General Information

1
Carps (Chapter 14)

• General Information
• Carps are seen from different perspectives in
  different parts of the world
• USA
• Ornamental fish Koi (common carp varieties),
  goldfish
• Common carp and other carps trash fish,
  invasive species
• Asian countries source of animal protein for
  millions of people
• 1998 statistics for carps
• 31 of world aquaculture production (including
  plants)
• 46 of total fish and shellfish production
• Almost 80 of freshwater fish and shellfish
  production
• Figure 14.1
• Topics
• Biology
• Artificial propagation
• Culture
• Genetic improvements
• Culture-based fisheries
• Conclusions

2
Carps

• Biology
• The Cyprinidae is the largest fish family which
  includes approximately 1600 freshwater species
  collectively known as carps, barbels or minnows
• They occur naturally in North America, Africa and
  Eurasia greatest species diversity found in Asia
• In the USA, this family includes the many small
  shiners and chubs, suckers, and others
• About 29 species are cultured, primarily (bold,
  in 1998 exceeded 1 million mt)
• Asian (Chinese) carps common carp, bighead carp,
  silver carp, grass carp, crucian carp, black
  carp, mud carp
• Indian major carps catla, rohu, others
• Species such as grass carp are zooplanktivorous
  in the larval and early juvenile stages and
  before transforming into a macrophyte feeder
• Fecundity of carps is very high, and most
  cultured carps attain sexual maturity at 3-years
  of age
• Spawning is usually once a year in the natural
  environment
• For Chinese carps, temperature and photoperiod
  are important cues for the timing of spawning
  for Indian major carps, a number of environmental
  factors interact (including lunar cycles)
• Captive Chinese and Indian major carps are not
  known to spawn spontaneously and thus artificial
  techniques of propagation are necessary for
  breeding

3
Carps

• Artificial Propagation
• As for most other cultured species, the
  development of techniques of artificial
  propagation was the single most important factor
  that contributed to the growth of carp culture
• Prior to this development, carp culture depended
  on the capture of natural seed

4
Reproduction, Early Life Stages, Growth
Reproduction hormones that control release of
gametes
5
Carps

• Artificial Propagation
• As for most other cultured species, the
  development of techniques of artificial
  propagation was the single most important factor
  that contributed to the growth of carp culture
• Prior to this development, carp culture depended
  on the capture of natural seed
• Most common procedure is
• Hypophysation
• injection of crude extract from common carp
  pituitary
• hCG injection
• Best procedure involves use of GnRH analog
  combined with dopamine antagonist (Linpe method).
  Commercial kits are available (Ovaprim)
• High rate of ovulation
• Consistency between broods
• Complete ovulation
• Time lag between injection and ovulation short
  and predictable
• It is possible to spawn carp twice a year by
  artificial propagation thus allowing a reduction
  in the numbers of broodstock that have to be
  maintained for breeding and eliminating
  completely the dependence on natural seed (but
  one needs to be mindful of good genetic
  management of broodstock)

6
Carps

• Artificial Propagation (continued)
• After hormone injection, malefemale fish are
  placed in spawning pond at ratio of 32.
  Floating eggs (Indian major carps) or egg masses
  (common carp) are removed from the pond for
  larval raising
• Alternatively, gametes may be stripped by gentle
  palpation and fertilized using a dry method
• Fertilized eggs are transferred to incubation
  tanks or hatching pools (Fig. 14.4)
• After hatching (2-3 days), the larvae will
  resorbe the yolk sac within 4-5 days and are then
  transferred to nursery ponds.

7
Carps

• Nutrient Requirements
• Among fishes, nutrient requirements are better
  known for common carp (amino acids,
  carbohydrates, lipids)

8
Carps

• Culture larval rearing
• Hatching occurs at 2-3 days at 23-27C in most
  cultured species
• Yolk continues to provide nutrition for an
  additional 3-4 days
• Usually exogenous feeds are made available before
  completion of yolk sac resorption.
• Two stages
• Post-larvae to fry stage, usually in hapas
• Fry to fingerling stage, usually in
  well-fertilized rearing ponds
• Practice of green manuring is usually employed
  to enhance pond productivity for larval rearing.
  This involves the sowing a short term crop of
  leguminous plants (beans, clover) and plowing and
  leveling pond when crop has grown to 6-10 cm
  (pond may also later be disinfected by use of
  biodegradable toxicant or quicklime)
• Either organic or inorganic fertilizers (but not
  mixture) to ensure good growth of zooplankton
• Larvae are stocked when it is certain that a
  substantial population of zooplankton has been
  established.
• Supplemental feeds include rice bran, oilcakes of
  peanut, coconut or mustard soybean milk and
  meal and egg yolk paste
• Formulated feeds are rarely used except for
  common carp in some countries

9
Carps

• Culture grow out
• The culture of most carps is semi-intensive and
  based on polyculture systems
• Exception is common carp, which are often
  intensively cultured in ponds or cages
• Polyculture systems started in China. Based on
  various combinations of several different species
  with different niches
• Black carp (prey snails)
• Grass carp (macrophytes)
• Silver carp (phytoplankton)
• Bighead carp (omnivorous zooplankton and other)
• Mud carp (bottom scavenger)
• Others (Fig. 2.8)
• In China and India, where carp culture is
  predominant, 2 or 3 species of either Chinese or
  Indian major carps are polycultured
• In most Asian countries, carp culture is also
  conducted as part of an Integrated
  Agri-Aquaculture System including swine or
  poultry (IAAS)
• Common fertilizers or organic manures are used to
  enhance pond productivity in semi-intensive carp
  farming
• Supplementary feeds are also applied e.g., brans
  or rice and wheat mixed with cakes or meals of
  various oilseeds such as mustard, canola or
  soybean
• Only common carp are grown out on artificial
  feeds in some countries

10
Carps

• Culture grow out (continued)
• Harvesting usually takes place when carps reach a
  mass of 1-1.5 kilograms
• Technique is usually by seining

11
Carps

• Genetic Improvement
• Some cyprinids such as the common carp and
  goldfish have been domesticated, but mainly for
  appearance and not for production
• Relatively recent studies have determined that
  cultured stocks of carp in some places have
  suffered from inbreeding depression and
  suggestions have been made to prevent this
  problem
• Efforts are underway in Asia to implement
  breeding programs for the selection of improved
  production traits in carps

12
Carps

• Culture-based Fisheries (or Stocking Programs)
• Stocking of hatchery-raised fingerlings for
  food-fish production (commercial fisheries) or
  recreational fisheries
• Culture-based fisheries for fish production is
  most developed in China where it is based on
  stocking of carps

13
Carps

• Conclusions
• Carps are an important food source, especially in
  countries or regions with lower financial
  resources
• Since living standards are generally increasing
  throughout the world, it has been suggested that
  carp culture may decline in importance
• However, there are pressures related to
  environmental concerns associated with the
  culture of carnivorous fishes (high energy/fish
  meal demands, high cost). In addition, production
  trends do not indicate a declining interest in
  carp culture.
• Carps may continue to provide a good quality
  source of animal protein at affordable prices, as
  they have for thousands of years