3D Technology Simulates Mangrove Underwater Predation Wonders AA Funds CUHK Research on Pearl River Estuary Ecosystem

Mangroves have always been one of the most important ecosystems in Hong Kong and even the Pearl River Estuary. The Airport Authority and the Chinese University of Hong Kong team pioneered the "photogrammetry" technology and 3D printing method to study the ecological value of mangroves for juvenile fish habitat in a simulated environment .

It was found that the more complex the structure of the mangroves, the higher the survival rate.

Helps young fish hide from predators.

Professor Li Chengye, director of the Li Fushan Marine Science Research Center of the Chinese University of Hong Kong, said that in the past, it was difficult to observe by traditional field investigations, and it took a lot of manpower and material resources. The mangroves are located in remote locations, which is more difficult, and it takes luck to meet the fish that you want to study.

The new technology studies the symbiotic relationship between fish and mangroves in a cost-effective manner, so as to formulate in-depth conservation strategies and mangrove management measures.

The world's first combination of "photogrammetry" and 3D printing technology

The Ocean Ecology Improvement Fund established by the Airport Authority has supported a team from the Chinese University of Hong Kong to conduct the world's first method combining "photogrammetry" and 3D printing technology to study the ecological value of mangroves for juvenile fish habitat.

Li Chengye, director of the Li Fushan Center for Marine Science Research at the Chinese University of Hong Kong, said that in the past, field visits to study mangroves required a lot of manpower and material resources, and the time was long but the results were low. In particular, it is difficult to carry a relatively large instrument for research.”

Mangrove habitat fragmentation in the Pearl River Estuary is becoming more serious

In addition, the mangrove habitat in the Pearl River Estuary is becoming more and more fragmented, and the number of large predators is becoming less and less, making natural predation more and more rare in this area.

Li Chengye pointed out, "We often have to take a chance to meet the fish we want to study, which happens to appear near the tree, but the chance is actually very small. Therefore, using the traditional field investigation method to carry out this research not only Difficult and cost-effective.”

In addition to field investigations, many previous studies have cut down the roots of mangroves and moved them back to the research center for research, but this will cause permanent damage to the trees.

There are also studies using rubber throats, iron pipes, wooden strips, etc. to imitate the structure of mangroves, but Professor Li believes that this research method is relatively crude, and the results obtained are difficult to explain the dynamics of fish in the wild.

More than 3,000 real photos were taken, 3D reconstructed digital model of mangrove

The CUHK research team then pioneered a research method combining "photogrammetry" and 3D printing technology to solve various difficulties encountered in the study of mangroves.

The researchers selected six mangroves from Ting Kok, Lai Chi Wo and Shui Hau with different structural complexity and densities, took more than 3,000 photos of the mangroves on the spot, and then used computer software to reconstruct the 3D mangrove digital model, and then used 3D printing technology to reconstruct the mangrove digital model. A total of three one-to-one 3D mangrove solid models were copied and set up in the experimental pool of the research center to simulate the mangrove habitat.

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The team placed red 𩵼 as predators, and young glass fish and aconitum as prey in the experimental pool, and used underwater cameras to film the activities of fish, and conducted multiple hunting experiments to study the predation behavior and survival rate of fish and provided by mangroves. relationship to habitat complexity.

The more complex the mangrove structure, the higher the survival rate of young fish

After 30 months of research, the more complex the structure of the mangroves, the higher the survival rate of young fish in general.

The researchers also observed that mangrove structures can hinder predators from hunting, and young fish can use the structures to hide.

When the water level is low, the juvenile fish will disperse and use the tree root structure to hide and avoid predators; but when the water level rises away from the tree root structure, the juvenile fish will also swarm and swim rapidly to increase the survival rate.

These are situations that were previously difficult to observe through traditional fieldwork.

Tan Fengyi, chairman of the Marine Ecology Fund Management Committee, said that the project uses innovative technology to study the ecological value of mangroves, which play an important role in marine ecology.

She continued that the research experiments can simply demonstrate the symbiotic relationship between mangroves and fish, which will help promote future education and conservation work.

In-depth study of the role of mangroves in the ecosystem, so as to formulate corresponding mangrove management measures.

AA Sustainability General Manager Li Chung-teng pointed out that the results of the project have enhanced exchanges between scholars, environmental groups, and stakeholders at the research and technical level, and provided useful information for the industry to discuss relevant conservation strategies in depth.

Since its establishment, the Marine Ecology Fund has provided a total of approximately HK$30 million to 25 projects. The Fund continues to accept applications, aiming to enhance the marine environment in the western waters of Hong Kong and beyond the Pearl River Estuary to benefit marine ecology.

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