overview on survey design differences in …1 sc/56/ia11 overview on survey design differences in...

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SC/56/IA11

Overview on survey design differences in IDCR/SOWER between the second and the third circumpolar cruises Shigetoshi Nishiwaki Contact email: [email protected] The Institute of Cetacean Research: 4-5, Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan

ABSTRACT

This paper outlines the changes in the survey design of IWC/IDCR/SOWER cruises. Changes in the survey design between the second (CPII) and third (CPIII) circumpolar cruises was made in the 1992/93 cruise in austral summer season. The priority of the survey design in CPII considered mainly longitudinal coverage and the whole IWC management area was surveyed in a single season. On the other hand, the survey design of CPIII took precedent latitudinal coverage and consequently it took two or more season to cover the whole area. The difference in this survey design was expressed by the survey area per unit of search efforts (SPSE) in the research strata . The SPSE in CPIII become larger through each research stratum than that in CPII. The negative correlation was found between the SPSE and the density index (DI). The difference in abundance estimate between CPII and CPIII could be caused by the following two factors, 1) Northern expansion of north stratum of research area. 2) Latitudinal expansion of south stratum. In addition, yearly difference of the shape of the ice edge line could have influenced greatly the abundance estimation.

KEY WORDS: SURVEY DESIGN, IDCR/SOWER, SOUTHERN OCEAN, ANTARCTIC

MINKE WHALES

INTRODUCTION

This paper presents an overview on survey design differences in the IDCR/SOWER cruises between CPII and III. The International Whaling Commission/International Decades of Cetacean Research (IWC/IDCR; 1978/79 until 1995/96) and IWC/Southern Ocean Whale and Ecosystem Research (IWC/SOWER; since 1996/97) have been conducted in austral summer season. With the start of the SOWER programme, a blue whale research component was added, but all cruises were designed for abundance estimation of the Antarctic minke whale (Butterworth et al. 1994).

The first circumpolar serie s, hereafter CPI (i.e. all six management Areas covered longitudinally) was between 1978/79 and 1983/84, CPII was between 1984/85 and 1990/91, while CPIII was between 1991/92 and 2003/04. During the early years, there was a major change in emphasis of cruises, with a shift from whale marking to sighting surveys. Procedural modification in survey design was made in 1992/93 season. Since then the complete coverage in each 10 degree longitudinal sector between 60 oS and ice edge was aimed because this corresponded to the choice of “small areas” in the application of the Revised Management Procedure to the Antarctic minke whales (Rowlett et al .1993).

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SURVEY ITEM

Research area First and second circumpolar series One of the IWC Antarctic Management Areas (Fig.1, see Donovan, 1991) was surveyed during each cruise in CPI and CPII. In each Area, longitudinal coverage took precedence over latitudinal coverage. The northern boundary of each Area was established around 60oS-61oS in Areas IV and VI, 62oS-65oS in Areas I and III, and 58oS-59oS in Areas II and V.

Third circumpolar series During CPIII, on all cruises since the 1991/92 cruise, priority has been given to latitudinal coverage (from the ice-edge to 60oS) instead of longitudinal coverage (i.e. there was additional coverage of northern waters compared with the first and second circumpolar cruises). The aim of the modification was to estimate abundance between 60oS and the northern boundary of earlier surveys. As a consequence of this modification, the southern stratum was also expanded to the north.

Survey design The transition from CPI to CPIII by the change of the survey design was summarized in Table 1 (Matsuoka et al. 2003). A major change of survey design is the shift from whale marking to the sighting. CPI is conducted mainly as the whale marking survey, while CPII and III were conducted as the sighting survey only. The first year of CP II was spent on an experiment cruise for standardization of the sighting survey.

Although the Normal Searching Closing mode (NSC) was applied for the whale marking survey, Independent Observer Passing mode (IOP) was adopted as standard specification of the sighting survey from 1985/86 season by introduction of the second platform.

The sighting experiment was conducted in 1984/85 cruise. The difference in the position of an observer platform which was different by the type of ship might influence in the collection of sighting information data. Full-scale sighting survey was started in 1985/86. Shonan-Maru type (SM) vessel was more suitable than Toshi-Maru type (TM) vessel as standard specification, and SM vessels were used in CPII and CPIII series. As for IOP, collection of the data used for presumption of g (0) in Antarctic Ocean was adopted. NSC and Normal Sighting Passing (NSP) modes are applied the two primary observers on the top barrel. Two primary observers in IOP were stationed at the top barrel and one primary observer was an IOP barrel.

Each IWC management area was stratified into two equally east and west sectors. This stratification was continued until CPIII. The north-south stratification was made into two layers or three layers depending on the number of research vessels. It was only 1985 / 86 and 1986/87 cruises in CPII which three layers were adopted in east and west sectors (1984 / 85 cruise was conducted sighting survey on three layers only in the west sector because of sighting experiment year).

The width of southern stratum from ice to 30n.miles offing, and the northern stratum was from a northern boundary of the southern stratum to 5 degree (300n.miles) in latitude. In 1983/84 cruise, a different research range was set up. 60oS was set as the north-side boundary of the research area. The research area was stratified north and south at 65oS. The north strata were able to cover in the first half of the CPII by three sighting vessels. Then the south- stratum was set up in the range from ice to 60n.miles offing. The area from the north-side boundary of south strata to 60o S was divided further to north and south. The north one was called to north stratum and on the south one was medium stratum. Two sighting vessels were used in the CPII in 1886/87 cruise and afterwards. The research range was stratified into north and south. In South stratum was set to the range of 60 n.miles offing from ice edge. North stratum was set to the range of 5 degrees latitude from the

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north-side boundary of the south stratum. CPIII aimed into more coverage of longitude than the coverage of latitude. The full coverage of all six management areas were made around in six years in CPI and CPII, it will spend 13 years in CPIII.

Sighting survey track line in CPI was parallel to ice edge line in south stratum, and the lattice-like track line was adopted in north stratum. The zigzag track line was adopted both in the north and south strata from 1983/84 cruise. The number of sighting survey track line is set up corresponding to number of research days and the area of research area. The number of sighting survey track line in each stratum was set up more than four evenly. The lattice-like track line is only adopted in south strata in 1988/89 cruise through CPII and CPIII. In CPIII, two zigzag track lines were set up at intervals of the five degrees longitude in south strata and ten degrees longitude in north strata.

The ice-edge line from 1978/79 to 1986/87 cruises was mapped based on the visual information by survey vessel. In 1987 /88 cruises and afterwards, it was mapped based on the ice information by the satellite data.

RESULTS

The distribution of Antarctic minke whale The distribution of Antarctic minke whales with survey track-lines in each Area was shown in Figure 5.In Area I, the ice edge line of CPII was located in more south than that of CPIII. The difference was remarkable in west sector. In east sector, ice edge line turned north in eastern sector by Antarctic Peninsula. The northern part of south strata in CPIII overlaps the southern part of north strata in CPII. The difference in the position of the ice edge line between CPII and CPIII has influenced greatly the distribution of Antarctic minke whales in research area.

In Area II, shape of ice edge line differs remarkably between CPII and CPIII. The difference in the shape is remarkable in the western sector. On the eastern sector, south strata in CPIII overlap with north strata in CPII. A sighting distribution of the minke whale in the southern stratum has depended on the difference in shape of ice edge line. The shape and size of the survey area in north strata differ greatly each other in CPII and III. These differences reflected into a difference in sighting distribution of minke whale.

The positions of the ice edge line in Area III differed greatly between CPII and CPIII. For this reason, the covered area of the western sector in the research area differs remarkably. The south strata in CPIII overlap north strata in CPII completely. These differences reflected into a difference in sighting distribution of minke whale.

In Area IV, the southern stratum in CPIII overlaps the northern stratum in CPII. The south strata in CPII were surveyed under the lattice-like track line. A sighting distribution of a minke whale is concentrated on the south portion of track line in southern stratum, and there is almost no sighting on the north portion of track line. These differences reflected into a difference in sighting distribution of minke whale.

As for the research area of Area V, the position of ice edge line has jutted out in CPIII compared with CPII. As for the southern stratum of eastern sector, the research area is remarkably narrow. The southern stratum of the western sector in CPIII overlaps the northern stratum of that in CPII. These differences reflected into a difference in sighting distribution of minke whale.

In Area VI, there is no significant difference in the position of ice edge line and the range of the research area between CPII and CPIII. There is no substantial difference in the sighting distribution of a minke whale between CPII and CPIII.

Survey area (n.miles2) The size of survey area (n.miles) for every circumpolar and research stratum in six Antarctic management Areas were shown in Figure3 (Branch and Butterworth, 2001). When CPIII is

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compared with CPII, the size of survey areas increased in Areas I, II, III, and V. Conversely, Areas IV and V were decreased. As for the Areas IV and V, the part of un-surveyed area is not included. Each research stratum of CPIII has expanded than that of CPII with change of a survey design. Survey area per unit of search efforts (SPSE) The survey area per unit of search efforts (SPSE) in each research area was shown in Figure 4. The Area I show that the value of CPIII is large in north and south strata. The Area II showed the high value except for the north-west stratum in each stratum of CPIII. The north-west stratum of CPII showed the highest value through all IDCR/SOWER cruises. There is no conspicuous difference SPSE between CPII and CPIII in Areas III, IV, V and VI Areas.

Relation between a density index (DI) and SPSE Relation between DI and SPSE in each research area were shown in Figure 5(Branch and Butterworth 2001). The DI in Area I showed smaller value in CPIII than CPII. As For the SPSE, CPIII was larger value than CPII.

As for DI in Area II, CPIII showed lower value than CPII except for north-west stratum. As for SPSE, CPIII showed larger value than CPII except for north-west stratum.

The DI and the SPSE is not different between CPII and CPIII in the Area III. The estimated mean school size (E(S)) showed the larger value in CPII than CPIII. This might be caused by the difference in the ice edge line between CPII and CPIII.

The SPSE in the Area IV does not have a difference between CPII and CPIII. As for the DI and the E(S), CPII showed the value higher than CPIII by south strata. This was caused by the difference in the design of track line between CPII and CPIII.

About the Area V, the opposite correlation in the SPSE and the DI is shown between CPII and CPIII. As for the difference in the E(S), position and its shape in the ice edge line might be influenced.

The DI and SPSE is no conspicuous difference between CPII and CPII in the Area VI. The E(S) showed the larger value at CPII than CPIII. This has suggested the influence by the difference in the ice edge line between CPII and CPIII.

DISCUSSION

The change in the survey design between CPII and CPIII cruises was made in the 1992/93 season. A survey design of CPII took precedence the coverage of longitude and surveyed one area in a single season. On the other hand, the survey design of CPIII took precedent latitudinal coverage and consequently it took two or more years. The difference in this survey design was expressed by the SPSE in the research strata. The SPSE in CPIII was suggested to become large through each sub research area than that of CPII. The negative correlation was shown between the DI and SPSE. It confirmed that the northern strata of CPII overlapped to the southern strata of CPIII. The survey design changes of CPIII brought a result which increased survey coverage at lower latitudes in the northern strata where most minke whales are solitary and the sea state trends to be worse. This has suggested that g(0) is changing between CPII and CPIII (Murase et al, 2004 in-prep.).

Further, the ice edge position of CPII located more south rather than CPIII and it might bring a result lower DI in the southern strata in CPIII. Such difference of ice edge position might influence also DI in the northern strata and E(S) in the southern strata in CPIII. The difference in abundance estimate between CPII and CPIII suggests the following two points as a factor related to a survey design, 1) Northern expansion of north stratum of research area. 2) Latitudinal expansion of south stratum. These two factors brought decrease in abundance estimate from CPII to CPIII.

It is concluded that direct comparisons of abundance estimates between CPII and CPIII are difficult. Further analyses are required to remove effect of survey design changes between CPII and CPIII. Whether such differences in survey design affect on abundance estimate can be

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investigated by simulation studies.

REFFERNCE

Branch, T. A. and Butterworth, D. S. 2001.Southern Hemisphere minke whales: standardized abundance estimates from 1978/79 to 1997/98 IDCR/SOWER surveys. J. Cetacean Res. Manage. 3(2):143-74.

Butterworth, D. S. Borchers, D. L., Chalis, S., De Decker, J.B. and Kasamatsu, F. 1994. Estimates

of abundance for Southern Hemisphere blue, fin, sei, humpback, sperm, killer and pilot whales from 1978/79 to 1990/91 IWC/IDCR sighting survey cruises, with extrapolations to the area south of 30S for the first five species based on Japanese scouting vessel data. Paper SC/46/SH24 presented to the IWC Scientific Committee, May 1994 (unpublished). 129pp. [Paper available from the Office of Journal].

Donovan, G. P. 1991. A review of IWC stock boundaries. Rep. int. whal. Commn (special issue)

13:39-68.

Matsuoka, K., Ensor, P. , Hakamada, T., Shimada, H., Nishiwaki, S., Kasamatsu, F. and Kato, H. 2003. Overview of minke whale sighting surveys conducted on IWC/IDCR and SOWER Antarctic cruises from 1978/79 to 2000/01. J. Cetacean Res. Manage. 5(2):173-201.

Murase, H., Matsuoka, K., Nishiwaki, S., Hakamada, H. and Mori, M. 2004. Effect of observed

covariates (school size, sighting cue, latitude and sea state) on the Antarctic minke whale abundance estimation parameters in the IWC/IDCR-SOWER surveys. J. Cetacean Res. Manage. (in-prep.) .

Rowlett, R. A., Nishiwaki, S., Abernethy R. B., Desportes, G., Findlay, K. P., Kira, M., Owada, A.

and Shimada, H. 1993. 1992-93 IWC/IDCR Southern Hemisphere Minke Whale Assessment Cruise, Area III (00E-40E) “The NEXT GENERATION”. Paper SC/45/SHBa5 presented to the IWC Scientific Committee, May 1993 (unpublished). 32pp.

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Table 1. The transition from CPI to CPIII by the change of the survey design（Data are quoted from Matsuoka et al 2003）

Circumpolar ＣＰⅢ

Year 1978/79－1982/83 1983/84 1984/85 1985/86・1986/87 1987/88 1988/89 1989/90-1990/91 1991/92-

Research activity Marking > Sighting Sighting > Marking Sighting = Experiment Sighting Sighting Sighting Sighting Sighting

Vessel Toshi-Maru type:Twovessels

Toshi-Maru type: onevessel, Shonan-Maru

type: Two vessels


type: Two vessels


type: Two vessels

Shonan-Maru type:Two vessels




Sighting survey mode NSC>NSP NSC>NSP NSC=NSP NSC=IOP NSC=IOP NSC=IOP NSC=IOP NSC=IOP

Stratum of researcharea

Research area wasdivided two sectors,by the middle positionin the longitudinalrange. These sectorswere further dividedtwo strata inlatitudinal range.


Research area wasdivided two sectors,by the middle positionin the longitudinalrange. The part ofwestern sector wasfurther divided threestrata in latitudinalrange.

Research area wasdivided three sectors,by the middle positionin the longitudinalrange. These sectorswere further dividedtwo strata inlatitudinal range.




The research areawas divided two stratain latitudinal range.

Range of research area

East and Westsectors: 30 digrees inrange of longitude.Southern stratum: onthe ice-edge and onthe locus from the 30n.miles from ice-edge.Northern stratum: onthe 30 n.miles fromice-edge and on thelocus from 65Slatitude line.

East and Westsectors: 35 digrees inrange of longitude.Southern stratum: onthe ice-edge and onthe locus from 65Slatitude line. Northernstratum: on the locusfrom 65S latitude lineand 60S latitude line.

East and Westsectors: 30 digrees inrange of longitude.Southern stratum: onthe ice-edge and onthe locus from the 60n.miles from ice-edge.Northern stratum:these were divided inmideum range oflatitude between onthe 60 n.miles fromice-edge and on thelocus from 60Slatitude.

East and Westsectors: 30 digrees inrange of longitude.Southern stratum: onthe ice-edge and onthe locus from the 60n.miles from ice-edge.Northern stratum:these were divided inmideum range oflatitude between onthe 60 n.miles fromice-edge and on thelocus from 60Slatitude.

East and Westsectors: 35 digrees inrange of longitude.Southern stratum: onthe ice-edge and onthe locus from the 60n.miles from ice-edge.Northern stratum: onthe 60 n.miles fromice-edge and on thelocus from 65Slatitude line.



Each 10 degreelongitudinal sectorwith inter stratumboundary establishedon fixed latitudinalline.

Track-line

Soutern stratum:wriggle line along iceedge. Northenstratum: lattice shapeline

Southern and Norternstrata: zig-zag line







Ice edge lineThe ice edge wasmapped by thesoutern survey vessel.

The ice edge wasmapped by thesoutern survey vessel.



Estimaton of theposition of the ice-edge from sateralliteinformation.




ＣＰⅠ ＣＰⅡ

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Figure1. The IWC Antarctic Areas for the management of baleen whale species

Figure2-a. The sighting distribution of Antarctic minke whales with survey track-lines in Area I (Left:

CPII. Right: CPIII)

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Figure2-ｂ. The sighting distribution of Antarctic minke whales with survey track-lines in Area II (Upper: CPII. Lower left: Western sector in CPIII. Lower right: Eastern sector in CPIII)

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Figure2-ｃ. The sighting distribution of Antarctic minke whales with survey track-lines in Area III

(Upper: CPII. Lower left: Western sector in CPIII. Lower right: Eastern sector in CPIII)

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Figure2-d. The sighting distribution of Antarctic minke whales with survey track-lines in Area IV

(Upper: CPII. Lower: CPIII)

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Figure2-e. The sighting distribution of Antarctic minke whales with survey track-lines in Area V

(Upper: CPII. Lower: CPIII)

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Figure2-ｄ. The sighting distribution of Antarctic minke whales with survey track-lines in Area VI

(Upper: CPII. Middle: Eastern sector in CPIII. Lower: Western sector in CPIII)

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Area I

0

50000

100000

150000

200000

250000

300000

350000

CPI CPII CPIII

Are

a(n.

mile

s2)

ＳＥ

ＮＷ

ＳＥ

ＳＷ

Area II

0

50000

100000

150000

200000

250000

300000

350000

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CPI CPII CPIII

Are

a(n.

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s2)

ＮＥ

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ＳＥ

ＳＷ

Area III

0

50000

100000

150000

200000

250000

300000

350000

400000

CPI CPII CPIII

Are

a(n.

mile

s2)

NE

NW

SE

SW

Area IV

0

50000

100000

150000

200000

250000

CPI CPII CPIII

Are

a(n.

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s)

ＮＥ

ＮＷＳＥ

ＳＷ

Area V

0

50000

100000

150000

200000

250000

300000

350000

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450000

500000

CPI CPII CPIII

Are

a(n.

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s2)

ＮＥ

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Area VI

0

50000

100000

150000

200000

250000

300000

350000

400000

CPI CPII CPIII

Are

a(n.

mile

s2)

ＮＥ

ＮＷ

ＳＥ

ＳＷ

Figure3. The survey area (n.miles2) in Antarctic Areas for the management of baleen whale species (Data are quoted from Branch and Butterworth 2001)

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Area I

142131

186

115

145

222

3645

68

1831

47

0

50

100

150

200

250

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Area II

83103

206

127

320

208

2541

56

3448

73

0

50

100

150

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250

300

350

CPI CPII CPIII

A/L

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iles2

)

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Area III

83

155

142

100

182189

31

79

62

35

60

32

0

20

40

60

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100

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CPI CPII CPIII

A/L

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iles)

NE

NW

SE

SW

Area IV

73

162

149

77

109

165

19

95

83

30

105

50

0

20

40

60

80

100

120

140

160

180

CPI CPII CPIII

A/L

(n.m

iles)

NE

NW

SE

SW

Area V237

150164

121

170

210

38

7262

49

7380

0

50

100

150

200

250

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Area VI

222

254

155

237

203216

145

114

53

120

4859

0

50

100

150

200

250

300

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Figure 4. The Coverage Survey area per amount of search Efforts (CSE) in each research area (Data are quoted from Branch and Butterworth 2001)

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Area I

142131

186

115

145

222

3645

68

1831

47

0

50

100

150

200

250

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Area II

83103

206

127

320

208

2541

56

3448

73

0

50

100

150

200

250

300

350

CPI CPII CPIII

A/L

(n.m

iles2

)

ＮＥ

ＮＷ

ＳＥ

ＳＷ

Area I

5.6 5.30.5

3.8 3.4 1.0

34.7

14.2 14.7

122.9

42.3

15.3

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

CPI CPII CPIII

n/A

*100

00

NE

NW

SE

SW

Area II

3.8

11.2

1.21.4 0.2 1.4

57.2

26.9

9.8

23.020.1

9.9

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

CPI CPII CPIII

n/A

*100

00

NE

NW

SE

SW

Area I

20.09.4

0.86.2 7.7

1.6

89.1

25.5 24.5

204.0

113.1

25.6

0.0

50.0

100.0

150.0

200.0

250.0

CPI CPII CPIII

Ssc

*n/A

*100

00

NE

NW

SE

SW

Area II

6.2

24.9

2.02.9 0.4 1.6

118.9

75.9

18.2

62.056.7

25.9

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

CPI CPII CPIII

Ssc

*n/A

*100

00

NE

NW

SE

SW

Figure 5-a. Relation between DI and CSE in Areas I and II (Data are quoted from Branch and

Butterworth 2001).

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Area III

83

155

142

100

182189

31

79

62

35

60

32

0

20

40

60

80

100

120

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CPI CPII CPIII

A/L

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iles)

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NW

SE

SW

Area IV

73

162

149

77

109

165

19

95

83

30

105

50

0

20

40

60

80

100

120

140

160

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CPI CPII CPIII

A/L

(n.m

iles)

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NW

SE

SW

Area III

2.60.7 1.5

2.6 2.4 1.6

39.8

4.4

9.6

41.1

27.3

30.4

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

CPI CPII CPIII

n/A

*100

00

NE

NW

SE

SW

Area IV

4.31.3 1.4

3.90.9 2.2

60.6

13.4

6.1

36.0

14.3

6.8

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

CPI CPII CPIII

n/A

*100

00 NE

NW

SE

SW

Area III

8.42.8 1.6

6.2 9.62.0

96.7

24.8 25.0

129.5

153.6

75.1

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

CPI CPII CPIII

Ssc

*n/A

*100

00

NE

NW

SE

SW

Area IV

11.9 5.6 1.810.7 3.7 2.7

356.8

48.3

7.8

101.2

51.5

8.6

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

CPI CPII CPIII

Ssc

*n/A

*100

00

NE

NW

SE

SW

Figure 5-b. Relation between DI and CSE in Areas III and IV (Data are quoted from Branch and

Butterworth 2001).

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Area V237

150

164

121

170

210

38

7262

49

7380

0

50

100

150

200

250

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Area VI

222

254

155

237

203216

145

114

53

120

4859

0

50

100

150

200

250

300

CPI CPII CPIII

A/L

(n.m

iles2

)

NE

NW

SE

SW

Area V

3.7

8.1

11.5

3.14.4

0.9

35.2

29.3

15.3

21.7

14.7

23.1

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

CPI CPII CPIII

n/A

*100

00

NE

NW

SE

SW

Area VI

0.91.5 1.7

2.4

0.8

1.9

3.0

5.4 5.5

4.5

9.3

10.2

0.0

2.0

4.0

6.0

8.0

10.0

12.0

CPI CPII CPIII

n/A

*100

00

NE

NW

SE

SW

Area V

7.0

25.8 29.1

7.8 8.42.4

118.1

90.4

22.0

73.9

52.1

33.2

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

CPI CPII CPIII

Ssc

*n/A

*100

00

SE

SW

SE

SW

Area VI

2.13.0

2.1

5.1

1.6

4.64.5

16.8

6.9

9.9

28.6

19.1

0.0

5.0

10.0

15.0

20.0

25.0

30.0

CPI CPII CPIII

Ssc

*n/A

*100

00

NE

NW

SE

SW

Figure 5-c. Relation between DI and CSE in Areas V and VI (Data are quoted from Branch and

Butterworth 2001).

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