On 13th June, we were back in P. Semakau for a transect survey. While we are permanently assigned for the seagrass transect (at least for the past year), my partner-in-crime was missing in action that day. Replacing her were 2 other GVs, EF and CY, who were first timers at seagrass transect.
We were initially fearful of a wasted trip as it started to rain the moment we arrived at the NEA office. Thankfully the rain didnt last long, and we could start the survey as planned. On our walk to the starting point, we were even greeted by a beautiful rainbow.
We were initially fearful of a wasted trip as it started to rain the moment we arrived at the NEA office. Thankfully the rain didnt last long, and we could start the survey as planned. On our walk to the starting point, we were even greeted by a beautiful rainbow.
As the 2 GVs were unfamiliar with seagrass survey, I walked them through the to-do list (to the best of my knowledge), while on the way to our assigned transect column.
Heres a brief outline of what we typically do:
1. With the shoreline on our right, we first measure the depth of water at our start point (marked beforehand) before laying the measuring tape (as straight as we can) for 30+m.
2. On our data recording sheet, distances where we should place a quadrat (a measured and marked square, in our case, the quadrat consists of 25 squares) are specified.
Heres a brief outline of what we typically do:
1. With the shoreline on our right, we first measure the depth of water at our start point (marked beforehand) before laying the measuring tape (as straight as we can) for 30+m.
2. On our data recording sheet, distances where we should place a quadrat (a measured and marked square, in our case, the quadrat consists of 25 squares) are specified.
3. We then place the quadrat at the respective specified distance and
a) identify the species of seagrass &
b) count+estimate the percentage of each species in that area of the quadrat.
4. The next task is to estimate the percentage of epiphyte on the seagrass (see the brown stuff growing on the green seagrass in photo below).
5. We also randomly pick 3 blades of leaves to measure its length.
6. Other plants (such as algae) or animals must also be recorded.
7. (although not quite part of the survey) Washing the equipment esp the measuring tape with clean water is a MUST, and is usually the most tedious task
If you ask me whats most challenging, identification of the species beats everything else, hands down. I remember how traumatic my first experience was, because all the species looked the same to me! No matter how hard we tried, we only seemed to be able to identify the tape seagrass, and we also took a long time to complete the tasks. Even recording the data was difficult, back then.
With practice, I'm sure we have improved in speed, and hopefully in accuracy of data too.
Heres what my team identified during the survey:
1) Tape Seagrass (Enhalus Acoroides): This is relatively easier to identify because of its long ribbon-like leafs. Feeling the sides of the leaves, you will also find that the leaf margins are in-rolled. The rhizomes of this species are thick with long black bristles. This time round, we even saw the spiky Enalus fruit (unfortunately, i was too busy to take a photo)!
2) Cymodocea serrulata: This seagrass may appear quite similar to the tape seagrass, but it has a serrated leaf edge, if you look carefully. A clear distinction is its smooth (and white?) rhizome (yes, in order for us to check this, we have to dig and feel the rhizome):
3) The last species (and my first time seeing it) is the Sryingodium isoetifolium. This is not too difficult though, as its cylindrical and hollow leaves are quite distinct, clearly different from the tape seagrass.
Apparently we should be able to see the spoon seagrass in our area as well. I gues we were not looking hard enough, or waiting long enough for the murky water to clear. Next time, we will!
Aside from the difficulty in identification, seagrass survey can be quite fun too, filled with occasional screams, more often than not, from our group (even the guy!!). Haha. Half the time, we scare ourselves with our imagination whenever we touched something underwater that does not feel like seagrass.
We still had some time after completing the survey, and took a slow walk back to the wash-up point. A fellow GV spotted a Feather star (another first time for me!), although she had a rude shock as she intially thought it was a flower till it moved! Feather stars have a hydraulic water-vascular system (unlike us humans who circulates blood in our system) similar to other echinoderms, and swim by the undulating movements of the arms.
Another first time for me, is the sighting of the Spiral Melongena (Pugilina cochilidum) laying eggs! This is another pole-vaulter who moves with the aid of its strong foot and operculum.
a) identify the species of seagrass &
b) count+estimate the percentage of each species in that area of the quadrat.
4. The next task is to estimate the percentage of epiphyte on the seagrass (see the brown stuff growing on the green seagrass in photo below).
5. We also randomly pick 3 blades of leaves to measure its length.
6. Other plants (such as algae) or animals must also be recorded.
7. (although not quite part of the survey) Washing the equipment esp the measuring tape with clean water is a MUST, and is usually the most tedious task
If you ask me whats most challenging, identification of the species beats everything else, hands down. I remember how traumatic my first experience was, because all the species looked the same to me! No matter how hard we tried, we only seemed to be able to identify the tape seagrass, and we also took a long time to complete the tasks. Even recording the data was difficult, back then.
With practice, I'm sure we have improved in speed, and hopefully in accuracy of data too.
Heres what my team identified during the survey:
1) Tape Seagrass (Enhalus Acoroides): This is relatively easier to identify because of its long ribbon-like leafs. Feeling the sides of the leaves, you will also find that the leaf margins are in-rolled. The rhizomes of this species are thick with long black bristles. This time round, we even saw the spiky Enalus fruit (unfortunately, i was too busy to take a photo)!
2) Cymodocea serrulata: This seagrass may appear quite similar to the tape seagrass, but it has a serrated leaf edge, if you look carefully. A clear distinction is its smooth (and white?) rhizome (yes, in order for us to check this, we have to dig and feel the rhizome): 3) The last species (and my first time seeing it) is the Sryingodium isoetifolium. This is not too difficult though, as its cylindrical and hollow leaves are quite distinct, clearly different from the tape seagrass.Apparently we should be able to see the spoon seagrass in our area as well. I gues we were not looking hard enough, or waiting long enough for the murky water to clear. Next time, we will!
Aside from the difficulty in identification, seagrass survey can be quite fun too, filled with occasional screams, more often than not, from our group (even the guy!!). Haha. Half the time, we scare ourselves with our imagination whenever we touched something underwater that does not feel like seagrass.
We still had some time after completing the survey, and took a slow walk back to the wash-up point. A fellow GV spotted a Feather star (another first time for me!), although she had a rude shock as she intially thought it was a flower till it moved! Feather stars have a hydraulic water-vascular system (unlike us humans who circulates blood in our system) similar to other echinoderms, and swim by the undulating movements of the arms.
Another first time for me, is the sighting of the Spiral Melongena (Pugilina cochilidum) laying eggs! This is another pole-vaulter who moves with the aid of its strong foot and operculum.
Though not my first, I was also glad to see 2 Mangrove horseshoe crabs (Carcinoscorpius rotundicauda). Horseshoe crabs are known to be the longest living fossils, since days even before T-rex. Although they are called 'crabs', they are more related to spiders and scorpions. Its sharp tail may look intimidating, but it is not venomous nor used as a weapon. It is merely a tool to overturned itself, so if you see a upsidedown horseshoe crab, don't be afraid to lend a helping hand! Another interesting fact about them is their blue blood which clots easily when in contact with bacteria.
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