Transcript Sustainable Marine Fish Culture

Juan Pablo Lazo
Talk layout
 State of the world fisheries
 Sustainability in aquaculture
 Efficiency of producing fish as food
 Fish-in : fish-out concept
 Sustainable marine fish culture
Status of the World Fisheries
 What is our current fisheries production?
 How are our current fish stocks?
 How much is aquaculture producing?
World Capture Fisheries & Aquaculture
Source: Sofia FAO, 2012
Status of the World Fisheries
 About 75 percent of the world's most valuable marine
fish stocks are either fished to the limits or over-fished.
 Capture has not increased in the last 20 years
 At the same time world fish consumption has
increased from 45 million MT in 1973 to more than 140
million in 2010
 FAO estimates an additional 40 million MT of seafood
will be required by 2030
Role of aquaculture
 In order to serve this increasing demand in the long
run, sustainable alternatives have to be strengthened.
 The most promising of these is the aquaculture
industry.
 With a growth rate of 8% per year since the 1980’s,
aquaculture is the fastest growing food-production
industry
 Today aquaculture accounts for almost 50% of the fish
consumed globally, up from 9% in 1980.
World Capture Fisheries & Aquaculture
Source: Sofia FAO, 2012
Fuente: FAO,2012
Sustainable aquaculture
 The sustainability of aquaculture is crucial if the
industry is not to go the way of the fisheries sector
 It is a concept to guarantee a liveable environment for
all people in the long term, encompassing at least
three fundamental components of sustainable
development:
 Preservation of a functional environment
 Economic welfare and
 Social equity
SustainAqua, 2009
Conceptual sustainability
SustainAqua, 2009
Producing food protein
 The efficiency with which various animals convert fed
into weight gain varies widely
 Food conversion ratio (FCR = fed/weight gain)
 Who is more effective?
 Cattle
 Pigs
 Chicken
 Fish
Efficiency of fish growth
 Cattle in feedlots, require 7 kilograms of grain to
produce a 1-kilogram gain in live weight
 For pork, the figure is close to 4 kilograms of grain per
kilogram of weight gain
 For poultry it is just over 2,
 For farmed fish (such as salmonids, carps, tilapia, and
catfish), it is less than 2
Energy efficiency
Species
Kg diet/
Kg
weight
gain
FCR
Trout
Protein (g)
Energy (Kcal)
Kcal/ g
protein
Per Kg
diet
Per Kg
gain
Per Kg
diet
Per Kg
gain
1.5
350
525
3000
4500
8.57
Catfish
1.8
300
480
3420
5472
11.40
Poultry
2.5
200
500
2950
7400
14.75
Pork
4.0
160
640
3300
13200
20.62
Cattle
8.0
100
800
2500
20000
25.00
Lovell, 2002
Why are fish so efficient?
Why are fish so efficient?
 Fish spend very little energy on basal metabolism
because they are
 Poikilotherm
 Floating in water
 Ammonotelic
 This saves up to 50-60% of the energy in the feed for
growth
Poikilotherm: do not spend energy to control
internal body temperature
Free
Expensive
Fish float: do not need to fight gravity
Ammonotelic: low energy
The urea cycle a
costly process!
Trend in the use of feeds in aquaculture
 While feed is generally perceived to be a major
constraint to aquaculture development, 35% of all
farmed food fish production (20x106 t) is currently
achieved without artificial feeding (i.e., oysters, clams,
herbivorous fish)
 However, in 2008, about 31.7x106 t (46.1% of total
global aquaculture) were feed-dependent
 So about 30 million t of feed were used
Fed vs non-fed species
Fuente:FAO, 2012
Use of fish meal and fish oil
 Within the animal productions systems, aquaculture is
the largest user of fishmeal and fish oil.
 Carnivorous organisms (higher-trophic-level) require
more:
 fishmeal inclusion levels of 17–65%
 fish oil of 3–25%
 However, low-trophic-level finfish species (carps,
tilapias, catfishes, milkfish, etc.) need much less
 between 2 and 10%
Why we use fish meal and fish oil
 Fish meal has a high protein content (65% P), excellent
amino acid profile and a high digestibility (90%
digestibility)
 Fish oil contains the best oils (long chain highly
unsaturated fatty acids (n-3 HUFAs or omega-3) that
are essential nutrients for fish (and humans)
Why we use fish meal and fish oil
Patrón de requerimiento
Fish meal a.a. profile and fish a.a. requirements
0.25
0.2
262
-desaturation of 22:5n-3 has been recently described for the first time in vertebrates in
0.15
Fatty acid synthesis
the herbivorous marine fish, Siganus canaliculatus (Li et al., 2010).
0.1
0.05
0
0
0.05
0.1
0.15
0.2
0.25
Patrón corporal
Figure 2. Potential pathways in fish for the biosynthesis of long-chain polyunsaturated fatty
acids from the C18 precursors, 18:2n-6 and 18:3n-3.
Fatty acyl desaturases
Monroig et al., 2011
The solution: alternative proteins and oils
 Many fish species can be grow with 0% fish meal in their
diets (i.e., tilapias, carps, some salmonids) without
affecting growth
 Key alternative proteins include grains (soya bean) and
animal by products (poultry by-product meal)
 Fish oil is a little more difficult to replace
 Key alternative lipids include vegetable oils rich in omega-3
(e.g. linseed, soybean and canola) and some yeast and marine
microalgae
 Although a reduction in lipid levels in diets would not have
any deleterious effect on the health of the fish, there may
be reduced health benefits to humans because of lower
HUFAs
Reduction in the use of FM and FO
 In the last 15 years fishmeal inclusion in major fish
diets has declined considerably.
 The FAO projects that, in the next 10 years, fishmeal
inclusion in the diets of carnivorous fish and
crustacean species will be further reduced by 10–22%,
and by 2–5% for omnivorous fishes.
Trends in the use of fishmeal
SOFIA, 2012
Fish-in Fish-out balance
 To fairly compare the use of fish meal and fish oil in
aquafeeds we need to transform FM and FO to live
weight
 The global average wet fish to fish meal processing
yield is 22.5% and wet fish to fish oil processing yield is
5% (Anon, 2006)
 With this we can calculate the pelagic live weight
equivalent (Tacon, 2008)
Pelagic forage equivalent
Tacon, 2008
Calculated pelagic forage fish equivalent per unit of production for major cultivated
species
Tacon, 2008
The Future of Marine Fish Culture
 Exposure to global markets has made farmers adopt
specialized systems targeting only one economically
attractive species (i.e., carnivorous fish)
 In terms of sustainability, and environmental impacts,
coastal aquaculture systems should, among many things,
use approaches that minimize dependence upon nonrenewable energy, reduce wastes and increase efficiency of
resource usage
 Reducing environmental impacts from aquaculture, and
various resource limitations (water, feed, energy, etc.) may
be achieved with integrated cultivation techniques.
(Troel, 2009)
Integrated Marine fish culture
 Polyculture: (i.e. multiple species co-cultured in a
pond/tank/cage
 Sequential integration: (PAS, Partitioned aquaculture
systems) on land and in open waters (direct a flow of
wastes sequentially between culture units with
different species)
 Temporal integration: replacement of species within
the same holding site, benefiting from wastes
generated by preceding cultured species
(Troel, 2009)
Integrated Marine Fish Culture
Scientific American, 2011
Food for thought….
Should we continue harvesting our oceans?
or
Should we increase aquaculture production?