Contents Monitoring fish and fisheries at Khone Falls MRC MEETING (12 - PowerPoint PPT Presentation

Don Sahong HPP for MoNRE 5/1/2015 Contents Monitoring fish and fisheries at Khone Falls MRC MEETING (12 Dec 2014) 1. Some background information 2. Objectives of monitoring fish & fisheries 3. Fish passage monitoring 4. Other fisheries surveys by DSPC in 2014 Don Sahong Hydropower Company 07/03/14 Slide 2 1

Don Sahong HPP for MoNRE 5/1/2015 Background Information Khone Falls Overview Map The location is unusually complex: • geography of the falls, many channels; • seasonal change in flows; l h fl • international border across the southern boundary; • most data from 1994 ‐ 1999 studies of fishers downstream of the falls; • species diversity – 200+ fish species; • fish migration • fish migration – many species migrate; many species migrate; • fisheries at the falls, upstream and downstream; • many other impacts on fish, up and downstream. Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 3 07/03/14 Slide 4 2

Don Sahong HPP for MoNRE 5/1/2015 Large channels 29 Jan 14 Natural Discharge (m 3 s ‐ 1 ) Approximate Channel width (m) 5 % ‐ ile Median 95 % ‐ ile Total Mekong* l k * 1300 ‐ 5500 29,982 4,691 1,674 Western Channels 600 ‐ 3500 19,679 1,555 84 Ee Dtout 100 ‐ 400 1,382 173 12 Xang Pheuak (Khone Lan) 250 ‐ 850 2,073 260 18 Sahong 90 ‐ 160 1,387 301 50 Sadam 50 ‐ 60 291 58 3 Phapheng p g 250 ‐ 500 5,170 , 2,344 , 1,505 , 17 Aug 14 Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 5 07/03/14 Slide 6 3

Don Sahong HPP for MoNRE 5/1/2015 Migrations from MRC LEK 1999 Fish migrations at Khone Falls Upstream 90 80 f reports 70 Champasak Province 60 34 fishers 34 fishers 50 50 No. of 40 218 reports 30 43 species 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 Month Downstream 18 16 rts 14 14 No. of repor 12 10 8 6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 Baran (2006) ... Baird et al. (2001) Month 07/03/14 Don Sahong Hydropower Company Slide 7 07/03/14 Don Sahong Hydropower Company Slide 8 4

Don Sahong HPP for MoNRE 5/1/2015 The need for data Objectives of Monitoring Fish & Fisheries • Most quantitative information on Khone Falls fisheries 1. Fish passage is out ‐ of ‐ date (1990s) and tells us only that fish are MRC PDG “The developer should provide effective fish passage killed in large quantities while trying to ascend the falls killed in large quantities while trying to ascend the falls. upstream and downstream. Effective fish passage is usually defined as upstream and downstream Effective fish passage is usually defined as “providing safe passage for 95% of the target species under all flow • A lot of information is based on old LEK of fishers. conditions.” • Many breeding fish are killed while migrating ‐ before ‐ Evaluate the effectiveness of fish passage mitigation measures for they can spawn. upstream ‐ migrating fish and provide information for ongoing fish passage improvement. • Some fish do migrate past the falls at certain times. ‐ Evaluate risk to downstream ‐ migrating fish and provide information • But there are no quantitative data on the proportions q p p needed to develop downstream fish passage mitigation measures needed to develop downstream fish passage mitigation measures. of fish that get past the falls (in total) or on the 2. Socio ‐ economic proportion that pass each channel at present. Importance and value of the fisheries to the people directly affected • Nobody can quantify fisheries losses at this stage. by the project. Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 9 07/03/14 Slide 10 5

Don Sahong HPP for MoNRE 5/1/2015 Fish Passage Monitoring General Approach Monitoring is at two scales: 1. Monitor fish upstream and downstream of the falls and compare abundance by species. 1 Through each of the natural channels – the main work now g Non ‐ capture methods Non capture methods • • 2 Through each modified fish pass Capture ‐ CPUE sampling • Establish the current rate of successful migration of fish – the Capture ‐ household (fisher) catches (socioeconomic • • baseline ‐ through each channel or fish passage. study) Set up monitoring that is standardised to provide comparable • results and can be sustained as the system changes due to 2. Tag or mark fish and recapture or track their movements g p construction and operations. i d i through the channels. 3. CPUE sampling of downstream ‐ migrating fish. Develop capacity, purchase and test equipment, set up databases • and analyses and adjust monitoring according to results. 4. Collect ancillary supporting data. Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 11 07/03/14 Slide 12 6

Don Sahong HPP for MoNRE 5/1/2015 Khone Falls Monitoring Locations Non ‐ capture methods 1. Direct observation – fish can be seen migrating if the water is clear. Not generally applicable because of scale, turbidity and habitat complexity. However, in the dry season fish are visible at certain places and could provide some information. 3 Fish (Schistosomiasis is a problem). Passage Sites 2. Photographic methods will be trialled in the fish passages in dry season of 2015 – may be useful for localised information. dry season of 2015 may be useful for localised information. Don Sahong Hydropower Company Don Sahong Hydropower Company 23/11/14 Slide 13 07/03/14 Slide 14 7

Don Sahong HPP for MoNRE 5/1/2015 Non ‐ capture methods Capture methods ‐ CPUE CPUE 14 2. Hydroacoustics – use of sound waves to detect 12 Fish are caught using standard methods, fish . 10 CPUE is compared over time and Standard units are not very effective because of Standard units are not very effective because of 8 8 between sites. Migration is inferred 6 large scale and complexity of habitat, shallow based on differences in CPUE. 4 depth in many places, fast turbulent water and 2 likely interferences. Cannot relate to species. 0 1. Migration peaks in 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 CPUE Date channels…..example Hi ‐ frequency multi ‐ beam sonar (e.g. Didson) is 14 12 better in turbid conditions, but has limited 2. Difference upstream – downstream in 10 range …. 15 m and could not identify most range …. 15 m and could not identify most CPUE CPUE. 8 species. 3. Difference across channels (laterally) 6 4 in CPUE. 2 4. Differences in size distribution of fish. 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 Date Viravong et al. 2006 Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 15 07/03/14 Slide 16 8

Don Sahong HPP for MoNRE 5/1/2015 CPUE example (Cacot 2007) For CPUE comparison to be effective ... • Requires standardization of gears and methods ‐ this is the basic approach used in many fisheries studies worldwide. • An assumption is that changes in CPUE (mostly) reflect underlying changes in abundance of fish. • The efficiency of the gears must be the same at each site (affected by habitat and water quality). • The catchability of the fish must be the same at each site (affected by behaviour, and also habitat and water quality). Don Sahong Hydropower Company Don Sahong Hydropower Company 07/03/14 Slide 17 Slide 18 9

Don Sahong HPP for MoNRE 5/1/2015 Luang Khang 2013 Gears must suit the habitat example of non ‐ standardisability Highly variable and site ‐ specific • Useful for catching fish for tagging. • Don Sahong Hydropower Company Don Sahong Hydropower Company Slide 19 Slide 20 10

Don Sahong HPP for MoNRE 5/1/2015 Standard methods of CPUE Monitoring Cast Nets Various gears have been trialed in 2014. Advantages Can be used in all habitats Now eight methods are used each day at 11 sites. • Catch a range of species and sizes. • Cast net large (5 5 cm mesh 3 5 m dia ) 20 casts Cast net ‐ large (5.5 cm mesh, 3.5 m dia.) ‐ 20 casts • • Easy replication – no. of casts. • Cast net ‐ small (2.5 cm mesh, 2.8 m dia.) ‐ 20 casts • Easy to standardise. • Panel gill net ‐ small (2.5 and 3 cm mesh, 15 m x 0.8) Common gear for fishers. • • Fish are alive and generally can be Panel gill net ‐ medium (4 ‐ 11 cm mesh, 16 m x 1.7 m) • • tagged. Panel gill net ‐ large (10 ‐ 16 cm mesh, 16 m x 1.7 m) • Trap ‐ small cylindrical x 2 • Disadvantages Trap – large cylindrical x 2 Not a common standard gear • • elsewhere. Fyke net x 1 • Subject to ‘operator error’. • Electrofishing, seining and others cannot be used routinely. Fish may be damaged by capture. • Don Sahong Hydropower Company Don Sahong Hydropower Company Slide 21 Slide 22 11

Don Sahong HPP for MoNRE 5/1/2015 Panel gill nets Traps Advantages Advantages Common gear worldwide. • Hoop traps or fyke nets are common • Catch a range of species and sizes. • gear worldwide. Use of multi meshes allows easy Use of multi ‐ meshes allows easy • • Catch a range of species and sizes. • replication. Easy replication. Easy to make with local materials. • • Concept is familiar to fishers. Gill nets are familiar to fishers. • • Fish are alive and can be tagged. • Disadvantages Cannot use in very fast water. • Disadvantages Can be torn or damaged, require • Selectivity. • ongoing maintenance or ongoing maintenance or replacement. Bulkiness. • Fish are dead or damaged, cannot be Sometimes low catches. • • tagged. Don Sahong Hydropower Company Don Sahong Hydropower Company Slide 23 Slide 24 12