SUNIER: Marine fish-ponds of Batavia. 207 
to be caught and sold at Pasar Malem (30th and 31st of January 1919) !), 
were thronging in the pond closely against this obstacle, trying their utmost 
to traverse it against the current. The animals pressed against the obstacle 
with such force and in such dense masses that the upper ones were 
continually being forced out of the water by those beneath them. Many 
of them also leapt a height of more than a metre above the surface of 
the water against the trellis-frame, so that some of them even fell on dry 
land. I can hardly assume that the slight difference in salinity existing in 
this case between the up-stream and the down-stream water would be 
sufficient to account for the excitement of the bandeng. 
The bandeng’s inclination for swimming against the current is moreover 
known to the empang-owner, who makes use of it especially to transfer 
bandeng from one pond to another and also sometimes to catch them. 
If in a sluice-gate (cf. photo 1, Plate VI) through which water is made 
to flow to the pond from which the bandeng must be gathered, the framed 
trellis-work (kereh) is adjusted up-stream, i.e. at the extremity of the 
sluice-gate away from that pond, the bandeng will crowd together from 
the pond into the sluice-gate. By subsequently also placing a trellis-fence at 
the downstream extremity of the sluice-gate the bandeng is locked up in 
the sluice-gate and can easily be handled. Thus on May 14th 1918 I saw 
bandeng, collected in this manner in a sluice-gate from a pond down- 
stream, being transferred across the lattice-fence into a pond situated up- 
stream by means of a landing-net, so that the fish could be counted at 
the same time. But for the desire to count the fish, it would have sufficed 
to remove the up-stream trellis-fence, upon which the bandeng would 
have swum spontaneously into the up-stream pond. 
§ 3. The Food of the Bandeng. 
Relative to the food of the bandeng reared in the Batavia empangs | 
collected the following data which I now draw from the diary I regularly 
kept during my investigation of the empangs. 
On March 5th 1918, Mr. Max H. Th. Görs caused four bandeng to 
be caught in my presence from one of his ponds, in which, as he expressed 
it, the fish fed on “mud”, and three bandeng from one of his empangs 
wherein, as he said, the fish ate “lumut” (— algae). 
Examination showed that the contents of the stomach (gizzard) of the 
four bandengs which had fed on “mud”, consisted of a considerable mass 
of Oscillatoria-threads among which there were also some Rotifera and 
some mineral particles. 
- The stomach-contents of two out of the three bandeng, which were 
said by Mr. Görs to have eaten “lumut”, consisted of a large quantity of 
the leaves of Najas falciculata R. BR. and Ruppia rostellata KOCH ?). 
1) cf. the note at the bottom of page 196. 
2) Compare Chapter IV. 
