Fluorescent Transgenic ‘GloFish’ and their rapid colonisation of Brazilian Waters.

depositphotos 237259012 stock photo macro beautiful fish glo tetra

To understand the rise of the GloFish, we must first look at the humble Zebrafish (Danio Rerio), which has been a staple of freshwater hobbyists globally since forever. Easily recognisable with its striped body, this hardy, sociable and attractive little fish of the minnow family has its origins in South Asia, namely India, Bangladesh, Nepal and Bhutan. 

Since the 1960s however, Zebrafish have been at the forefront of a lot of biochemical research. Coined a ‘model organism’ due to how easy they are to keep and breed, coupled with their suitability for complex, experimental procedures. They also possess several advantages over rodents – they are cheaper and transparent to name just two! – and are used to model human diseases.

They are particularly useful in the advancement of precision medicine in areas concerned with mental disorders, metabolic issues and developmental problems. This incredible fish has helped us understand the biological processes behind muscular dystrophy and the development of cancer.

While the scientific interest in Zebrafish always ran at a parallel with the pet industry, it is now clear the field of biology has coalesced entirely with the ornamental fish trade. In 1999, the National University of Singapore successfully extracted genes from a jellyfish and introduced them to a Zebrafish embryo. It integrated itself in the genome and this transgene endeavour produced a fish which presented with a fluorescent green hue under natural and ultraviolet light.

This transgenic fish was originally conceptualised to detect environmental toxins, with the idea being that the modified Zebrafish would spontaneously fluoresce when it came into contact with harmful substances, much like a canary in a coal mine, these fish would be used as beacons in pollution tracking in the first instance. The original engineered fish were fluorescent permanently, but were a vital first step in achieving this goal. Subsequently, the National University of Singapore filed a patent.

After this initial breakthrough, the experimentation leaned towards engineering certain colours, with the help of sea coral and another variant of jellyfish gene, red and yellow-orange fluorescent fish were created.

The novelty and marketability of these fish clearly wasn’t lost on anybody, as the scientists from the University and head honchos from Yorktown Technologies L.P – A Texas based company – colluded and a deal was signed. Yorktown Technologies were handed the worldwide rights to market the fluorescent fish. It was from here that the newly branded ‘GloFish’ was born, and exploded onto the ornamental freshwater scene.

The GloFish was the first genetically modified animal to become commercially available and was introduced to the States in 2003, after gaining approval from the Food and Drug Administration (The FDA) whose jurisdiction carries over all GM plants and animals.

They deemed the GloFish as presenting no risk to public health or the environment, ceasing any need for more stringent regulation. This decision was met with concern and hesitancy by the Center for Food Safety (a non-government, non-profit association), who argued that the FDA’s assessment was unwise, and could set a precedent whereby releasing the floodgates to more non-food, genetically modified organisms, which could have unsafe and unethical consequences, a view supported by numerous scientific review boards. Unfortunately for the Center of Food Safety, these concerns were deemed to be without merit and their case was dismissed in 2005.

Since 2003, GloFish popularity has boomed in the aquarium trade and the scope for what can be engineered to fluoresce has been widened further, with the addition of Bettas, Tetras, Barbs and even sharks, with more trademarked colours available too. In 2011, genes were incorporated from corals which induced dazzling blue and purple zebrafish, these were released and their fluorescent lines branded as ‘Cosmic Blue’ and ‘Galactic Purple’. GloFish continue to be diversified and sold, with the brand being bought by Spectrum Brands Inc in 2017, for a fee in excess of 50 million dollars.

Although aesthetically pleasing, and considered by the average consumer as harmless and colourful; issues of morality and legality still persist in Canada and Europe, where the fish are banned. In 2014, a single GloFish was sighted in Tampa Bay, Florida. Then in 2015 in the South American continent. Questions were raised by concerned biologists, as a potentially more sinister development continues to unfold in the creeks of the Atlantic Forest in Brazil.

In the South Easterly region, transgenic zebrafish have become inadvertently established in the waterways after escaping from local fish farms. Although now banned in Brazil, biologists and ecologists alike worry these illegal alien fish could pose a real zoological threat in one of the most diverse ecosystems in the world. First spotted by biologist André Magalhães, he and his colleagues went on to survey 5 different waterways in 3 different municipalities in 2017, only to discover GloFish in all of them.

Ecologist Jean Vitule, at the Federal University of Paraná, Curitiba. Described the velocity with which the GloFish populations have increased as “serious” and the impacts “unpredictable”.  It troubles him to think that these fluorescent genes could become prevalent in native fish, making them more vulnerable to predation. He said the introduction of these fish was “like a shot in the dark”.

In 2020, isolated GloFish were seen in South and North East Brazil in ponds and streams and although it remains to be seen whether they colonise the whole of Brazil, their current breeding success speaks for itself as they continue to spread.

Although negative long term implications are yet to be established – a point which is made by GloFish enthusiasts and retailers alike – it can be argued that the occurrence of a detrimental effect increases with the prevalence of the animal, and that if a long term effect does manifest, it will be harder and harder to manage as the population booms, much like shutting the stable door after the horse has bolted. A simple shrugging of the shoulders shows a lack of understanding about the complexities and sensitivities of ecosystems. For now though, GloFish remain a popular choice for hobbyists, as the varieties grow along with the demand. Whether this will raise more questions ethically and environmentally, only time will tell.

Here at Tankbred, we take the view that prevention is better than cure. While we understand the appeal of these alluring fish, we would rather stop an ecological disaster from ever occurring, than try to reverse the damage at a later date, which is much harder. We support the EU’s prohibition of GloFish, as right now, the data just isn’t available to guarantee that the GloFish’s presence in the wild won’t cause harm somewhere in the food chain and the surrounding delicate ecosystems.

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