Lady Scientist Converts Degraded Streams Into Fish Habitats

By Zac B. Sarian

Dr. Macrina Zafaralla is a one-woman army going around the country to promote her advocacy of reviving degraded shallow streams and rivers by a very simple and doable technique that rids the water of pollution so that fish will thrive and multiply.

Dr. Macrina T. Zafaralla, professor emeritus and an environmental scientist of UP Los Baños.

In the scientist’s words, the technique is called Aquatic Macrophyte Biosorption System (AMBS). In layman’s terms, the technique simply uses water plants (water hyacinth or kangkong) that are held in place by a barrier made of short bamboo poles. The plants’ roots form a mat that filters out floating solids while absorbing and adsorbing substances that are dissolved in water. With the clean water, various fish species make the place their home. This way, the rehabilitated water system becomes a fish habitat that becomes a continuing source of food for the people.

By the way, Dr. Zafaralla is an environmental scientist who is professor emeritus at the Institute of Biological Science in UP Los Baños. She conceived of the AMBS technique about seven years ago, and it has been proven to work wonders, starting from the Molawin Creek within the UPLB campus, down to rivers in Tanay, the Silang-Santa Rosa river in Laguna and Cavite, the Pangao river Lipa, and elsewhere.

As early as the second day after placement of the water hyacinth, fingerlings or fry appear in the water, according to Dr. Zafaralla. The eggs or fry could have been brought with the plants from the source. For as long as the water is kept clean (no dumping of wastes), the stream will continue to nurture fish.

The ideal depth of the water is knee-deep and it should be flowing, albeit slowly, so that there will be the aeration needed by the fish. Also important is to control the volume of the socalled macrophytes (water hyacinth and kangkong) to prevent overcrowded conditions that could deplete oxygen in the water.

The bamboo barrier is placed across the stream or shallow river. Each barrier can be installed a hundred meters apart, with each place provided with water hyacinth about one or two feet wide. That’s enough to attract the fish to lay their eggs and multiply there, according to Dr. Zafaralla. The marine life commonly found in the ABMS include tilapia, shrimps, dalag, hito, and even edible snails.

What inspired Dr. Zafaralla to hatch the idea? It all started, she said, when she saw a little girl bathing in the polluted water of Molawin Creek. She said the girl was splashing the polluted water on her face and perhaps even drinking from the stream. She told herself that the little girl must be saved from the danger of playing and bathing in polluted water.

She thought of finding a way to rid the water of pollution. And what she saw in her travels to China and Japan gave her the idea that water plants could help by absorbing and adsorbing the pollutants dissolved in the water. And, voila! The technique worked.

It has since become the advocacy of the Institute of Biological Science to disseminate the technology. But since the members of the faculty are busy with their work, Dr. Zafaralla is doing the dissemination mostly by herself, sometimes with NGOs (non-government organizations) and students. Only recently, she expounded on the benefits that could be derived from AMBS before residents along the Pangao river in Lipa City. And she has an invitation from the governor of Rizal to do the same there soon.

This appeared in Agriculture Monthly’s November 2016 issue. 

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