Eel and flat fish culture
--The present status and sustainable
development of eel and turbot culture in China
Tongjun Ren, Mingling Liao
College of Fisheries and Life Science,
Dalian Ocean University, China
0
50,000
100,000
150,000
200,000
250,000
China Japan Korea Taiwan
Th
e p
rod
ucti
on
of
Jap
an
ese e
el
(t)
2009
2010
2011
Data source: FAO
The production of Japanese eel
Data source: FAO
The value of Japanese eel production
0
100,000
200,000
300,000
400,000
500,000
600,000
China Japan Korea Taiwan
Th
e v
alu
e o
f Jap
an
ese e
el
pro
du
cti
on
(U
SD
1000)
2009
2010
2011
Data source: www.chinaeel.com
The stocking volume of Japanese eel
0
5
10
15
20
25
2011 2012 2013
Th
e s
tockin
g v
olu
me
of
Jap
an
ese e
el
(t)
China
Japan
Korea
Taiwan
Data source: China customs
Eel marketing
Export volume (t) Unit price ($/kg)
2011 2012 Growth rate (%) 2011 2012 Growth rate (%)
Japan 5,505 3,390 -38.40 27.35 47.62 74.10
Hong Kong 845 524 -38.00 14.56 24.09 65.50
Korea 647 13 -98.00 10.84 29.77 174.60
Total 7,000 3,950 -43.60 24.28 44.28 82.40
Live eel export of China
80-85%
Data source: China customs
Eel marketing
Export volume (t) Unit price ($/kg)
2011 2012 Growth rate (%) 2011 2012 Growth rate (%)
Japan 19,658 19,339 -1.60 22.16 32.11 44.90
Hong Kong 785 2,494 217.70 25.72 24.43 -5.00
Korea 690 250 -63.80 23.42 25.24 7.80
USA 4,221 3,430 -18.70 25.85 38.53 49.10
Russia 3,421 4,446 30.00 23.61 36.17 53.20
Singapore 508 294 -42.10 24.31 35.06 44.20
Germany 243 279 14.80 25.17 38.59 53.30
Total 33,318 34,395 3.20 22.74 32.01 40.80
Grilled eel export of China
≈60%
Pond culture
• Low cost
• Low power & water consumption
• Easy to master the technique
• Low production
• Difficult to prevent and cure
disease
• Uncontrolled temperature
Eel culture system
Industrial culture
• High production
• Short culture cycle
• Low water consumption
• System stability
• High cost
• High technique required
• Advanced Equipment required
Eel culture system
Cage culture
• An intensive culture and affects
enormously the ambient waters.
• A newly-developing culture system
in southern China, whereas the
proportion is relatively small.
Eel culture system
Eel nutrition
García-Gallego et. al (1998); Higuera et. al
(1999); Tibbetts et. al (2000)
Protein & Fishmeal replacement
• Optimum dietary protein level for juvenile American eel ------ 47%
Replacement study:
Meat meal
Sunflower meal etc.
Eel nutritionGunasekera et. al (2002); Agradi et. al
(1995); Furuita et. al (2007)Lipids
• Lipid source affect lipid digestibility of Australian short fin eel;
•Cod liver oil diet----- highest lipid digestibility.
• Fish oil and vitamin E supplements can contribute to the
accumulation of physiologically important lipid components affecting
the mechanisms controlling ammonia excretion in stressed animals.
• Both n-3 and n-6 fatty acids are necessary for reproduction as well
as growth of eel brood stock, and a higher ratio of n-6 to n-3 fatty acids
negatively affected embryogenesis.
Eel nutrition
• The digestibility of energy in wheat meal was 97.11%, in corn meal
40.13%, in sorghum meal 42.66%, in potato meal 63.25%, in potato
starch meal 96.66% and in cottonseed meal 46.51%.
• The optimum digestible protein/digestible energy (DP/DE) ratio for
juvenile American eel was 22.1 g DP/MJ DE.
Suárez et. al (1995); Degani (2004); Tibbetts
et. al (2002)Digestibility
• European eel showed a certain capacity to adapt intermediary
metabolism to changes in diet composition.
Eel nutrition
Ren et. al (2005); Ren et. al (2007); Hirt-
Chabbert et. al (2012); Lee et. al (2013)Vitamin C and others
• Optimum dietary level of ascorbic acid (AsA) for juvenile Japanese
> 27mg AsA/kg.
•Vitamin C and lactoferrin could improved blood chemistry and non-
specific immune function of Japanese eel.
• The incorporation of feeding stimulants into a pelleted diet was
beneficial on the overall performance of European glass eels and
elvers.
• Lactobacillus pentosus PL11 is a potential alternative to antibiotic
supplementation to improve the growth and health performance of
Japanese eel.
Turbot Scophthalmus maximus L
* The most important culture species of flat fish
* High market price 9-12 USD/kg
Turbot productionAquaculture production of turbot in China
World total except China
2003 2004 2005 2006 2007 2008 2009 2010
Year
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
(Ton)
Lei et al., 2012
Turbot seedlingEU: 10,000,000 N/ year
YearNumber of
hatcheryTank area
Number of
seedling
(m2) (x106ind)
2009 155 280,400 145
2010 124 227,443 189
2011 129 251,700 199
Number of hatcheries, tank area and seedlings of turbot
produced in China
Turbot culture
+
Vinyl house+ well sea water
Seedling size: 6-10cm
Market size: 700g+
Feeding period: 12 month
Tank area: 4,649,000 m
Density: 80-150N/m2
2
Water temperature: 10-20℃
Salinity: 25-30‰
DO: 4ml/L+
Turbot culture
Net cage cultureNet cage culture
Culture area: 156,200 m
Production:1834 t
2
Turbot culture
Recycling system
*Typical culture model in EU
*Future direction for China
Turbot nutrition
Ma et al. (2001); Chen et al. (2003); Cui et al.
(2011); Mai et al. (2009); Ma et al (2009)Protein
• Optimum dietary protein level----------- >42%
• Optimum P/E level-----------92.7-102.5
Fish meal replacement:
Beer yeast; soybean meal; rapeseed meal etc.,
Turbot nutrition
Ma et al. (2001); Bell et al. (1995); Sargent et
al. (1999)Lipid
• Optimum lipid level----------- 12-16%
• 22:6(n-3) level for juvenile --------->1%
• 22:6(n-3)/20:5(n-3) for larval ----------2:1
Ma et al. (2003)Carbohydrate
• Optimum dietary carbohydrate level----------- 4%
Turbot nutritionMartinez-Tapia et al. (1993); Cowey et al. (1975);
Adron et al. (1978); Merchie et all. (1996)Vitamins
• VE ----- required
•VB1 ----- 0.6-2.6mg/kg
•VB6 ----- 1.0-2.5mg/kg
• VC ----- 20mg/kg
Chen et al. (2003)Minerals
• Zn ----- 100-150mg/kg
• Cu ----- 30-50mg/kg
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