Fundamental of Aquaculture &�Fisheries
Dr. Suman Bhattarai
FAF
B.V.Sc & A.H
Kisan Polytechnic Institute
Chapakot-10, Syanja
Introduction to Fisheries
Unit- 1
Definition
General characteristics of fish
General Morphology of fish
Taxonomy of the fishes of Nepal
Desirable characters of fish for culture
Importance of fish
Biology of Cultivated fish species
DEFINITION
• Fish
• Cold blooded (??)
• Aquatic vertebrates (??)
• Breathe by means of pharyngeal gills (?)
• Propelling and balancing by means of fins (appendages)
• Supported by dermal fin rays
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FISH…
• 1st successful class of chordates
• Long evolution
• Large number of genera and species
• Currently, around 30,000 living species in different
aquatic habitats
• Cold water- Warm water
• Fresh water- Estuarine habitat- Marine habitat
• Several adaptive features according to habitat.
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GENERAL CHARACTERISTICS OF FISH
• Large no. of genera and species
• Large variation
• Generalization is difficult
• A lot of exceptions
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GENERAL CHARACTERISTICS OF FISHES
• Aquatic and cold blooded
• Body generally fusiform and streamlined
• A number of variations is present
• General plan is bilaterally symmetrical with prominent
lateral line system.
• Body generally covered by tough skins armored with a
variety of scales
• Placoid, cosmoid, ganoid, cycloid, and ctenoid
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BILATERALLY SYMMETRICAL??
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GENERAL CHARACTERISTICS OF FISHES
• Appendages comprise fins
• Paired- Pectoral and Pelvic
• Unpaired- Dorsal, Anal, and Caudal
• Main locomotory organs
• Mouth generally at the anterior end of head and anus
in the second half of the overall length of individual.
• Anus is behind the bases of the pelvic fins and just in
front of the anal fins
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GENERAL CHARACTERISTICS OF FISHES
• Major respiratory organs in the form of gills
• Accessory respiratory organs are also present
• Nostrils paired but do not open into the pharynx
• Exception lung-fishes and lobed-fishes
• In others mainly functions as olfactory organ
• Digestive tract is complete.
• Heart bi-valved, venous type and pumps blood to gills for
oxygenation.
• 2 or 4 chambered??
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GENERAL CHARACTERISTICS OF FISHES
• Kidneys paired, longitudinal structures lying dorsally in
body cavity almost attached to the vertebral column.
• Brain well developed with 10(+1) pairs of cranial nerves.
• Mostly oviparous but some are ovoviviparous as well as
viviparous.
• Fertilization generally external
• Eggs are large with much yolk
• Development is direct.
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FISHERIES
• Activities related to fish
• Farming/ culture, capture, processing, marketing etc.
• One of the fastest growing sector globally
• Can be divided into:
• Capture fisheries,
• Enhanced fisheries, and
• Culture fisheries or aquaculture
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Aquatic organisms, which are exploitable by the public as a common property resource with or without appropriate license is known as fishery. For example: Riverine fisheries, lake fisheries, fishing on rice fields, wetlands etc
CAPTURE FISHERIES :
• No stocking
• No management practices
• Only harvesting
• Provides table fish for consumption
• Provides seed and feed aquaculture
• Provides seed for enhanced fisheries
• Riverine fisheries, lake fisheries, fishing in rice field, wetlands
etc.
• May be licensed or non-licensed
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All kinds of harvesting of naturally occurring living organisms in both marine & Fresh water environments.
ENHANCED FISHERIES
• Only stocking
• No management practices
• Harvesting
• Provides table fish for consumption
• Provides feed for aquaculture
Eg: Enhanced fishing in Lakes, rivers, wetlands, etc.
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Wild caught of aquatic organisms that involve some degree of aquaculture
CULTURE FISHERIES/ AQUACULTURE
• Stocking
• Management practices
• Harvesting
• Generally done in owned ponds/ land
• The product is used in a variety of ways
• Definition of aquaculture??
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AQUACULTURE DEFINITION
• 2 Greeks words: Aqua- Water; Culture- farming
• Simply farming in water
• Aquatic equivalent to farming on land or agriculture
• Involves both plants and animals
• Both in inland as well as coastal waters
• Both in cold as well as warm waters
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AQUACULTURE
• Farming of aquatic organisms, including fish, mollusks,
crustaceans, and aquatic plants
• Implies some form of intervention in the rearing
processes to enhance production such as
• Regular stocking, feeding, protection from predators etc.
• Also implies individual or corporate ownership
• FAO (1988)
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AQUACULTURE…
• Aquaculture-
• Aquatic organisms have individual or corporate
ownership throughout the rearing period and also
harvested by individual or corporate ownership.
• Fisheries-
• Aquatic organisms are exploitable by the public as a
common property with or without appropriate license.
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GROUPS OF FARMED AQUATIC ORGANISMS
Plants
Animals
Algae (e.g.: seaweed,
freshwater algae)
Fin fishes (e.g.: carps,
catfishes, chichlids etc.)
Higher plants (e.g.: lotus,
water mimosa, water spinach shrimps, lobsters, crabs etc.)
etc.)
Crustaceans (e.g. prawns,
Mollusks (e.g.: oysters,
clams, mussels, cockles etc.)
Amphibians (e.g.: frogs)
Reptiles (e.g.: turtles,
crocodiles)
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NATIONAL FISH PRODUCTION (TREND)
Capture Fisheries
Aquaculture
100
90
80
70
60
50
40
30
20
10
0
Fiscal year
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DESIRABLE CHARACTERS OF FISH FOR CULTURE
• Aquaculture (fish) aims at
• Production of maximum quantity of edible fish flesh
• From a given quantity of organic matter
• In the shortest possible time
• Thus, species selected must have certain essential
qualities
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DESIRABLE CHARACTERS OF FISH FOR CULTURE
• The number of total cultured species in Asian region
has reached 170 in 1997 (FAO, 1999)
• Among them, fewer are cultured commercially
• A universal fish is not available to be cultured
• There are certain characters that a fish must posses to
be selected for culture.
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DESIRABLE CHARACTERS OF FISH FOR CULTURE
• Growth rate
• Efficient conversion of food
• Short food chain
• Aptitude for commercial/ formulated feed
• Adaptation to climate
• Disease and poor water quality resistance
• Meat quality/ Consumer’s acceptance
• Easy to breed in captivity
• High fecundity
• Economic and market consideration
• Compatible with other species
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CHARACTERS…
• Growth rate
• Fish that grow to large size in shorter period
• Must have natural ability to grow fast so that they can
attain a marketable size in shorter time
• Small fish species are not suitable for culture even if
they have other good characters
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CHARACTERS…
• Efficient conversion of food
• Must be an efficient converter of feed
• Give more edible flesh per unit of food consumed
• More edible flesh per unit weight
퐴푝푝푎푟푒푛푡 푓푒푒푑 푐표푛푣푒푟푠ꢀ표푛 푟푎푡ꢀ표(퐴퐹퐶푅)
퐹푒푒푑 ꢀ푛푡푎푘푒 (푘푔)
=
푊푒ꢀ푔ℎ푡 푔푎ꢀ푛 (푘푔
푊푒ꢀ푔ℎ푡 푔푎ꢀ푛 (푘푔)
퐹푒푒푑 ꢀ푛푡푎푘푒
퐹푒푒푑 푒푓푓ꢀ푐ꢀ푒푛푐푦 % =
× 100
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CHARACTERS…
• Short food chain
• Fish with short food chain are ideal
• Helps to reduce the loss of energy from passage to one
link of production to the next.
• At every trophic level, there is loss of 90% of the energy
• Best fish are herbivorous, planktivorous, omnivorous,
microphagous, and detritivores
• Carnivorous fish need high protein and thus can be
expensive to grow.
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CHARACTERS…
• Short food chain
Fish
Short food chain
Phytoplankton
Zooplankton
Worms/ Insects
Long food chain
Small fish
Fish
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CHARACTERS…
• Aptitude for artificial food
• To obtain high production, it is necessary that reared fish
accept an abundance of cheap, formulated feed
• Raising live foods is comparatively more difficult and
expensive
• Adaptation to climate
• Essential, as it limits the use of cold and warm water species
• Also limits the use of freshwater and marine species
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CHARACTERS…
• Disease and poor water quality resistance
• Disease occurs after stressful events
• Must withstand handling and transportation stress
• Must have low susceptibility to disease
• Must be tolerant to wide range of environmental
parameters
• Low DO, high ammonia, wide range of temperature and pH
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CHARACTERS…
• Meat quality/ Consumer ’s acceptance
• Consumer acceptance is most essential
• Must have high meat quality and suit the taste of
consumers
• In Asian countries, carp is preferred while Americans prefer
catfish over carps
• Tilapia and Pangas are preferred in a wide range
• But till now have lower preference in most of the Nepalese
communities
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CHARACTERS…
• Easy to breed in captivity
• To assure the easy and constant supply of fish for rearing
• But, a prolific breeding habit can create population density
problem
• High fecundity
• Higher fecundity means higher number of larva for rearing
• A shorter incubation period and larval cycle often contribute
to lower mortality of larvae and greater survival
• Increase the availability of seed
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CHARACTERS…
• Economic and market consideration
• Economic considerations more important than
biological factors
• Cultured fish must be economically viable and easy to
market
• Compatibility with other species
• Must live together without troubling other species
• Carnivores should be cultured separately.
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IMPORTANCE OF FISH
• Fish- one of the most important group in aquaculture
• Economic importance
• Food value
• Nutritive value
• Medicinal value
• Fish products
• Biological control
• Sports and games
• Decorative value
• Employment opportunity
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FOOD VALUE
• Serves as an important food for human
• Approximately 65% of raw weight of fish is eaten
compared with 50% of chicken and pigs, and 40% of
sheep and goats
• Terrestrial animals require strong bones as compared
to fish
• Trash fish are also used as animal feed
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NUTRITIVE VALUE
• Fish- highly nutritious
• Provides tasty, low calories meal with high quality
protein
• Almost zero carbohydrate food, good for diabetes and
other such patients
• Protein content varies form 15-30% on wet weight and
60-80% of dry weight basis
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NUTRITIVE VALUE…
• Fish protein is highly digestible with well balanced
amino acids
• Have low fat and cholesterol
• Good source of vitamins- A, B, and D
• Also is a good source of Ca, I, F, Mg, and Zn
• Rich in poly-unsaturated fatty acids (ω-3)
• Good to reduce the cholesterol level in the blood, thus
minimize the risk of heart attack.
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MEDICINAL VALUE
• Fish have low fat, high protein and an excellent source
of ω-3 fatty acids
• Regular fish consumption can reduce the risk of
various diseases and disorders.
• Some findings indicate that ω-3 can contribute to the
health of brain tissue and retina of the eye.
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MEDICINAL VALUE…
• Helps in lower blood cholesterol, reduce asthma,
different types of cancers, dementia, depression,
diabetes, and premature delivery
• Different fish are also used in ‘Ayurvedic’ medicines
helping in the treatment of ulcers, skin diseases, night
blindness, weakness, loss of appetite, cough and cold,
bronchitis, asthma, tuberculosis etc.
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FISH PRODUCTS
• Fish meal
• Fish oil
• Fish leather
• Fish fin
• Fish silage
• Fish flour
• Fish caviar
• Fish pearls
• Fish manure and guano • Fish insulin
• Fish glue
• Isinglass
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FISH PRODUCTS…
• Fish meal
• Dried and grounded unused or trash fish
• Highly nutritive and excellent feed for poultry, pig, cattle and fish
• May contain about 60-70% crude protein, 2-15% of oil and 10-20% minerals
• Fish oil
• Body oil and liver oil
• Body oil mostly used in manufacture of paints, varnishes, soaps, lubricants,
candle, printing inks etc.
• Also used in dressing of leather, tanning of skin and smearing the surface of
boats for longer preservation
• Liver oil has medicinal value and used in pharmaceutical industries
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FISH PRODUCTS…
• Fish silage
• A liquid or semi-liquid product made by the enzymatic action in the
presence of an added acid
• Used as an ingredient in animal feed
• Mainly in fish feeds and moist feed pellets
• Fish flour
• Made up of dried and powdered fish
• High quality fish meal used for human consumption
• Also known as hydrolyzed protein of fish
• Can be mixed with wheat or maize flour to enrich the nutritive value
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FISH PRODUCTS…
• Fish manure and guano
• Low grade, inedible fish and offal from fish processing
industries are utilized to prepare fish manure
• The residues are dried, ground, mixed with ash and
converted into manure
• Fish guano is prepared from the material left over after
extracting oil form fish
• Both of them contains high percentage of nitrogen and
phosphorus
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FISH PRODUCTS…
• Fish glue
• Gelatinous adhesive material obtained from the connective
tissues of skin and bones (especially cod)
• Used in gummed tape, letterpress printing plates, blueprint
paper, and adhering the wood, leather, glass etc.
• Isinglass
• Obtained from dried swim bladders of fish (powder form)
• Contains high grade collagen
• Used mainly for clarification of wine, beer, and vinegar
• Can also be cooked into paste for gluing purposes
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FISH PRODUCTS…
• Fish leather
• Coarse scaly skins (e.g.: sharks
and rays) used for
manufacturing, polishing and
smoothing materials
• Dried and processed skin is also
used for preparing high quality
jackets, shoes, moneybags,
suitcases, belts, phone cases etc.
• An eco-friendly alternative to
the typical exotic leathers such
as crocodile and snake
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FISH PRODUCTS…
• Fish fin
• Fins of the sharks and rays are used to make tasteful sauce and
soups
• Considered as a luxury item in Chinese culture
• Fish caviar
• Salt-cured eggs of certain species of fish (e.g.: sturgeon, salmon,
and trout)
• Considered as a delicacy and luxurious food
• Price depends on age and species
• Caviar of 60-100 years old Iranian beluga sturgeon costs about
$35,000/kg
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FISH PRODUCTS…
• Fish pearls
• Material obtained by scraping the silvery coating of the
scales of certain fishes
• Used for polishing the hollow glass beads
• The glass beads are then filled with wax and marketed as
artificial pearls
• Fish insulin
• Extracted from the pancreas of large fishes such as sharks
• Prior to the introduction of biosynthetic insulin, it was
derived from sharks and other fishes
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BIOLOGICAL CONTROL
• Many species of carnivorous and larvivorous fish prey
upon insects and their larvae in water
• Used to control harmful insects.
• E.g.: Gambusia affinis, Brachydanio spp., Colis spp.,
Puntius spp. etc.
• Some species are also used to control the aquatic
weeds and vegetation
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SPORTS AND GAMES
• Sport or recreational fishing- for pleasure or
competition
• Common sport fishes in Nepal are Sahar (Tor spp.),
Asla (Schizothorax spp.) and rainbow trout
(Oncorhynchus mykiss)
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SPORT FISHING…
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DECORATIVE VALUE
• Many species of colorful fish are kept in aquarium,
oceanarium, ponds and lakes for decoration or
ornamentation.
• Common ornamental fish in Nepal are Gold fish
(Carassius spp.), Gourami (Trichogaster spp.), Zebra
fish (Brachydanio rerio), Fighting fish (Betta
splendens), Koi (Cyprinus carpio) etc.
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ORNAMENTAL FISH
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EMPLOYMENT GENERATION
• Fisheries and aquaculture sector provide, either directly or
indirectly, a great employment opportunity
• About 58.5 million people was directly involvement in fisheries
or aquaculture directly or indirectly in 2020 (CFPCC, 2021).
• 21% women
• 35% in aquaculture and
• 65% in capture fisheries
• Employment in the processing industries as well as marketing.
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THANK YOU
End of Unit 1
Next lecture on
Biology of cultivated fish species
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