Fisheries production in Southeast Asian Farmer Managed Aquatic Systems (FMAS) II. Diversity of aquatic resources and management impacts on catch rates E. Amilhat a , K. Lorenzen a, ⁎, E.J. Morales b , A. Yakupitiyage c , D.C. Little b a Division of Biology, Imperial College London, Silwood Park, Ascot SL5 7PY, UK b Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK c Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand abstract article info Article history: Received 31 January 2009 Received in revised form 26 September 2009 Accepted 28 September 2009 Keywords: Indigenous management practices Farmer Managed Aquatic Systems Self-recruiting species Rice farming landscapes Southeast Asian rice farmers often manage aquatic habitats and resources on their land to increase harvest of aquatic animals (Amilhat, E., Lorenzen, K., Morales, E.J., Yakupitiyage, A., Little, D.C., 2009. Fisheries production in Southeast Asian farmer-managed aquatic systems (FMAS). I. Characterisation of systems. Aquaculture 296, 219–226). We characterize the diversity of aquatic resources harvested from such Farmer Managed Aquatic Systems (FMAS) and evaluate the effectiveness of management practices within contrasting FMAS in Cambodia, Thailand and Vietnam. Farmers harvested diverse self-recruiting species (SRS) from FMAS in all study areas: 24 locally recognized species in Cambodia, 66 in Thailand and 17 in Vietnam. Fish accounted for the largest share of SRS by weight in all areas but frogs, snails, crustaceans and insects were also important. Amphibious species, well adapted to rice farming landscapes, dominated catches of both fish and non-fish SRS. Stocked cultured species (CS) comprised only fish, were less diverse and differed between countries according to aquaculture practices. SRS catch rates in FMAS were significantly higher than wild animal catch rates in open aquatic systems in Cambodia and Thailand, indicating an underlying difference in abundance. This positive effect is likely attributable to lower harvesting effort in FMAS (where access was restricted to owners), agricultural inputs, and management measures aimed specifically at increasing aquatic animal production. Various management measures were recorded, but only the construction of brush parks and fertilisation was associated with positive effects on catch rates in the SRS-dominated FMAS of Cambodia and Thailand. Ponds in Vietnamese FMAS were managed intensively as carp polyculture systems, and catch rates within them responded positively to a wide range of management inputs. FMAS support a high abundance of aquatic animals including diverse SRS and benefit nutrition and income of farming households, agro-ecosystem services, and biodiversity conservation. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Rice farming landscapes constitute large man-made wetlands where aquatic resources form an important component of the agro-ecosystem and associated livelihoods, and are often actively managed by farmers (Gregory and Guttman, 2002a; Smith et al., 2005; Nguyen Khoa et al., 2005). Farmer Managed Aquatic Systems (FMAS) are seasonal or permanent aquatic habitats such as rice fields or ponds, of which farm households have private ownership or exclusive access rights (Amilhat et al., 2009). By contrast, open water bodies (OWB) are those subject to public or communal ownership or access arrangements. Typically, FMAS are smaller and more intensively managed than OWB. Aquatic animals that occur naturally in FMAS without regular stocking of hatchery- reared juveniles are referred to as ‘self-recruiting-species’ (SRS), while animals that are regularly stocked are referred to as ‘cultured species’ (CS). Amilhat et al. (2009) reported that FMAS provide more than two thirds of the total aquatic animal catch obtained by farm households in SE Asia. Amilhat et al. (2009) characterized FMAS in Southeast Asian rice farming landscapes in three countries subject to contrasting agricul- tural practices and socio-economic settings. Cambodia boasted the greatest diversity of FMAS in terms of physical characteristics and the combinations of systems on a household basis. The systems were geared towards the production of SRS as well as CS and combined both traditional and modified elements (cf. Edwards et al., 1997). The Cambodian FMAS operated in a context of low population density and largely rainfed, low external input rice farming systems. Access to markets and off-farm employment was limited. Cambodian FMAS formed a flexible part of diversified semi-subsistence livelihoods geared towards making the best use of local resources and household assets (cf. Smith et al., 2005). In the Thai study area, FMAS diversity was low and dominated by the rice field-trap pond combination. Thai FMAS were carefully designed exploit ecology and movement Aquaculture 298 (2009) 57–63 ⁎ Corresponding author. Tel./fax: +44 20 75942213. E-mail address: k.lorenzen@imperial.ac.uk (K. Lorenzen). 0044-8486/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2009.09.027 Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online