Course:EOSC270/2023/Aquarium Trade Impacts on Marine Ecosystems

What is the problem?

Figure 1. Trade flow of marine aquarium fishes and invertebrates from source nations into the US during 2008, 2009 and 2011. Retrieved from Rhyne, A. L., Tlusty, M. F., Szczebak, J. T., & Holmberg, R. J. (2017).

The aquarium trade is a system of markets for marine animal specimens, usually harvested in tropical waters in South America, Southeast Asia, Oceania or Africa . These specimens are harvested from their natural habitats and sold commercially, in order to supply other nations with a number of fish and invertebrate species to be used for decoration — or as pets.

Challenges in Tracking the Trade

Across the world, live specimens of marine species that are often targeted for the aquarium trade are being harvested from their natural habitats, and being sold commercially. This market is known to have had a significant impact on marine biodiversity, as the market has increased over time and harvested species have become increasingly overexploited . There is a wide variation in estimates of the extent of harvesting practices, however recent estimates suggest the market transports between 13-35 million marine fish annually . Attempts to record and track the aquarium trade have also proven difficult, for several reasons. Firstly, the informal nature of many aquarium markets has made it difficult to assess their full extent — estimates of the total value of the aquarium trade vary widely, ranging from $800 million USD to $30 billion USD . The scale of many aquarium harvesting operations also make them difficult to track. In contrast to large-scale commercial fishing operations, aquarium harvesting operations tend to be run by small-scale artisanal fishers who are able to catch and export live specimens more easily . Finally, the aquarium trade also spans an incredible diversity of taxa — thousands of species of marine fish are harvested, in addition to many crustaceans, corals, molluscs and other invertebrates . To illustrate the scale of the trade, Figure 1 shows the trade flow of marine aquarium fishes and invertebrates from source nations into the US during 2008, 2009, and 2011.

Economic Benefits

Although the aquarium trade presents a notable problem for marine biodiversity — especially in tropical areas with an abundance of rare and otherwise at-risk species — these markets have proven to be fruitful for many coastal economies, particularly in regions such as Southeast Asia and Oceania. For example, some estimates have suggested that one kilogram of aquarium trade fish may be worth as much as 300 times more than a kilogram of fish for human consumption . The export of ornamental marine life from coral reefs can provide a significant source of income and job opportunities for these communities, sustaining livelihoods and economic development. Some research has argued that the economic benefits to be gained from aquarium harvesting can be a critical factor in developing a balance between coastal communities and marine biodiversity hotspots . However, the current state of the aquarium trade involves harmful harvesting practices which can make the practice deadly to local wildlife.

Environmental Costs

A number of different methods may be used for capturing marine life to be exported for use in aquariums, depending on the taxa that are being harvested. Aquarium fish are generally harvested using basic pole-and-line fishing, or by diving with hand nets on coral reefs . In addition to the issue of overharvesting, the methods used to capture marine life for the aquarium trade can also be harmful to the environment. The efforts of fishers are often augmented through the use of cyanide fishing — a practice where toxic cyanide is added to the waters surrounding coral reefs in order to stun fish . Cyanide fishing is a notable impact of the aquarium trade, especially in Southeast Asia where it is used most frequently — as it has been known to be deadly to fish, coral zooxanthellae and anemones alike . Similarly, coral is generally broken directly off from reefs for transport . This practice can be a significant threat to local biodiversity, as coral reefs take years to form and are known to underpin a significant portion of marine food webs . The impacts of the aquarium trade are explored more thoroughly below.

How does this problem impact marine ecosystems?

Scale of Impact

Figure 2. Estimated minimum and maximum number of marine ornamental fishes traded globally (blue) between 1984 and 2010 and imports to the United States (green) and European Union (red) 2004/2005. Credit: Biondo V., Monica & Burki P., Rainer (2020)

Millions of coral reef fishes are being traded every year. The number of different species of coral reef fishes has also been consistently increasing at a rapid pace. In 1991 only 200 of the 4000 species were reported to being in trade in the United States; between 2008 and 2011, that number increased to more than 2300 species. Clearly demonstrating the limited number of regulations regarding aquarium trade. 1000 aquarium fish collectors, using 75kg of sodium cyanide per year, that’s 75,000kg of sodium cyanide each year, which is a fraction of the amount of people that use cyanide for the aquarium trade. The severity this is not just declining populations of these species, but release of these species in unnatural habitats. Once a species becomes established, invasive, or not, eradicating them from that area is nearly impossible.

Effects on marine species

Scientists can save many species on the cusp of extinction, and eventually reintroduce them to the wild through breeding rare fish species in captivity.  Another benefit to captive breeding is that fishers don’t need to go into the wild as often to capture fish. The downsides, however, include the introduction of non-native species into foreign habitats, impacting not just the survival of those species, but other aquatic species who belong to that habitat. Furthermore, fish have specific temperatures that they can tolerate, which makes introducing non-native species to foreign environments an illogical approach. Destructive fishing practices, such as the use of cyanide causes multiple disruptions in physiological functions in fish and invertebrates, as well as damaging corals.

Effects on marine ecosystems

Marine ecosystems face a lot of the consequences from the aquarium trade. The limited benefits surround strict regulations that are in place, specifically in the United States and Australia; and the reintroduction of fish into habitats that they previously inhabited.  On the downside, coral reefs, which are home to many different fish species are suffering from the rapidly changing climate, overfishing, and pollution. In addition, the usage of cyanide for fishing can coat the corals so that they are hidden; on top of that, the breakage of corals during the recruitment of fish can lead to further damage to the reef, with natural recovery a minute possibility. Additionally, by decreasing the population of some fish, for example cleaner fish, due to exploitation of rare fish due to the aquarium trade, other fish as well as reefs are impacted negatively. In Brazil, for example, the E. figaro, is a rare fish species, found in isolated locations. Since the E. figaro acts as a cleaner for reefs in the area, without them, the coral reefs will have a more difficult time recovering from bleaching and other damage.

What is the extent of the problem?

Global Effects

The aquarium trade has provided many economic benefits, especially to coastal communities. Coastal communities are defined as those that reside on thin land strips or where the land and sea meet.  Coastal communities rely on the aquarium trade as their main source of income; 60% of ornamental exports are from developing countries.

Marine life is the main food source for coastal communities and other countries with water surroundings.  A major consequence of the growing aquarium trade is the potential food web collapse.  It was found that the majority of reef fish are carnivores and have a fish biomass three to four times greater than herbivorous fish biomass, whereas the plant biomass is much lower than the herbivorous fish biomass. Overfishing of reef fish could lead to ecosystem collapse due to the fish occupying the tier of higher order consumers.  Without the higher order consumers, the lower order biomass could increase to the point of food being a limited resource and further causing environmental destruction from increased foraging.

Overall, the impacts of aquarium trade are largely underestimated. Though the aquarium trade was started in the 1930s, the data encompassing the numbers and species traded are unclear due to lack of reliable monitoring.  Another issue is the available data not being separated into freshwater and marine species.  It is reported that between 15 to 30 million coral reef fishes are traded annually, though the numbers could be up to 150 million individuals. Little is known about the number and species in the trade due to the species not being able to be traced to their countries of origin.  This is largely due to countries not having proper monitoring systems already.

Figure 3. The number of individuals from two clownfish species, A. percula and A. ocellaris, imported into the US compared to all fish imported. Retrieved from Militz, Thane A. & Foale, Simon (2017)

Influence From Media and Culture

It is generally hypothesized that media representation increases demand, though this is not the case for the films, Finding Nemo and Finding Dory.  Following the release of Finding Nemo in 2003, there was a small increase of less than 2% in the import of clownfish in the United States of America over the span of seven months. It is shown in Figure 3. that the imports of A. percula and A. ocellaris, two species of clownfish, generally follows the trend of all fish imported into the US, though since 2004, it is seen that there is no growth in the popularity of clownfish import, with a small, consistent decrease being observed. This decrease is suggested to stem from the films’ wildlife representation, which is thought to shape humans’ interactions with wildlife.  After the release of Finding Dory in 2016, the media reported that the sales of the Blue Tang (Paracanthurus hepatus) increased dramatically due to the large feature in the film.  It was discovered that there was an increase in the global online searches for the fish species two to three weeks after the release, but no increase in the imports of the Blue Tang into the United States of America or increase of visitors to aquariums. The result of no increase in imports of the Blue Tang is most likely due to the film revolving around the topic of wildlife conservation.

Given the impact, what are the solutions?

Legislation

One issue with the ornamental fish trade is the lack of reliable monitoring. It can be difficult to find specific information about traded fish, such as its origin or how many of its species are in circulation. Thus, the introduction of a compulsory global monitoring system is vital to further understand the aquarium fish trade. The Trade Control and Expert System (TRACES), already in use in Europe to facilitate the exchange of information in animal trading, could potentially be modified and used in the marine aquarium fish trade to track relevant information. This would help people understand the full effects of the fish trade and inform further action.

Legislation surrounding the aquarium fish trade exists at both the international and national levels. However, despite progress made in closing them, loopholes still exist. Issues in the interpretation of the laws alongside bureaucratic delays results in lowered effectiveness of the legislations. There is also the issue of a lack of conformity in laws, e.g. different states in America having different laws in regards to endangered species. Although legislation is useful, it needs more to be more uniform and efficient in order to be best enforced.

Figure 4. Schematic of a typical distribution/trade process for fish (or corals or other invertebrates) destined for ornamental aquarium use. Credit: Frank A. Chapman, UF/IFAS

Responsible Trading

Despite the multitude of issues with the current aquarium fish trade, it is not inherently a negative thing. Responsible fish trading can be the solution to the current fish trade. Although aquariums have caused destruction to habitats and the near extinction of many fish species, they can also help maintain species that, in the wild, have already gone extinct. If managed and appropriately regulated, with a focus on sustainability, aquariums can still participate in the ornamental fish trade while also being part of the solution.

The trading process for fish is complicated, with many different steps and people involved. As such, individuals may not know where their fish come from and what effects their collection is having on the environment. As such, it is imperative for those interested in the ornamental fish trade to be educated and responsible about their own personal involvement. Public awareness could also be raised through the ornamental fish trade itself. An interest in ornamental fish could be expanded into an interest in fish-related environmental problems. Some of the profits from the ornamental fish trade could also be put toward fish conservation efforts. If these efforts are done consistently, both individuals and groups can provide benefits to fish conservation efforts and the environment while still partaking in the aquarium fish trade.