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328. Small Fish (Zako) with Big Potential

Related Research Program



World Food Day, October 16, was designated by the United Nations in 1981 as an international day to commemorate the founding of the Food and Agriculture Organization (FAO) on October 16, 1945, and to think about the world's food problems. In honor of World Food Day, the World Food Prize is awarded each year to a person who has made a significant contribution to increasing global food production. The 2021 World Food Prize was awarded to Dr. Shakuntala Haraksingh Thilsted, a Trinidad-born nutrition expert from Denmark, for her contribution to increasing food production, micronutrient intake and livelihoods of the rural population of Bangladesh by introducing small indigenous fish, rich in micronutrients and fatty acids, into the commercial fish farming system, with the primary objective of enhancing nutrition. In developing countries and regions around the world, health problems caused by inadequate intake of animal protein and micronutrients are of great concern. In Southeast Asia, in particular, the rate of infant stunting in Laos and Cambodia exceeds 40%, and this is a major social problem.

JIRCAS has also been developing fish farming techniques and conducting nutritional assessments of indigenous fish species that are regularly consumed by rural residents in mountainous areas with high nutritional problems, mainly in Laos (Fujita et al. 2019, 2020). In addition, we have been conducting ecological surveys and fish farming research for the conservation and effective use of small indigenous fish species, so-called "zako", which exist in large numbers in Laos and are extremely important foodstuffs in rural areas, but are rarely distributed in markets (Morioka et al. 2012, 2019). In particular, many of these small fishes are planktonic or omnivorous, and their small size and low cost of food and fish farming facilities make them a viable fish farming system for small-scale farmers in mountainous areas. These small fishes are not only consumed as fresh fish, but are also important as a dry material, and are also prized as materials of a fermented seasoning called padaek in Laos (Marui 2019). Since most of these small fishes are often eaten whole, they can lead to the intake of various nutrients, including minerals such as calcium and phosphorus, which are abundant in the bones, and contribute to the improvement of stunted growth in young children. 

However, the habitat of the native fishes in the region is deteriorating year by year due to the expansion of urban areas and farmlands caused by the recent population growth, water pollution caused by urban and agricultural wastewater, and the pressure on their habitat by alien fishes such as the Nile tilapia that live in a wide area. This situation is not only a crisis for fish resources as a food source, but is also a major threat to the conservation of biodiversity in the region. In particular, small indigenous fishes are indispensable as food for large fishes and various animals in the same water body, and are important components of the diverse biota of the region. Because of their importance as a food resource and from the perspective of biodiversity conservation, research on the ecology and cultivation of small fishes is becoming increasingly important. JIRCAS is currently working on the research project “Ecosystem approach to aquaculture” under the Food Program to enhance the stocks of small indigenous fishes and to develop techniques for their utilization to improve malnutrition in rural areas in tropical regions.


Kaori Fujita et al. (2019) Analysis of the nutritional composition of aquatic species toward nutritional improvement in a Lao PDR rural area. JARQ 53, 191-199

Kaori Fujita et al. (2020) Variations of basic nutritional compositions by seasons and sizes in four freshwater fishes as common food sources in Lao PDR. JARQ 54, 53-61 

Shinsuke Morioka et al. (2012) Growth and morphological development of laboratory-reared larval and juvenile three-spot gourami Trichogaster trichopterus. Ichthyological Research 59, 53–62 

Shinsuke Morioka et al. (2019) Characteristics of two populations of Thai river sprat Clupeichthys aesarnensis from man‑made reservoirs in Thailand and Laos, with aspects of gonad development.
Fisheries Science 85, 667–675 

Jun-ichiro Marui (2019) Taste of Laos, scientific study on padaek. Kagaku 89, 824–829 (In Japanese) 

Contributor: MORIOKA Shinsuke (Fisheries Division)