GROWTH PERFORMANCE OF AFRICAN CATFISH Clarias gariepinus LARVAE AT VARIOUS FEEDING REGIMES  IN CONTINUOUS SALINE AND DARK CONDITIONS  

African catfish production in the Philippines cannot meet market demand due to several challenges including  poor growth and survival during larval rearing. This 12-day study was conducted to determine effects of various feeding regimes on growth performance of C. gariepinus larvae under combined saline and dark conditions. Larvae at 48 h after hatching (mean weight  = 2 mg;  total length = 7mm) were distributed randomly into 12 black tanks (6-liter volume) at the rate of 10 larvae per liter. Except for the control which salinity was 0 ppt, the rest of the tanks had a salinity of 3.5 ppt. All tanks were provided with a black plastic cover to create a dark condition. The tanks were aerated and placed in a water bath to maintain an average temperature of 28⁰C. Two groups of larvae  in  0 ppt (SA 0) (control) and 3.5 ppt (SA 3.5) were  fed  continuously with Artemia the entire duration of the experiment.  Two other groups of larvae were also reared  in 3.5 ppt and fed  Artemia for 3 (3DA 3.5) and 6 (6DA) days.  The Artemia nauplii were fresh-hatched and given ad libitum, whereas the formulated diet was fed 50% and 40% of the body weight of the catfish larvae  for the first 3 days after the Artemia feeding days in 3DA 3.5 and 2nd  six days of the culture in 6DA 3.5, respectively.  Feeding of  Artemia and formulated diet was done every 4 hours in 24 hours, 7 days a week.

Larvae exhibited significant differences in growth (P<0.01). Mean weight and specific growth rate (SGR) were the highest in SA 3.5 and 6 DA 3.5. Growth of the larvae fed 3 days Artemia in 3.5 ppt  (3DA 3.5) did not vary significantly from larvae fed continuously Artemia the entire culture duration in 0 ppt. Survival of catfish larvae was the highest in the control  (SA 0) (P<0.05) compared to the rest of the treatments. No significant differences in survival were seen in larvae reared  in 3.5 ppt at various feeding regimes (SA 3.5, 3DA 3.5 and 6DA 3.5). No significant differences were also found in condition factor (K), performance index (PI) and feed conversion ratio (FCR) between treatments. Under the condition of the experiment, it is  concluded that larval rearing of  African catfish larvae at reduced Artemia feeding days does not sacrifice growth and the general condition and performance of the larvae are the same when cultured  in 0 and 3.5ppt.