“When we were young, we were very skinny, only about 50kg, then we became like this…” - hearing me exclaiming about the tall and strong physique of each diver in the group, looking really “cool”, Pham Van Chien, a diver from the Institute of Marine Environment and Resources (Vietnam Academy of Science and Technology) smiled and explained. At that time, I also nodded in agreement, but after the trip to the sea with them, watching them dive like otters, someone who could only swim a dozen meters before… “running out of breath” like me seemed to understand many things.
In early June, we had the opportunity to follow scientists from the Institute of Marine Resources and Environment to survey marine biodiversity in the Ha Mai, Thuong Mai (Van Don) and Co To sea areas. The group of 6 people were experts in researching marine life such as seaweed, fish, corals, etc.
Starting from Cai Rong port, the canoe rented by the group sailed across Bai Tu Long Bay for about 45 minutes to reach Ha Mai Island, the outermost island of the Bai Tu Long island system, belonging to Ngoc Vung island commune, Van Don. The sun was bright yellow, the sky was clear and the sea was as blue as jade. Looking at the rare clear water, we were all amazed. With weather like this and water like this, diving or recording images of the seabed promises to be very favorable.
Talking about the survey method, Dr. Nguyen Duc The, the head of this team, said that the diving team will send a diver to go first to spread the rope, then the other groups will dive behind and survey the area around the spread rope, about 2m wide on each side, about 100-200m long. The survey is done by point, each group has a camera to take pictures or record images of the seabed...
Having no expertise, we were quite surprised when listening to his sharing. Meanwhile, the experts had changed into diving suits, prepared their equipment and in just a moment, with a "boom" sound, they were under the sea.
Just looking at them, you can see how heavy they are: thick diving suits that absorb water, dozens of kilograms of air tanks, flippers and lead straps wrapped around their bodies for another dozen kilograms. All of these help them… sink best, and the outer protective layer protects the diver’s body underwater. The final step is to transfer the camera so they can work. With such a series of operations and heavy equipment, the team has a separate person to help on shore. When the divers gradually sink below the surface, the water bubbles that follow the breathing air rise to the top, which is the basis for knowing where the divers are. However, that is with a professional eye, but we can see clearly up close, but after a while, we can only see one-colored waves…
About half an hour later, the experts began to surface. The net bag containing the collected specimens was loaded onto the boat first, followed by the lead seal and propeller, and finally the divers boarded the boat. We were really excited and wanted to ask questions right away, but thinking about how exhausting it was to dive for so long, we held back our emotions and let the experts “breathe first”.
The Ha Mai area surveyed did not seem to be as expected. While brushing his wet hair that was falling in front of his face, Master Pham Van Chien said: From the shore, the sea looks so clear, but when diving down, it is a bit cloudy, visibility is only 1-2m. I study vertebrates such as marine fish and marine vertebrates, but with the seabed being so turbid, it is impossible to film fish swimming.
Dr. Nguyen Dang Ngai, Deputy Director of the Institute of Marine Resources and Environment, a coral research expert, said: Ha Mai Island is located relatively far from shore, so surveys of corals in particular and marine biota in general here are quite rare. This is the third time the unit has conducted a survey in Ha Mai in the past 20 years. In terms of biological characteristics, the Ha Mai area is far from shore, less affected by human factors or environmental pollution, the water is also quite clean, but the coral reefs are not as expected. Here, there are mainly small coral colonies, less than 50cm in diameter, it seems that the reefs are recovering after degradation, unlike in Bai Tu Long Bay and Ha Long Bay, which have large coral colonies...
We didn’t get to talk much because the dives had to be continued. The two dives at Ha Mai ended at noon, we stopped at Ha Mai Island, and asked the officers at the Ha Mai Border Control Station to let us stop and have lunch on the island. The island truly has its own value, after a few hours of bobbing on the canoe, when we set foot on the island we felt a completely different sense of stability.
Lunch was simple with sticky rice and some fruit that the group had brought since morning. I was concerned when observing the appetite of the team, it was clear that all the divers were tall and big, diving deep was very tiring but they ate very little, not only at lunch but also during breaks between dives, they ate very little. Explaining to us, Dr. Nguyen Duc The said that when you eat a lot and dive deep, you can't stand it. If you want to eat to make up for your energy, save it for dinner...
Lunch ended very quickly, the whole group did not rest but almost immediately returned to the boat to move to the Thuong Mai area. Here, the group continued to dive at 2 more survey points and finished diving at around 3pm. They could not dive too early or too late, that is why they took advantage of the sunny time in the morning and early afternoon like that.
The survey results at Thuong Mai seemed to be more positive. The divers were all happy because the seabed was clearer, the corals were more beautiful and plentiful, the types of seaweed found were also more interesting, and the coral reef fish were also more abundant. More specimens were collected, along with pieces and branches of coral, and seaweed samples were giant clams as big as an adult’s hand, with many types of seaweed attached to their bodies…
Through conversation, scientists from the Institute of Marine Resources and Environment said: The sea area of Quang Ninh, concentrated in the area of Ha Long Bay, Bai Tu Long Bay and the ancient Co To archipelago, has been dived and surveyed by them for many years and highly appreciated for the richness of coral reefs as well as the population of fish species that develop in association with coral reefs. The areas all have rare species, listed in the Vietnam Red Book. In particular, the coral reefs in Hong Van (Co To) area are very developed, once 3-4 km long and 1 km wide. In this area, in the 90s, through surveys, there were also dense seaweed beds like forests and up to 4m high, but now they have decreased significantly for many reasons...
Following the survey dive in Van Don, the group moved to Co To, which can be considered extremely rich in corals and seaweeds. The survey area at Thanh Lan Island is quite close to shore but the water is very clear, about 2-3m deep, but just looking from the boat we can see the dark coral beds at the bottom of the water. In the Co To Con area, the water is deeper, about 6-8m. While waiting for the divers, the boat owner Vo Van Sat told a story: The corals at Hong Van beach used to be very abundant, stretching for kilometers, but later due to destructive fishing methods, they are no longer there, only a few block corals and branch corals remain. Now people no longer exploit them like that, but fishermen from other places have not yet completely banned them.
Absorbed in diving and filming the seabed, Dr. The emerged from the water with one cheek starting to turn red. He said that because he was so busy filming, he did not avoid the fire jellyfish that hit his face, it was like being electrocuted, followed by a burning sensation... This is an occupational hazard for divers. After he got on the boat, we still observed the small jellyfish with a meter-long tail swimming in the water.
After a while of “first aid”, we took the opportunity to ask him. Dr. The said that the unit has had many projects to survey and investigate biodiversity in the Co To sea area. On this survey trip, he filmed more schools of fish swimming on the coral reef. Dr. The explained: Coral reef fish are a group of fish that indicate the health of the reef. In the Thuong Mai area (Van Don), Co To, we saw the appearance of this group of fish, mainly butterfly fish, damselfish, and wrasse. When the coral reef is in good health or has recovered, this group of fish appears more abundantly. Compared with the results of the Institute's recent survey in Co To from 2017 to 2019 in the project to build the Co To - Tran Island marine reserve, the diversity of coral reef fish has recovered to a certain extent.
This trip had a diving veteran with 40 years of experience specializing in seaweed research, Associate Professor Dr. Dam Duc Tien. Early this morning, when it was still dark, he and his colleagues woke up early to go to Hong Van beach to collect seaweed samples washed ashore. And when the ship approached the shore in the Hong Van area, which is also a large seaweed beach in season in Co To, he changed into a diving suit to directly survey this seaweed beach.
At his age of over 60, few people still dive, but he was absorbed in diving for nearly 30 minutes in the seaweed field. Only when his students urged him did he agree to get on the boat, his face unable to hide his regret. He said: This is probably the most abundant seaweed field in terms of species composition in Co To at present. Now is the right seaweed season, the biomass is concentrated in some groups, such as white seaweed, fan seaweed..., in which the white seaweed group can reach 10kg fresh/m2. In addition, many seaweed groups in our country that were previously thought to have only one species are now discovered to have many species in Co To...
After a whole day of diving under the sea, everyone seemed to be exhausted when returning to the group. The dives had relatively good results, showing that the marine biodiversity resources in the waters of Van Don and Co To are recovering well. Of course, this is just the beginning of future in-depth research by experts. We also had another experience with scuba diving, although we did not dive or swim a meter, the "sky was calm and the sea was calm" and no one got seasick, but when we stepped on the shore, we still felt "unsteady" from time to time.
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