NUSH Otters

photo credits here

By Lim Yi He

To help boost local biodiversity, NUSH Otters is a VIA group dedicated to cleaning up Pandan Mangrove, a small but diverse mangrove located in south-western Singapore at the mouth of the Sungei Pandan. Due to its proximity to industrial areas and human activities, there is a constant source of trash coming into the mangrove.

On 2nd July, the NUSH Otters team consisting of 23 people embarked to Pandan Mangrove for the second clean-up of the year. Armed with tongs and rubbish bags, we ventured into the mangrove in search of trash.

Litter was scattered throughout the mangrove; it seemed that we had our work cut out for us indeed.

Mangroves host a multitude of unique organisms as well, such as lobsters, mudskippers, gastropods and bivalves. During the trip, we were very lucky to have encountered various organisms including some horseshoe crabs and face-banded sesarmine crabs.

Horseshoe crab numbers are dwindling due to fishing and loss of habitat, but we managed to spot two of them beneath a tree root. These ancient creatures are often seen in pairs, with the smaller male resting on top and behind the larger female. They can exist in mangroves or coastal areas, sometimes half-buried in mud or sand to remain inconspicuous.  

Face-banded sesarmine crabs are easily identified by their brightly coloured facial bands. They feed on mangrove leaves, animal and plant matter, therefore playing an important role in the mangroves by recycling the nutrients. The one pictured here has dark-coloured third maxillipeds (one of the mouthparts), which identify it as Perisesarma eumolpe.

The mangrove trees at Pandan Mangrove are mostly Bruguiera gymnorrhiza, also known as Tumu Merah due to the vivid red colour of the flowers. Quite common in Singapore, they are usually found in mud or dry, well-aerated soil with freshwater. Mangrove trees carry out vivipary – the seed within the fruit starts to germinate while it is still on the mother tree.

Mangrove forest cover has been reduced to only 0.5% of the total land area. Yet people are still causing damage to them, many unaware of the presence of wildlife there. For this clean-up, we have collected a total of 94.75kg of trash in merely two hours. That’s 16.44kg more than what was collected in May 11. We found also a rusted metal tyre and a piece of metal as long as my arm.

It is disheartening to see such callous treatment to our country’s mangroves.

The next clean-ups will be on September 3 and November 12. NUSH Otters are going to recruit new volunteers soon to aid in our cause – both staff and students can keep an eye out and join us in our next quest to vanquish trash from the mangroves!

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