Major cultivable species for aquaculture

1.3 Major cultivable species for aquaculture: freshwater

Introduction

All kinds of fishes are not cultivable as they have different feeding habits.
Some of the fish feeds on only plant origin food, so they are called
herbivorous while other fish feeds on insects and its larvae are called insectivorous.
Some other fish feed on only fish, they are called carnivorous and while some
other fish feed on any thing available in the pond ecosystem and are called
omnivorous

In culture practice mostly fish of Carp family are cultured as they do not disturb
the others, grow fast and give good production.

Cultivable  Fresh water fishes

Carps form the largest fish family in the world. They have large scales on the body and lack
teeth. Many carps have a pair of barbels (small hair like processes on the jaw
or on the head) while a few have more than two pairs. Several species
of carps are found in the Indian waters. Among
them catla, rohu and rnrigal are the commonly recommended Indian
major carps. Their characteristics and identification marks are briefly described
here.

1. Catla catla

· Catla (Catla catla) is
found naturally in the major rivers of India. It is characterized by
its big head, high back, heavy body, heavy lower jaw and the mouth opening
upward.

· There are no hair like processes on the jaws.

· The back of the fish is gray while
the sides are white in colour.

· But according to the environmental situation
catla may be darkish in colour.

· Catla generally attains maturity during the
second year.



They mostly feed on
the macro fauna

· The mouth being open upwards they collect their food from the upper surface
of the water. Hence it is known as a surface feeding fish.

· If plenty of feed is
available and in less crowded situation catla fish may grow up to five kilogram
per year. They usually attain an average weight ranging between 800 to 1000
grams per year.

2. Rohu

· Rohu (Labeo rohita) is also found commonly in the Indian
rivers.

· The body is long and round; the
head is small and slightly pointed; the back is bent and slopping down
both towards the front and back.

· The upper and lower lips have fold or
frills. On the upper lip there may be two hair like structures.

· In general rohu has slightly
reddish gray scales; however the scales on the back have dark brownish
colour while those on the underneath and lower sides have less white scales.

· One of the easily
identifying marks is that it has reddish fins (wings).

· Rohu mainly gathers its feed from the middle layers of
water column and hence they are known as
middle feeders. This is in confirmation to the direction of the opening of
the mouth which is situated at the mid point opening forward (as opposed to up
ward or downward opening) making it easy for them to gather the feed at
the middle layers of water.

· When they are young they feed on the micro fauna but as
they grow up they start feeding on the micro flora like algae and decayed
organic materials.

· Besides they also feed on
small worms, shell fishes and other lower forms of aquatic life

· Though rohu can grow up to
3.5 kg weight within a year in the commercial composite fish
culture they are found to grow up to only an average weight ranging between 600
to 1090 grams per year.

·  However it is to be mentioned here that among the
recommended carps for commercial growing, rohu is tastier than others. Rohu
matures in the second year of its life.

3. Mrigal

· Mrigal (Cirrhinus mrigala) also like catla and rohu is
commonly found in the  Indian rivers.

· The body of mrigal is longer and less thicker than rohu.

· The head is small and
pointed,,- The mouth opens downwards; the lower lip has no folds or frills
like the rohu. But the upper lip has two hair like structures called barbels.

· In general the scales are yellowish white in colour though
the. scales at the back have a grayish
look.

· Mrigal matures in the second
year of its life.

· Mrigal gather feed mainly
from the bottom layers of the water column.

· When they are young they feed on micro fauna like
crustaceans and rotifers; but as they grow bigger they
feed mostly on the decaying plant materials.

· They also eat on the algae
and other small plants. Like rohu the average live weight gained in one year is
between 600 to 1000 grams though it has the capacity to grow up to 3 to 3.5 kg per
year under sufficient feed availability

Exotic Carps

There are three exotic carps silver carp, grass carp and common carp are
introduced into India and are recommended
for the composite fish culture.

1. Silver carp

· Silver carp (Hypophthalmicthy molitrix) though native of
China was introduced into India from Japan in 1959 and is now a well
established fish among the fish farmers

· It has a flat body, round mouth opening upward, slightly protruding lower
jaws, small eyes.

· The scales are comparatively smaller and white in colour.

· Silver carp gathers feed from the top layers of water
column and hence like the Indian carp catla is a surface feeder.

· When they are young they feed mainly on the micro fauna
but later they mostly feed on the micro and small plants.

· Though they have the
capacity to grow up to 5.5 kg per year under the composite growing conditions
they are found to attain an average weight between 1 to 2.5 kg per year. This
also matures in the second year of its life.

2. Grass carp

· Grass carp (Ctenopharyngodon idella) was originally found
in the big riversof China and Russia.

· But it was brought to India
from Hongkong. It has flat head, short and round face; lower lips are longer
than the upper one; the mouthis round.

· The back is dark gray and
the lower region and abdomen are white.

· They mature by the end of the 2nd year.

Grass carp feeds
mainly on micro fauna till they are about 1.7 to 1.8 cm long.

· Thereafter they feed mostly on all types of aquatic plants.
They are voracious eaters and can consume
grass and other leaves as n1uch as eight times its body

weight per day and
attains weight up to eight kilogram per year.

· This fish can be extensively grown
to control the aquatic weeds in canals, ponds and lakes.

· Besides aquatic plants grass carp also can eat green fodder
grasses. But in the composite fish culture
people do not bother to feed sufficient- ly the grass carp and hence the
weight gain may be less than the optimum.

· It can also grow in slightly saline
alkaline water.

3. Common carp

· Common carp (Cyprinus
carpio) is originally from Russia and China but has been introduced
to India in 1939 through Sri Lanka. There are three types of common carps:

· (a) common carps with small
scales covered allover the body called scale carp,

· (b) those with shining
3;fid big scales covered all over the body called mirror carp and

· (c) Those with only few
scales on the body called leather carp. However the
scale and mirror carps have become popular in India due to its ability
to survive in hot climate.

· The colour varies from gray
to orange. From the physical shape of view two types of common I carps
are noticed one with big stomach and other with long body.

· The body is flat on both sides. The mouth can be
extended forward as it opens up. The lips are thin and smooth.

· There are four barbels (hair like structures) on the upper
lips with one pair slightly bigger than the
other pair.

Principles of Aquaculture Study Material

INTRODUCTION
TO FISHERIES/BASICS OF AQUACULTURE

1.1 Definition, Significance and
History of Aquaculture

Definition

The cultivation of aquatic animals and plants,
especially fish, shellfish, and seaweed, in natural or controlled marine or
freshwater environments is called Aquaculture.

It has been called as the rearing of aquatic
organisms under controlled or semi controlled condition - thus it is underwater
agriculture.

Significance

Fish touch our lives in countless ways in terms of
providing food, nutrition, livelihood, employment, recreation, and many more.

Fish is an excellent source of protein and it
provides more than 25% of the world’s dietary protein. Human population
annually consumes over 100 million metric tons of fish.

Fish is an aquatic animal.  There are nearly 22000 species of
fishes.  Fish form the most important
protein rich and fatless food to humans. 
Fish is a good and readily digestible protein.  Most of fishes contain 15-25% protein and
1-5% fats.  Fish is a good source of
vitamin A, D and B.  fish meat also
contain rich amounts of Calcium and Iodine. 
Fish is a good source for Omega3 fatty acids which reduce blood
cholesterol.

History
of Fisheries

Fisheries and agricultural farming have evolved
rather parallel in the history of human civilization.  Interest in fish
eating dates back to the prehistoric times.  At the dwelling sites of the
old stone age (40thousand years ago) heaps of refuse of shellfish or seafish
have been found.  In new stone age (10000 BC), evidences are found that
fishes were sundried, smoked to preserve them.

In roman empire (400BC) highly organized fisheries
were found. Mullets and other fish were cultivated  along the Italian coast by the Romans.  Egypt pyramids show tilapia hieroglyphics.
China cultivated carps 2500 years ago.  Sushrutha made reference about
classification of fishes in 600BC.  Kautilya mentioned in his arthashastra
(300BC) about the culture of fishes as a source of income.

Bloch published a book on Indian fishes in 1785.  Russel described 200 species of India in
1803. Hamilton made a description of 289 species of fishes from Ganges.  Francis Day 1878-1889) provided vast
description of fishes of India.

Scope
of Aqua culture

1. To
increase the production for per capita consumption and per capita income by
which national income will be higher.

2.
Ornamental purpose like culture of angel fish, black molly, red sword tail,
blue gourami, kissing gourami etc.

3.
Sports and game purpose like culture of trouts and mahseers.

4.
Available natural waer resource utilization.

5.
Earning foreign exchange

6.
Upliftment of socio-economic status of the people.

7.
Create employment opportunity.

8.
Utlization of by-products of fish like isinglass, pearl essence, fish liver oil,
fish protein concentrate, fish glue etc.

9.
Controlling parasites like mosquito larae by larvicidal fishes (Lebistes, reticuilaus,
Gambossia affinis).

10.
Utlization of medicinal added value of fishery products

1.2 Present status of Aquaculture –
Global and National scenario

India is the second largest fish producing country in
the world with the current estimated fish production of 12.6 million metric
tonnes during 2017-18.

Fish and fish products have presently emerged as one
of the largest groups in agricultural exports of India with 13.77 lakh tonnes
in terms of quantity and Rs. 45,106.89 crore in value.

Indian Fisheries
Global position	3rd in Fisheries 2nd in Aquaculture
Contribution of Fisheries to GDP (%)	0.91
Contribution to Agril. GDP (%)	5.23
Per capita fish availability (Kg.)	9.0
Annual Export earnings (Rs. In Crore)	45,106.89
Employment in sector (million)	14.0

The fishery sector in India (culture and capture
fisheries combined) contributes 5.23% to the Gross Domestic Production (GDP) of
the agriculture sector and 0.91% to the total GDP of the country.

Globally, annual fisheries exports are valued at 85
to 90 billion dollars. Fisheries and aquaculture provide employment to more
than 43 million individuals worldwide. In India, Fisheries and aquaculture
provide gainful employment and livelihood support to more than 14 million
people by engaging them in different fisheries and related activities

Fisheries in India is a very important economic
activity and a flourishing sector with varied resources and potentials. There
is a  11–fold increase that India
achieved in fish production in just six decades, i.e. from 0.75 million tonnes
in 1950-51 to 9.6 million tonnes during 2012–13. This made India Second
Largest country in the world after china in aquaculture production.

Resources
Coastline	8118 kms
Exclusive Economic Zone	2.02 million sq. km
Continental Shelf	0.530 million sq. km
Rivers and Canals	1,95,210 km
Reservoirs	3.150 million ha
Ponds and Tanks	2.414 million ha
Flood Plains lakes and derelict waters	0.798 million ha
Brackishwaters	1.240 million ha
Estuaries	0.290 million ha

Freshwater aquaculture showed an overwhelming
ten-fold growth from 0.37 million tonnes in 1980 to 4.03 million tonnes in
2010;

The freshwater aquaculture comprises of the culture
of carp fishes, culture of catfishes (air breathing and non-air breathing), culture
of freshwater prawns, culture of pangasius, and culture of tilapia.

In addition, in brackishwater sector, the aquaculture
includes culture of shrimp varieties mainly, the native giant tiger prawn
(Penaeus monodon) and exotic whitelegshrimp (Penaeus vannamei).

The three Indian major carps, namely catla (Catla
catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala) contribute the bulk
of production to the extent of 70 to 75 percent of the total fresh water fish
production.

Catfishes forming a second important group
contributing the balance of 25 to 30 percent.

It is estimated that only about 40 percent of the
available area of 2.36 million hectares of ponds and tanks has been put to use
and an immense scope for expansion of area exists under freshwater aquaculture

The national mean production levels from still-water
ponds has gone up from about 600 kg/hectare/year in 1974 to over 2 900
kg/hectare/annum at present and several farmers are even demonstrating higher
production levels of 8–12 tonnes/hectare/year. (Handbook of Fisheries and
Aquaculture, 2013, ICAR publication, India).

The technologies of induced carp breeding and
polyculture in static ponds and tanks virtually revolutionized the freshwater
aquaculture sector and turned the sector into a fast growing commercial sector.

Some Facts
Present fish Production (Capture)	7.0 mmt
Inland	3.2 mmt
Marine	3.8 mmt
Potential fish production	8.4 mmt
Fish seed production	40,000 million fry
Hatcheries	1,604 units

The freshwater prawn farming has received increased
attention only in the last two decades due to its high consumer demand. The
giant river prawn, Macrobrachium rosenbergii, the largest and fastest growing
prawn species, is cultured either under monoculture or polyculture with major
carps.

Culture for mariculture species has been initiated in
the country and is presently carried out to a limited extent for seaweeds, and
mussels as a commercial activity and some fish species like seabass and cobia
on an experimental basis to standardize the technology.

In addition, there is contribution from cold water
fisheries. They constitute about 1% of total fish production. Important food
fishes of cold waters are tor tor, 
mahaseer etc.

India has an estimated total estuarine area of 3.9
million hectares; Of this, about 15 percent of the potential area has been put
into aquaculture purpose.

Apart from the giant tiger prawn (P. monodon),
certain marine/brackish water fish/shrimp species such as milkfish, pearl-spot
and mullets have shown a lot of promises for commercial aquaculture

India's aquaculture production basically can be
classified into freshwater and brackish water production.  Some of the important species cultured in
India are the Indian major carps and shrimp. Besides these, ornamental fish
culture and seaweed farming, are slowly gaining importance

Induced breeding of carps and catfishes helped in
rapid growth of aquaculture.  Production
of 4–5 tonnes under carp polyculture is quite common, farmers of several
regions are able to produce 8–12 tonnes/ha/year.

Integrated fish farming with livestock and
horticulture has not only been able to utilize the by-products/wastes as
principal inputs, but also made the farming practice highly remunerative and
farmers’ friendly.

Development of genitically improved rohu (Jayanti)
through selective breeding with a record of 17 percent higher growth is a mile
stone in indian carp industry.

 Availability
of balanced supplementary feed for different life stages for various organisms
also paved the way for the strengthning of this field.

Mariculture in India, although limited to the farming
of mussels and edible oysters undertaken in some coastal region of Kerala over
the years, has successfully produced sea cage farming in recent years,
initially with seabass and most recently cobia, which has shown the prospects
of commercial mariculture in the country.

Andhrapradesh
fisheries

Andhra Pradesh has been contributing significantly to
the fish basket of the country in the recent years through an effective
strategy in both coastal and freshwater aquaculture and marketing.

The state has 5.17 lakh ha of freshwater ponds and
tanks, 11,514 km of rivers and canals, 4.58 lakh ha of reservoirs and 150,000
ha of water areas suitable for coastal aquaculture. The inland fish production
is 6.8 lakh tonnes, with the mean yield of pond aquaculture is around 3.5
tonnes/ha/year, above the national average.

Further, by virtue of its 974 km long coastline, the
state produces 2.97 lakh tonnes of marine fish annually.