Rice field ecology and fish culture — an overview

Abstract

Rice fields are an integral part of the landscape throughout most of the tropics. Rice is also grown widely in higher latitudes. Most rice cultivation is done in flooded fields where a temporary aquatic fauna is generated. Rice cultivation has sustained some of the oldest civilizations but the use of the aquatic phase for raising a crop of fish has not been practiced widely although fragmentary records indicate that rice and fish have been cultivated concurrently but rarely over 2 or 3 millennia. We have more reliable records of rice and fish culture in rice fields during the past 150 years.Rice cultivation is now very highly mechanized and uses high fertilizer and pesticide inputs and extensive irrigation facilities have been constructed to increase the area of rice cultivation and enhance yields. Rice cultivation also provides a suitable habitat for the breeding of mosquitoes, some of which are vectors for diseases. It appears that in regions outside the tropics aquatic pests of rice are also encountered. In the tropics indigenous fishes and other organisms including copepods act as biological control agents for mosquitoes and aquatic rice pests.The rice field is usually a successor of shallow marshes or a lowland area which can be supplied with adequate water. In addition deep water rice is grown in permanent marshes and rice is also grown in terraced hillsides, not to mention relatively dry localities where dry-land rice is cultivated. The marsh habitat is usually rich in plant and animal species. Some of these survive in rice fields. The water supplied to rice fields come via irrigation systems which bring a complement of plants, animals, and other organisms seasonally to colonize the rice field. The rice field is thus a new habitat, like a reservoir, with some similarities to a marsh but manipulated for cultivation of rice. This creates a unique, temporary and rapidly changing habitat which is often very productive and can be used to raise fish on an artisanal or intensive scale.Fish culture in rice fields has had a checkered history during the past 150 years when records are available. Its earlier history is obscure. Long-term records of fish culture activities are not available from any part of the world although apparently thriving enterprises seem to have existed in Japan, Italy, USSR and China. Attempts to culture fish in rice fields have been made on all continents except Australasia and Antarctica of course. At the present time the focus of rice-cultivation seems to have shifted to China, Indonesia, and Thailand. Whether this enterprise will endure even in these countries cannot be predicted with any degree of certainty.

Techno‐economic viability of rice‐fish culture in Assam

“…Several reviews on historical, socio-economic, and ecological aspects of rice-fish fanning have been published in the past decade with either a global or a national focus (Li 1988;Fernando 1993a;Halwart 1994;MacKay 1995;Choudhury 1995;Little et al 1996).…”

Diversity and Distribution Pattern of Rice Stem Periphyton in Water-Logged Rice Fields under Different Cropping Seasons in Barak Valley, Assam

“…Moreover, Bacillariophyceae prefer to exhibit periphytic life on organic substrates over planktonic life [30].Morphological and physiological nature of rice stem might have also influenced the development of attached algae, as the submerged rice had the ability to secrete mucilage to form stalks or mucilaginous matrices, allowing attachment to substrates [31]. Seasonal changes of periphyton in natural system are affected by seasonal changes in the vegetation upon which it grows [32]. Rice vegetation is a rapidly changing system [33]and therefore the rice stem greatly influences succession pattern of periphyton on it.…”

Potentiality of Periphyton-based Aquaculture Technology in Rice-fish Environment

“…It harbours lots of phytoplankton and filamentous higher algae in its aquatic phase [64]. All these aquatic fauna and flora play important role on the overall ecology of rice field.…”

“…Horne and Golderman [34] also suggested that seasonal changes of epiphyton in natural system are affected by seasonal changes in the vegetation upon which it grows. If such considerations are hypothesized, the rice vegetation is rapidly changing system [64] and therefore the rice stem greatly influences succession pattern of periphyton on it. Most of the attached forms including diatom were secured to living substrate by jelly-like secretions, while others were attached to gelatinous stalks [84].…”