- NPV at 15% DF : Rs 43434
- BCR at 15% DF : 1.51 : 1
- IRR : 169 %
There is only limited demand for the mussel meat due
to lack of awareness among the consumers . However ,
there is scope for its export to Southeast Asian
countries. A marketing tie-up with the processing plants
will be useful for marketing of the product.
10. Interest rate for ultimate
borrowers Banks are free to decide the rate of
interest within the overall RBI guidelines. However, for
working out the financial viability and bankability of
the model project we have assumed the rate of interest
as 12% per annum.
11. Interest rate for refinance from
As per the circulars of NABARD issued from time to
12. Repayment period
The loan amount of Rs 39,500/- can be repaid in five
years starting from first year onwards as the culture
period is for 6 months and it is possible to take the
first crop during the first year itself.
Banks may take a decision as per RBI guidelines.
ANNEXURE - I
Farming Technology of Green Mussel
The scientific name of the green mussel is
Perna viridis. The mussel has organ
systems similar to those found in oysters with some
modifications. It has a foot as in clams though smaller
in size, providing limited mobility. A mussel can
discard the byssal strands and secrete new ones for
enabling it to change position. Phytoplanktons forms the
food of the mussels, and they are filter feeders.
P.viridis in the natural conditions grow
to 63 mm in 6 months to 133 mm in 4 years. However , the
growth in culture operations have been more than in the
natural conditions. In mussel the sexes are separate and
the gonads which are located in the body proliferate in
to mantle. The male gonad is creamy white in colour
while in the female it is pink or reddish. The mussel
attains first maturity at 15.5 to 28 mm size.
2. Technology of mussel culture
A) Seed collection / Availability
The spawning season of the green mussel is between
July and September and the spats are found carpeting the
inter tidal and submerged rocks. At present they are
collected manually and during the peak season an
individual would be able to collect 10-12 kg of seed in
one hour. The seeds can also be collected using spat
collectors such as roof tiles, coir ropes and nylon
ropes. Even though the hatchery technique for commercial
mussel spat production has been perfected by Central
Marine Fisheries Research Institute , Cochi, there is no
commercial hatchery at present in India. As such the
culture operations have to depend on the availability of
natural seed .
B) Farming models
Three types of farming are practiced for culture of
the mussels as follows:
i. Sea Farming - Longline culture of
mussel is practised in shallow waters of 10 - 15 m depth
. This method of culture can withstand the severe
monsoon conditions in the west coast. The longline unit
consist of 60 mt long horizontal HPD rope of 20-24 mm
thickness anchored at both the ends with 150 Kg concrete
blocks and a series of 100 liters capacity barrels as
floats fixed at 3 m intervals. Vertical lines of 6 m
length seeded with mussel spats are hung at a distance
of 75 cm between two floats in the main line. A longline
unit of 60x60 mt can accommodate 12 horizontal ropes and
920 - 1000 vertical ropes. The distance between two
horizontal lines is 5 mt . At every 20 mt the horizontal
lines are connected using additional horizontal lines.
ii) Estuarine farming - Pole culture
and stake culture are done in estuaries at a depth of
1.5 to 3 m. The spats of 15 to 25 mm are wrapped around
the poles or stakes with cotton mosquito nettings. The
spats gets attached to the poles in three or four days
and by this time the cotton netting will disintegrate.
Periodical thinning is necessary.
iii) Rope culture - Rope culture of
mussel is widely adopted in Northern Kerala. Ropes are
suspended from rack made of casuarina and bamboo poles.
The average area of rack is 400 sq m and length of the
ropes used for seeding ranges from 1-1.25 mt depending
on the depth of the water column. Poly propylene ropes
wound with coir ropes are used for seeding. These ropes
are hung down from the racks at an interval of 1 feet
and nearly 500 - 550 ropes could be suspended from one
rack. The seeds collected from wild are being sold in
units of one bag and one bag of seed can be used to seed
8-10 ropes. The normal size of the seed ranges from
35-65 mm. Seed collected has to be seeded on the same
day and it is estimated that one person can seed around
60-70 ropes in a day. The culture period in Northern
Kerala where the activity is taken up fairly on a large
scale starts from November and ends in the middle of May
before the rains. Once in a fortnight the ropes are
lifted for monitoring the growth and removal of fowling
organisms . The mussel grows to 80-100 mm size with in 6
months of culture period and it is estimated that around
2 lakhs mussels can be harvested from 400 sq mtrs.
3. Harvesting of Mussels
The mussels are harvested after attaining a size of
80-100 mm with in a period of six months. Indication of
good mussel could be measured by the condition index
which is the ratio of wet meat weight to the total
weight of the mussel. The condition index shows seasonal
changes and is usually related to reproductive cycle. It
is generally high before spawning. The wet meat normally
forms 33 to 40% of the total weight in mussel as found
in different experiments.
Before removing the meat from the mussel it is
necessary to carry out depuration which is a process in
which the mussels are kept for 18 hours in clean sea
water which will purify the mussels of bacterial
pollution. The mussels can be processed in different
forms like frozen, canned, smoked, dried and marinated.
The mussel shell is used as a liming agent in coconut
plantations. The mussel shell gives good quality lime
which finds application in many industries.
Annexure - II
Estimated financial outlay for
culture of Green mussel P.viridis in 400 sq m area Rack
A. Capital Cost