CATFISH IN TROPICAL AND SUBTROPICAL REGION : CATFISH IN TROPICAL AND SUBTROPICAL REGION Author: FICKNARD ROWLAND(G.M) AQUACULTURE GRADUATE FROM SOKOINE UNIVERSITY OF AGRICULTURE 2010 publication
Author: Ficknard Rowland
Department of animal science and Production: Sokoine University of Agriculture: Faculty of Agriculture P.O.Box 3004, Morogoro, Tanzania
email@example.com CATFISH IN TROPICAL AND SUBTROPICAL REGION : CATFISH IN TROPICAL AND SUBTROPICAL REGION CONTENTS CARRIED
species known in tropical And Sub
How they tend to grow
Anatomy of clarias spp
Patterns or forms in natural propagation
Appropriate techniques in artificial propagation
Prons and even corns of each propagation INTRODODUCTION : INTRODODUCTION Catfish belong to the fish order called siluriformes subdivided into the families ictaluridae, pangasidae , and clariidae and consist of both marine and fresh water fish species found in most parts of the world BIOLOGY : BIOLOGY SPECIES FOUND
The commonly classes found in tropical area are clarius gariepinus,, clarius ngamensis , clarius liocephalus , clarias alluaudi, clarias werneri, clarias theodorae .
Catfish are bottom dweller
In general catfishes are found in fresh water especially in swamp ( papyrus, marginal ) and stream among rock ar vegetations
catfish have either a naked skin or their skin is covered with bony plates .
also have eye with free border.
Sides of head behind eyes bony.
Dorsal and anal fin separates from caudal fin ,
And then air breathing organs well developed.
HOW IT GROW
Average growth rates in pond of catfish is
500-1500gram (1st year)
1000-2500grams (2nd years)
It is difficult to judge maximum growth with accuracy in catfish due to influence in many factor
The growth is directly influenced by temperature, oxygen contents of the water and availability of the pelleted feeds. At early stage catfish grow faster COURTSHIP BEHAVIOUR OF CATFISH : COURTSHIP BEHAVIOUR OF CATFISH Male catfish dig holes of about 20-30cm under the water surface then female inspect the holes before releasing the eggs
Catfish also show pair spawning, which is characterized by degree of mating selection and behavior interaction PATTERN OR FORMS OF NATURAL PROPAGATION IN CATFISH : PATTERN OR FORMS OF NATURAL PROPAGATION IN CATFISH Catfishes are oviparous seasonal spawners as they can propagate during a particular season of the years
They depending on environmental factors like
substrates APPROPRIATE TECHNIQUES IN ARTIFICIAL PROPAGATION : APPROPRIATE TECHNIQUES IN ARTIFICIAL PROPAGATION This involves the human intervention skill on the natural propagation there are two techniques
FRY COLLECTION FROM NATURAL WATER
The equipments needed much are funnel shaped nets to collect the catfish’s eggs, larvae or fry.
After the collection larvae are kept temporary on the earthen pit
later are transferred to the nursery for further rearing
It starts with procurement of brood fish from the wild or captive Broodstock until they reach maturity. .
The spawning season is generally during the rainy season
NB: in some species like clarias pangasinus can not spawn in confined water until they are treated with the hormones Continues……. : Continues……. INDUCEMENT OF SPAWNING BY HORMONES
The brood fish is selected from the stock
injected with the pituitary gland .
After 40-12 hrs the female can be striped .
Then eggs are fertilized from male milt
incubation is carried out
The egg hatching follows next 24-30 hrs, temperature range of 29-32oc.
Yolk is absorbed fully within two days after hatching.
Larvae grow to fry which will be taken to nursery for further. PRONS AND CORNS OF BOTH NATURAL AND ARTIFICIAL PROPAGATION : PRONS AND CORNS OF BOTH NATURAL AND ARTIFICIAL PROPAGATION PRONS OF ARTIFICIAL PROPAGATION
PRONS OF ARTIFICIAL PROPAGATION
Better rate of fertilization and hatching
Protection against enemies and unfavorable environmental condition
Better condition for growth and survival
CORNS OF ARTIFICIAL PROPAGATION
It is difficult to adopt
It needs capital to undertake
Prons of natural propagation
Good area for survival adaptation
Corns of natural propagation
Poor rate of fertilization
Poor rates of hatiching
It cant provide enough stock for commercial culture