ASSESSMENT OF SIZE DISTRIBUTION, GROWTH AND SURVIVAL OF NILE TILAPIA, Oreochromis niloticus L. FRY COLLECTED FROM DIFFERENT HATCHING SYSTEMS Investigators Bolivar, R. B. 1, H. L. Bolivar 2, R.M. V. Sayco 1, E.B. T. Jimenez 1, R.L. B. Argueza 1, L. B. Dadag 2, A. G. Taduan 2 and R. Borski 3

AFFILIATIONS 1 Freshwater Aquaculture Center-College of Fisheries, Central Luzon State University (CLSU), Science City of Muñoz, Nueva Ecija, Philippines 2 GIFT Foundation International, Incorporated (GFII), CLSU Compound, Science City of Muñoz, Nueva Ecija, Philippines 3 Department of Zoology, North Carolina State University (NCSU), Raleigh, NC

INTRODUCTION Tilapia is the main cultured finfishes in freshwater pond production and the third among the major cultured species for aquaculture in the Philippines The main production systems for tilapia aquaculture are ponds, cages and fishpens

Tilapia Production in the Philippines (2005) by Major Types of Culture System 90,335 MT 59,204 MT 13,438 MT

INTRODUCTION The development of genetically improved tilapia strains such as GIFT, FaST, GMT, BFAR-GET ExCEL, GENOMAR, etc. paved the way in the increase of tilapia production in the Philippines Seed production is an essential component of successful production of any organism The study was conducted from October to December, 2007 at the GFII facility

Top Ten Tilapia Producing Countries (2006)

STATEMENT OF THE PROBLEM Shortage of tilapia fry has remained an important constraint to further the development of aquaculture in many parts of the world

OBJECTIVES OF THE STUDY To assess the size distribution, growth and survival of fry collected from artificial incubation units, hapas and ponds after 23 days of sex reversal treatment

METHODOLOGY Experimental Units Breeding Fourteen (14) 2.5 x 10 x 1 m fine mesh hapas Fourteen (14) 2.5 x 10 x 1 m fine mesh hapas Four (4) 100 m 2 earthen ponds Four (4) 100 m 2 earthen ponds Sex-Reversal Treatment Twelve (12) 2 x 4 x 1 m fine mesh hapas Twelve (12) 2 x 4 x 1 m fine mesh hapas

METHODOLOGYTreatments I – Incubation-hatched fry I – Incubation-hatched fry II – Hapa-hatched fry III – Pond-hatched fry III – Pond-hatched fry IV – Combination of hatched fry from TI, II and III IV – Combination of hatched fry from TI, II and III There were 3 replicates per treatment

Hatching Systems Hapas Ponds Artificial Incubation Units

METHODOLOGY Tilapia fry were stocked in hapas at the rate of 850 m 2 Tilapia fry were stocked in hapas at the rate of 850 m 2 Feeding with androgen-treated fry mash was done six (6) times a day for 23 days Feeding with androgen-treated fry mash was done six (6) times a day for 23 days Fish sampling was done once a week Fish sampling was done once a week Data analysis was done using analysis of variance (ANOVA) in Randomized Complete Block Design (RCBD) with three replications followed by Least Significant Difference for comparison of means Data analysis was done using analysis of variance (ANOVA) in Randomized Complete Block Design (RCBD) with three replications followed by Least Significant Difference for comparison of means

Collection of fry in breeding hapas Collection of fry from mouthbrooding females Collection of fry in ponds using a dip net Fry collection

RESULTS AND DISCUSSION Note: Analysis of variance showed no significant difference among treatment means (P>0.05) Treatment Initial Length (mm) Final Length (mm) Initial Weight (g) Final Weight (g) I II III IV Initial and final mean length and weight of fry reared in hapas

Gain in length, weight and specific growth rate of tilapia fry in hapas Note: Analysis of variance indicated no significant differences among treatment means for length, weight and specific growth rate (P>0.05) Treatment Gain in Length (mm) + S.D. Gain in Weight (g) + S.D. Specific Growth Rate (%) + S.D. I II III IV

Growth pattern of fry in hapas

Percent survival of fry in hapas Note: Treatment means with the same letter/s are not significantly different (P>0.05) a b ab b

Size distribution of tilapia fry in hapas

SUMMARY The experiment was conducted to evaluate size distribution, growth and survival of tilapia fry collected from different hatching systems The experiment was conducted to evaluate size distribution, growth and survival of tilapia fry collected from different hatching systems Collected fry were sex-reversed in 2 x 4 x 1 m hapas and were stocked at a stocking density of 850 per m 2 Collected fry were sex-reversed in 2 x 4 x 1 m hapas and were stocked at a stocking density of 850 per m 2 Data on length, weight, size distribution and survival were gathered along with the water quality parameters Data on length, weight, size distribution and survival were gathered along with the water quality parameters

SUMMARY Treatment I had the least size variability of fry produced after the sex- reversal treatment Treatment I had the least size variability of fry produced after the sex- reversal treatment Treatment I also had the highest percent survival among treatments Treatment I also had the highest percent survival among treatments There were no significant difference on the gain in length, gain in weight and specific growth rate among treatments There were no significant difference on the gain in length, gain in weight and specific growth rate among treatments

CONCLUSIONS Tilapia fry from artificial incubation units had a significant advantage in terms of survival and uniformity in size as compared to the fry from the other hatching systems Tilapia fry from artificial incubation units had a significant advantage in terms of survival and uniformity in size as compared to the fry from the other hatching systems

Further study is recommended to assess other hatching systems like cages and tanks in the production of tilapia fry Further study is recommended to assess other hatching systems like cages and tanks in the production of tilapia fry It is also recommended to conduct the study at different season to see the possible effect of weather condition on the hatching systems used in the production of tilapia fry It is also recommended to conduct the study at different season to see the possible effect of weather condition on the hatching systems used in the production of tilapia fry RECOMMENDATIONS

Funding for this research was provided by the Aquaculture and Fisheries Collaborative Research Support Program The AquaFish CRSP is funded in part by United States Agency for International Development (USAID) Grant No. LAG-G and by participating institutions.

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