Studv Area and Methodsshodhganga.inflibnet.ac.in/bitstream/10603/423/11/11_chapter2.pdfStudy area and Methods in this year was ... kmz in Kerala State and 114 km2 in Tamil ... Thekkady

Studv Area and

Methods

MAP OF THE PERIYAR

Chapter 2 -- - - - -

STUDY AREA AND METHODS

Periyar Tiger Reserve that takes its name from the river Periyar, the largest

river in Kerala, lies between 9' 16' and 9"40' N iat and hetwecn 7 6 " ~ ~ ' and

77"25' E long. The reserve having an area of 777 krn2 is situated on the

Western Ghats in the ldukki district of Kerala (PLATE 11).

2.1 Boundaries.

East: Part of interstate boundary between Kerala and Tamil Nadu

West: Privately owned cardamom and tea estates and also eastern

boundary of Kottayam district.

North: Part of interstate boundary between Kerala and Tamil Nadu

South: Northern boundary of Ranni Forest Division, Pamba river also

forms southern boundary.

2.2 Geornorphology.

The tract is hilly and the terrain undulating in many areas of Periyar

plataeu and rugged with loRy peaks and precipitous slopes it1 other areas.

The elevation ranges from' 400 to 2014 m. There are a large number of

Study area and Methads

peaks in the Sanctuary and in its with Tamil Nadu Some of them '

rise above 2000 nl and Vellimalai the highest peak has an elevation of

2014 m. The Periyar River which originates from Chokkampetty with its

manifold tributaries drains the Sanctuary area The river Mullayar which

originates at Kottamalai, joins Periyar at Mullakudy and forms the

Mullaperiyar River. The Periyar Lake had been formed by constructing a

dam across the Mullaperiyar River by the erstwhile Madras Government in

1895. The lake is at an elevation of 900m. The water spread area of the

lake is 26 km2 with depth rangins from 46 m to 321n. Portions on the

western side of the plateau are drained by rivers Pamha and Azhutha,

which form the boundary of the reserve. Rocks are crystalline and of

plutonic origin There are occasional outcrops of gneiss) and numerous 1 LJ

boulders on the ground particularly in the stream beds and stream banks

Depths of the soil varies according to the terrain, and the soil is n~ostly

wet.

2.3 Vegetation

Vegetation of the reserve comprises tropical evergreen and semi evergreen

forests (74 6%) moist deciduous forests (12.7%), grasslands ( I 5%) and

eucaliptus plantations 97 1%)

The tropical evergreen forests (305 km2) consist of trees like kzleria

iticiicn, l ) ip/crocarl~~i .~ hotrrdillio~ii, I'crlnqrrititrrn el/ipficum, Moslm ,firretr,

E/eocarp~rs it~berctrlatiis, ' C,'ar~ariiim sfricft~rn etc. Reeds are found i n wet - - FISHERY MANAGEMENT IN PERIYAR LAKE 10

I >

areas. Undergrowth

C~irrcirma sp., etc. Semi

hirsirta, Hopeapnrvrfira, Tetrnrneles rl~rdrjora etc. Undergrowth is thick

at many places. Moist deciduous forests (99 km2) consist of 72ctot1a

grai~dis, Dalbergin larifolia, Pterocorpirs mnr,nrpilrm, 7't.rmit1olio

par~iculata. Hridelia re/rrsn, Lmblica ~ f l c i r ~ d i s , Greu~iu iil~a~fi)lin,

Bombax sp. etc. In a preliminary survey, 64 species of grasses, 209

species of trees and 75 species of herbs have been identified in this area.

(Srivasthava et a1 1994, KFD 1986).

2.4 Climate

The climate in the tiger reserve area can be described as cool and humid

with heavy rainfall.

2.5 Temperature

The temperature varies from 1 5 . 5 ' ~ in December - January to 31" C in

April - May.

2.6 Rainfall

The average rainfall of the area is 2500 mm. The area receives both

Southwest and NorthEast monsoons

FISHERY MANAGEMENT IN PERlYAR LAKE 1 1

Study area and Metllods

A Cornparison of the data for '95, '96 and '97 shows a maximum rainf'all

of 561 mm and 529 rnm at damsite and at Thekkady respectively i n July

1996. The minimum rainfall of 1 mrn was recorded at Periyar Darn in

~ e b r u a r ~ in 1995 and at Thekkady in January 1997. Year wise analysis of

rainfall data for 1995, '96 and '97 at Periyar Dam and Thekkady maximum

rainfall was noticed at Periyar Dam in 1995 and minimurn also al the same

site in 1996. Comparing the average rainfall data for the 3 years the

highest rainfall was noticed in the year 1997 arid lowest in the year 1996.

(Table 1, Figure. 1)

Table 1

Year wise rain fall statement for 1995, '96 & '97 (In mm)

Year Periyar Dam Thekkady Average

FISHERY MANAGEMENT IN PERIYAR LAKE 12

Study area and Methods

Figure I

Year wise rain fall statement for 1995, '96 & '97 (Cn mm)



In 1995, maximum rainfall was recorded in August (422 nim) and

minimum, in February (1 mm), both at damsite. No rainfall was recorded

at damsite in December and at Thekkady in February. The maximum and

minimum rainfall recorded at Thekkady wen265 mm (in July) and 2 mtn

(in December) respectively. The total rainfall occurred in this year were

2461 mm at damsite and 1804 mm at Thekkady with an average of 2132.5

mm. (Table 2, Figure 2)

2.6.2 1996

In 1996 the maximum and minimum rainfall recorded at dam site were

561 mm (in July) and 9 mm (in February) respectively. In December no

rainfall occurred at damsite At Thekkady the maximrim and minimum

rainfall recorded were 529 mm (in July) and 21 mrn (in May) respectively

The total rainfall got in this year were 1662 mm at damsite and 2052 mm

at Thekkady respectively with an average of 1857mm. (Table 2 , Figure 3)

In 1997 maximum and minimum rainfall recorded at Thekkady were

456mm (in October) and 1 mm (in January) rcspectively. No rainfall was

recorded at damsite in January and February and at Thekkady in

February. At damsite the maximum and minimum rainfall recorded were

446mm (in July) and 46 mm (in March) respectively. The total rainfall got


in this year was 2263 mm at damsite and 2070 mm at l'hekkady

respectively, the average being 2166.Smm (Tablc 2, Figure 4).

2.7 Humidity

The maximum precipitation recorded was in the month of July and

minimum in January

2.8 Water

The whole area is drained by Periyar River and its tributaries. The Periyar

Lake extending to about 26 km2 in the middle and luxuriant evergreen and

semi evergreen vegetation covering almost 60 % of the area ensures water

conservation and keep all the streams as perennial water source for the

animal life. The Periyar Lake plays an important role in the conservation

and management of animals. All types of vegetation can be seen along the

fringes of the lake. There are many islands within the lake.

The largest river in Kerala in terms of water volume and length, the west

flowing Periyar runs for some 244 kms, till much swollen and polluted

before it enters the Arabian sea. This river has a catchment area of 5284

kmz in Kerala State and 114 km2 in Tamil Nadu making a total of 5398

kmz. In Kerala this river basin is located in two districts viz., ldukki and

Ernakulam.


Rainfall Data for 1995,1996 & 1997 ( In mm)

Year Sites J F M A M A J J Y A U S 0 N D Total

Periyar Dam 9 1 45 117 375 397 409 422 371 142 173 Nil 2461 1995

Thekkady 16 Nil 59 77 252 247 265 253 252 191 190 2 1804

Periyar Dam 2.3 9 38 114 5; 381 561 212 51 207 13 Nil 1662 1996

TheMtady 30 32 39 248 21 279 529 170 94 338 83 89 2052

PeriyuDam Nil Nil 46 144 72 125 446 325 217 400 359 129 2263 1997

Thekkady 1 Nil 40 87 84 170 337 223 89 465 406 168 2070

FISHERY MANAGEMENT IN PERlYAR LAKE


J F M A M a J J y A u S O N D

B Per j a r Dam Thekkady

Figure 2

Rainfall data for 1995 (In mm)

FISHERY MANAGEMENT IN PERlYAR LAKE 17


Figure 3

Rain fall data for 1996 (Jn mm)



Figure 4

Rain fail data for 1997 (In mrn)


PLATE I11

Picture 3 The Periyar Dam - a captive view


2.9 Periyar Lake

2.9.1 Physical Features

Physical features such as water level, discharge and inflow of the dam

were recorded for the years 1995 ' 96 and '97.

2.9.1.1 Water level (ft)

The maximum water level of 139.7 R was recorded in November in 1997

and the minimum of 106.8 in July in 1997 (Table 3, Fibwres 5,6 & 7).

2.9.1.2 Discharge (M.C.F.T) of Water

Maximum discharge of 1915.00 was recorded in November 1997 and a

minimum of 6.05 M.C.F.T in March 1996. No outflow was noted in

March, April and May in 1995 and May, June, and November in 1996

(Table 4, Figures 8 , 9 Rr 10)

2.9.1.3 Inflow (M.C.F.T) of Water

Maximum inflow of 10400.00 M.C.F.T was recorded in October 1997

and the minimum of 3.69 M.C.F.T in October 1995. In nionths such as

January, February, March, April, June, November and Deccmber in 1995



and January, February, March, April, May, June, July and December in

1996, no inflow was recorded (Table 5, Figures 1 I , 12 Rr 13).

-


Table 3

Water Level in Periyar Lake for 1995,1996 & 1997

Year J F M A Ma J JY A S 0 N D

Maximum 121.6 113.8 109.7 112.5 119.2 120.7 127.1 126.5 138.2 119.5 120 115.2 1995

Minimum 114.0 109.4 108.6 109.7 112.7 117.3 120.5 119.4 129.9 118.9 115.5 109.8

Maximum 110.2 109.2 108.2 109.0 108.0 117.9 133.0 133.0 125.4 135.1 131.8 124.8 1996 '

Minimum 108.5 108.2 106.9 106.9 108.0 108.5 114.9 125.7 121.4 121.3 125.4 114.3

Maximum 114.1 109.9 107.8 107.9 108.3 107.5 114.8 119.0 118.3 131.4 139.7 137.4 1997

hlinimum 110.1 107.8 107.1 107.4 107.4 106.8 107.4 115.3 117.2 117.0 132.7 135.6

FISHERY MANAGEMENT IN PERIYAR L4KE

Table 4

Discharge of Water for 1995, 1996 & 1997

Year J F M A Ma J JY A S 0 N D

Maximum 109.21 42.25 20.30 10.54 36.89 91 41 12390 123.98 179.54 144.98 99.79 67.05 1995

Minimum 37.5 21.95 Nil Nil Nil I l l 5 64.97 100.74 114.74 90.55 69.72 21.43

Maximum 19.27 13.39 10.37 11.06 10.80 75.60 160.00 156.38 130.46 162.26 164.85 175.31 1996

Minimum 8.99 9.76 6.05 6 3 1 Nil Nil 34.65 128.30 53.48 106.79 Nil 44.84

Maximum 511.00 254.00 170.00 73.00 92.00 65.00 483.00 919.00 714.00 1676.00 1915.00 1904.00 1997

Minimum 254.00 149.00 58.00 58.00 61.00 58.00 62.00 615.00 691.00 697.00 1661.00 1610.00

FISHERY MANAGEMENT IN PERIYAR LAKE

Inflow of Water in Periyar Lake for 1995,1996 & 1997

Year J F M A Ma J JY 4 S 0 N D

Maximum 123.60 15.02 43.96 64.00 242.70 197.44 431.95 561.96 931.48 172.32 200.53 30.53 1995

Minimum Nil Nil Nil Nil 4.84 Nil 49.98 10.30 33.16 3.69 Nil Nil

Maximum 245.75 58.06 24.55 70.78 10.45 308.00 557.92 156.00 208.38 769.80 90.46 261.85 1996

Minimum Nil Nil Nil Nil Nil Nil Nil 50.03 33.48 31.69 22.18 Nil

Maximum 496.00 245.00 417.00 428.00 424.00 239.00 1580.00 1932.00 1540.0 10400.00 9250.00 4661.00 1997

hfinirnum 254.00 191.00 160.00 64.00 66.00 185.00 82.00 81.00 287.00 292.00 1829.00 413.00

FISHERY MANAGEMENT IN PERIYAR LAKE


Figure 6

Water level for 1996



I Maximum Minimum

Figure 8

Discharge of water for 1995

FISHERY MANAGEMENT IN PERiYAR LAKE 2 8


Maximum Minimum

Figure 9

Discharge of water for 1996



I Maximum EI Miniman (

Figure 10

Discharge of water for 1.997

- FISHERY MANAGEMENT IN PERIYAR LAKE 30

I Maximum IEI Minimum I

Figure 1 I

Inflow of water for 1995

FISHERY MANAGEMENT IN PERIYAR LAKE 3 1


1 Maximm 81 Minirmm I

Figure 12

Inflow of water for 1996



Figure 13

Inflow of water fsr 1997



2.9.1.4 Water Quality

Water analysis of the Iake has been carried out in March, April, May and

June, in 1994 by KeraIa Forest Research Institute, Peechi. The dissolved

0 2 content at different depths of different sites varied from 5.75 to 7.5

rng./lit. Total hardness varied from 6.66 to 7.5 mg /lit. The amount of

free COz varied between 3.0 and 8.0 mg/lit. The range o f pH measured at

different depths of the lake varied between 6.62 and 7.68. Alkalinity and

Chloride were ranging from 38.8 to 59.9 mg/lit and 5.12 to 6.83 mg /lit

respectively.

2.9.2 Biological Features

2.9.2.1 Fauna

According to Luther and Rzoska (1971) no information is available on the

Iimnology of Periyar Lake.

A preliminary survey has shown that a variety of animal forms other than

fishes occur in the lake. Fresh water sponge E~rrrapi~rs cnrteri, Fresh

water medusa Limnocnih indica, Rotifers such as Brm~chiomis falcalus,

Keratella iropica and Trichozria tetracfl~ and Crustaceans (Cladocera)

such as Ceriodaph~ia corn~rta, Bosmina lorzgirostris and Bosminopsis

deitersi and Molluscans such as Nerilina (Ifittinu) perolfetiatla, Palzrdomus

FISHERY MANAGEMENT IN PERtYAR LAKE 3 4


(Paludomus) annandalei ( both Gastropods) and /,an~el/iden~ margi17alis

(Pelecypoda) are identified in the lake.

Besides these invertebrates, the pond Terrapin Melanochc/y,v Irtj~t~rcr, a / c

number of fish eating @ such as Cormorants, Darter, Herons, Egrets,

the Osprey and the Grey headed Fishing Eagle and the Common Otter

.also occurs in the lake. The Common Otter Llrlra l~rlt-ci occurring in the

lake and the rivers in fairly good numbers cause considerable damage to

the fishermen by destroying their nets and eating away their catches.

2.9.2.2 People

Four hill tribes viz, Mannans, Paliyans, Uralis and Mala Arayans are found

in the reserve. They have their unique culture and traditions. Four tribal

settlements are situated in the borders of the reserve. The tribal people

were given agriculture land with plantations of pepper, coffee and other

spices but these are very poorly maintained. Of the tribes the Mannans

are traditionally engaged in fishing in the lake, called fishermen in the

foregoing text. Many of them prefer to continue fishing, after giving their

larid on Lease to outside people

2.10 Materials and Methods

Fishes for the present study were colIected from Periyar Lake, either from

the fishermen directly or using cast net, hook and line and vatty (a local

method). FISHERY MANAGEMENT IN PERIYAR LAKE 3 5


2.10.1 Methods

i. Details of the dam such as physical features and morphomctry for

the years 1995, 1996 and 1997 were collected from the Dam

Superintendent, P.W.D, Tamil Nadu

ii. Data on the distribution of fishes in the lake were collected by

C, examining the catches of the fishermen at the points i b.

(Nellikampetty and Anchuruli) where they brought their catches for

sale in the year 1996, from January to December All fishes in the

catches were identified, counted and measurements of selected

species were taken at these localities. Obstervation were also made

twice a week at Nellikampetty and once at Anchuruli and the data

pooled together for annual population estimates and catch

proportion of different species.

A study of the characters of 4 selected species of fishes have been carried

out. This was based on the measurements of 50 specimens of 7i1r khrrdree

in the size range of 225 mm, to 890 mm., 50 specimens of Hy~~.~eloharbw.~

krtrali in the size range of 145 mm, to 320 mm., 50 specimens of

Cypri~~us carpio var. communis in the size range of 225 mm to 550 mm

and 50 specimens of Oreochromis mos.~ambira in the size range of 180

mm. to 230 mm.



Biological parameters such as (a) Morphometric measurements and (b)

Meristic characters were studied using the methods described by 1.owe-Mc

Connel (1971) Morphometric measurements such as ( I ) Total length (2)

Standard length (3) Head length (4) Predorsal length (5) Snout length (6)

Eye diameter (7) Post orbital length (8) Inter - orbifal width (9) Gapc (10)

Length of the barbels (1 1) Head depth (12) Body depth (13) Least height

of the body (14) Length of the caudal peduncle ( 1 5) Length of the dorsal

fin (16) Length of free margin of dorsal fin (17) Height of dorsal fin (18)

He~ght of pectroal fin (19) Height of ventral fin (20) Height of anal fin

(21) Length of the base of the anal fin and (22) Girth were takcn All

linear measurements were made to the nearest 0 I Omm , then converted to

a percentage of the standard length Mean and range were tabulated and

compared

Meristic counts were taken for the Number of rays in the dorsal fin,

pectoral fin, ventral fin, anal fin, caudal fin, lateral line scales and lateral

line transverse scales.

Mean biometric index was worked out using the method described by

Tobor (1974) for characters such as Head length, lnter - orbital width, Eye

--.\

diamter, Gape and Girth. Biometric index has been calculated to see

whether it is constant or varying with the increase in total length. For Tor

khudree, Hypselobarhus kurali and (jiprirrus carpio for each character, a


mean index for each 50.0 mm, length groups has been calculated and for

Orerrochromi.~ mossnmbica the biometric index has been calciilatcd for

each 10.0 mm length groups. Only 13 groups of Tbr, 3 groups of

Hy,t).wlobarh~rs, 6 groups of Cypri117rs carpio and 5 groups of 0reochromi.s

could be made.

(iii) Monthly collections of 4 species of the lake have been made for gut

content analysis. Two indigenous species viz., 7br klir~dree and

Hyp.seloharbrrs krtrcrli and two exotics viz., Cv1)rinlr.s carpio var.

commtrnis and Oreochromis mossnmhica were selected to study the extent

of overlap of food and the impact of exotics on native species. Regarding

Ibr, specimens were collected from the lake and from the river Periyar for

comparing its food in the two systems and thereby studying the impact of

dam on the species. For this, 50 specimens from both the sources were

collected in different months at random and their gut contents were

analysed. For the other three species also, gut contents of 50 specimens

were collected every month and analysed.

Soon after collection, the specimens were dissected, the digestive tracts

were carehlly taken out and preserved in 5% formalin. Preserved guts

were then uncoiled, cleaned off the attached tissues, cut opened and the

contents were scrapped out into a petridish. The scrapped out contents of

guts were identified under a binocular microscope as far as possible upto



generic level except in the cases where the state of digestion rendered it

difficult to do so.

(iv) The tribal fishermen settled in the reserve area were interviewed for

the socioeconomic study. Data were collected by meeting each fishermen

personally.


Documents

Studv Area and Methodsshodhganga.inflibnet.ac.in/bitstream/10603/423/11/11_chapter2.pdfStudy area and Methods in this year was ... kmz in Kerala State and 114 km2 in Tamil ... Thekkady