00b 1.680.00c
Cost of working capital 0.120.00a 0.150.00b 0.170.00c
Total Cost 4.450.00a 5.970.02b 6.690.08b
Mean cost per tank 4.450.00b 5.970.02c 2.230.03a
Net return per tank -0.570.84 1.230.64 0.480.46
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Conclusions

• Older aquaculture crops often used systems that
  damaged biodiversity in local area
• Modern certification and organic standards are
  forcing aquaculture to use less damaging systems
• Overall effects have been both positive and
  negative to biodiversity, and can be managed
• Management balance of cost of technology, benefit
  in sales, and regulations or forcing by market