The potential of periphyton-based aquaculture production systems

Key words : Periphyton; Biofilm; Artificial substrates; Pond productivity; Tropical aquaculture; Monoculture; Polyculture; Fertilization; Proximate composition; Stocking ratio; Stable isotope ratio; Nutrient efficiency; Production economics; Indian major carps; Catla catla ; Labeo rohita ; Labeo gonius ; Labeo calbasu . The overall objective of this study was to determine the technical and economical performance of periphyton-based aquaculture systems in Bangladesh. It thus addressed one of the key constraints for the poor to benefit from fish culture - limited access to resources such as fertilizers and feeds - while trying to maximize the conversion of these resources into fish. The suitability of four locally available substrates for periphyton growth was evaluated and the optimal fertilization regime determined. The production and growth of four indigenous species, rohu Labeo rohita (Hamilton), catla Catla catla (Hamilton), kalbaush L. calbasu (Hamilton) and gonia L. gonius (Linnaeus), was evaluated under single species and polyculture conditions. The species were selected on the basis oftheir feeding behaviour, ease of culture and high market demand. The periphyton production rate was around 2.5 g of ash free dry matter m -2d -1. Considering the total periphyton substrate area in the pond, this rate can support an estimated fish production of 5,000 kg ha -1y -1. Periphyton production effectively doubled the autotrophic C production, while no trade-off in production between phytoplankton and periphyton communities was observed. The nutritional quality of periphyton was adequate to support the dietary needs of the experimental fish. Nitrogen retention in fish in substrate-based systems was about 1.6 times higher than in control systems without substrate. As periphyton substrate, bamboo ( Bambusa sp.) proved better than hizol branch ( Barringtonia sp.), bamboo side shoot or jute stick ( Corchorus sp.) in terms of nutritional quality and periphyton productivity. Jute stick, however, provided better economical returns.In single species culture, fish yields of rohu and kalbaush increased on average 80% compared to control systems without substrate, whereas with gonia, no significant production increase was observed. In periphyton-based polyculture systems, 70-180% greater fish production compared to controls was obtained. A three species periphyton-based polyculture technology was developed. Using the 75 m 2experimental freshwater ponds, provided with a substrate surface area approximately equal to the pond water surface area and stocked at the rate of 6,000 rohu, 4,000 catla and 1,500 kalbaush (total 11,500 juveniles) per hectare, a fish production of 2,306 kg was achieved within a 90-days culture period.A pilot scale trial in an extended number of household ponds, distributed over different agro-ecological zones of the country, has been proposed before dissemination of this technology for wider use as a means of poverty alleviation and nutritional security in Bangladesh and elsewhere in the region.

Bibliographic Details

Main Author:	Ul Azim, M.E.
Other Authors:	Huisman, E.A.
Format:	Doctoral thesis biblioteca
Language:	English
Subjects:	aquaculture, fish, fish culture, fisheries, production, aquacultuur, productie, vis, visserij, visteelt,
Online Access:	https://research.wur.nl/en/publications/the-potential-of-periphyton-based-aquaculture-production-systems
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