Horseshoe Crabs of Kranji

The trials and tribulations of an undergraduate research project on mangrove horseshoe crabs.

Saturday, January 31, 2004

Sampling techniques

Methods using and data recording

1. Main areas with possible sightings:
-Mudflats beside bund
-Main Stream
-Mudflats in front of KR3

--> Will further qualify location through better understanding of prefered areas by the horseshoe crabs after next field trip.

2. Data recording
a) Species: Tachypleus gigas or Carcinoscopius rotundicauda
-T. gigas has an edgy telson (triangular in transverse cross section) while C. rotundicauda has a rounded telson (circular in transverse cross section)

b) Stage class: Adult or Juvenile
- Chela breaks off in adult males after first mating (have to see how the real chela looks like !!)
- Juveniles have no mating scars on carapace

c) Sex
- Males have claspers meant for holding on to females during mating (have to learn how to identify claspers too!!)

d) Body measurements: using measuring tape (recording by centimetres)
- Intra-ocular length
- Maximum width of prosoma
- Length of telson

e) Location and remarks
- sites have to be further divided and named
- substrate type: Sandy, clayey or silty soils
- others: eg. at the edge of water, on the banks, buried half in mud

f) Tagging
- going to try using liquid paper
- Marking at top right hand corner of prosoma, using specific markings (eg. circle, stroke, number) by location

Wednesday, January 07, 2004

Our first recce - tidal height calibration

On our first recce on 22nd Dec at Kranji Nature Trial had a primary objective of checking out what a suitable working tide would be. Subsequently, we can then plan the rest of our field-trips.

The tide looked high that afternoon and the tide table (for Sembawang) read 1.0m. At the end of the day, we decided that a suitable tide would be anything less or equal to 0.6m.
However, later on Siva commented that the tide table may not reflect well (because its for Sembawang not Kranji mangroves). We had to calibrate the tidal heights accordingly. Eventually we reset the minimum workable tide to 1.0m.

Friday, January 02, 2004

Lesson 1

Get the aim of the project, as well as your supervisor's 'demands' right first.

Secondly, head off to begin your literature search (click on link to check out yenling's blog for details). This is a preliminary search and thus should be as wide as possible (but still related to your topic).

Thirdly, get your tide tables. Depending on the nature of your research, either high tides or low tides are required for your field-trips (this can be found out from the literatures obtained).

Last but not least for lesson 1, is setting up a blog for the project. Findings, progress or other related materials can then be put up via blog for easy access (especially to Siva). The blog can also serve as reference for others to come.

Watch out for coming posts of 'WHAT A UROPS STUDENT (under Siva) WILL NEED TO KNOW'