IMAGINE dunking one's head in a rapid Himalayan stream and coming up with a mouthful of chemicals and weeds, instead of pristine water. This is not a totally unlikely scenario, according to the editors of this volume, a compilation of 26 articles on the freshwater ecology of the Himalayas. If left unchecked, the dyes from the carpet weaving industry and domestic sewage that is being discharged into Himalayan streams, could well turn the water into a chemical soup, with weeds and other unwanted plants growing luxuriantly.

This volume intends to fill the gap in the research on the running waters of the Himalaya. Hence, the editors have promised they would pay "more attention to the highly complex and harrowing subject of river ecology in the mountains".

The authors have kept their promise and covered a wide range of issues relating to the river ecology of the Himalayan mountains. A multitude of insects and plants that inhabit the rivers and streams are described and classified according to their microhabitats, with case studies from the northwestern Himalaya. These sections are spread over the entire volume, sometimes leading one to wonder if one is reading a catalogue of the flora and fauna of the Himalaya.

Till now, 164 fish species have been identified in the Himalaya aquatic system. But the siltation of the rivers and streams, due to increasing deforestation, has played havoc with the fish population. Siltation, industrial pollution and using such destructive fishing practices as dynamiting, using bleaching powder and using nets with a very fine mesh, have led to the virtual extermination of some well-known species, such as the mahseer and the snow trout. A suggestion is made to develop an aquarium for the Himalayan fish.

One theme, though not clearly articulated, runs through the entire length of the book. Repeated human assaults on mountain ecosystems can damage the environment there irreparably and destroy the life-support systems. The need of the hour is for a pragmatic resource conservation policy, balancing short-term benefits and long-term gains. Judicious exploitation of the natural riverine resources, allied to planned developmental activities, could reverse the tide of degradation. Conservation strategies offered by the authors underscore the need for an urgent reappraisal of the existing patterns of resource consumption and regeneration.

The book is rich in description, but poor in analysis. Descriptions of flora and fauna run long, severely restricting their use to specialists. Furthermore, the subject matter is indiscriminately arranged, obscuring the theme of the book. On the whole, the papers are more of articles on individual streams, rather than a statement of Himalayan mountain waters.

K Rajesh is a research associate at the Foundation to Aid Industrial Recovery, New Delhi.