I just returned from the remote island of Kat O, a historic fishing village located in Hong Kong’s North District.
The island was once a major fishing settlement, but is now home to fewer than 50 permanent residents, leaving only scattered remains of this previously sprawling hub available to maintain fishing and aquaculture. My mission: introduce new diving technology within this old-world setting to develop new roles and an increased value for humans to have as the aquaculture research industry grows to feed the growing population.
With a population density of 17,000 people per square mile, Hong Kong is no stranger to the pressures of the modern world. High on the list of priorities is finding enough protein to feed this massive population center. With the city resting alongside the South China Sea, the seafood industry here trumps all, and Hong Kongers’ diverse palette includes just about every creature in the sea, whether the species is part of a sustainable fishery or not.
Still popular among the Kat O resident fisherman is the use of fish rafts, the old-world version of pen raising commercial species. The point of this week’s journey was to take part in raising the stakes in Hong Kong’s sustainable fisheries with new techniques in Integrated Multi-Trophic Aquaculture (IMTA) developed by the City University of Hong Kong at their very modernized fish raft.
Like an Underwater SimCity
The City University of Hong Kong’s State Key Laboratory in Marine Pollution, under the leadership of Dr. Leo Chan, has established a state-of-the-art IMTA platform off the shores of Kat O. It’s a bit of a surreal environment—the remote village on Kat O lies across the way from Shenzen which is a major shipping port. In between, new technology meets old methodologies with Dr. Chan’s IMTA fish raft.
IMTA’s are an approach to aquaculture where the entire platform strives to be self-sustaining by culturing and harvesting species throughout various layers of the food web. Each level of predator and prey provides a critical component within the IMTA ecosystem, and in turn helps to sustain the system, and offer a positive impact on the local environment. Marine species are raised in pens, holding tanks, or grown on various materials in a manner that allows for interactions that will ultimately result in a self-sustaining and commercially viable ecosystem. It’s almost like setting up a perfectly-running SimCity.
In addition to pen raising commercially viable fish to bring to market, the new experimental fish raft serves as a platform for aquaculture related research on sustainability, public health, and food safety.
While still at its start-up stage of developing a sustainable research model, the fish raft is ideally situated to have a major impact on the local fishery, and serve as a model for new practices in sustainable aquaculture. The project has already engaged partners in industry, academia, the private sector, and community groups.
Enter the Diver
My role in the project was to bring in some diving technology to improve the role of the human in this IMTA system.
Some might consider diving as simply a tool for humans to do husbandry work and conduct research at the fish raft. Dr. Chan and I are advocating that humans themselves play a role within this food web, and human interactions within the environment stand to influence management of the system, and ultiamtely sustainability of both the food web, and ourselves.
Diving is emerging as a high-priority activity for both academic scientists and citizen scientists in both Hong Kong and on mainland China, perhaps moreso than anywhere in the world, and is considered a priority vehicle for pursuing marine studies. This stems from a deep appreciation for the added value in placing humans beneath the sea to observe, interact with, and interpret the environment. This all makes good sense to me, so while aquaculture is typically not on my day-to-day work agenda, Dr. Chan’s invitation to take part in the program was warmly welcomed.
The Job at Hand
Step one was to integrate “hookah” style diving systems into the Kat O fish raft. Most people think of diving as requiring a tank on your back, but an alternative is to use air supplied by a compressor via a hose to the diver, basically giving the diver an endless supply of air. Being remote, the shuttling of scuba cylinders to and from the raft can become exhausting, so with hookah systems the divers can stay underwater all day for husbandry and research purposes with little logistical running around.
I also introduced underwater communications to the team, which changed the game for them: in the very low-visibility conditions surrounding the fish raft, the team could interact like never before.
Step two was a bit of a test for my own work, as I deployed a second generation Ocean Space Habitat beneath the fish raft. The Ocean Space Habitat is basically an underwater balloon that creates an air filled void underwater to provide divers space to rest during the long hours they have to spend in “decompression” when they wait for pressurized gasses to slowly work out of their tissues before surfacing. Decompression is needed in order to prevent the sudden release of that gas as bubbles, which creates the crippling pain called “the bends.”
In the last few years since Gen I’s deployment in the Bahamas, the system has been refined to include its own life support systems, and has become smaller, lighter, and more form-fitting for the occupants. Within the forseeable future, this type of technology will allow diving scientists to have vastly expanded underwater experiences, in both shallow and deeper water, and with low cost and a very small logistical footprint.
Over a brief period, several student researchers from City University visited me in the habitat and were able to consider new ways to make use of this previously non-existent underwater space. Simply viewing the underwater world through this new lens proved inspiring for many, as discussions ensued about conducting future aquaculture experiments from within the habitat’s space, culturing microbiologics, installing bioreactors, and simply extending the stay to an overnight or more … all well within reach as we consider new, portable, lightweight, affordable approaches to life in the sea.
With 26 hours of travel to get home to Western civilization, I gained some clarity in appreciating just how bold a step the Kat O IMTA fish raft really is—showcasing the new while immersed in the old is having a major impact on aquaculture practices in the East, and may very well be the start of solving a major problem in sustainable seafood production, and our own survival.