Comparing three representative lakes in Monsoon Asia

AP-BON Freshwater group

Monsoon Asia…….one of the highest rainfall in the world…….rich freshwater biodiversity

Not only rivers, but also natural lakes which haveoutstanding freshwater biodiversity……
Lake Biwa
Inle Lake

Tonle-sap Lake

Tonle-sap Lake and Mekong (by Dr. Bunthang Touch and Dr. Thach Phanara)

Features of Tonle-sap Lake

• One of the most famous sightseeing areas in Cambodia• Largest flood-palin in SE Asia (dry season 2500 -> rainyseaon 16000 km2 [x4 larger])• Rice paddy around• High alpha diversity (300 fish species)• Likely impacted by future hydropower dam
development of Mekong Basin

-The Mekong River has the highest fish biodiversity in the world after the Amazon River.

-

850 freshwater fish species recorded from the Mekong River Basin-With a total estimate of about 1,100 fish species if the possible coastal or marine visitors
are included.

> 60% (448species) in
Cambodianinland waters;
ranked 18thAmazon
1217

Mekong781
Zaïre624 Orinoco
549

Paraná
438

Rio
Negro
330

Chao
Phraya
318

Niger
261

Paraguay
Uruguay257228

The fish species diversity of the Tonle Sap lake in Cambodia isranked third (i.e. 296 species) in the world after the East-Africanlakes Malawi and Tanganyika. It the largest lake in the SE Asiaand the most productive lake in the world.

•Fish species richness of the
top ten lakes in the worldMalawi
438

Tanganyika
316-Grey fish 43%-White fish 40%

Tonle
SapVictoria-Black fish 17%

225 Tonle Sap296
Victoria

197 Chad/Chari
226
172

Biwa
69

Baikal64

Taal63

Turkana
60

Rukwa
59

Social Access…….via political, communal, familial “nonmarket” mechanisms
Subsistence fisheries
Cambodia: 70% of rural households dependon fisheries
Mostly small-scale and partly large scale
nature
Women and children play important role(ensuring food and nutrition security andlivelihood)
Community fisheries
Large participation throughout value chains

Economic Access…….via market mechanisms, purchasing power- Over 6 million Cambodians = part-time fishing and related
fishing activities = 45.5% of the total population- More than 1.5 million full-time fishers• 87% = small-scale fishers• 9% = medium-scale fishers• 4% = large-scale fishers
High employment factor throughout value chains
High income generating factor throughout value chains
Affordable, especially for poor people

Economic Value of Cambodiafisheries• An estimated Value of fisheries US$ 1.2 – 1.6 billion• Value of inland fisheries = US$ 0.8 – 1.0 billion• This estimated value accounts for about 8.0-12% ofCambodia’s GDP.
• The fisheries accounted for 25% of the Agriculture

GDP, ahead of animal production (15.5%), forestry(6.9%) and nearly half of rice and crop production(52.6%).
• Export: approx. 50,000 tons to many Asian countries

and Australia and USA = US$250 million/year

Food Security Value• Fish consumption estimated based on:- Official statistical data (Average): 52.4 kg/person/year- Household survey (Average): 60 - 66 kg/person/year- Household (Tonle Sap and plain region): 67 – 80kg/person/year•This rate is in the mid-upper level ofworld ranges of 15 – 90kg/person/year.
• Fish provide 81.5% of total animal protein intake forthe population.

Characteristics of main fish groups
White fishes• Long distance migrators undertaking migrations
between upper and lower
Mekong mainstream and its
major tributaries.
• Short distance migrators –undertaking migrations
between lower floodplainsand Mekong mainstream
and its major tributaries

37% of species richness
36% of capture
Source: MRC

Characteristics of main fish groups
Black fish- Floodplain
resident fish, with limited
lateral migrations from theriver onto floodplains andno longitudinal migrations
upstream and downstream.

13% of species richness
50% of capture
Source: MRC

Characteristics of main fish groups
Grey fish:
ecologically intermediate
between two previous
groups, corresponds tofishes that do not spend
the dry season infloodplain ponds, but do
not undertake long
distance migrations either.

50% of species richness
14% capture
Source: MRC

Pressures on Mekong fisheries

MiningSediment
extraction

Forestry

Navigation

Rice farming

Conservation

Fisheries

Hydropower

CLIMATE CHANGE

AquacultureHydropower dams
9 planned dams on LMB(mainstream) – two underconstruction.
23 existed dams (> 20 MW)
on tributaries
Many more tributary dams
are projected or underconstruction

Pak Beng(2018)

Pak Lay(2019)

Xayaburi(2012)

Don Sahong(2014)

Species richness

Future hydropower dam impact in Lower Mekong⊿ -28%

Total generating capacity (MW)Future hydropower dam impact in Cambodia

Species richness

Biodiversity loss without electric gain…..

⊿ -12%

Total generating capacity (MW)The Contribution of IFReDI
Agricultural Strategic Development Plan
2019-2023 (ASDP 2019-2023)
Objective of ASDP 2019-2023 “….to maintain wild
catches at around 600,000 tons per year,……."
IFReDI Activities:
Scientific research and technology on inland fisheries resources onissues such as stock status, catch per unit of effort, gear selectivity, ecosystems impacts, critical habitats, socio-economics, costs and earnings
studies, etc,
Encourage and strengthen research collaboration on inland fisheries
resources, with national, regional and international research institutes,
universities and other relevant institutions,
Disseminate results of researchAfter spending more than 10 years of research and development, IFReDI
of the Fisheries Administration of Cambodia has last week published aField Guide Book on Fishes of the Cambodia Freshwater Bodies, the firstbook in the Mekong region.
Funded by Nagao National Foundation Environment, Japan and MRC

Inle Lake (by Dr. May Thet Su Kyaw Tint and Yuichi Kano)

Features of Inle Lake

• One of the most famous sightseeing areas in Myanmar• Ancient Lake (3~4 million years ago?)• Rice paddy around• Endemic cultures• Many endemic species (fish: 13) including an ancient
carp Cyprinus intha• Alien fishes, but local people do not think it a problem:
local people like to eat Nile Tilapia• Water pollution from Nyaungshe City and floating
garden agricultureCurrent environment condition of Inle Lake Basin

Around Nyaungshwe City, polluted

Southern part of Inle Lake, looks
good condition
Moe Bye Dam, looks good condition

Main Livelihoods of the local people
Floating
Agriculture

WeavingFishing

Tourism-related Activities
25

Local fish markets of Inle Lake Basin

Imported from Yangon

Kano 2016

No information 1918 - 2016
Annandale 1918

Hybrid between Cyprinus intha (endemic) and C. rubrofuscus (introduced)

Cyprinus intha

Cyprinus rubrofuscus

HybridSystomus compressiformis (endemic) has been likely extinguishedThe last specimen in 1990s

Silurus burmanensis (endemic) might been extinguishedThe last observation in 2010

Floating Agriculture
Used weeds and silt from the lakebottom, put them onto floating beds
Bamboo poles are used to anchor
the floating bed in position

About 2 m wide and 180 m long

Commercial tomato production
31Tourism in Inlelake
32

Commercial boating

Agrochemicalsusage

Water quality
degradation

Disposalofgarbage
andsewage
contaminationsOvercrowding bywater hyacinths
Water quality has declined at an increasing rate.
(Butkus and Myint, 2001)
33

Commercial tomato
production : Hybridvariety, High input ofagrochemicals of
pesticides, fungicides andfertilizers
34

Comparison of mean values of potassium
during agriculture season and off season

StationOutletWeaving…
FG 2
FG 1
Inlet 2Center
Inlet 1
Tourist hub
0.0

OffSeason
AgriSeason

2.0
4.0
Potassium (mg/L)

6.0

Higher concentrations in agri-season except
tourist hub station
High input of agro-chemicals

35

Table 1 Comparison of water quality results between
December 2004 and December 2017
LocationsCl(mg/L)
Alkalinity (mg/L)
Previou This PreviousThiss study study
studystudy(2004) (2017) (2004)(2017)

NO3-N (mg/L)
PreviousThisstudystudy(2004)(2017)

Tourist hub
Inlet 1
CenterInlet 2
Weavingvillage

3.67
2.51
2.26
2.55
2.05

ND
0.008
ND
ND
0.454

110.2
118.4
121.7
121.7
128.8

140
129
140
117
117

381
370
385
325
329

1.30
0.70
1.46
0.70
1.03

ND= Not Detected36Conclusions

There were significantly increased in the concentrationof Cl, Alkalinity and Nitrate nitrogen between December
2004 and 2017.
The most polluted region, tourist hub station and Inlet
1 station (Group 1) which is located near Township,
because of human activities such as commercial boating,and sewage and garbage contamination.
The concentration of nitrate nitrogen is become
increasing and it is leading to water pollution as well as
eutrophication due to the usage of chemical fertilizers
and pesticides.
37

Lake Biwa (by Dr. Koji Mabuchi)

Features of Lake Biwa

• The largest lake in Japan• Ancient Lake (4 million years ago)
• Rice paddy around• Many endemic species (fish: 16) while most of them
are endangered• Problem of alien fish
• Water level is artificially controlled against flooding

Lake Biwa Endemic fishes as edible fishes“Funa-zushi”,
http://www.uoju.jp/product2/index.html

Small fishes boiled down in soy sauce

fermented “Nigoro-buna” crucian carp,a traditional dish of Shiga Pref.

https://kyodonewsprwire.jp/release/201807256317

Sliced raw “Biwa-masu” salmon

Grilled “Hon-moroko” minnow“The most tasty cyprinid fish in Japan”
https://www.tokkuri-otsu.com/ippin.html
https://mainichi.jp/articles/20181006/ddl/k25/040/48
2000c

Sliced raw “Iwatoko-namazu” catfish

Reproduction sites of Lake Biwa endemic fishes

Vegetation zoneHonmoroko

Rocky zone
Nigorobuna

Sandy zoneRiver
https://mainichi.jp/articles/20181006/ddl/k25/040/48
2000c

Shallowlakeshore

Two major invasive alien species in Lake Biwa
Considered to be the main cause of the native fish decrease

Largemouth bass

Bluegill

Both from North America
Micropterus salmoides

Lepomis macrochirus• Typical fish-eating fish
• Omnivorous fish that also eats fish eggs
• One of the 100 of the world’s worst
and fry
invasive alien species• One of the 100 of the Japanese worst• Popular game fish in Japaninvasive alien species

Targeted for removal in Shiga Pref.

Alien fishes’ propagation and native fishes’ decline
Annual removal amount of the twoalien fishes (ton)Largemouth bass: LB800
https://www.pref.shiga.lg.jp/ippan/shigotosangyou/suisan/18681.html

Micropterus
salmoides

400

Bluegill: BG
Lepomis macrochirus

0Annual catch ofnative vegetation-zone spawners (ton)

1600
Data from http://www.pref.shiga.lg.jp/g/suisan/toukei/files/h27biwakogyogyougyosyubetsugyokakuryou.pdf

1200

800

1965 BG

1974 LBFirst detection

1983 LB

1993BG

Significant propagation

26201401954 昭和29
1957 32
1960 35
1963 381966 411969 44
1972 47
1975 50
1978 53
1981 56
1984 59
1987 62
1990 平成 25199381996
1999 112002 142005 172008 20
2011 23400

Three factors affecting the decline of vegetation-zone spawners
Propagation of alien fishes

Micropterus salmoides

Lepomis macrochirus

Vegetation-zone reduction caused by infrastructure projects

Artificial water level control by Seta River Dam

Japanese‘s government countermeasure for improvement

Seta River Dam is operated by the Ministry ofLand, Infrastructure, Transport and Tourism, not
Shiga Prefecture

On the other hand, the low water levelsetting in the rainy and typhoon season
has been maintained based on theoperation rules determined by law

Lake Biwa
surface level(cm)4030
20100-10-20-30-40

Rainy& Typhoonseason

1日
月

121日

1日

11
月

1日

月

101日

9月

1日

8月

1日

7月

1日

6月

1日

5月

1日

4月

1日

3月

2月

1月

Slowing down the water level drop rate athigh water level due to heavy rain

1日

Spawningseason*Number of species affectedMajor threats to 16 Lake Biwa endemic fishes
Data from “Red Data Book of Shiga Prefecture 2015”15* Most species are affected by multiple factors

1050外来魚湖岸改変

底質悪化

乱獲

水位操作

Supposed factors

河川改修

圃場整備

その他

Comparing the three lakes
Tonle-sap

Inle

Biwa

Area

2500-16000 km2

43.5km2

670km2

Depth

Max. 9-13m

Max 3.1m

Max 104m

Ancient Lake

No

Yes

Yes

Fishery

Very HighHigh

MiddleSightseeing

HighHigh

MiddleFlood Plain

Yes

Partially

No

Yes

Yes

Yes

Water quality
Rice Paddy

Comparing the three lakes
Tonle-sap

Inle

Biwa

Fish α diversity(native)

High (300)Low (30)

Middle (65)Fish β diversity(endemic)

Low (3-5)

High (13)High (16)Alien fishes

Low (5-10)

High (17)High (14)Conservationissues• Overfishing (increasingpopulation)• Illegal fishing (weaklaw enforcement)• Water quality(pesticide, Open toilet)• Flooded forest(convert to fields)• Water level regulation(potentially byhydropower dam)
• Sedimentation loading,erosion by dam• Climate change• Waste gavages• Alien fishes• Waterdegradation(floating garden,deforestation,erosion, opentoilet)• Climate change• Increasing
population(tourism)• overfishing• Alien fish
• Lake shoremodification• Bottom degradation• Overfishing• Water level regulation• River/paddyimprovement(concreted)• Climate change (pooroxi.. deep water)

Example
Parameter

Evaluation

Action plan

2009-20192019-2030

To Do(within 3-5 yrs)

Mapping ofdiversity oftree
species

Encourage fieldworks in
Cambodia, ...

Collectionofphenologicalinformationof tree
species

Encourage to collectphenological informationin each countries

SDGs
Contribution

Urgentquestionincreased

no change

decreased

Recommend

Generalquestion1. Biodiversity research and monitoring
Parameter

Evaluation

Action plan

2009-20192019-2030

WG:
SDGs
Contribution

To Do
Encourage fieldworks in Wholeof SE Asia

1.Monitoringstates andchanges ofbiodiversity

To increase collaboration(Collaboration with MRC,Larvae monitoring, dai fisheries
monitoring, fish abundant
diversity monitoring, Mekong 3SRivers, Tonlesap Lake, Riverecological health monitoring)
To find researchers from AP
countries to fill the gap
Communicate with other fieldresearchers/specialists
To gather information on waterplants, mollusks, crustacean,other aquatic animals

2.Fillinggaps in data
availability

Urgentquestionincreased

no change

decreased

Recommend

Generalquestion

WG
Parameter

Evaluation Action plan
2009-20192019-2030:SDGs
Contribution

To Do

3.Increasing
access todata (datasharing)

Datapaper
Online database
Keep AP-BON workshop

4.Improving
knowledge
on cuttingedge
technologieseDNA
AI for species
identification
Big dataSonar sensor

Urgentquestionincreased

no change

decreased

Recommend

Generalquestion1. Biodiversity research and monitoring

WG:

5. How can we contribute to AO-GEO pilot studies
1) Mekong 2) Pacific islands 3) Himalaya
1) Research on Tonlesap Lake
2) N/A
3) Research on Inle Lake (Geographically easternmost Himalaya?)

6. How can we raise funds for AP-BON activities?
1) Now Inle Lake survey team [Watanabe (Kyoto-U) and Kano (Kyushu-U) ] is raising afund “Sumitomo Foundation”
2) Raising a fund for “Comparing Tonlesap, Inle and Biwa lakes”???

2. Networking of networks
Parameter

WG

Evaluation Action plan
2009-20192019-2030

1)
Networking
withobservationsites andnetworks:
SDGs
Contribution

To Do
Enhance collaborative
researches
Find possible
researchers in AP-BON
Workshop, etc.
Discussion andagreement abouttransboundary rivers
Transfer technology
Lessens learned

2)
Networkingwith global
platform,
policyrelevant
communitiesUrgent
questionincreased

no change

decreased

RecommendGeneralquestion3. Outreach activities, Capacity building, Actions for biodiversityof networks
Parameter

Evaluation Action plan
2009-20192019-2030

1) Outreachactivities &social
communication

WG

:
SDGs
Contribution

To Do
Improve publicawareness (meeting,books, forum,conference, Radio/TV, )Find funding
Human resource2) Capacity
building

Urgentquestionincreased

no change

decreased

Recommend

Generalquestion

Agenda

1.

Monitoring states and changes of biodiversity (networking)2.

Filling gaps in data availability

3.

Increasing access to data (data sharing, capacity building)

4.

Improving knowledge on cutting-edge technologies

5.

Mapping achievements and working plans using the template figure
format (including SDGs etc)

6.

Contributions to AOGEO pilot studies 1) Mekong, 2) Pacific islands, 3)
Himalaya

7.

Raising funds

1. Monitoring states and changes of biodiversity (networking)Tonle-sap

Inle

Biwa

IFReDI
MRC
Kagoshima University(finished)

Kyoto-Kyushu University(finished)

Many institutes of Japan2. Filling gaps in data availability

Tonle-sap

Inle

Biwa

2. Filling gaps in data availability
3. Increasing access to data (data sharing, capacity building)Tonle-sap

Inle• Several scientific papers• Annandale 1918

• Mekong River Committee(many online publications)• Kano et al. (2016)[datapaper]• Nagao Natural• No data available between
Environmental Foundation
1918-2016(many capacity building
activities in Indo-china)

Biwa

Many scientific publications
and information

4. Improving knowledge on cutting-edge technologies

Tonle-sap

Inle

Biwa

eDNA (Eva et al. 2016 [JiantCatfish])eDNA (Jerde et al. 2019)
eDNA (Kanno et al.
unpubished data)

Unknown…
Several JICA projects are nowrunningeDNA by many researchers5. Mapping achievements and working plans using the template
figure format (including SDGs etc)

6. Contributions to AOGEO pilot studies 1) Mekong, 2) Pacific islands, 3) Himalaya

Tonle-sap

Inle

Biwa

Yes (Mekong)

Yes??
(Geographicallyeasternmost Himalaya?)No

7. Raising funds

Tonle-sap

Inle

Biwa

Watanabe, Kano andTokuchi(Sumitomo foundation)
Raising fund that compare the three lakes from aspects of not only biodiversity butalso culture