Horseshoe Crabs of Kranji

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

Friday, June 11, 2004

A finale

Visit my website: Fiona's Mangrove Haven for the full report and other information.

Despite the bloopers throughout this study, I did not fail this module. So it is true that UROPs is a good place for beginners like me to make a headstart into research, whether it is to prepare ourselves for honours or masters, or just to find out if research is the field for us.

I have learnt tremendously through this project, especially from Siva and Yenling, and of course the horseshoe crabs. And so here I'll like to highly recommend UROPs to NUS science students who would like to give research a try. If you would like to know more about personal experiences whatsoever, please feel free to email me at my singnet account: hong0655

In the mean time, get muddy and wet!

Where are the eggs stored?

A few days ago, I chanced upon a Taiwanese documentary on cable (channel 52 if I'm not wrong). Unfortunately, I only caught the last 15 minutes.

The documentary was on the captive breeding of Tachypleus (not entirely sure of species; probably T. tridentatus). Males and females were caught and checked regularly for presence of gravid in the females. The interesting thing that I saw, was that the eggs are actually located in a sort of storage sac near the book gills and a gentle squeeze at the opening releases the eggs. Previously, I thought that gravid was stored near the anterior of the prosoma/shell.

This may mean that females I thought to be 'non-gravid' may posibly have been fertile and eeven ready for spawning! This is definitely a question to be answered in future field trips.

During the last sampling trip on 25th March 2004, I encountered this dead female, with eggs seemingly spilling out from around its book gills.



Back to the documentary - the scientists brought the males and gravid females to the beach and released them (temporarily) for pairing and spawning. After that the horseshoe crabs were picked up again and returned to the lab.

A Brief Recap

After the last sampling trip on the 25th of March, both Yenling and I began working on our final report to be submitted to the department. The sections in the report, like most scientific journals include a short Abstract, Introduction, Methodology, Results, Discussion, Conclusion and of course Appendix. It was also during that time, that I realised I had more loose ends to tie than I expected. Loopholes in results, missing data, and improper sampling techniques made the analysis of results tedious.

Eventually, the conclusions that could be made from my study are:
1. Juveniles (<60mm) can be found in high numbers in specific micro-habitats (flat mudbanks of streams imperforated with small pools and shallow streamlets).
2. Horseshoe crabs >60mm may bury themselves fully in mud
3. January to March is either not the mating season, or there is no season at all.
4. Mudflats are an important area to look into next due to presence of fully buried horseshoe crabs

The night before the submission of the report, all three of us (Yenling, Siva and me) skipped our night's rest to rush out it out. On top of the full report, we also had to submit a 4 page abstract for the department's record. To add on to the stress, I also had a language oral exam on the day of submission. It is definitely an experience not to be forgotten.