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. |
