The Urgency for Conservation of Tachypleus gigas at Disturbed Breeding Beaches on the East Coast of

Peninsular Malaysia

Bryan Raveen Nelson Institute of Tropical Aquaculture, Universiti Malaysia

Terengganu

brav_11@hotmail.com

About Malaysia

Food

Horseshoe crab diversity

Chatterji et al., 1992, Sekiguchi and Nakamura, 1979

Size

Horseshoe crab sightings in Malaysia

123

4

5

6789

101113

12

14

1516

-Tt-Tt

-Tg-Tg

-Tg

-Tg

-Cr

-Tg-Tg & -Cr

-Tg

-Tg-Tg & -Cr

-Tg & -Cr-Tg

-Tg-Tg & -Cr

NN

Tachypleus gigas of Malaysia

Male

Female

Day 2 egg

Horseshoe crab embryogenesis (T. gigas)

Chatterji, 1994

1 3 5

34

3127

13 187

38 43

22

Nelson et al., 2012

*Numbers represent days*Alphabet represent stage

Ecological pressure during embryogenesis

T. gigas nesting sites on east coast of Peninsular Malaysia

Case Study #1: Pantai Balok

Pantai Balok (Abundance of T. gigas (M+F) and nests)

Precipitation, decreased salinity

Sheltered area

Before severe human intervention

Highest tides

Recovery from intervention

Situation at Pantai Balok

Before disturbance: 2009-2010 After disturbance: 2011-2013

Situation at Pantai Balok (Con’t)

Dry Monsoon

Wet Monsoon

Nest Shifting: Pantai Balok

Case Study #2: Tanjung Selangor

Tanjung Selangor (Abundance of T. gigas (M+F) and nests)

Precipitation,

decreased salinity Sheltered area

Before severe human intervention

Situation at Tanjung Selangor

Before disturbance: 2009 After disturbance: 2010-2011

Situation at Tanjung Selangor (Con’t)

Dry Monsoon

Wet Monsoon

>Moisture Depth

<Moisture Depth

Nest Shifting: Tanjung Selangor

*Key= human impacts

S1-3 = Study sites

It's easier to dump trash here and there !

Unregulated waste

management

Fishing and boating

activities

However,

Compromised embryogenesis

Aspergilus sp. Streptococcus sp. (30 %) in+exBacillus sp. (20 %) exVibrio sp. (15 %) in+exMyxobacter (15 %) ex

Staphylococcus sp. (10 %) ex

Shigella sp. (10 %) in+ex

*Key: in = yolk plasmaex = embryonic shell

1st instar impairments (in situ)

Conservation efforts

Conservation challenges

‘Protected area’

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We are harmless. Why hurt us ???