Fish preservation & processing :Aquaculture

Preservation & processing of harvested fish:-

This is the method use to keep the surplus fish good conditions for later consorption. It is the process (primary processing) & preserve (2 processing) of the fish to transport to a target market of factories while it is good quality.

Processing of fish:-

Fish processing is the process associate with fish and fish products between the time of fish are caught and the time of final product is delivered to the costume.

The hardest fish should be cleaned and cooled as soon as possible due to their stong digestive juice, which is responsible for fish spoilage cleaned fish first be put in plastic bags and then in ice to prevent.

Contamination from hand, working area, cutting board, knife and other interleave should be properly cleaned with water.

Fish preservation:-

Preservation is processing of food to store to the fish for a longer time & to prevent spoilage of fishes.

Fishes preservation is the method of extending the self life to fish and other fishery products by applying the principal of chemistry and other branches of science in order to improve the quality of products.

Some of the important reason for preserving food are:-

  • To take care of excess produce.
  • Reach areas where the food item is not available.
  • Make transportation and storage of fish earlier.
  • Preserving food at home.

Method of fish preservation:-

Fish can be preserved by following method:-

  • Salting
  • Dehydration & sun drying
  • Increasing temperatures
  • Lowering temperatures
  • Using preservative


Salt is the preservative agents lengthen the shape life of fish & fishery products as it absorb moisture from organism and drastically reduce spoilage.

The 2 chief techniques of salting are:-

  • Weight salting
  • Dry salting


  • Weight salting:-

Weight salting is the chiefer since it required lesser amount of salts. It is required to keep the fish for a long time in brine in water tite container. It is best cut of the head and gut of large fish and can be salted whole.

  • Dry salting:-

In dry salting method the fish is salted at the ratio of 2:1 but juice, sline & brine are allow to flow layers of fish must be separated by haps of salt.

Dehydration & sundry:-

In drying process the moisture is removed by exposer to natural air flow and humidity is regulated by climatic conditions. In this process very small & thin fishes are dry straight away in shiting sun if the sunlight is not enough, the 1st must be put for 1night in brine or dry salted.

Increasing temperature-(smoking) :-

Temperatures is increased by smoking all fishes can be smoked by 3main methods of smoking. They are:-

  • Cold smoking
  • Long smoking
  • Hot smoking

Cold smoking:-

Cold smoking is customerly perform below 30°c to prevent underserved change in the muscle texture. Uniform drying & preserved the desired colour by using of indirect source of heat and smoke. Cold smoking process in primarily use for salmon cod.

Hot smoking:-

This system is used for immediate consumption or to keep the fish for a maximum 48hrs. Small fish can be salted first for half an hour and put on from spites and dried in a windy place or the  sun for another half hour and then hot smoke. The fish will be ready in 1 hours with golden yellow colour skin.

Long smoking:-

By this process non only fishes can be kept for langer period for this purpose a small closed shead made of pulm leaves or other local materials are used. This can also be loid on loosely over matting.

Lowering temperatures:-

Lowering temperatures is done by chilling or freezing.


This is done by covering the fish with layer of ice, but not for long preservation as melting water bring about a short of liching of valuable flash content.

But it is effective for short term preservation which needed for transportation.


This is more effective then chilling, freezing is achieved either of mixture if ice and salt or refrigeration. The subzero temperatures. So obtain keep the fish frozen thrown out. This protect against exposer or fish fat to atmospheric oxygen.

Using preservation:-

By using of different preservation fish can be preserved. Which can be done by canning & picking.


This is very costly & effective method in which the fish remain good and retain much of flavour fish is clean and cut to proper bundle pieces in filleting plant. These fishes are brine or pickle to improve test.


By this method pickles fish most be stored in refrigerator at temperatures not higher then 40°f and for best fever it must be used within 4to6 weels.

Fishery Bio product:-

Fishery is an great important to human being an addition to providing food, most of the fishing industry yield a no of bio product of commercial importance. The chif among fishery bio product are describe below:-

Fish oils:-

Fish oils is extracted from fatty tissue from fishes. It is a mixture of Triglycerides containing cholesterol other fish oil is group into body oil & liver oil.

Body oil:

Body oil is extracted from whole fish body,body oil is again further sub grouped into following 2 types.

Dry oil:-

It is obtain from salmond, saldine, herring and white fish.

Semidry oil:-

It can be obtain from carps. Body oil is used for industrial purpose like cosmetics, lubricant.

Liver oil:-

It has great medicine value. Since ancient times. It is the main source of vitamin A in some species of fishes liver oil contain vitamin C, D & E.

Vitamin A and D obtain from cud, shark etc. also obtain from helibute &tuna.

Liver contain lower% (4% to 28%) of weight & higher % of Vitamin A e.g. Tuna.

Fish meal:-

Fish meal is traditionally is used as livestock feed supliment which has high quality protein , high level of licene, methionine and eysteve and these 3 are the most essential amino acid. Which the animal can not synthesis and this can not make is an unrevealled constituent of feed stafs, it is also of good source of vitamin D like fe, phosphorus, cu.

Process of manufacturing:-

Fish can reduce to fish meal by 2 general process:-

  • Dry rendering process
  • Weight rendering process

Dry rendering process:-

Dry rendering is the process employed to process from non oily fishes like shark, silver belles, Jew fish etc.

Weight rendering process:-

This process is normally allied to fatty fish. Where simultaneously production takes place fish meal and body oil. This process consists off:-

  • Grinding
  • Cooking
  • Pressing to expellow lequice &oil
  • Cakes

Uses of fish meal:-

The principal use of fish meal is as an ingredients in the life stock feed often supplement in animals & pultry.

Fish silage :-

It can be defined as a product made from whole or part of the fishes which  no other material has been added other then acid, by treating with mineral acid or organic acid and in which lequefication of fish is brought about by enzymes already present in the feed.

Fish silage can be done where material can be available where there is no fish meal plant no reasonable transport to the nearest plant.


Fish silage is used as cattle feed either as whole mass or decant liqued portion.

Fish floor:-

It is highly nutritive food for human being & prepared commercial by solvent extraction process.

It is easilly prepared in 3 to 4 month. It is also form in the biscuits, bread, cakes, sweet & soop.

It has particular odour so it has treated chemical to remove the bad smells.


Chitin is white hard, elastic, nitrogenous Polysaccharide widely distributed in the exoskeleton of insects crabs shrimp and also internal str. Of other invertebrates. It is the single largest source of chitin in India.


Chitin is extensive used as growth promotor in birds as use an ingredients in their feed.

Prown head meal & sell wast:-

The hard & shell of shrimps of prown contain a good percentage of protein  & chitin other than minerals.

Fish fertilizer:-

The waste obtain during the preparation of fish meal converted into fertilizer.

These are widely used as mange for coffee, tea & tobacco, plantation, fish fertilizer are of 3types:-

Dry fish manure:-

It is obtained from destroyed fishes , which are adable . It contains nitrogen 5 to 7% phosphorus 4to 6 % and ca 4 to 6 %.

Pit fish:-

It is obtain by the burning the weste nitrogen 3-5% phosphorus 3-6% ca 1.5%.

Fish ghana:-

The refuse of cook fish body obtain after proper pressing during the extraction of oil of contain 8-10% N, phosphoric acid etc.

Fish fin:-

Fish fin used to prepare shite. It’s used to polish wood.

Fish skin:-

The hard skin of fishes & shark are use to  prepared leather products.

Silver scale:-

The scale of black fish which is found in Europe are used in the manufacturers of artificial pearl.

Fish glue:-

Fish glue is prepared from the skin and bones of fishes like cud, Head dock.

Fishing glass:-

This is  a highgrade collagen which is prepared from air bladder of cat fish & carps. It is used to prepared of parse.

Pharmacopeia :-

Certain Byproducts of fish industry are use in Ayurvedic in unani system of medicine.

Shark are used in the cure of duodenal alter certain biproducts of fishes are used in Night blindness, cold, skin disease, cough, bronchitis & tuberculosis.


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