World Aquaculture - September 2023

54 SEPTEMBER 2023 • WORLD AQUACULTURE • WWW.WAS.ORG sp.), were held in cages with the primary objective of keeping them alive until sold. Later, it became a common technology in South-east Asian countries such as China, the Philippines, Indonesia and Thailand, where a wide range of freshwater species are cultured in cages. In traditional cage culture, people used locally available materials for cage construction and simple feeding practices. However, in modern cage culture, people use more durable synthetic materials for cage construction and commercial diets for feeding the fish. Modern practices were initiated in Japan during 1950’s for rearing of yellowtail and the same approach was adopted later in Norway for culturing Atlantic salmon. In the US, cage culture was introduced during the late 1960’s. Presently, China contributes around 68 percent of global freshwater cage culture harvests, followed by Vietnam (12.2 percent), Indonesia (6.6 percent) and the Philippines (5.9 percent). Around 72 fish species are cultured in freshwater cages at a global level, with pangasius being the leading species followed by Nile tilapia, common carp, rainbow trout and salmon. In India, the first attempts at freshwater cage culture were in swamps and in the Yamuna and Ganga rivers, using air-breathing catfishes and Indian major carps, respectively. Later, the Central Institute of Fisheries Education, Mumbai, conducted cage culture experiments for rearing of fingerlings and table sized fishes in the Powai, Govindsagar, Halali, Tandula and Dimbe reservoirs. Presently, species like Indian major carps, tilapia, pangasius, exotic carps, snakehead, and cat shes are being reared in freshwater cages (Table 1). Cage culture is a relatively new aquaculture technique in India, and recommended management practices need to be disseminated to farmers. Unplanned expansion of cage culture can lead to undesirable environmental impacts and therefore there is also a need for proper guidelines to be established to ensure sustainable growth of this sector. In the recent past, regulations on establishing cage culture in freshwater bodies have been improved by government agencies. The National Fisheries Development Board has developed guidelines for cage culture and it is also promoting the activity in rural areas by providing financial assistance. Most of the Indian states which have freshwater resources such as lakes, reservoirs and check dams have started utilizing those water bodies for cage culture to boost fish production. India, being the second largest aquaculture producer in the world, is planning to boost its fish production, especially inland production, using available open water resources. India has huge resources of inland open water bodies, including 2.25 million ha of ponds and tanks, 3.5 million ha of reservoirs, 29000 km of rivers and 0.78 million ha of swamps, beels, and other water bodies, all of which could be effectively used for inland cage culture. India has projected three times more fish production in the coming years than current levels. Hence, there is a growing interest in developing commercial inland aquaculture activities to meet the country’s projected fish demand. There is a need to develop and adapt efficient, eco-friendly farming practices to support diversified species and sustain the valuable fish production of the inland sector. The production of farmed aquatic organisms using cage enclosures has been a relatively recent innovation in India, especially in freshwaters such as reservoirs, rivers and other impoundments. In India cages were initially used to hold fish temporarily during transportation and marketing. Presently, they are used for commercial rearing purposes. In the past 20 years, freshwater cage culture has grown tremendously and presently it is used at a commercial level in many developed as well as developing countries. In the meantime, fish consumption has increased by an estimated 57 percent and 4 percent in developing and developed countries, respectively. Cage culture is widely considered as an opportunity to enhance fish production from inland open waters as a partial answer for the increased demand for animal protein. Cage culture utilizes existing open water resources but confines the fish inside the cages using some type of mesh enclosure. This allows free flow of the water between the cage interior and the surrounding water body, which helps to maintain the water quality needed for fish culture. Cage culture in freshwater bodies has proven to be a successful technology due to higher production of biomass per unit area, providing income generation and economic benefits to fisher-folk. Cage culture technology can be adopted in inland waters with various agro-climatic conditions. Status of Freshwater Cage Farming The practice of cage aquaculture originated around 200 years ago in Cambodia where fish, especially catfish (Clarias Freshwater Cage Culture in India: Prospects and Constraints Rameshwar Venkatrao Bhosle, Stephen Sampath Kumar and Somu Sunder Lingam TABLE 1. Freshwater species cultured in cages in India. Species Percentage of Harvests Pangasius 41.1% Tilapia 26.7% Common carp 6.6% Rainbow trout 4.1% Salmon 3.7%