A team of marine scientists were able to document 33 new records of seaweeds from a recent expedition in the Kalayaan Island Group, and suggested that even more are likely to be discovered in the future.
Seaweed biodiversity in the Philippines “is very high” and the country is considered to have the most diverse seaweed flora in the tropical western Pacific, according to Dr. Wilfred John Santiañez of the University of the Philippines-Marine Science Institute (UP-MSI).
Based on latest reports and herbarium records, the Philippines has more than 1,000 seaweed taxa. It is composed of red seaweeds or Rhodophyta (57 percent), green seaweeds or Chlorophyta (25 percent), and brown seaweeds or Ochrophyta (18 percent).
Of the estimated 1,000 seaweed taxa in the Philippines, there are about 350 species that have known economic value, Santiañez said.
However, Santiañez said much of the scientists' knowledge on seaweed resources in the country is only based on collection from a few areas.
"Little is known in the Pacific Seaboard, Southern Mindanao, and the Kalayaan Island Group," he said during a webinar organized by the Department of Environment and Natural Resources-Biodiversity Management Bureau (DENR-BMB) Wednesday.
Ecological and economic values of seaweeds
"Seaweeds are habitat to many marine organisms from invertebrates to different fishes. They are at the bottom of the food chain because they are primary producers and they are sources of food to marine invertebrates and fishes, and even sea turtles," he said.
They also have a very significant role in reef formation. They are often overlooked as a component of the reef but they are actually crucial in preparing the substrate on which your corals settle, where coral reefs form. They are very important in aggregating the substrate towards the stabilizing and can act as buffer to a wave action and even storm surges,” he said.
Seaweeds are also important economically.
They are sources of food in many populations, particularly in the western Pacific. In China, Japan, and Korea, and even here in the Philippines, seaweeds are consumed as food. Among the seaweeds that we consume are the Caulerpa or ‘lato,’ Eucheuma or ‘guso,’ and Phycocalidia or ‘gamet,'” he said.
Seaweeds are also sources of high-value natural products, such as Phycocolloids, Carrageenan, and Alginate.
"Carrageenan in particular is very important in the food industry. It is used as one of the thickening gelling agent in many of our food products. It is one of the major components of toothpaste and some gel ballpens. Production of carrageenan is also one of the major sources of livelihood among coastal population. Particularly, seaweed farming industry is based on Carrageenan-producing seaweeds," Santiañez said.
In 2018, he pointed out, seaweed production contributed 13 percent to the total value of aquaculture production in the Philippines. Seaweed production was valued at P11 billion in 2018 alone.
Aside from that, he said that seaweeds are important sources of fertilizers, fodder, biofuel feedstock, and bioactive compounds used in medical and pharmaceutical industries.
West Philippine Sea expedition
In 2019, the DENR-BMB and the Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR) funded a research expedition to conduct a survey, and part of it was to look into the diversity of seaweed resources in the Kalayaan Island Group.
Dr. Deo Florence Onda, Deputy Director for Research of the UP-MSI, spearheaded the research expedition of the PROTECT-WPS (Predicting Responses between Ocean Transport and Ecological Connectivity of Threatened ecosystems in the West Philippines Sea) Research Cruise.
Santiañez said collection efforts involved shallow and deep dives in the Ulugan Bay, Sabina Shoal (two stations), and Pag-asa Island (five stations).
Focusing his report on Sabina Shoal and Pag-asa Island, Santiañez said the group of scientists was able to collect 105 samples from the Sabina Shoal and 391 samples from Pag-asa Island.
He said they compared the latest samples from the collections deposited at the UP-MSI herbariums that date back in the late 1990s, "the last time that seaweeds of Kalayaan Island Group were studied."
"There were a total of 71 species that were deposited at the MSI herbarium, 45 percent are green seaweeds, 35 percent are red seaweeds, and 20 percent are brown seaweeds," Santiañez said.
"When we looked at our seaweed from the latest collection effort, we were able to identify a total of 95 seaweeds composed of 57 percent red seaweeds, 38 percent green seaweeds, and five percent brown seaweeds," he noted.
"In the Protect WPS expedition, there were a lot of red seaweeds collected primarily because one of the advantages of our current effort is that we were able to go deeper by scuba diving, and much of these red seaweeds were collected from deeper areas," he added.
Although the team of experts was not able to collect samples of 21 previously recorded seaweeds, Santiañez reported that of the 95 samples collected, 33 new seaweed records were added to the marine flora of the Kalayaan Island Group. Most of the new records of seaweeds were red seaweeds, he added.
New seaweed species, other interesting find
Santiañez said one of the interesting finds from the expedition was the Flahaultia sp., which is not a common seaweed in the Philippines. “It is the first time that I saw this seaweed,” he said.
Another interesting find, which is widely distributed in the Philippines is the Gibsmithia hawaiiensis. They have feathery bodies and they can be sometimes mistaken for soft corals,” he added.
We were able to grow some of the seaweeds from the Kalayaan Island Group. One of which is the Griffithsia, which is known to produce griffithsin, an active anti-HIV compound. However, we were not able to successfully maintain this seaweed,” he said.
However, he noted that "it is apparent that Kalayaan Island Group can be a good source of novel compounds that can be used for biomedical purposes."
Santiañez also shared that they are conducting further studies on a red seaweed that "can be a new species from the Philippines."
We are also working on the identification and looking at the life history of a red seaweed, a putative new species of Hypoglossum from the Kalayaan Island Group. Much of the samples that we were able to grow died during the lockdown so we are now trying to recover this so that we can continue our work on this seaweed,” Santiañez said.
Further studies
The total number of the seaweeds within the Kalayaan Island Group is "very low" and "remains poorly known" as compared to other areas such as Balabac Island with 176 species and Bolinao in Pangasinan which has 168 species, Santiañez said.
But with more collection efforts, we will be able to uncover the seaweed biodiversity resources of the Kalayaan Island Group, he added.
"Many species are still hidden in plain sight. We need to continue and increase support to efforts on generating foundational marine biodiversity knowledge," he said.
"There are still a lot, even with our recent collections, I believe we still have a lot of opportunities to discover (new records and species). It’s just that our capacity to work on them is very limited because there are very few of us that work on them at the moment. But definitely there is a high chance of discovering records even describing new seaweed taxa," he added.