When Gordon Watson was a child, his interest in the ocean’s inhabitants was sparked by Fred, an aquarium-dwelling goldfish brought home from a fair near his landlocked home in Bedford, England.
Now, as a marine ecologist at the United Kingdom’s University of Portsmouth, Watson’s fascination with aquariums has grown to a global scale.
While the world of saltwater aquarium enthusiasts has caused concern about collectors pillaging sensitive coral ecosystems to fill living room showcases, there are many unknowns about the industry: how big it is, its economic value, and its potential for both environmental harm and environmental good.
When Watson set out to answer some of these questions, the answers surprised him. The saltwater aquarium world, it turns out, is even bigger than he expected. As many as 6.7 million hobbyists are fueling an industry with more than $2 billion in annual retail sales involving the transport of as many as 100 million organisms each year, according to a new study from Watson and colleagues in Science Advances.
The results were “a definite light-bulb moment about the potential of this industry for coral reef protection,” Watson wrote in an email.
There is both promise and peril in those numbers. As Watson’s comment suggests, he sees a big upside. That’s because the myriad people involved—from Indonesian villagers earning money by collecting reef crabs to wealthy aquarium owners—could serve as advocates for conserving the reefs on which this industry depends.
“If we can show the true value of the trade and the link to the communities and reefs that support it, it can provide the leverage to be a force for good, moving the industry to be an exemplar of sustainable practices,” Watson said.
The new paper spells out some elements of a sustainable system. Species and areas at high risk of being overfished could be identified and more carefully managed to encourage sustainable collecting. A certification system might be used to help steer collectors toward buying organisms from more sustainable fisheries, similar to rating systems for people buying fish at grocery stores.
“I want the research to be a ‘call-to-arms’; spurring the MAT (marine aquarium trade) industry and regulators to identify the good practice already happening and then to develop clear plans about expanding this,” said Watson.
But his new research also points to dangers facing both the reefs and people in the aquarium trade. As part of the work, Watson gathered data about which species were being sold and in what volumes in aquarium stores in the United Kingdom, Italy and the United States, enabling him to construct a picture of the broader international aquarium trade.
Pairing this data with information about where different species are found and their condition led Watson to highlight 25 species or groups of species most at risk of being overfished. The list includes invertebrates such as hermit crabs, shrimp, sponges, snails and some kinds of corals, as well as fish found in few habitats, such as the golden-hued Armitage angelfish, and other more widely distributed fish that are subject to intense collection pressure, such as the multi-hued pearlscale butterflyfish.
While reefs around the world face fishing pressure from the aquarium trade, the new research pinpoints the waters around Indonesia and the Philippines as places where the risk of overfishing are greatest, thanks to the concentration of species that are rare or in high demand.
The future of these reefs, however, hinges on more than control of overfishing. Underwater heatwaves tied to global warming have been devastating reefs around the world, triggering massive bleaching and death of corals that are the linchpin of these ecosystems. Watson points to forecasts that nearly all of the world’s reefs will be severely damaged by 2050 if greenhouse gas pollution continues unabated.
As reefs decline, it threatens to create a feedback loop that would hasten their destruction, Watson warned. If the aquarium industry shifts to farm-grown saltwater species to fill their tanks, people who earn a living capturing wild organisms for the industry might turn to activities such as food fishing that are more harmful to reefs.
Meanwhile, Watson has experienced his own personal decline when it comes to aquariums. As an adult Watson had expanded from Fred the goldfish to a 60-liter saltwater aquarium. But family life and financial pressures forced him to get rid of it last year. “I console myself with still having some interesting marine inverts in the tanks in our aquarium at the institute,” Watson said.
Watson, et. al. “Can the global marine aquarium trade (MAT) be a model for sustainable coral reef fisheries?” Science Advances. Dec. 6, 2023.