Catfish
Last semester, we had done experiments on Induced Breeding,seed production,cryopreservation of sperm as well as In Vitro Fertilization and triploidy Induction on a Catfish species known as the Clarias gariepinus or better known as the African sharptooth catfish. I have to agree that my whole class enjoyed getting involved in these experiments as it was one of the very first times we were experimenting directly on a live animal.
Catfishes are indeed very unique creatures.The specimens we obtained were around 8 kilograms each and was up to 2 feets in length. We bought them from a local fish breeder very near to our college.
Here is a picture of a male Catfish that we used for the experiment :
After the experiment, well of course all of us must hand in a report and here's some information that i managed to gather while i did mine.
Catfishes constitute a large family of the freshwater fish group, there are about
2000 species of catfishes in the world (about 8% of the total number of fishes).
Here's one interesting piece of information :
One out of every four freshwater fish, one out of ten fishes, and one out of twenty vertebrates, is a catfish. From this the Mekong giant catfish(Pangasianodon gigas) is the largest. The giant is called Pla Buek in Thai, the giant catfish can weigh as much as 650 pounds (300 kilograms) and measure up to 10 feet (3 meters) in length. They are the largest scaleless freshwater fish in the world.
Picture of the Giant :
there are few more pics from the national geographic site. Here's the link
Here's a pic of the giant caught, what a pity:
Catfishes are widely distributed around the world. They live in large rivers where at times few hundred species may exists, for example in the Amazon rivers. They vary in size from tiny parasitic species with a total length of less than 5 mm to giant forms such as some of the Pangasius species, the wels (Silurus glanis), the vundu (Heterobranchus longifilis) and the African sharptooth catfish (Clarias gariepinus) which exceed 30 kg in mass.
After reading from the net that the African catfish i was dealing with can exceed 30 kg in mass, i decided to look for a picture that could show the proof. This is because the fish we had was just 2 feet and nearly 8 Kilograms. How big would a 30 Kilogram one would be?
Here's a picture of one that weighs 20 kg:
In this experiment we choose the Clarias gariepinus as it can be obtained easily and is economical. It is from the Clariidae family and only 8 species from this family exists in Southern Africa.
Female Fish
12 hours before the spawning, Hormonal injection is given to the fishes so that they will be sexually ripe the next day. Ovaprim hormone injection is done intramuscularly and midway between dorsal fin and lateral line (the muscular nape region) and is made perpendicular to the fish so that it doesn’t hit the vertebrae. The injections are done vertically, slightly above the vent towards the head. The needle is then inserted into the body cavity at an angle pointing towards the head parallel to the fish
Brood female member of the Claria gariepinus has a bulky abdomen (ovaries) indicating the presence of about 50,000 eggs inside. The ovaries of C.gariepinus are paired elongate organs situated dorsally in the body cavity. The oviducts of the two ovaries fuse and open into a urinogenital papilla, which is round, protruding, and reddish. Mature females have very large ovaries which fill the body cavity and may constitute 7 - 10% of the total body weight. Approximately 12 hours after injection at a temperature of 28 C the female fish is ready to be stripped.
The urinogenital papilla of female fish :
I personally had the opportunity to touch and strip the eggs from the female fish. The abdomen felt very smooth and rubbery with a slippery coat on its scaleless skin.
My lecturer warned me not to put too much pressure as he knew i could be nervous due tobeing a first timer. Anyhow, after a few attempts he decided to do it by himself. perhaps i was too slow.
Here's a picture of the female being stripped by my lecturer:
To watch the stripped eggs come out from the urinogenital papilla was not a pleasant sight. In the notes i read, it said that the fishes are relieved from the heavy burden they were carying. But perhaps, eggs oozing out naturally may be a relieve, but when it comes to human hand? I wonder how true is that statement. An unexperienced hand may accidently strip too hard that it may cause internal abdominal damage to the fish.
Male Fish
Male species of C.gariepinus has paired testes which is connected by a fused spermatic duct opening into an elongated pointed urinogenital papilla. This urinogenital papilla is protruded and pointed and this is the only external feature upon which male and females can be distinguished from each other.
Male fish's potruding urinogenital papilla :
This was the sad part because the male fishes used for this experiment has to be Sacrificed. I was informed that although stripping technique could be used for obtaining the sperm but it would not be sufficient. Thus both testicles has to be removed and the fish discarded. Later the testicles are macerated and placed in a Sodium Chloride solution to maintain it in a homogenized state. The milt from the testicles are mixed with the eggs later. Water is added too to enhance sperm movement.
Fertilization
Fertilization of the eggs takes place externally. Catfish sperm is motile for 80 to 120 seconds, which is a very short period compared to other fresh water species. Sperm takes 3-5 minutes to fertilize the eggs. Fertilized eggs will be in pale yellow colour and the unfertilized ones will be either dark or orange. Egg and larval development is rapid. The eggs hatch after 24 to 48 hours, depending on the incubation temperature. Rapidly hatching larvae begin to swim 35 hours after fertilisation and exogenous feeding commences within 80 hours.
Fertilized eggs :
Development of fry
well..that's some little information i managed to type here about the catfish. The information above is very general and i did not discuss in depth of a particular experiment.
Catfishes are indeed very unique creatures.The specimens we obtained were around 8 kilograms each and was up to 2 feets in length. We bought them from a local fish breeder very near to our college.
Here is a picture of a male Catfish that we used for the experiment :
After the experiment, well of course all of us must hand in a report and here's some information that i managed to gather while i did mine.
Catfishes constitute a large family of the freshwater fish group, there are about
2000 species of catfishes in the world (about 8% of the total number of fishes).
Here's one interesting piece of information :
One out of every four freshwater fish, one out of ten fishes, and one out of twenty vertebrates, is a catfish. From this the Mekong giant catfish(Pangasianodon gigas) is the largest. The giant is called Pla Buek in Thai, the giant catfish can weigh as much as 650 pounds (300 kilograms) and measure up to 10 feet (3 meters) in length. They are the largest scaleless freshwater fish in the world.
Picture of the Giant :
there are few more pics from the national geographic site. Here's the link
Links
Here's a pic of the giant caught, what a pity:
Catfishes are widely distributed around the world. They live in large rivers where at times few hundred species may exists, for example in the Amazon rivers. They vary in size from tiny parasitic species with a total length of less than 5 mm to giant forms such as some of the Pangasius species, the wels (Silurus glanis), the vundu (Heterobranchus longifilis) and the African sharptooth catfish (Clarias gariepinus) which exceed 30 kg in mass.
After reading from the net that the African catfish i was dealing with can exceed 30 kg in mass, i decided to look for a picture that could show the proof. This is because the fish we had was just 2 feet and nearly 8 Kilograms. How big would a 30 Kilogram one would be?
Here's a picture of one that weighs 20 kg:
In this experiment we choose the Clarias gariepinus as it can be obtained easily and is economical. It is from the Clariidae family and only 8 species from this family exists in Southern Africa.
Female Fish
12 hours before the spawning, Hormonal injection is given to the fishes so that they will be sexually ripe the next day. Ovaprim hormone injection is done intramuscularly and midway between dorsal fin and lateral line (the muscular nape region) and is made perpendicular to the fish so that it doesn’t hit the vertebrae. The injections are done vertically, slightly above the vent towards the head. The needle is then inserted into the body cavity at an angle pointing towards the head parallel to the fish
Brood female member of the Claria gariepinus has a bulky abdomen (ovaries) indicating the presence of about 50,000 eggs inside. The ovaries of C.gariepinus are paired elongate organs situated dorsally in the body cavity. The oviducts of the two ovaries fuse and open into a urinogenital papilla, which is round, protruding, and reddish. Mature females have very large ovaries which fill the body cavity and may constitute 7 - 10% of the total body weight. Approximately 12 hours after injection at a temperature of 28 C the female fish is ready to be stripped.
The urinogenital papilla of female fish :
I personally had the opportunity to touch and strip the eggs from the female fish. The abdomen felt very smooth and rubbery with a slippery coat on its scaleless skin.
My lecturer warned me not to put too much pressure as he knew i could be nervous due tobeing a first timer. Anyhow, after a few attempts he decided to do it by himself. perhaps i was too slow.
Here's a picture of the female being stripped by my lecturer:
To watch the stripped eggs come out from the urinogenital papilla was not a pleasant sight. In the notes i read, it said that the fishes are relieved from the heavy burden they were carying. But perhaps, eggs oozing out naturally may be a relieve, but when it comes to human hand? I wonder how true is that statement. An unexperienced hand may accidently strip too hard that it may cause internal abdominal damage to the fish.
Male Fish
Male species of C.gariepinus has paired testes which is connected by a fused spermatic duct opening into an elongated pointed urinogenital papilla. This urinogenital papilla is protruded and pointed and this is the only external feature upon which male and females can be distinguished from each other.
Male fish's potruding urinogenital papilla :
This was the sad part because the male fishes used for this experiment has to be Sacrificed. I was informed that although stripping technique could be used for obtaining the sperm but it would not be sufficient. Thus both testicles has to be removed and the fish discarded. Later the testicles are macerated and placed in a Sodium Chloride solution to maintain it in a homogenized state. The milt from the testicles are mixed with the eggs later. Water is added too to enhance sperm movement.
Fertilization
Fertilization of the eggs takes place externally. Catfish sperm is motile for 80 to 120 seconds, which is a very short period compared to other fresh water species. Sperm takes 3-5 minutes to fertilize the eggs. Fertilized eggs will be in pale yellow colour and the unfertilized ones will be either dark or orange. Egg and larval development is rapid. The eggs hatch after 24 to 48 hours, depending on the incubation temperature. Rapidly hatching larvae begin to swim 35 hours after fertilisation and exogenous feeding commences within 80 hours.
Fertilized eggs :
Development of fry
well..that's some little information i managed to type here about the catfish. The information above is very general and i did not discuss in depth of a particular experiment.
posted by llemrin at 7:11 AM
1 Comments:
nice post about artificial insemination on catfish. I wish you would have gone into more details on the dissection and method used to squeeze the semen. are you able to free this semen as well? If so, can you purchase this and have it shipped? Interesting,, that way i dont have to sacrifice my males :) thanks!
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