effects of stocking density presentation

EFFECTS OF STOCKING DENSITY ON

GROWTH AND SURVIVAL OF NILE

TILAPIA, Oreochromis niloticus L.

FRY AT SON FISH FARM

BY

NTANZI RONALD BFA(III)10/U/1036

8/15/2013 1

OUTLINE

Introduction

Materials and methods

Results and discussion

Conclusion and recommendations

8/15/2013 2

IntroductionTilapia is the world’s second most

important fish in aquaculture after carp

and Uganda’s second important in

aquaculture after catfish

Stocking density is an important factor

affecting fish maturation and growth.

In Nile tilapia fry it can range from as low

as 500fry/m3 to as high as 20,000fry/m3

8/15/2013 3

Problem Statement

Lack of sufficient knowledge on the best

practice of Nile tilapia fry stocking densities

that would maximize production.

8/15/2013 4

Objectives of the study

To establish the most appropriate stocking density by determining how growth rate and survival vary with stocking density

for Nile tilapia fry in hapas set in earthen ponds

8/15/2013 5

Methodology(1)

Experimental Units

Breeding

• One (1) 500 m2 (20x25) earthen pond

Sex-Reversal Treatment

• Twelve (12) 2 x 1 x 1 m fine mesh hapas

• One (1) 2100 m2 (70x30) earthen pond

8/15/2013 6

Methodology (2)

Treatments

1000fry/m3

1330fry/m3

2000fry/m3

2670fry/m3

4000fry/m3

5330fry/m3

There were two replicates per treatment

8/15/2013 7

Methodology (3)

• Tilapia fry were stocked in hapas and fed 20% body weight and 45% CP.

• Feeding with androgen-treated fry crumble was done six (6) times a day for 23 days

• Fish sampling was done once a week

• Data analysis was done using ANOVA

8/15/2013 8

Sampling of fry during

experiment

Scooping fry for stocking Labeled hapas stocked with fry

LFL feeds for fry

8/15/2013 9

Results and discussion(1)Length and Weight

15

17

19

21

23

25

27

1000 1330 2000 2670 4000 5330

Mean

len

gth

(mm

)

stocking density(fry/m3 )

week 1 sampling

week 2 sampling

week 3 sampling

Mean length at start and sampling 1 was not significantly

different(ANOVA P>0.05)

On sampling 2 &3 there was a great significance in mean

length (ANOVA P< 0.0001). 8/15/2013 10

Results and discussion(2)Length and Weight

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3

av

eag

e b

od

y w

eig

ht

(g)

samplings

1000fry/m3

1330 fry/m3

2000fry/m3

2670fry/m3

4000fry/m3

5330fry/m3

8/15/2013 11

Results and discussion(3)

Survival Rate

There was a significant difference between survival

rates at 4000fry/m3 and 5330 fry/m3 (P=0.0672 and

0.0901 respectively)

75

80

85

90

95

100

1000 1330 2000 2670 4000 5330

93

95

92.1

96.9

87

82.8

SU

RV

IVA

L(%

)

STOCKING DENSITY(fry/m3

8/15/2013 12

Results and discussion(4)Growth homogeneity

1000 1330 2000 2670 4000 5330

Below 24 4 7 3 22 7 36

24-25 2 22 14 15 26 10

26-27 18 12 19 8 10 4

28-29 18 6 11 4 7 0

30-31 7 2 3 1 0 0

32+ 1 1 0 0 0 0

Length frequency groups for week three sampling in millimeters

Length frequency groups for week one sampling in millimeters

Length frequency groups for week two sampling in millimeters1000 1330 2000 2670 4000 5330

Below 19 4 8 1 6 1 28

19-20 8 13 15 23 19 10

21-22 16 13 11 9 17 12

23-24 10 12 19 6 10 0

25-26 8 4 4 6 3 0

27+ 4 0 0 0 0 0

1000 1330 2000 2670 4000 5330

Below 13 1 4 0 0 1 5

13-14 13 3 13 9 14 11

15-16 13 18 14 18 21 16

17-18 12 16 8 12 6 12

19-20 10 8 15 10 8 5

21+ 1 1 0 1 0 1

. 13

Conclusion and recommendations(1)

Conclusion

Survival is the most important factor as

far as rearing tilapia fish fry in nursery

ponds is concerned.

Increasing stocking density in Nile tilapia

fry to extremes results into homogenous

growth.

Further research is needed to know how

these factors vary along the whole

production line.

8/15/2013 14

Conclusion and recommendations(2)

Recommendations

Its recommended not to have stocking

densities of more than 2670 fry/m3 while

rearing Nile tilapia fry in the same conditions

as in the study.

8/15/2013 15

.

Thank

You!

8/15/2013 16