11 March 2012

Sexy stars but sad seagrasses on Cyrene

How nice to see Knobbly sea stars in spawning position today at Cyrene!
I was out with a large contingent of TeamSeagrass volunteers for seagrass monitoring and to help Siti with her seagrass experiment there.

Here's another Knobbly sea star on tip toes! I first observed this behaviour, also on Cyrene, in Aug 2011.
Knobbly sea stars (Protoreaster nodosus) are quite abundant on Cyrene Reef, where we also often see many juvenile Knobblies. Indeed, according to the Star Trackers, "the presence of juveniles, subadults and adults indicated that there is a healthy level of recruitment at Cyrene Reef. This habitat may be the only sustainable population of knobbly seastars left in Singapore today".
Chris Mah shared more about this behaviour on his awesome Echinoblog post Starfish Standing on their Tippy Toes: The Strangeness of Spawning! From his Echinoblog, I learnt that this posture is believed to be a part of the sea star spawning, BUT we don't really know much about this behaviour! I also learnt that some sea stars spawn 'flat', without standing on their toes. And in some species, different individuals take on different spawning postures. Chris Mah in fact lists quite a lot of questions regarding this behaviour that still needs further study! So much more to discover about our shores!

Joining us today is Kristine White, an amphipod expert. And she has found many of her favourite critters on Cyrene! Hurray! Kristine is here with for Singapore's First Marine Biodiversity Expedition which just ended on Friday.
Sadly, the seagrasses on Cyrene have not improved much. We saw many patches of bleached and burnt seagrasses. Most of the large strap-like seagrasses were affected especially Tape seagrass (Enhalus acoroides) and Sickle seagrass (Thalassia hemprichii). The Noodle seagrass (Syringodium isoetifolium) and Spoon seagrasses (Halophila ovalis) that we saw were alright, and Needle seagrasses (Halodule sp.) less affected. But overall seagrass coverage and the variety of seagrasses seen remains good
These were the 'tallest' Tape seagrasses that I came across. Sigh. It's rather sad that this situation of cropped Tape seagrasses has not show signs of improvement since it was first observed in Nov 2010.
The big pool which used to be full of long lush Tape seagrass remains bare of Tape seagrasses. But other seagrass species are growing on the sandy bottom. More about the seagrass situation today on the TeamSeagrass blog.
Another sad encounter, a small fish trap on Site 2. It was weighed down with small rocks.
There were three large Stone crabs (Myomenippe hardwickii) in them.
I released the crabs and we removed the trap. Some of those monitoring Site 1 saw people laying huge fish traps on the reefy southern edge of Cyrene. Sigh. This is another job for Project Driftnet.
Nor Aishah and Wei Ling also said that they encountered films of oil on their Site 1 while monitoring the seagrasses there.

There's so much more to learn and do for our shores!


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