It is some 15 minutes before the poison begins to take effect and then the women and children at the traps may have a busy time removing the fish in order to keep their traps free for the entrance of more. During this time the men and boys scurry around jabbing, hitting, missing, and rushing from side to side with mad shouts of joy and exultation, sometimes two or three after some fine big dazed fish of extra size. Thus they may continue for a few hours if the river is a good sized one and the fish plentiful, for at the beginning a great number of fish probably dart up side creeks, thus escaping from the effects of the poison, and when all the fish in the main stream have fallen a prey, these lurkers must be sought out.
Túba has a deleterious effect on man, producing colic and diarrhea, if taken in fairly strong solution. Yet the fish that die from the effects of it are perfectly harmless in that respect. The famous ís-da of the Agúsan Valley is the only fish that does not succumb to the effects of this poison.
The túbli method.--The root of the túbli plant is used for poisoning. It is a quicker-acting poison and more universal than the preceding, in the sense that nothing, not even shellfish, escapes its baneful effects. As the plant has to be cultivated, it is obvious that it is not obtainable in large quantities, and for this reason is not used as a rule on the main streams, the quantity available not being sufficient to have an effect. It is used in the same manner as túba.
The lágtañg method.--The lágtañg is the seed of a tree that is not found in the middle and upper Agúsan Valley. I never witnessed the use of this poison on a large scale, due undoubtedly to the absence of it in the middle and upper Agúsan. The following was the procedure followed in using it as witnessed by me.
A few handfuls of the seeds are toasted in a frying pan and then pounded in a rice mortar. Then ordinary earthworms, or even the intestines of a bird, are cut into small bits and mixed with the poison. A deep quiet pool in a river or a likely place in a lake is selected and the mixture of worms and lágtañg dropped into the water at the edge of the pool. In less than five minutes the minnows and small fish rise to the surface, and begin to circle around giddily. These are followed by the larger ones but it is not an easy undertaking to catch them till they have exhausted themselves in their giddy circles or die in the tall runo grass that grows along the banks.
This poison affects only such fish as eat the worms. People who eat fish caught in this way seem to suffer no ill effects.
There are other vegetable poisons used in killing fish, but I remember only the name of the tree called tigaú.