Chapter 3.24

Fisheries of the rivers of Southeast Asia Robin L. Welcomme1, Ian G. Baird2, David Dudgeon3, Ashley Halls4, Dirk Lamberts5 and Md Golam Mustafa6 Department of Ecology and Evolution, Imperial College Conservation Science, Berkshire, UK Department of Geography, University of Wisconsin‐Madison, Madison, USA 3  School of Biological Sciences, The University of Hong Kong, Hong Kong, China 4  Aquae Sulis (Research) Ltd (ASL), Bradford‐on‐Avon, Wiltshire, UK 5  Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Leuven, Belgium 6  WorldFish, Dhaka, Bangladesh 1  2 

Abstract: The lower, potamonic parts of the Ganges–Brahmaputra, the Ayeyarwady (Irrawaddy), the Salween, the Chao Phraya and the Mekong and Lancang Rivers are among the longest and most productive rivers for inland fisheries in the world. Except for the Chao Phraya, they arise on the Tibetan Plateau. All have steep and turbulent upper courses within deep mountain valleys and flat lower courses associated with large deltaic wetlands. Much of the riparian wetlands have been converted to rice culture. They all have rich and diverse fish faunas, comprising >100 families, that are adapted to a wide range of river channel and floodplain habitats. Many species are migratory whitefishes, but more sedentary blackfishes are more important in the fisheries of some rivers. Fisheries may be commercial, artisanal or subsistence and employ a wide range of static and moving gear, some of which requires considerable investment. Most species caught are consumed. Larger fishes are sold for the table; smaller individuals are often processed into a variety of forms including dried products, fish pastes and sauces. Small, low‐value fishes are also utilized for animal feed (mainly for aquaculture) sometimes after processing. There are a wide range of potential threats to the inland fishes and fisheries of Asia including dam development for hydropower and irrigation, overexploitation, pollution, land use change, mining, the introduction of invasive species, and water diversion for agriculture and other purposes. Fisheries are managed either as open access fisheries or lot fisheries which are assigned to particular groups on the basis of auctions. At present, management at local, national, basin and international levels is not meeting the needs of fish and fishery conservation and urgently needs to be reformed to better protect the fisheries in the face of mounting pressures from other users of the aquatic resource. Keywords: Lowland river fisheries: Ganges R, Brahmaputra R, Irrawaddy R, Salween R, Mekong R, Chao Phraya R

Introduction Southeast Asian lowland rivers are among the longest and most productive rivers for wild‐capture inland fisheries in the world. They have many elements in common: they mostly arise on the Tibetan Plateau and have steep and turbulent upper courses within deep mountain valleys and flat lower courses associated with large deltaic wetlands. Their lower basins are now densely inhabited and were the site of early civilizations culminating in  the Mughal (Ganges), Khmer (Mekong), Siamese (Chao Phraya) and Pagan (Irrawaddy). Historically, these rivers have been associated with intensive wet rice cultivation, which has involved modification of the landscape including adjacent floodplains and associated wetlands, with more recent ongoing

and planned changes due to hydroelectric dams. Some, like the Ganges, are also grossly polluted and abused by the discharge of large quantities of domestic and industrial effluents; this represents a peculiar paradox given the river’s central place in Hindu mythology. Three of the six systems included in this chapter have been studied intensively through national institutions and various government and non‐government projects, so knowledge of the resources and their exploitation, while far from complete, is better advanced than for many other inland fisheries. This chapter deals with the lower, potamonic parts of the Ganges–Brahmaputra, especially the extensive deltaic and flood systems of Bangladesh, the Ayeyarwady (Irrawaddy), the Salween, the Chao Phraya and the Mekong and Lancang (Fig. 3.24.1).

Freshwater Fisheries Ecology, First Edition. Edited by John F. Craig. © 2016 John Wiley & Sons, Ltd. Published 2016 by John Wiley & Sons, Ltd.

363

364   Freshwater resources

Salween Brahmaputra

Irrawaddy

Mekong

Ganges Chao Pharaya

Figure 3.24.1  Location of main Southeast Asia rivers.

Description of habitats The 2525 km long Ganges is fed by several major tributaries that drain the Himalayan massif whose upper courses are steep mountain rivers that debouche onto fertile alluvial plains. The Brahmaputra (2900 km) originates on the Tibetan Plateau and combines with the Ganges and the Meghna Rivers to form an extensive deltaic and flood system lying mainly in Bangladesh and Bengal (India). The three rivers together drain an area of 1 086 005 km2 and dominate the fluvial geography of the northern Indian subcontinent. The combined deltaic floodplain (the largest in the world) covers nearly all of Bangladesh’s 147 570 km2 area and is formed by a network of the major rivers: the Padma, the Meghna, the Jamuna and the Brahmaputra. Seventy per cent of the delta is 200 × 103 people in the delta (De Silva & Phuong, 2011).

370   Freshwater resources

c. 120 kg ha−1 year−1 (Hortle et al., 2008). Thus, any changes that affect the extent and duration of flooding are detrimental to fish production.

Figure 3.24.10  Culture cages in Tonle Sap, Mekong. Photograph by Robin

L. Welcomme.

In Bangladesh, aquaculture provides a more lucrative use of land and water than alternative activities, and a hectare of land under aquaculture generates at least 43% higher income than a hectare of land under crop cultivation (Hasan & Talukder, 2004). The most important practices and species cultured are carp polyculture, Pangasius monoculture, shrimp and giant freshwater prawn Macrobrachium rosenbergii and genetically improved farmed tilapia Oreochromis niloticus (GIFT).

Threats to fisheries production There are a wide range of potential threats to the inland fishes and fisheries of Asia. These include hydropower dam development, overfishing and other unsustainable exploitation practices, pollution, land use change, mining, the introduction of invasive species, and water diversion for agriculture and other purposes, and habitat alteration by dams. These will interact and their synergistic effects can be unpredictable, but in general terms, the outcomes are likely to be continued decline in fishery yields and in the abundance of large species. Such declines have been occurring for some time (Dudgeon, 1992) and have been reviewed at some length in recent publications (Dudgeon, 2011, 2012; Kottelat et al., 2012), and thus, they will be described here in outline only. It must be stressed that because of the migratory habits of many Southeast Asian river fishes, and their use of the floodplain to complete their life cycles, they are especially sensitive to any human intervention that alters the connectivity of the main channels of rivers and their tributaries and limits access to floodplain habitats. Catches for floodplain fisheries are high mainly because of the richness of the floodplain habitats arising from the flood pulse effect (Junk et al., 1989). The annual yield for Bangladeshi floodplains ranges between 50 and 400 kg ha−1 (Craig et al., 2004). Yields from wild rice paddies are

Dams One of the most serious potential threats to fishes and fisheries in many of the river basins in the region, especially the Mekong Basin, is the proposed construction of large numbers of hydropower dams, both on the river mainstreams (Cronin, 2009; Baird, 2011; Kottelat et al., 2012) and on their tributaries (Ziv et al., 2012). China has already built a number of dams on the upper course of the Mekong (along the Lancang Jiang), and the effects on fisheries are not known in detail although this ­section of the river does not have an extensive floodplain. Dams on the Lower Mekong mainstream will have very serious ­consequences as they have the potential to block migrations or ­diminish survival and reproductive success (both upstream and downstream), destroy habitat, alter water quality and dramatically change hydrological patterns both upstream and d ­ ownstream. Changes to flow conditions not only affect fish growth but also have the potential to reduce reproductive ­success, particularly the transport of developing early life history stages of fishes to suitable habitat (Halls et al., 2013b). Changes to hydrological conditions also have the potential to disrupt reproductive behaviour because the appropriate recruitment cues (changes in flow, temperature or turbidity) are lacking. Predicting the impact of dams on the highly diverse and dynamic fisheries is made more complex by the limited availability of baseline information on drivers of natural variability in fisheries stock, on the precise effects of dam construction and on the consequences of dam operation on flood pulses (Lamberts & Koponen, 2008). In some cases, dams act as ecological traps. In this context, it is regrettable that construction of one mainstream dam on the Lower Mekong in Laos, the Xayaburi Dam, began in early 2012; most of the estimated US $ 3.5 × 109 cost of this dam will be met by Thailand, which will be the primary market for the electricity generated by it. Information on how the local fishery impacts in Lao PDR will be mitigated or offset and the implications for fisher livelihoods are lacking thus far. Ziv et al. (2012) speculate that the 11 mainstream dams in the Lower Mekong Basin may reduce biomass of migratory species by 51%. If built, the 78 planned tributary dams could reduce biomass by a further 19% by 2030, and if all projected dams are built, the combined loss could exceed 70% of migratory fish biomass. The cumulative impacts of cascades of mainstream dams have been examined by Halls and Kshatriya (2009). The study concluded that fish passes would need to be highly efficient to ensure the persistence of those populations of fishes selected for study, particularly those with a large body size. Such required levels of fish pass efficiency have rarely been achieved elsewhere [see Agostinho et al. (2002) for South American rivers]. Given the dependence on many inhabitants of the Lower Mekong Basin on fisheries for their livelihood, these studies provide grounds for grave concern. In Laos and, especially,

Fisheries of the rivers of Southeast Asia    371

Cambodia, for example, fishes are a major source of animal protein for humans. If fish stocks are reduced significantly by dams, then the shortfall in protein will need to be met from alternative sources, such as pigs or other livestock, and such a shift from fishing to animal husbandry may be neither environmentally nor economically sustainable nor even practical for many communities. The complexity in predicting the impact of dams on the highly diverse and dynamic fisheries is exacerbated by the limited availability baseline information of drivers of natural variability in fisheries stock, and the precise effects of dam construction and subsequent operation on flood pulse and consequences thereof (Lamberts & Koponen, 2008) acting, in some cases, as ecological traps. The impacts of dams on the Ayeyarwady have yet to be assessed, in part because the location and operation of a number that have been proposed have yet to be finalized. Details are scarce, but a partnership with Chinese engineers involves plans for at least five dams along the mainstream including the massive 228 m tall Tasang Dam. The lower Salween remains the only undammed river in Asia, but preparations for some of a cascade on 13 dams along the Nujiang, the upper course of the Salween River in China, began illegally in 2003 and were suspended in 2004 only after the intervention of the Chinese Premier, but these dams are likely to be constructed within the next few years as part of China’s attempt to reduce the intensity of carbon‐ based energy sources (Dudgeon, 2011). The Chao Phraya Dam started regulating the Chao Phraya River in 1957 and is mainly a flood control mechanism for regulating flow in the delta. Systematic studies have not been done, although it is likely to be a barrier to fish migration within the river and, through reduced flooding of the plain downstream, has blocked access to the normal breeding, feeding and nursery grounds of many species; only an estimated 30 of the 190 native species can reproduce in the river mainstream (Compagno & Cook, 2005). The major dam in the Ganges–Brahmaputra system is the Farakka Barrage on the Ganges River. It has been in operation since 1975 and has been the source of much dispute between Bangladesh and India. Its main impact on fisheries has been the dramatic decline in catches of the anadromous T. ilisha in the Bangladesh fishery (Payne et al., 2004), and catches of the species have reduced from 24% in 1985 to 11% in 2010–2011 (DoF, 2012). This decline occurred despite warnings, dating back decades, of the damaging potential of dams for this species (Hickling, 1961). Floodplain drainage and management In some systems, particularly the Bangladesh rivers and the Ayeyarwady and increasingly also the Tonle Sap Lake, the floodplain is modified by bunding to enclose areas for greater flood control (Craig et al., 2004). Such enclosures limit access of fishes to their habitual spawning and nursery grounds. The negative impacts of this can be mitigated to some extent by appropriate management of sluice gates for the benefit of

both fisheries and agriculture (Sultana & Thompson, 1997; Halls et al., 2008). In Bangladesh, particularly, floodplain aquaculture systems within the enclosures are filled with flood water from adjacent rivers or canals. Water is then trapped in the system, and the connectivity of waterbodies to the river is hampered in such a way as to obstruct natural fish life cycles. Wild species that enter the enclosures may subsequently grow too large to escape. While these may be a valuable by‐catch, the isolation of large broodfish precludes free recruitment of fishes into the capture fishery, and thus, there is a need for careful control of natural reproduction (Blake & Barr, 2005). Craig et al. (2004) estimate that some 5.74 × 106 ha of the Bangladesh floodplain is liable to be under flood controls of this type, resulting in the loss of c. 151 × 103 t of fishes. Pollution Many rivers in the region suffer from low water quality. Pollution from industrial sources and eutrophication from untreated urban discharges are common, and mining effluents may also be locally important. Smaller tributaries that lack the dilution potential of larger rivers are especially affected to the extent that fish stocks can be drastically reduced and fishes may even be entirely eliminated under low‐flow conditions in the dry season. Even in some large rivers, such as the Ganges, however, much of the mainstream is in very poor condition, and fish populations, especially major carps, have been greatly reduced (Natarajan, 1989). The Chao Phraya is also highly polluted in places, and increasing industrial activity on other rivers is reducing water quality especially adjacent to major urban centres. Thus far, pollution does not pose a major threat to the Mekong, although some local impacts from aquaculture and soil acidification have occurred in the delta. Water abstractions Water abstraction for irrigated agriculture is common in some rivers. In the Ganges, in particular, several of the major tributaries have very reduced flows. Water abstraction can also be detrimental to the duration and intensity of flooding of the riparian wetlands impacting on fish reproduction and growth (Shankar et al., 2005). Introduction of non‐native species The FAO Database for Introduced Aquatic Species (DIAS) (http://www.fao.org/fishery/topic/14786/en) lists many species as having been introduced into the countries of the region, and a summary of major invasive freshwater species in Southeast Asia is given by Dudgeon (2012). Reasons for the introduction vary, but most of the fishes that are listed are aquaculture species. Many other small species, often undocumented, are for the aquarium fish trade and are reared in Vietnam and Thailand for export elsewhere. Some invasive species originate from other river basins in the region, such as the Indian major carps or the Chinese cyprinids. Others are from as far afield as Africa or Latin America. Many of the

372   Freshwater resources

species were initially introduced into Thailand and dispersed to other countries from there. Despite the high number of species introduced, very few appear to have been successful in establishing wild populations, although there have been widespread escapes from aquaculture installations. Even fewer constitute a nuisance (Welcomme & Vidthayanon, 2003); although there are some exceptions, and invasive species such as South American loricariids and mosquito fish Gambusia affinis have the potential to impact native biota (Dudgeon, 2012). By contrast, tilapias, in particular Oreochromis niloticus, O. mossambicus and the GIFT tilapia, which form a mainstay of pond aquaculture and stocked lake fisheries, have brought livelihood benefits for humans, although the ecological effects of widely established feral populations have not been investigated in the region. Climate change Most of the major rivers of Southeast Asia are fed by precipitation and glacial melt from the Tibetan Plateau and Himalaya, which determines their discharge patterns. As climate change has the capacity to alter both the persistence of glaciers and the rainfall patterns, long‐term effects on the timing and duration of river flooding can be anticipated (Xu et al., 2009). Potential scenarios and consequences for the Mekong have been analysed by Schipper et al. (2010) and Chu Thai Hoanh et al. (2010). Most climate change scenarios for Southeast Asia are that extreme flow events will become more common and the wet‐ season floods will become more intense and dry‐season drought will lengthen (Dudgeon, 2012). Other specific projections for the Mekong include elevated mean annual temperatures and greater duration of warm periods, as well as an increase in annual precipitation and greater river flows (Bezuijen, 2011). Monsoonal flows in the Salween also are expected to increase over the latter part of this century (Xu et al., 2009). Allison et al. (2009) ranked Vietnam and Cambodia as two of the most ­vulnerable countries in tropical Asia to suffer the impacts of climate change on their fisheries along with Bangladesh, ­ Pakistan and Yemen. The extent to which fishes will adapt to such changes and the implications for fisheries remain largely speculative. Higher temperatures and more climatic extremes will lead to adaptation by humans, which will involve increases in water use and abstraction for agriculture and dam building (for water storage, flood protection and hydropower generation) leading to additional fragmentation of rivers. None of these adaptation measures are likely to augur well for fishes or fisheries, and adaptation to climate change may well have greater impact on fishes than the change itself. Modelling studies described by Mainuddin et al. (2010) concluded that climate change impacts on fisheries yield from the Mekong River would not be detectable because of the significant natural variation in hydrological conditions in the system that would overshadow climate change‐related effects. One of the most severe future impacts of climate change is the  anticipated rise in sea levels. This would place several of

the low‐lying deltaic areas at risk of permanent flooding, particularly parts of Bangladesh and the Chao Phraya delta. Delta shrinkage and reductions in the rate of aggradation (due to sediment trapping by upstream dams) have already been ­ reported for the Chao Phraya (Thailand) and Mekong (Syvitski et al., 2009). The extension of saltwater intrusion in freshwater or brackish delta waters will further alter habitats.

Management activities Two main types of fishery management are practised across Southeast Asia: leasable fisheries and open fisheries. An example of these management systems as practiced in Myanmar is given by FAO (2003). Leasable fisheries (also known as fisheries Figure 3.24.2) consist in the assignment of sections of the environment, ­ usually floodplain waterbodies or particular main channel fishing locations, to individual fishers or groups of fishers. The assignment is usually by auction which confers on the successful bidder exclusive exploitation rights for a specified time. This system, while efficient at gathering revenue, may result in heavy overexploitation if the lease period is too short. Longer lease periods result in better management and conservation, such as the Bangladesh system for stocked floodplain enclosures. Open fisheries are freely accessible to all, in principle, although local institutions may limit access to certain groups, particularly under current trends towards co‐management. In many places, leasable and open fisheries coexist, and the management type depends on the nature of the fishery (commercial v. subsistence) or the season. Despite some trends to liberalization of inland fisheries in Southeast Asian countries, the Fisheries Departments remain in control of regulation and enforcement. This they do by managing the leasing process and by setting regulations governing the type and specifications of gear used, setting closed seasons and areas and regulating markets. They also are responsible for  ­running hatcheries to support stocking programmes into reservoirs and rice fields. Community‐based management and other forms of co‐management are gradually gaining momentum in the region, replacing large private leases as in Cambodia. In the Tonle Sap floodplain, the leases play an important but largely unintended role in biodiversity conservation (Lamberts, 2008b). Most of the rivers of the region flow through more than one country. Some international river organizations exist to harmonize fisheries interests between the various countries. In the Mekong in particular, the MRC brings ministerial represen­ tative of Cambodia, Thailand, Laos and Vietnam together, although part of the basin is in Myanmar and China. It provides a forum for discussion of fisheries matters, sustainable development of the river, and the MRC is responsible for commissioning much basic research. The MRC does not have a direct role in national fisheries management, however, and its advice is ­sometimes ambiguous and is frequently ignored when activities

Fisheries of the rivers of Southeast Asia    373

such as dam building are at issue. The recent commencement of ­construction of the Xayaburi Dam by Lao PDR was in the face of strenuous objections by Vietnamese and Cambodian representatives at the MRC, and a declaration by the MRC secretariat that a 10 year moratorium on dam building on the river mainstream would be desirable to allow investigation of the potential environmental impacts of proposed dams (Dudgeon, 2011). The fisheries sector in Bangladesh has multiple stakeholders, of which government agencies play a vital role in terms of aquatic ecological management, administration and power relations. The Ministries of Fisheries and Livestock (MoFL), Land (MoL) and Youth (MoY) play crucial roles in natural resources management. The MoL owns all lands and waterbodies in Bangladesh, while the Department of Fisheries (DoF) is the only implementing agency under the key ministry, MoFL, and authorization must come to MoFL from MoL for management of aquatic ecology (Mustafa & Brooks, 2009). The management of these resources, based upon a combination of short‐term leased access to waterbodies or supported by a combination of conventional management interventions, often excludes the poorest fishers and encourages leaseholders to effectively ‘mine’ resources at non‐sustainable levels of exploitation.

Conclusions The fisheries of the lower parts of the rivers of the Southeast Asian region are among the most productive and intensely exploited in the world. The fisheries are extremely complex socially and politically, and there is a wide range of gears and approaches to catching, marketing and regulating the fisheries. As well as the high fishing pressure, the inland water environments with their many river channels and extensive riparian wetlands are under considerable pressure for a range of other human activities. Of these, dam building for hydropower, pollution, water abstractions, deforestation and drainage and modification of floodplains are increasingly serious and, together with overexploitation, pose threats to the continued productivity and sustainability of catches. As human populations continue to grow and economic development proceeds apace over much of the region, pollution, environmental degradation and intensity of threat to river fishes can be expected to increase. Without appropriate national, regional and international mechanisms to ensure that greater care is taken of the aquatic environments, a decline in the important fisheries yields and significant changes in fish community structure are to be expected. To a certain extent, such declines may be offset by intensifying management of sectors of the fishery and by a wider diffusion of aquaculture. The extent of endangerment of megafishes in the Mekong River, which is still relatively pristine and unpolluted, could be seen as an early sign of things to come. Moreover, national imperatives that prioritize economic development over environmental ­protection, exemplified by plans for dam cascades along the region’s major rivers, do not inspire confidence that the wise

course of careful long‐term management for conservation of river fishes will prevail over short‐term considerations. A wider appreciation of the value of river fishes (for instance, their consumptive value as food) may help to ensure their conservation, as would greater consideration of the role that fishes and fisheries play in sustaining livelihoods and the logistical ­difficulties of replacing that role with other sources of animal protein. A greater awareness of the importance of fishes as components of healthy functioning ecosystems that provide irreplaceable ‘free’ services for humans (for instance, clean, fresh water) could enhance efforts to conserve and manage river fishes, and education of citizens and decision‐makers will be key to such initiatives. The identification of flagship species could be a first step to enhance public consciousness of river fishes, and such an approach has been used for the tambaqui Colossoma macropomum, a giant characid that has become a symbol of the need to  protect Amazonian floodplain habitats (Araujo‐Lima & Goulding, 1997). As it is an important food fish, C. macropomum embodies the problems that need to be resolved in order to sustainably manage an entire multi‐species fishery in the Amazon. Identification of suitable candidate species from Southeast Asia should not be too challenging: for instance, the giant P. gigas or P. jullieni could be flagship species for the Mekong. This will only be an initial stage in a more wide‐­ranging process that must involve innovative partnerships that combine the efforts of, for example, fishery scientists, ­conservation organizations, citizens’ groups and those charged with managing natural resources in national governments. It will also require decision‐makers to commit to action that will sustainably manage an irreplaceable natural resource. A particular responsibility of fishery scientists is to ensure that the research they do contributes to management of fish stocks and the collection of data that allows determination of trajectories of catch composition and population change so that the effectiveness of management measures can be assessed. More must be done to identify and undertake the research necessary to s­ upport m ­ anagement strategies that reconcile human use of Southeast Asian rivers with the preservation of ecosystem integrity and maintenance of fish stocks.

References Allan, J. D., Abell, R., Hogan, Z., Revenga, C., Taylor, B. W., Welcomme, R. L. & Winemiller, K. 2005. Overfishing of inland waters. BioScience 55, 1041–1051. Agostinho, A. A., Gomes, L. C., Fernandez, D. R. & Suzuki, H. I. 2002. Efficiency of fish ladders for neotropical ichthyofauna. River Research and Applications 8, 299–306. Allison, E. H., Perry, L., Badjeck, M. C., Adger, N. W., Brown, K., Conway, D., Halls, A. S., Pilling, G. M., Reynolds, J. D., Andrew, N. L. & Dulvy, N. K. (2009). Vulnerability of national economies to the impacts of climate change on fisheries. Fish and Fisheries 10, 173–196. Araujo‐Lima, C. & Goulding, M. (1997). So Fruitful a Fish: Ecology, Conservation, and Aquaculture of the Amazon’s Tambaqui. New York, NY: Columbia University Press.

374   Freshwater resources

Baird, I. G. (2006a). Strength in diversity: Fish sanctuaries and deep‐ water pools in Laos. Fisheries Management and Ecology 13, 1–8. Baird, I. G. (2006b). Probarbus jullieni and Probarbus labeamajor: The management and conservation of two of the largest fish species in the Mekong River in southern Laos. Aquatic Conservation: Freshwater and Marine Ecosystems 16, 517–532. Baird, I. G. (2011). The Don Sahong Dam: Potential impacts on regional fish migrations, livelihoods and human health. Critical Asian Studies 43, 211–235. Baird, I. G. & Flaherty, M. S. (2004). Beyond national borders: Important Mekong River medium sized migratory carps (Cyprinidae) and ­fisheries in Laos and Cambodia. Asian Fisheries Science 17, 279–298. Baird, I. G., Hogan, Z., Phylaivanh, B. & Moyle, P. (2001). A communal fishery for the migratory catfish Pangasius macronema in the Mekong River. Asian Fisheries Science 14, 25–41. Baird, I. G., Flaherty, M. S. & Phylavanh, B. (2003). Rhythms of the river: Lunar phases and migrations of small carps (Cyprinidae) in the Mekong River. Natural History Bulletin of the Siam Society 51, 5–36. Baird, I. G., Flaherty, M. S. & Phylavanh, B. (2004). Mekong River Pangasiidae catfish migrations and the Khone Falls wing trap fishery in southern Laos. Natural History Bulletin of the Siam Society 52, 81–109. Baran, E., Baird, I. G. & Cans, G. (2005). Fisheries Bioecology in the Khone Falls area (Mekong River, Southern Laos). Penang: WorldFish Center. Bezuijen, M. R. (2011). Wetland Biodiversity and Climate Change Briefing Paper: Rapid Assessment of the Impacts of Climate Change to Wetland Biodiversity in the Lower Mekong Basin. Hanoi: International Centre for Environmental Management (ICEM). Blake, B. & Barr, J. (2005). Fourth Output to Purpose Review Report (December 2005). Dhaka: Rural Livelihoods Evaluation Partnership. Bush, S. R. (2004). Scales and sales: Changing social and spatial fish trading networks in the Siphandone fishery, Lao PDR. Singapore Journal of Tropical Geography 25, 32–50. Coates, D. 2002. Inland Capture Fishery Statistics of Southeast Asia: Current Status and Information Needs. Publication No. 2002/11. Bangkok: Asia‐Pacific Fishery Commission. Craig, J. F., Halls, A. S., Barr, J. J. F & Bean, C. W. (2004). The Bangladesh floodplain fisheries. Fisheries Research 66, 271–286. Cronin, R. (2009). Mekong dams and the perils of peace. Survival 51, 147–160. Daconto, G. (Ed.) (2001). Siphandone Wetlands. Bergamo: Environmental Projection and Community Development in Siphandone Wetland Project CESVI. Deap, L., Degen, P. & van Zalinge, N. (2003) Fishing Gears of the Cambodian Mekong Inland Fisheries. Phom Penh: Inland Fisheries Research and Development Institute of Cambodia. De Silva, S. S. & Funge‐Smith, S. (2005). A Review of the Stock Enhancement Practices in the Inland Water Fisheries of Asia. Bangkok: FAO. De Silva, S. & Phuong, N. (2011) Striped catfish farming in the Mekong Delta, Vietnam: A tumultuous path to a global success. Reviews in Aquaculture 3, 45–73. DoF (Department of Fisheries) (2012). National Fish Week 2012 Compendium. Bangladesh: Department of Fisheries, Ministry of Fisheries and Livestock (in Bengali). Dudgeon, D. (1992). Endangered ecosystems: A review of the conservation status of tropical Asian rivers. Hydrobiologia 248, 167–191. Dudgeon, D. (2011). Asian river fishes in the Anthropocene: Threats and conservation challenges in an era of rapid environmental change. Journal of Fish Biology 79, 1487–1524.

Dudgeon, D (2012). Threats to freshwater biodiversity globally and in the Indo‐Burma Biodiversity Hotspot. In The Status and Distribution of Freshwater Biodiversity in Indo‐Burma (Allen, D.J., Smith, K.G. & Darwall, W.R.T., eds). Cambridge and Gland: IUCN. FAO (1995). Review of the state of the world fishery resources: inland capture fisheries. FAO Fisheries and Aquaculture Circular 885. FAO (2003). Myanmar Aquaculture and Inland Fisheries. Bangkok: FAO. Halls, A. S. & Kshatriya, M. (2009) Modelling the cumulative barrier and passage effects of mainstream hydropower dams on migratory fish populations in the Lower Mekong Basin. MRC Technical Paper No. 25. Vientiane: Mekong River Commission. Halls, A. S. & Paxton, B. R. (2014). The stationary trawl (dai) fishery of  the tonle sap‐great lake system, Cambodia. In Inland Fisheries Evolution and Management – Case Studies from Four Continents, (Welcomme, R., Valbo‐Jorgensen, J. & Halls, A. S., eds), pp. 33–47. FAO Fisheries and Aquaculture Technical Paper 579. Halls, A. S., Hoggarth, D. D. & Debnath, D. (1999). Impacts of hydraulic engineering on the dynamics and production potential of floodplain fish populations in Bangladesh. Fisheries Management and Ecology 6, 261–285. Halls, A. S., Payne, A. I., Alam, S. S. & Barman, S. K. (2008). Impacts of flood control schemes on inland fisheries in Bangladesh: Guidelines for mitigation. Hydrobiologia 69, 45–58. Halls, A. S., Paxton, B. R., Hall, N., Peng Bun, N., Lieng, S., Pengby, N. & So, N. (2013a). The Stationary Trawl (Dai) Fishery of the Tonle Sap‐Great Lake, Cambodia. Phnom Penh, Cambodia: Mekong River Commission. Halls, A. S., Conlan, I., Wisesjindawat, W., Phouthavongs, K., Viravong, S., Chan, S. & Vu, V. A. (2013b). Atlas of deep pools in the Lower Mekong River and some of its tributaries. MRC Technical Paper No. 31. Phnom Penh, Cambodia: Mekong River Commission. Halls, A. S., Paxton, B. R., Hall, N., Hortle, K. G., So, N., Chea, T., Chheng, P., Putrea, S., Lieng, S., Peng Bun, N., Pengby, N., Chan, S., Vu, V. A., Nguyen Nguyen, D., Doan, V. T., Sinthavong, V., Douangkham, S., Vannaxay, S., Renu, S., Suntornratana, U., Tiwarat, T. & Boonsong, S. (2013c). Integrated analysis of data from MRC fisheries monitoring programmes in the lower Mekong Basin. MRC Technical Paper No. 33. Phnom Penh, Cambodia: Mekong River Commission. Hasan M. R. & Talukder, M. M. R. (2004). Development of management strategies for culture based fisheries in Oxbow lakes in Bangladesh. Bangladesh Journal of Fisheries (Special issue) 27, 57–58. Hickling, C. L. (1961). Tropical Inland Fisheries. London: Longmans. Hill, M. T. (1995). Fisheries ecology of the lower Mekong River: Myanmar to Tonlé Sap River. Natural History Bulletin of the Siam Society 43, 263–288. Hogan, Z., Baird, I. G., Radtke, R. M & Vander Zanden, M. J. (2007). Long distance migration and marine habitation in the Asian catfish, Pangasius krempfi. Journal of Fish Biology 71, 818–832. Hoanh, C. T., Jirayoot, K., Lacombe, G. & Srinetr, V. (2010). Impacts of climate change and development on Mekong flow regime. First ­assessment – 2009. MRC Technical Paper No. 29. Vientiane: Mekong River Commission. Hogan, Z. S., Pengbun, N. & van Zalinge, N. (2001). Status and conservation of two endangered fish species, the Mekong giant catfish Pangasianodon gigas and the giant carp Catlocarpio siamensis, in Cambodia’s Tonle Sap River. Natural History Bulletin of the Siam Society 49, 269–282.

Fisheries of the rivers of Southeast Asia    375

Hortle, K. G. (2007). Consumption and the yield of fish and other aquatic animals from the Lower Mekong Basin. MRC Technical Paper No. 16. Vientiane: Mekong River Commission. Hortle, K. G., Troeung, R. & Lieng, S. (2008) Yield and value of the wild fishery of rice fields in battambang province, near the Tonle Sap Lake, Cambodia. MRC Technical Paper No. 18. Vientiane: Mekong River Commission. Junk, W. J., Bayley, P. B. & Sparks, R. E. (1989). The flood pulse concept in river‐floodplain systems. In Proceedings of the International Large Rivers Symposium (Dodge, D. P., ed.), pp. 110–127. Canadian Journal Fisheries and Aquatic Sciences Special Publication 106. Kottelat, M., Baird, I. G., Kullander, S. O., Ng, H. H., Parenti, L. R., Rainboth, W. J. & Vidthayanon, C. (2012). The status and distribution of freshwater fishes of Indo‐Burma. In The Status and Distribution of Freshwater Biodiversity in Indo‐Burma (Allen, D.J., Smith, K.G. & Darwall, W. R. T., eds), pp. 36–65. Cambridge and Gland: IUCN. Kummu, M., Tes, S., Yin, S., Adamson, P., Józsa, J., Koponen, J., Richey, J. & Sarkkula, J. (2014). Water balance analysis for the Tonle Sap Lake–floodplain system. Hydrological Processes 28, 1722–1733 doi:10.1002/hyp.9718. Lamberts, D. (2006). The Tonle Sap Lake as a productive ecosystem. International Journal of Water Resources Development 22, 481–495. Lamberts, D. (2008a). Little impact, much damage: The consequences of Mekong River flow alterations for the Tonle Sap ecosystem. In Modern Myths of the Mekong – a Critical Review of Water and Development Concepts, Principles and Policies (Kummu, M., Keskinen, M. & Varis, O., eds), pp. 3–18. Helsinki: Water & Development Publications, Helsinki University of Technology. Lamberts, D. (2008b). The unintended role of the local private sector in biodiversity conservation in the Tonle Sap Biosphere Reserve, Cambodia. Local Environment 13, 43–54. Lamberts, D. & Koponen, J. (2008). Flood pulse alterations and productivity of the Tonle Sap ecosystem: A model for impact assessment. Ambio 37, 178–184. Lieng, S., Yim, C. & Van Zalinge, N. P. (1995). Fisheries of the Tonic Sap River Cambodia, I: The Bagnet (Dai) fishery. Asian Fisheries Science 8, 258–265. Lymer, D., Funge‐Smith, S., Khemakorn, P., Naruepon, S. & Ubolratana, S. (2008a). A review and synthesis of capture fisheries data in Thailand – Large versus small‐scale fisheries. RAP Publication 2008/17. Bangkok: FAO Regional Office for Asia and the Pacific, Lymer, D., Funge‐Smith, S. J., Clausen, J. & Weimin, M. (2008b). Status and potential of fisheries and aquaculture in Asia and the Pacific. RAP Publication 2008/15. Bangkok: FAO Regional Office for Asia and the Pacific. Miao, W., Silva, S. D. & Davy, B. (Eds) (2010). Inland fisheries enhancement and conservation in Asia, Bangkok, Thailand. RAP Publication 2010/22. Bangkok: FAO Regional Office for Asia and the Pacific. Mustafa, M. G. (2009). Fishery resources trends and community‐based management approaches adopted in the river Titas in Bangladesh. International Journal of River Basin Management 7, 135–145. Mustafa, M. G. & Brooks, A. C. (2009). A comparative study of two seasonal floodplain aquaculture systems in Bangladesh. Water Policy 11 (Suppl.1), 69–79. Natarajan, A. V. (1989). Environmental impact of Ganga Basin development on gene‐pool and fisheries of the Ganga River system. Canadian Special Publications in Fisheries and Aquatic Sciences 106, 545–560.

Payne, A. I. Sinha, R., Singh, H. R. & Huq, S. (2004) A review of the Ganges basin: Its fish and fisheries. In Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries, Vol. I, (Welcomme, R. & Petr, T., eds), pp. 229–251. Bangkok: FAO. Phen, C., Nam, S., Peng Bun, N. & Thuok, N. (2012). Record fish catch on Tonle Sap River. Catch & Culture 18, 4–5. Poulsen, A., Poeu, O., Viravong, S., Suntornratana, U. & Tung, N. T. (2002a). Deep pools as dry season fish habitats in the Mekong Basin. MRC Technical Paper No. 4. Phnom Penh: Mekong River Commission. Poulsen, A. F., Poeu, O., Viravong, S., Suntornratana, U. & Tung, N. T. (2002b). Fish migrations of the Lower Mekong River Basin: implications for development, planning and environmental management. MRC Technical Paper No. 8. Phnom Penh: Mekong River Commission. Rahman, A. K. A. (1989). Freshwater Fishes of Bangladesh. Dhaka: Zoological Society of Bangladesh. Roberts, T. R. (1993). Artisanal fisheries and fish ecology below the great waterfalls in the Mekong River in southern Laos. Natural History Bulletin of the Siam Society 41, 31–62. Roberts, T. R. & Baird, I. G. (1995). Traditional fisheries and fish ecology on the Mekong River at Khone Waterfalls in Southern Laos. Natural History Bulletin of the Siam Society 43, 219–262. Schipper, L., Liu, W., Krawanchid, D. & Chanthy, S. (2010) Review of climate change adaptation methods and tools. MRC Technical Paper No. 34. Vientiane: Mekong River Commission. Shankar, B., Halls, A. S. & Barr, J. (2005). The effects of surface water abstraction for rice irrigation on floodplain fish production in Bangladesh. International Journal of Water 3, 61–68. So, N., Eng, T., Souen, N. & Hortle, K. G. (2005) Use of freshwater low value fish for aquaculture development in the Cambodia’s Mekong basin. Regional Workshop on Low Value and ‘Trash Fish’ in the Asia‐ Pacific Region, 7–9 June 2005. Hanoi: Asia-Pacific Fishery Commission. Sultana, P. & Thompson, P. M. (1997). Effects of flood control and drainage on fisheries in Bangladesh and the design of mitigating measures. Regulated Rivers: Research & Management 13, 43–55. Syvitski, J. P. M., Kettner, A. J., Overeem, I., Hutton, E. W. H., Hannon, M. T., Brakenridge, G. R., Day, J., Vörösmarty, C., Saito, Y., Giosan, L. & Nicholls, R. J. (2009). Sinking deltas due to human activities. Nature Geoscience 2, 681–686. Warren, T. J., Chapman, G. C. & Singhanouvong, D. (2005). The wet season movements and general biology of some important fish species at the great fault line on the Lower Mekong River of the Lao P.D.R. Asian Fisheries Science 18, 225–240. Warren, T. J., Chapman, G. C. & Singhanouvong, D. (1998). The upstream dry‐season migrations of some important fish species in  the Lower Mekong River in Laos. Asian Fisheries Science 11, 239–251. Welcomme, R. L. (1999). A review of a model for qualitative evaluation of exploitation levels in multi‐species fisheries. Fisheries Management and Ecology 6, 1–20. Welcomme, R. & Vidthayonon, C. (2003). The impacts of introductions and stocking of exotic species in the Mekong Basin and policies for their control. MRC Technical Paper No. 9. Phnom Penh: Mekong River Commission. Welcomme, R. L. & Halls A. (2004). Dependence of tropical river fisheries on flow. In Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries, Vols I and II, (Welcomme, R. L. & Petr, T., eds), pp. 267–284. Bangkok: FAO.

376   Freshwater resources

Welcomme, R. L., Valbo‐Jorgensen, J. & Halls, A. S. (Eds) (2012). Inland Fisheries Evolution and Management – Case Studies from Four Continents. Rome: FAO. Xu, J., Grumbine, R. E., Shrestha, A., Eriksson, M., Yang, X., Wang, Y. & Wilkes, A. (2009). The melting Himalayas: Cascading effects of climate change on water, biodiversity, and livelihoods. Conservation Biology 23, 520–530. Ziv, G., Baran, E., Nam, S., Rodríguez‐Iturbe, I. & Levina, S. A. (2012). Trading‐off fish biodiversity, food security, and hydropower in the Mekong River Basin. Proceedings of the National Academy of Sciences of the United States of America 109, 5609–5614.

Electronic References Compagno, L. J. V. & Cook, S. F. (2005). Himantura chaophraya. IUCN Red List of Threatened Species, Version 2010.4. Available at http:// www.iucnredlist.org (last accessed 4 April 2011).

Halls, A. S. & Johns, M. (2013) Assessment of the Vulnerability of the Mekong Delta Pangasius Catfish Industry to Development and Climate Change in the Lower Mekong Basin. Report prepared for the Sustainable Fisheries Partnership, January 2013. Available at http://­cmsdevelopment. sustainablefish.org.s3.amazonaws.com/2013/01/22/Pangasius% 20Mekong%20Delta‐4b2036ad.pdf (last accessed 10 November 2013). Mainuddin, M., Hoanh, C. T., Jirayoot, K., Halls, A. S., Kirby, M., Lacombe, G. & Srinetr, V. (2010). Adaptation Options to Reduce the Vulnerability of Mekong Water Resources, Food Security and the Environment to Impacts of Development and Climate Change. Available at https://publications.csiro.au/rpr/download?pid=csiro: EP103009&dsid=DS8 (last accessed 29 December 2014). Mustafa, M. G. & Halls, A. S. (2006). Community Based Fisheries Management‐Fisheries Yields and Sustainability. Policy Brief 2 (Dickson, M. & Brooks, A., eds). Dhaka: World Fish Center. Available at http://www.worldfishcenter.org/resource_centre/Fisheries% 20Yields%20and%20sustainabilities.pdf (last accessed 29 December 2014).