Fish catch and community composition in a data-poor Mekong River subcatchment characterised through participatory surveys of harvest from an artisanal fishery Harmony C. Patricio A,D , Stephen A. Zipper B,E , Matthew L. Peterson B , Shaara M. Ainsley C,F , Erin K. Loury C , Sinsamout Ounboundisane A and Doug B. Demko B A FISHBIO, Ban Phonesavanh Nuea Unit 18, Dongpaina Road, Vientiane Capital, Lao PDR. B FISHBIO, 180 East 4th Street, Suite 160, Chico, CA 95928, USA. C FISHBIO, 519 Seabright Avenue, Suite 208, Santa Cruz, CA 95062, USA. D Present address: Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Qld 4111, Australia. E Present address: SWCA Environmental Consultants, 5467 Jefferson Street NE, Albuquerque, NM 87109, USA. F Corresponding author. Email: shaaraainsley@fishbio.com Abstract. Many inland artisanal fisheries have not been surveyed by scientists. In this study we used some participatory research methods to characterise a data-poor fishery in a tributary of the Mekong River. Sixteen local villagers from four villages were trained to record harvest data along a 25-km reach of the lower Nam Kading River. Catch records included 65 fish genera representing at least 93 species, with 11 species of concern on the IUCN Red List. During 894 individual fisher landing surveys, a total of 1433.8 kg of fish catch was reported. The majority of fishers (87%) used nets, and the catch per unit effort with gill-nets averaged 66 g net À1 h À1 . Analysis revealed differences in catch rates and the genus assemblage among villages. High levels of diversity, and the presence of species assessed as endangered by the IUCN Red List, highlight the need for further studies and conservation interventions in the area. The National Fisheries Law in Lao PDR provides a unique opportunity for co-management, because shared management between civil society and government is written into the law and implemented extensively. Participatory research activities can serve as a bridge for communities to engage with government to inform fisheries management. Additional keywords: assemblage, catch per unit effort, fresh water, Lao PDR, Laos, subsistence fishery. Received 10 November 2017, accepted 18 June 2018, published online 23 September 2018 Introduction The Mekong River hosts the second-highest fish diversity of any river globally, with between 500 (Allen et al. 2012) and 850 freshwater species (Hortle 2009b). The river supports the most productive inland fishery in the world, with estimated annual harvests of 2.1 Â 10 6 Mg (International Centre for Environ- mental Management 2010). The river flows ,4900 km south from headwaters in Tibet, through China, Myanmar, Lao Peo- ple’s Democratic Republic (henceforth ‘Lao PDR’ or ‘Laos’), Thailand, Cambodia and Vietnam. Most of the 80 million people living in the basin depend on the river for subsistence, and exhibit some of the highest fish consumption rates in the world (upwards of 61 kg per capita per year in some provinces; FAO 2012; Hortle 2007). However, physical and environmental changes threaten the persistence of many fish populations. With numerous hydroelectric dams already built on tributar- ies, and a few on the main stem in China, the Mekong River is undergoing rapid change. There are currently two dams under construction on the main stem Mekong in Lao PDR, with plans to construct up to 11 more on the main stem and over 100 more on tributaries throughout the basin (International Centre for Environmental Management 2010). Power generated by dams may provide much-needed income and services for developing nations in the basin, but could also block migrations of key fishes, alter the river’s ecology and threaten food security (Dudgeon 2011; Ziv et al. 2012; Hallwass et al. 2013). The effects will vary considerably depending on construction sce- narios (Ferguson et al. 2011; Ziv et al. 2012) and operations (Baird and Quastel 2015). Other major threats to Mekong fishes include overharvest, pollution, land use change, habitat degra- dation and the effects of global climate change (Allen et al. 2012). Temperatures throughout the basin are predicted to increase, shifting the snow-melt season and augmenting upper basin flows from April to June and causing decreased flows from CSIRO PUBLISHING Marine and Freshwater Research, 2019, 70, 153–168 https://doi.org/10.1071/MF17338 Journal compilation Ó CSIRO 2019 www.publish.csiro.au/journals/mfr