# LECTURE NOTE OPENWATER STOCKING

BY

Oopatham Pavaputanon

Prediction of fish potential yield models

1. Ryder model

MEI = TDS /Z

Fish yield can be calculated from

y = kxa

y = fish yield × = MEI d = constant

a = exponent » 0.5

Fish yield of temperate lakes

y = 2.094 × 0.446

transformed to metric unit

y = 1.24 × 0.446

y = kg 1 ha/y

z = meter

2. Henderson, & Welcomme

 31 African lakes Y = 8.7489 × 0.3813 r = 0.5073 Data of lakes which have less than 1 fishman/km2 are excluded y = 14.3736 × 0.4681 r = 0.6864

3. Jenkins model

y = 2.07 + 0.164x

Y = log standing crop × = log MEI

121 reservoirs sport harvest

y = 0.88 + 0.183x

commercial harvest of 46 US reservoirs

y = 0.52 + 0.210x

4 Jenkins and Morais

Sport harvest

y = 0.2775 - 0.2401x1 + 1.0201x2 - 0.2756x3

y = log total kg/ha, x1 = log area, x2 = log growing season and x3 log age of reservoir

5. Trophodynamic model

8 African lakes

Log Fy = 0.113PG + 0.91

r = 0.57

15 tropical indian lakes

Log Fy = 0.122PG + 0.95

r = 0.82

Fy = Fish yield     PG = gross photosysthesis

Temperate lakes log Y1 = -1.98 + 1.17 log CHLs

Y1 = annual yield dry weight/m2 of lake serface

CHLs = chlorophyll, summer phytoplankton standing crop

Table 3 The results of sea bass cage cultured by Rayong Brackish Water Fisheries Station in 1983. (Period of culture was 6 months).

 Cage No. 1 Cage No. 2 Cage No. 3 Total Average Size in m2 (2×3×1.5m.) 6 6 6 18 6 Average size of initial fish in length (cm) 15.25 14.36 13.91 43.52 14.51 Average size of initial fish in weight (gm.) 49.42 40.38 37.25 127.05 42.32 No of fish were stocked 600 600 600 1,800 600 Final mean individual weight of fish (gm.) 622.03 633.41 621.21 1,876.65 625.55 Growth rate (gm/day) 3.18 3.29 3.25 9.72 3.24 Survival rate (%) 96.17 93.33 94.00 283.50 94.50 Yeild/cage (kg) 360.40 348.94 358.12 1,067.46 355.82 Yeild/m2 (kg) 60.07 58.16 59.69 177.92 59.31 Yeild/m3 (kg) 46.21 44.78 45.91 136.84 45.62 Food conversion ratio 4.61:1

GROUP REPORT ON THE PRACTICALS OF UBONRATCHATHANI

1. Standing crop of the reservoir in kg/rai:

 a) Shallow H20: 40 cm. deep b) Deep H20 : 2 m. deep

2. No. of species of fish obtained:

a) Shallow H2O = 23 species (excluding 1 specie of prawn)

b) Deep H2O = 2 species

2. Species composition:

 a) Shallow H2O b) Deep H2O 1. Botia modesta - 1 pc 1. Botia modester - 12 pcs. 2. Botia sp. - 1 pc. 2. Choncla siamensis - 206 pcs. 3. Chanda siamensis 1 3 pc. 3. Cirrhinus jullieni - 1 pc. 4. Cirrhinus jullieni - 17 pcs. 4. Clupeichthys alseanensis - 13 pcs. 5. Clarias batrachus - 2 pcs. 5. Cyclocheilichthys apogan - 12 pcs. 6. Cyclocheilichthys apogon - pcs. 6. Hampala dispar - pcs. 7. Hampala macrolepidota - pc. 7. Osteochilus sp. - pcs. 8. Lobochilus quadrilineotus - pc. 8. Pristolepsis fasciatus - 7 pcs. 9. Mastocenbelus armatus favus - 3 pcs. 9. Tetradon leiurus - 69 pcs. 10. Notopterus notopterus - 31 pcs. 10. Trichopsis viffatus - 77 pcs. 11. Ompok binaculatus - 1 pc. 11. Xenentodon cancila 4 - pcs. 12. Ophicephalus striatus - 216 pcs. 12. Hampala macrolepidota - 14 pcs. 13. Osteochilus hasselti - 3 pcs. 14. Oxycleotias marmoratus - 300 pcs. 15. Pristolepsis fasciatus - 110 pcs.