Photos’ credit: Mouhamed Hosni Kouotou (Cameroon)
Description: Abdel Rahman El Gamal (Founder of the website/FB page)
Because the testes of the males of African catfish (Clarias gariepinus) are situated in the dorsal part of the abdominal cavity, and because of the anatomy of the species and the presence of the seminal vesicle and internal organs block the flow of milt and prevent its release under abdominal massage from live males in captivity. Thus, in order to obtain milt for artificially fertilizing eggs, males are generally sacrificed before testes are removed and squeezed to release the milt.
Losing a male catfish after another could limit their numbers along with the possible production problems. Added to that, sacrificing catfish males hinder particular genetic applications that require the repeated use of the same male especially in the absence of cryopreservation facilities.
In order to avoid sacrificing the catfish males, surgical operations have been successfully practiced. The operation begins with the selection of sexually mature males based on their genital papilla. Afterwards, the chosen fish is anesthetized usually in bath treatment to the level that allows the surgical operation. Even though severalanesthetics have been used, the Tranquil (Tricaine) MS-222 is the only anesthetic approved by FDA for use in food fish.
Once the fish are totally anesthetized, the ventral side of fish abdomen should be disinfected using a proper substance such as methylated spirit (40% alcohol). Immediately after, an incision is made on the ventral side of the abdomen using surgical scissors and the testes are exposed for ablation whereas about three quarter of the testes were removed for the use in the fertilization of catfish eggs.
The incisions are typically sutured in a way similar to surgical operations. On the average, the surgical operation lasts about 10-15 min. An antiseptic medicine is used to treat the wound and skin infection. Afterwards, fish are to be placed in anesthetic-free, aerated water for recovery which is expected to take place within few minutes.
For a relatively long-term treatment, operated fish may be placed in a tank containing water with antibiotics such as Oxtetracycline at proper dosage for recommended period of time; 50mg/L for 5 days. Operated fish should be fed high quality feed as required for speeding the regeneration process of ablated testes which is usually reached after a period ranging from as short as 30 days to as long as 120 days from post the ablation. On the average, the operated male may be used again after about 90 days and so on.