Some aspects on the habitat

of Tachypleus gigas

in Malaysia

Annie Christianus and Che Roos Saad

Department of Aquaculture, Faculty of Agriculture,

Universiti Putra Malaysia, 43400 Serdang, Selangor,

Malaysia

annie@putra.upm.edu.my

•Introduction

•Importance of the study

•Methodology

Site selection

Data collection

•Results

•Discussions

•Conclusion

Outlines

T. tridentatus, T. gigas, C. rotundicauda

& L. polyphemus - similar spawning

habitat, sandy beach

Introduction

Lost of spawning ground

Due to many factors:

-development of coastal areas (hotel, resort)

-anthropogenic activities (beach & water sports)

-aquaculture

-pollution

Importance of the study

Coastal developments & Human activities

Coastal developments & Human activities

Coastal developments & Human activities

Coastal developments & Human activities

Concrete walls

Receding coastal areas- due to erosion, water

level rise

Identification of sites for samples collection:

~Existing spawning sites:

i. Sitiawan

ii. Pantai Balok

iii. Seri Menanti

iv. Minyak Beku

Methodology

Sites Selection ►

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Parameters measured:

i. Water (at the sites)~ pH, DO,

temperature, salinity

ii. Sand/soil samples~ temperature, pH,

EC, minerals, particles size

Methodology

Results

i. Water Parameters (at the sites):

pH ~ 6.7- 7.8

DO ~ 4.3- 7.9 ppm

Temperature ~ 28- 31.9ºC

Salinity ~ 20- 32 ppt

Results

ii. Sand/soil samples:

Temperature ~ 29-35ºC

pH ~ 7.40- 8.15

EC ~ 561-1894 µS/cm

Minerals

N ~ 0.03-0.08

P ~ 33.3- 53.4

K ~ 31.4- 57.5

Ca ~ 160- 6804

Mg ~ 74- 152 (Unit µg/g)

Na ~ 302- 982

Fe ~ 12.9- 281.1

Cu ~ 1.74- 2.72

Zn ~ 1.38- 4.56

Mn ~ 4.85- 9.60

Results

Types of sand/soil:

Clay (<2 µm) ~ 0-1.8%

Silt (2-50 µm) ~ 0.5-22.7%

Sand (>50 µm) ~ 77.1-99.3%

Sand/soil types

Results

Particles size for sand:

Fine sand (100-250 µm) ~ 4-30%

Medium sand (250-500 µm) ~ 21-25%

Coarse sand (>500 µm) ~ 48-68%

These data provide characteristics – useful as

guidelines for the:

i. Establishment of artificial spawning ground

for T. gigas in Malaysia

ii. For the sand/soil characteristics suitable for

artificial incubation of T. gigas eggs

Discussion

Important characteristics of sand/soil for

spawning site and eggs incubation:

Sand size & percentage: Medium-coarse

sand (at least >250 m)

Incubation temperature ~ 29-35ºC

Expose to water salinity ~ 20-32 ppt

Sand/soil pH ~ 7.40- 8.15

Conclusion

Incubation of T. gigas eggs in sand

Laboratory incubation of horseshoe crab eggs

using sand as media

On-going study

-Compare the incubation period of T. gigas eggs when incubated

in sand (solid medium) and in water (liquid medium)

On-going study

►Universiti Putra Malaysia

► Organizing Committee for International

Workshop on the Science & Conservation of

Asian Horseshoe Crabs

Acknowledgement

Thank you….!!!