Wednesday, January 9, 2019

Sungai Miri Fireflies Revisit

Sungai Miri Revisit : Survey of 17Km of Sungai Miri from Taniku Ferry to Piasau Utara

Display trees along a section of Sungai Miri.

The first ever firefly reconnaisance at Sungai Miri was carried out between Pujut Corner up until the section where the Bakun Power Line crosses Sungai Miri. I found rows of synchronous fireflies display trees on both sides of the river. I took some samples and several specimens were preserved. At the time, I did not yet know how to conduct a firefly survey, it was my first congregating firefly survey.With me doing this recee were Suria Timon, Nazeri Jaraee and Pak Par the boat man.

This is one of the sample preserved from the area

Sungai Miri WPTs and display trees from 2010.

After attending a firefly symposium and identification course for two weeks in KL, I executed Miri's first (if not Northern Sarawak) proper firefly survey for the main section of Miri river of about 15 kms from Taniku ferry point to Mat Shah Jetty on the 10th July 2010. A good survey record was achieved together with several Curtin students, Faye Othman (MNS Miri member). The students from Curtin were Aju, Salam, Faiz Nasir, and Faiz Djamil. These young students were very observant, we recorded a total of 283 congregating firefly trees along survey’s length.

Sungai Miri survey route.

The second survey was executed by a group of firefly symposium attendees from Kuala Lumpur. They were made up of several firefly experts coming to Miri to see what I have told them about Miri river fireflies during the symposium. They were Lynn Faust from the United States, while Luis Vasconcelos, Maria and Jose were from Portugal. We carried out the survey again on the 10th Aug 2010. At the end of it, we recorded 101 congregating firefly trees along 16 km of Sungai Miri. The number of trees marked were less this time around. This was due to some gps waypoints not being properly logged when overexcitement at seeing so many display trees overcame all of us.

Most of the river bank still contain a good Display trees

Due to many new commitments I have not carried out any firefly surveys since late 2011, it has been almost 8 years now. Recently I felt that I had to do a factfinding firefly boat trip rather than a full survey over the same section of Sungai Miri.

I called Ian of Coco-dive to sponsor a boat, which he kindly agreed to. I was so excited at the prospect of being able to go back to Sungai Miri and seeing the fireflies again. With the help of MNS members, Jacey and Brain, I acquired new batteries for my night vision scope and a new aquarium thermometer to get water temperature readings ready for night out on the river with fireflies.

All was set to take place on the 6th of January 2019, deemed the best day for this which correlated well with the feeding window of fish and other animals. During this dark moon period all faunas are active feeding and fireflies should be in the same state.

New measurement

Tide table for Miri for the day.

Jacey Yap was assigned as a recorder, and I as coordinator. Anis Lee was tasked with logging waypoints, while Achmed was tasked with locating distant firefly trees using the nightvision scope to warn us in advance of any approaching display trees. Brain was given the job of taking sample fireflies within reach of the scoop net that we used for collecting samples. 

Checking our survey gear.

Unfortunately late during the day of the survey Achmed called to cancel his participation due to an unforeseen emergency at his worksite. I called two other interested MNS Members who were on the list for the survey but both individuals were not contactable at the time.

By 5pm, the others and I gathered at the jetty. Jimmy Yong the Coco-dive Boat Manager with his daughter Isabelle came to the jetty to see us depart. We took a group photo and later handed out the instruments to the participants fitting the preassigned tasks. During the trip I discovered that my GPS unit had an issue with problem with unstable battery contact, so it was decided to just leave it on the boat bench. Brain was reassigned to get water samples and pH readings.

Group photo with Jimmy the Coco-dive manager

We left the Piasau Utara jetty at 17:25hrs using a powerful and quiet 140HP four strokes Suzuki outboard engine. We cruised fast towards Taniku ferry point some 17 kilometres away and reached the site at 18:19hrs. While waiting for darkness to fall we took water samples to read pH and specific gravity. Water was light brown having Sg of 1 and pH of 5.

Before set sail to Taniku Ferry

What surprised us while cruising along the river was that there seemed to be no birds flying. Only the sounds made by two frog species and a White Breasted Waterhen were heard.  We did not hear any splashes of fish on the water feeding, we also saw several moths.

 Brain has a beautiful note given to me as follows.
"As an observer invited on last nights evening boat trip with Musa, I found the river devoid of any form of life. Any healthy stretch of water anywhere the size of Miri river, should, at that time in the evening and night should be alive with natural sound, fish jumping, insects and creatures. Any type of reptile surviving in this river would probably be scavenging the stuff thrown away by the human inhabitants living alongside the banks.

Brain reading pH

At 19:08hrs we started to move. It has been long time since I used the nightvision scope. I mistook sparkles of light in the trees and thought they were fireflies, which later turned out to be stars fleeting between the leaves. After moving some 100 meters, I started to sense that something was not quite right. There were no congregating fireflies observed along the stretch of familiar display trees of several years back.

The first lone firefly seen and first WPT433 was logged. All along the way we only see single firefly fleeting about. Thus I came to the conclusion they are rovers, a single flying firefly. Only after nine WPTs we saw rovers. At this section we saw a single crocodile yearling and logged WPT448.

Jacey getting ready to log and take notes

All the way after WPT 449 we did not see any congregating fireflies though many familiar congregating trees were spotted, not a single firefly was seen.

I readjusted the night vision scope I and looked hard, but not avail. There were no fireflies spotted.
It was clear that the best rows of congregating fireflies at Sonneratia caseolaris and hibiscus bush along the river bank trees were supposed to have very good display of synchronizing firefly of the Pteroptyx tener (Olivier, 1907) specie. As my sample of Miri-13 was taken from this area. This area was well lit by a swift farm security lighting.

You can you imagine trying to hear your partner speaking while someone else is playing very loud music. Firefly needs darkness to communicate, this section was definitely not ideal for them. The water quality in the vicinity could also be another contributing factor.

Where are the fireflies display

I was devastated that I nearly cried. Passing Pujut settlement area, even Pujut 7 bridge area was supposed to have congregation of fireflies.  There were no fireflies on the previously logged display trees.

Passing Kpg Pengkalan, the waterfront was lighted so brightly it seemed like it was daytime. The display trees as well were devoid of fireflies. My hope was another area next of Lutong Bridge where another synchronous group display at a low Sonneratia caseolaris.  It was unfortunately bright there too. A brightly lit disco faces right into the riverfront.

2019 Survey route and WPTs.

I had high hopes for the area near the old Lutong Airport and the Piasau Nature Reserve on the river side. “Wouldn’t it be great for the PNR to have a stretch of river with congregating fireflies alongside it?”, I wishfully thought. From afar I saw through my night vision the lights of Bayshore and Kpg Piasau Utara residential area dominated the entire area, my high hopes quickly dashed. There were no displaying fireflies.

Where have all the fireflies gone? It is very sad to think that these indicator species have all moved away from their 2010 locations which incidentally could be described as being well within Miri Resort city limits.

Clearly we need to study this section again … it would be the saddest thing if indeed all the fireflies had left Sungai Miri … could their departure be telling us something more ominous?

Text and images by Musa Musbah, Jan 2019.
Please visit Sarawak Fireflies for more.

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