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Model Bankable Projects



Mussel Culture


Mussels are bivalve molluscs and are found attached to rocks or any other hard substratum by means of byssus thread secreted by the body. They belong to the family Mytilidae. In India two species of marine mussels namely Perna viridis the Green mussel and Perna indica the Brown mussel forms the major part of the fishery. Kerala State can be called as the Mussel fishery zone of India since extensive beds of both the green and brown mussel occur in this state which also account for the bulk of mussel production in India.

Of the two species commercially important the green mussel P. viridis is widely distributed and found in the beds of Chilka lake , Visakhapatnam, Kakinada, Madras , Pondichery, Cuddalore and Porto Nova on the East coast and extensively around Quilon, Alleppey, Cochin, Calicut to Kasargod, Manglore, Karwar, Goa, Malwan , Ratnagiri and the Gulf of Kutch on the West coast. P. viridis occurs from the inter tidal zone to a depth of 15 m. On the other hand , P indica has restricted distribution and is found along the southwest coast from Varkala near Quilon to Kanyakumari and from there to Tiruchendur along the southeast coast. It occurs from the inter tidal zone to 10 m depth. P.viridis is widely distributed and hence more suitable for farming.

2. Area suitable for farming

For sea farming, coastal waters beyond surf zone at 10 - 15 mt depth is normally selected. The area should be sheltered from strong wave action. The site should be free from any major industrial effluent and should not interfere with transport or any other fishing activity. Clear water with good phytoplankton production and moderate current to bring in the food and carry away waste products is required. A salinity range of 30-35 ppt is preferred.

3. Technical parameters

The biology, technical parameters required for the culture of green mussel P. viridis and farming methods are described in detail in Annexure - I.

4. Borrowers profile

The borrowers should have experience in Mussel farming and should be able to manage culture , marketing and other related aspects.

5. Financial outlay

The details of the financial outlay have been indicated in Annexure - II . The capital cost for 400 sq m rack culture unit works out to be Rs 21,500/- , while the operational cost for the first year is estimated to be Rs 20,050/- which may be capitalised for working out the bank loan. The unit cost is illustrative and actual cost need to be worked out based on the field level conditions while submitting the project to the Bank.

6. Margin Money and Bank loan

Depending on the borrowers profile he is expected to meet 5-25 % of the project cost as margin money out of his resources. The balance would be provided as loan from the Bank.

7. Refinance

Refinance to the scheduled banks is available from NABARD for such activities which are technically feasible and financially viable and the rate of refinance will be as prescribed by NABARD from time to time.

8. Financial viability

The following assumptions have been made on the basis of the farming practiced in Kerala for working out the financial viability of the project.

1 Unit size of rack ( Area )    400 sq m
2 Culture period    6 months
3 Size of the seed (Spats) at the time of seeding    35-65 mm
4 Size at harvesting    80-100 mm
5 Number of mussel that could be harvested from    400 sq m 2 lakh
6 Production       
     1st year 70%     
     2nd year 80%    
     Third year and onward 100%  
7 Sale price     Rs 22 per 100 No of mussels.  

The financial analysis has been shown in the annexure-III. The broad indicators exhibiting financial viability are

  1. NPV at 15% DF : Rs 43434
  2. BCR at 15% DF : 1.51 : 1
  3. IRR : 169 %

9. Marketing

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 NABARD

As per the circulars of NABARD issued from time to time..

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.

13. Security

Banks may take a decision as per RBI guidelines.


Farming Technology of Green Mussel

1. Biology

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.

4. Processing

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 culture unit

A. Capital Cost

S.No Particulars Amount ( Rs )
1 Small Dugout Cannoe 5000/-
2 Bamboo Poles 3000/-
3 Polypropylene Rope ( 10 mm thickness) 9450/-
4 Coir Rope ( 10 mm thickness ) 1950/-
5 Tarpaulin 1500/-
6 Nylon Net 500/-
7 Lease Amount ( for 5 years ) 125/-
  Total 21525/-

B. Recurring Cost

S.No Particulars Amount ( Rs )
1 Seed cost 70 bags @ Rs 215 per bag ( including transportation ) 15050/-
2 Cloth for seeding 1000/-
3 Labour charges ( L.S ) 3000/-
4 Miscellaneous ( including basket , twine etc. ) 1000/-
  Total 20050/-

C. Total Cost ( A + B ) = ( Rs 21525 + 20050 ) = Rs 41575

D. Income

S.No Particulars  
1 Total Production
    2,00,000 Nos
2 Sale Price
    Rs 22 per 100 No of mussels
3 Gross Income
    Rs 44000

Annexure - III

Financial Analysis

Items Years


  1 2 3 4 5
Capital Cost 21525        
Recurring Cost 20050 20050 20050 20050 20050
Total 41575 20050 20050 20050 20050
Income 30800 35200 44000 44000 44000
Net Benefits -10775 15150 23950 23950 23950
PW of Costs @ 15 % DF 85928        
PW of Benefits @ 15 % DF 129362        
NPW 85928        
BCR 1.51 : 1        
IRR 169%        

Annexure - IV

Estimated Bank Loan and Repayment Period ( Illustrative )

Total Outlay = Rs 41575/-

Margin 5 % = Rs 2080/-

Bank Loan = Rs 39495 Say Rs 39500/-                                                                   

( In Rs )

Year Bank Loan Net Income   Repayment   Bank Loan Outstanding Net Surplus
      Interest @ 12 % Principal Total    
1 2 3 4 5 6 7 8
1 39500 30800 4740 3480 8220 36020 22580
2 36020 15150 4322 4768 9090 31252 6060
3 31252 23950 3750 10620 14370 20633 9580
4 20633 23950 2476 11894 14370 8739 9580
5 8739 23950 1049 8739 9788 0 14162

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