Unlike clownfish (Nemo), Pacific blue tang fish (Dory) cannot be bred in captivity. nostri-imago/flickr, CC BY

Finding Nemo – and Dory – is easy. Deciding whether they should be pets is harder

Coral reefs across the globe are under threat from climate change. Fishing of any kind is often seen as a further assault on these ecosystems, and any perceived increase in fishing, especially when not for subsistence, is often met with calls to stop taking fish from the sea.

As has been the case with other movies featuring pets, “Finding Nemo” was reported to increase sales of clownfish for aquariums. This weekend, “Finding Dory” is being released, and this is leading to renewed calls to stop taking aquarium fish off reefs including Dory’s species, the Pacific blue tang.

These reef fisheries, however, are important economic drivers for the reef-side communities. If we end these fisheries, what will the fishermen do? Acting without fully understanding the trade in marine ornamental fish could lead to a host of unintended consequences. Our actions in the name of conservation could actually harm the health of coral reefs and the communities that depend on them.

Imported fish are not always wild

Understanding the trade of fish destined for saltwater aquariums is difficult, since statistics on the pet trade are poor at best. Following the release of the movie “Zootopia,” the LA Times and the Guardian reported a rise in interest and sales of fennec foxes – one of the animals depicted in the film – as pets. But researchers Diogo Verissimo and Anita Wan found there was no evidence for an increase in trade in this fox.

Here, we examine what is known about the trade in clownfish and Pacific blue tang. Finding data will help develop solutions that are best not only for the fish, but also for the reefs where they live and the communities that rely so heavily on these ecosystems.

To overcome the lack of reliable data on the market for aquarium fish, we developed Aquariumtradedata.org. This project collects and analyzes data from invoices of the marine aquarium fish entering into the U.S. To date we have examined nearly 30,000 invoices, with 2011 the most current year in the database.

Most of the clownfish in the trade are captive bred, but wild clownfish are commonly imported into the U.S. for home aquariums from the Philippines. Values are averages of 2008, 2009 and 2011. Aquariumtradedata.org, Author provided
Contrary to what popular movies may say, tangs are very difficult to breed in the laboratory. Values are averages of 2008, 2009 and 2011. Aquariumtradedata.org, Author provided

There are many types of clownfish imported into the U.S. – 24 different species from 25 different countries. But the real confusion in understanding the trade in clownfish is trying to tell the species apart. Many clownfish species are similar in appearance, and thus cannot be differentiated in trade statistics.

Nemo is technically the percula clown fish (Amphiprion percula), since he lived on the Great Barrier Reef. This species is often misidentified as the common or false-percula clownfish (Amphiprion ocellaris), and because of the mistakes in identification, these species are combined in trade statistics. In 2011, just over 250,000 percula and ocellaris clownfish were imported into the U.S., making this species complex the seventh most popular marine aquarium fish import.

The global wild Nemo population is estimated to be between 13 and 18 million fish. Unfortunately, trade statistics do not accurately reflect if imported fish are wild or from aquaculture. Clownfish have been bred in captivity (aquaculture) since 1973, and they have the capacity to produce all fish in the trade. Marine aquaculture companies such as Florida-based ORA, one of the largest U.S. based companies, can produce hundreds of thousands of clownfish in captivity each year, yet there are no official trade statistics to compare domestic production to international supply.

There are also numerous companies internationally, so even if there was an increase in clownfish sales after the release of “Finding Dory,” this demand could be met by increases in captive production. Wild collection of clownfish has been decreasing steadily over the past 10 years, commercial aquaculture can meet any spikes in demand for Nemo (and is also offering designer clownfish).

So concerns over “Finding Dory” and its impact on clownfish populations are likely unwarranted. In fact, there are no data we are aware of that support claims of increased fishing pressure on clownfish because of “Finding Nemo.”

The problem with aquaculture for Dory

The Pacific blue tang (Dory) should be kept on the reef.

This species occurs in much lower numbers in the marine aquarium trade, and will remain limited because it has not been successfully bred in captivity (the larval fish are really small and challenging to grow). In addition, the Pacific blue tang is a species for only experienced hobbyist if for no other reason than it needs much much more room to swim than clownfish. It also costs much more than the clownfish.

The aquarium industry has released several PR campaigns to dissuade potential impulse purchases. All these factors will likely limit sales. Regardless, a responsible approach by the aquarium trade would be to not give in to any potential increase in demand. The Pacific blue tang is a species of concern.

While the message of keeping all fish on the reef is relevant to some species, this overly simplistic message drastically overlooks the power of reef fish as a driver of rural economies and reef conservation.

Many fish in the aquarium trade are also collected at larger sizes and sold in food markets, such as this one in Taiwan, for a much lower price. Michael Tlusty

Ornamental marine fish are a high-value fish, and they are caught by the individual - not by the net full. Prices average US$500/kilogram ($1,100 per pound). This is a significant economic opportunity for the communities that reside next to the reef.

Groups such as the marine conservation nonprofit LINI in Indonesia work with the marine aquarium fishers to restore reefs, teach them better methods and even catch baby wild fish and grow them in cages for eventual release back onto the reef.

Small-scale fisheries can recover quickly through local control along with creation of marine protected areas. If we stop the wild collection of these marine fish, what will be the drive to protect the reefs from overfishing? We need to harness the power of these fisheries to sustain the communities that will in turn protect the reefs.

Role for ornamental fish in conservation

The marine aquarium trade can be a force for conservation good. It can stimulate rural economies and, at the same time, drive the development of scientific curiosity of children half a world away.

But we need balance to the debate – we should not blindly select wild or aquaculture fish without knowing the good and the bad of each. There are risks and benefits to aquaculture, and this flow chart addresses the species that should be traded, and if they should be wild caught or produced in aquaculture.

Clownfish are one of the first and best examples of aquaculture success in marine ornamental fish. camrich345/flickr, CC BY-SA

There is no one right answer. For most consumers, Dory and Nemo should not be sourced from wild populations, but for very different reasons. Fish are a wonderful way to teach children about hypothesis testing and cause and effect. These lessons can be broadened to engage children about healthy functioning ecosystems.

These are similar lessons that can be applied at the source of these fish, to engage local communities to protect their reef resources to provide economic benefits from these healthy reefs. But we are data-poor about this trade, and this lack of understanding may result in uninformed decisions that may have unintended consequences. By finding data, we can best understand the role ornamental fish can have in being a force for conservation good.