Table 1 Morphological characteristics of specimens used in the present study.

A. bicolor bicolor

Temurun, Langkawi Islands, Kedah*

female

1

732

805

II

Ayer Hitam, Kedah

all

13

638 ± 48.5

568–705

557 ± 145

362–824

female

12

639 ± 50.6

568–705

558 ± 152

362–824

II–IV

unknown

1

626

553

Kampung Permatang Bongor, Penang

female

1

625

425

II

Penang Island, Penang**

all

392

441 ± 133

203–810

195 ± 182

9.8–1270

(12 sites)

female

279

492 ± 118

219–810

252 ± 187

17.3–1270

I–V

male

23

346 ± 71.4

215–558

74.9 ± 37.1

13.6–154

I–III

unknown

90

290 ± 54.3

203–518

39.7 ± 28.8

9.8–177

Hujung Rintis, Perak

female

1

679

571

(downstream, estuary, tidal zone)

A. bengalensis bengalensis

Temurun, Langkawi Islands, Kedah*

unknown

2

462–492

155–205

Penang Island, Penang**

all

42

594 ± 142

357–920

484 ± 459

51.8–2340

(8 sites)

female

23

691 ± 107

487–920

722 ± 500

257–2340

I–V

male

6

467 ± 66.3

357–557

160 ± 99.2

51.8–313

I–II

unknown

13

481 ± 80.0

375–610

212 ± 121

65.8–445

Kuala Kangsar, Perak

female

10

983 ± 130

830–1295

2110 ± 972

1001–4400

II–V

(upstream, non tidal effects)

A. marmorata

Penang Island, Penang

female

1

904

2335

IV

(midstream, non tidal effects)