Stunted seed production & culture practices

Stunted Seed Production &
Culture Practices
jitenderanduat@gmail.com

Need of the hour- Seed production
632 million fry (1986-87)
18.5 billion fry (2002-03)
20 billion today
2.5 m ha
ponds & Tanks
2.0 m ha
reservoir
31 billion
fingerling

Need for seed
• Target of 12mmt during 2020 to meet the protein
requirement of huge human population.
• The high stocking density, etc resulting in
detrimental consequences in aquatic organisms
(Reubush and Heath, 1996).
• Production of stunted fingerlings of Indian major
carp (IMC) has become a general practice where
fish are stocked at high density with restricted
ration.

Need for seed
• Rearing of these fingerlings is adopted by the
farmers with an assurance of low mortality and
compensatory growth during the grow-out
phase.
• The subsequent growth of the stunted fingerlings
up to marketable size is believed to be rapid
(Nandeesha et al., 1994).
• No systematic work has been carried out yet to
understand the stress caused due to food
deprivation on fish.

Why use fingerlings?
High
survival
Short
culture
period
Multi
cropping
Can fetch
good price
Superfast
growth

How to produce large sized
fingerlings?
1-Nurturing spawn in high density, followed by thinning of fry which
are then raised to fry and fingerlings.
2-Nursing spawn at low density ,which makes fry grow faster. In 1-
2 months fingerlings are there from fry.
3-Producing spawn through early breeding before onset of
monsoon to maximize time available for growth.
4-Rearing fry at higher densities for 10-12 months to get stunted
fingerlings/ yearlings.
5-Supply of quality food and low density helps to ensure healthy
seed with fast growth and survival of fingerlings.

Seed production
Fingerling
Fry
Spawn
Egg
Yearling
3 days
15-20 days
60-90 days
7-8 months

Reasons behind Stunted seed
Technology
• The gap between demand and supply of
quality seeds, by and large, remains a
daunting task in aquaculture development.
• Carps are known to grow rapidly during the
second year of their age.
• To address the problems related to fish growth
and yield.

History
• Yearlings are produced traditionally in village
ponds. When farmers fail to sale their
fingerlings and they continue to rear them up
to May-June. Before monsoon, when ponds
are prepared for next fry rearing crops,
farmers harvest stunted fish for consumption
as they are grown with reduced nutrient
uptake.

History
• Nikolsky (1963), reported that partial or
complete starvation of tropical fish species is
followed by a voracious feeding period and
subsequent restoration of growth during the
ensuing more favourable conditions.
• Stunted populations are frequently observed
in fishes (Roff, 1992).

• stunted fish seed = aged, but have not yet
attained full growth potential.
• A stunted population as consisting of
individuals that grow slowly and mature early
and at a small size, in which growth is
restricted by density-dependent mechanisms,
and the diminished maximum size is not
genetically determined.
What is stunted seed????

Causes
1. Resource limitation (arising from intraspecific
density dependence)
2. size- or age-dependent survival probabilities
• Fish whose growth was arrested as juveniles
under controlled conditions can subsequently
compensate growth when suitable conditions
return.
• Level of this compensation is mediated by the
quality of the grow-out
environment.(Ylikarjula etal 1999)

Causes
• Several ecological factors, including increased
survival from reduced predation and decreased
food availability, may influence the development
of individuals in stunted populations (Roff, 1992;
Ylikarjula et al., 1999; van Kooten et al., 2007).
• Stunting is a phenotypic change resulting from
unfavourable environmental conditions, such as
overcrowding and limited food availability
(Noakes & Balon 1982; Björnsson etal. 1988).
• Overwintering

Procedure
Rearing pond of 0.4-3.0 ha
Fry stocking @ 50,000-70,000 seed/ha.
Manuring @5000-10,000 kg/ha
6-12 months fry will become fingerling of 100-
200g
Feeding@ 0.5-1.0%

Procedure
• Stocking spawn at shallow water depth (35-45
cm) followed by phased increase of water
level at 3 - 4 days intervals, results higher fry
recovery of 50-70 %.

Orissa
• Some of the village fish farmers produce yearlings
and/or stunted fingerlings with improved
management on commercial scale. In this, the
fingerlings stocked in well prepared ponds at high
density July-August.
• During culture period ponds are fertilised
monthly once.
• Complete harvesting of yearlings is done by
repeated netting from May-June.
• The farmers of Kantapada and Bhatpadagarh are
producing 3-5 tonnes of yearlings every year.

Feeding
• Fingerlings are fed with the mixture of ground
nut oil cake and rice bran in the ratio of 1:1.
• Fortification of micro-nutrients in artificial
feeds is also enhances the growth and survival
of fry. A commercially available multiplex pre-
minerals mixture with vitamins accelerates
plankton production and fry survival in
nursery ponds.

Feeding
• Farmers in Andhra Pradesh incorporate salt
along with feeds to improve the growth of fish
@ 0.5 to 2 percent along with the feed.
• Used in many parts of Asia.
• It is possible to improve the growth of carps
by incorporating the salt at 0.5 to 2 percent
for different species (Gangadhara et al., 2004).

Changes
• Metabolic depression seems to be an important
strategy developed by fish in response to periods of
food scarcity (Cook et al., 2000; O'Connor et al., 2000;
Rios et al., 2002).
• When the fish is deprived of food, it tries to cope with
the change by reducing the energy expenditure and
this is reflected by lower oxygen consumption.
• A decline in oxygen consumption may be a
consequence of lower activity by the fish in an attempt
to conserve body energy reserves during periods of
food shortage.

Changes
• L. rohita fingerlings can tolerate the stressor
arising out of feed deprivation up to 3 weeks
(Cara et al. 2005).
• He Demonstrated that food-deprived trout larvae
were more tolerant to thermal shock than its fed
counterparts because of the protection conferred
by fasting-induced Hsp.
• The reduced oxygen consumption by L. rohita
fingerlings in the 3rd week of starvation may
suggest reduced metabolic needs for energy so
that the fish can sustain limited nutrient supply
from body reserves.

Changes
• Under normal growing conditions, energy is
available for allocation to somatic growth, which
has the effect of increasing the somatic tissue at a
similar rate to the continuous growth of the bony
structures.
• Alternatively, stunted fish may allocate less
energy to somatic growth because of food
limitation, resulting in a body that remains
undifferentiated compared to the bony structures
in the head.

Compensatory fish growth
• Compensatory growth in fish is a phase of fast
growth, which occurs after the re feeding of fish
following a period of feed deprivation or after
abnormal conditions such as low temperature.
• Compensatory growth is usually accompanied by
hyperphagia (an increase in appetite).
• Compensatory growth in fish is regulated by
many environmental factors such as water
temperature, Water quality , social aggression
and dietary protein and energy contents during
re-alimentation period.

Compensatory fish growth
• The period of feed deprivation that elicits
compensatory growth varies among fish
species (Jobling et al.).
• Carassius auratus gibelio, which showed
improved feed efficiency and preferential
protein growth during compensatory growth.

Advantages
• Overwintering and ‘stunting’ has economic
significance. Brood fish and fry/fingerlings may be
stunted intentionally through manipulation of
feed and stocking density to reduce costs of feed
and space and to service market demand better
for both seed and table fish.
• The culture of stunted Indian major carp has
become established in parts of India because the
subsequent growth of the fish is believed to be
rapid (Nandeesha, Dathathri, Krishnamurthy,
Vargese, Gangadar & Umesh 1994).

Advantages
• Stunted fingerlings/ yearling are the most
preferred stocking material by grow out farmers
and fetch a higher price than the normal
fingerlings.
• High survivability of stunted fish (95%).
• Farmers are now able to obtain, most commonly
an average yield of 8 tonnes/ha and some of the
progressive farmers obtain a yield of more than
15 tonnes/ha/year.

Applicability
• Used for herbivores fishes.
• High mortality
• Not applicable for prawn.
• Fishes having fast growth not in first year.
• Seed should be in appropriate quantity.

•Growth of carp fingerlings during prolonged nursing (5 or 12
months) was stunted compared with fish nursed over a
conventional duration of 3 months but showed superior
growth subsequently.
•This trial indicates that fish whose growth was arrested as
juveniles under controlled conditions can subsequently
compensate growth when suitable conditions return, and that
the level of this compensation is mediated by the quality of
the grow-out environment.jitenderanduat@gmail.com

Case study
• The economic viability of stunting juvenile fish
has been established for milkfish (Baliao,
Franco & Agbayani 1987) and tilapia (Dan &
Little 2000) for conditions in the Philippines
and northern Vietnam, respectively, but the
viability of stunting carps is likely to be system
and site specific.

Case study
• Stunting or retarding the growth of milkfish
for fingerling production has been practiced in
the Philippines for some time.
• This practice has been necessitated by the
irregularity of fry supply from the wild, which
adversely affects continuous production of the
ponds. Stunting has also been shown to be a
profitable activity in milkfish culture
operation.

Stocking duration
6 months 9 months 12 months
A- fixed costs
Depreciation of
nylon substrates
50.00 50.00 50.00
Salary of pond
care taker
25.92 25.92 25.92
Repair and
maitenance
61.10 61.10 61.10
B- Variable costs
Pond preparation
Lime 22.03 22.03 22.03
Chicken manure 17.05 17.05 17.05
16-20-0 5.76 5.76 5.76
45-0-0 2.88 2.88 2.88
Economics

Stocking density
Installation of substrates
Stocking
2 months old fingerlings
(At P0.31/each) 892.80 892.80 892.80
Stunting operation
feeding
Trash fish 42.88 64.32 85.76
Rice bran 21.44 32.16 42.88
Harvesting
Labor for
harvesting
12.50 12.50 12.50
Interest charges 71.09 106.64 142.18
Economics

Stocking density
Total cost 1226.25 1306.92 1387.58
No. of fingerling
harvested
2505.00 2274.00 1499.00
Cost/piece 0.49 0.57 0.92
Net
income/piece
P700/thousand
0.21 0.13 (0.22)
Total net income 526.05 295.62 (329.78)
Average rate of
return
33.50 18.87 (21.06)
Economics

Conclusion
• Fisher community sells off as much as they
can to satisfy current year demand and then
go for producing stunted fingerlings.
• No systematic work has been carried out yet
to understand the stress caused due to food
deprivation on fish.

Stunted seed production &amp; culture practices

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