Climate change impacts on coastal resources and

dependent livelihood in Tamil Nadu, Southeastern India

Edward JK Patterson

Suganthi Devadason Marine Research Institute

Tuticorin – 628 001, Tamil Nadu, INDIA

www.sdmri.in

Tamil Nadu

• Coast - 1076 km

• 13 coastal districts

• > 800,000 active

fishermen

• Key coastal habitats like coral reefs, seagrass beds, mangroves, estuaries etc.

Map source: Ramesh et al., 2008 (modified)

Rivers

• There are 7 rivers

• Mostly seasonal now

• Several check dams

• Flow reduced

• Encroachment for aquaculture, construction etc.

• Sand mining

• Monsoon failure

• Loss of nutrient input in coastal systems

Human induced threats

• Population

• High dependency on fishery resources

• Destructive and over fishing (Trawling, Shore

seine, push net, traps etc.)

• Pollution - Domestic and Industrial

• Coral mining

• Mangrove deforestation

Others (incl. natural threats)

• Climate change

• Monsoon failure

• Increase of disease prevalence

• Cyclone, tsunami• Cyclone, tsunami

Gulf of Mannar - Case study 1 (Corals

reefs)

Reef status• Reef areas in Gulf of Mannar are formed around 21 islands at a depth

between 0.5 and 6 m.

• Total reef cover - 110 Sq.km; Present cover - 75-80 Sq.km

• Coral bleaching during 1998 – about 60%, over 90% recovery.

• Present live coral status - 40%

• Coral species – 117

• Associated flora and fauna - over 3900

Threats to coral reefs of Gulf of Mannar

• Coral mining

In 1970’s it was estimated that the exploitation of corals was about

60,000 cubic meters (about 25,000 metric tones) per annum.

In July 2001, the federal government included all corals under

schedule - I of Wildlife (Protection) Act, 1972.

• Fishing in reef areas (Inshore trawling, shore seine, traps)• Fishing in reef areas (Inshore trawling, shore seine, traps)

• Seaweed collection in reef areas

• Pollution - domestic

• Invasion of exotic seaweed

• Cyclone, tsunami

• Climate change

Coral status

• Regular Monitoring

since 2005

• Shows resilience

• Mortality (9.77%) in 2010

due to prolonged

elevated SST 0

10

20

30

40

50

60

2003- 2007 2008 2009 2010 2011C

ora

l cover

(mean%

± S

D)

elevated SST2003-

2005

2007 2008 2009 2010 2011C

ora

l cover

(mean%

± S

D)

22

25

28

31

34

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

SS

T (

0C

)

2005

2006

2007

2008

2009

Average monthly SST values in the Gulf of Mannar during 2005 to 2009

31.6

32.6

31.6 31.6

33.5

32.1

31.6

32.9

31.7

31.0

32.5

31.331.0

32.5

31.3

30

30

31

31

32

32

33

33

34

34

Ap

r'0

5

Ma

y'0

5

Ju

n'0

5

Ap

r'0

6

Ma

y'0

6

Ju

n'0

6

Ap

r'0

7

Ma

y'0

7

Ju

n'0

7

Ap

r'0

8

Ma

y'0

8

Ju

n'0

8

Ap

r'0

9

Ma

y'0

9

Ju

n'0

9

2005 2006 2007 2008 2009

SST (

0C

)

Sea surface temperature (0 C) in summer (April, May and June) during 2005 to 2009

Coral bleaching

20

14.615.6

12.9

10.58.93

0

5

10

15

2005 2006 2007 2008 2009

Ble

achin

g (%

)

Temperature (0C) in Gulf of Mannar in 2010

28.6

29.6

31.5

32.2

33.2 33.132.8

31.2

29.4

28.3

27

28

29

30

31

32

33

34SST (

0C

)

25

26

Jan'10 Feb'10 Mar'10 Apr'10 May'10 Jun'10 Jul'10 Aug'10 Sep'10 Oct'10

Coral disease prevalence

• 6.7% in 2007 & 10.6%

in 2011

• Nine distinct types of

diseases

• disease susceptibility

increases when

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

Mandapam group Keezhakarai group Vembar group Tuticorin group

Perc

enta

ge %

increases when

elevated temp. 2007 2008 2009 2010 2011

Reef Associated Ornamental Fishes

• Over 70 reef associated fish species identified.

• Over 50% of the identified fishes are now become rare, threatened or highly

threatened – due to over exploitation and climate change effects

• Recent studies reveal that these fishes are seen in abundance in deeper

areas, where hard substrates (pars) with patch corals are available - 15 km

away from reefs with depth over 20m.

Algal Bloom in Reef Area

• October 2008 - algal bloom in reef area - Noctiluca scintillans.

• The oxygen level - 0.7 - 1.2 mg/l

• Over 5000 dead fishes and bivalves observed

• Several coral colonies were bleached.

• Seagrass beds was also affected.

27

27.528

28.5

29

29.530

30.5

Se

p'0

8

10

.10

.08

12

.10

.08

Se

p'0

8

10

.10

.08

12

.10

.08

Se

p'0

8

10

.10

.08

12

.10

.08

Se

p'0

8

10

.10

.08

12

.10

.08

Station-1 Station-2 Station-3 Station-4

Te

mp

era

ture

(0

C)

Surface

Bottom

Gulf of Mannar - Case study 2(Loss of Loss of LactariusLactarius lactariuslactarius fishery)fishery)

Fishery StatusFishing area /

village

1980-1990 Now

Tuticorin Over 10 tons per

day during peak

season

• Dissipating status

• 150 kg per day during peak season.

• Few catches are recorded from

Yeruvadi and Kanyakumari coast

• Fishermen pointed out that the

fishery has now changed towards

the Thalaimannar area of Sri Lankathe Thalaimannar area of Sri Lanka

Abundance of

False Trevally in

depths of 2 -5

fathoms

Fishermen need to travel 40-45 miles.

Fishing at depths over 20 fathoms.

Country crafts

had good catches

(300 – 500 kg)

Country crafts do not get Lactarius

Exclusive fishery

for False Trevally

No exclusive fishery - only by catch

Landing data of Lactarius in Tamil Nadu

1822

137313481400

1600

1800

2000

landin

gs in tons

640722

775 740840

938

537

679

537611

470

1028

1348

977

823

175

372

201

633714

234329

0

200

400

600

800

1000

1200

years from 1969 - 1993

landin

gs in tons

Reason for the loss of fishery

• Both nature and man are responsible.

• Lack of rain fall.

Out of 2 major rivers, Thamirparani flows throughout year,

but Vaipar has totally dried. Other two small rivers, Kallar

and Vembar also totally dried.

Lack of supply of food in the coastal waters, which is supported by • Lack of supply of food in the coastal waters, which is supported by continuous, unsustainable and repeated fishing in the same area..

• The effect of El-Nino during 1998 has caused a change in the climatic pattern - by an increase in temperature and decrease in rain fall.

• The climatic factor also supported by the destructive fishing practices.

Rainfall data

0

200

400

600

800

1000

1200

1994 1996 1998 2000 2002 2004

Years

Rain

fall in m

m

Average mean temperature

28.8

29

29.2

29.4

29.6

29.8

1994 1996 1998 2000 2002 2004

Years

Tem

pera

ture

in

Celc

ius

Effect on the socio-economics of dependent fishermen

• A decade ago

Fisherman with country craft able to earn Rs.600-700/day (peak season)

Fisherman with trawl boat – Rs.1000-1500/day

• Now

There is no exclusive fisheryThere is no exclusive fishery

Traditional fishermen are most affected

Summary• Tamil Nadu coast has productive key habitats which support good fishery.

• Traditional fishermen fully depend on fishery resources for livelihood.

• Human induced threats along with climate change impacts affect key habitats, associated fishery and livelihood of fishermen.

• The total cover and health of coral reefs, seagrass beds, mangroves and estuaries are reduced.

• Loss of fishery is noticed on various fish species - including Lactarius, Mackeral, Snapper, Barracuda, Pomfret, Grouper, Jacks, Lobster and Mud crab crab

• Migration, change of fishing practice, change of profession are seen among fishermen.

• The key habitats are managed under varied conservation status.

• Though the human influence is reduced within the Protected Areas, the climate change impacts cause series damage.

• Within the Protected Areas there are signs of resilience because of various management measures, including Coastal Ecosystem Rehabilitation activities to support the resilience.

• However, the combined effects of human influence and climate change hold the key.

•