The Science Behind Genetically Modified Salmon: How It’s Made and Why It Grows Faster

Salmon has long been a favorite at the dinner table, but with increasing demand, fish farms and wild populations have struggled to keep up. Enter genetically modified (GM) salmon, a scientific marvel engineered to grow faster, reduce pressure on wild fisheries, and meet the world’s growing hunger for seafood. But how exactly does this salmon achieve its rapid growth? And what does this innovation mean for aquaculture and the environment?

In this article, we'll break down the science behind genetically modified salmon, how it’s made, and why it grows faster, all while examining the benefits and concerns this breakthrough brings.

A New Kind of Fish: How Is GM Salmon Made?

The genetically modified salmon that has generated so much discussion is officially called AquaAdvantage Salmon. It’s the brainchild of AquaBounty Technologies, a company pioneering the use of genetic engineering in aquaculture. AquaAdvantage Salmon isn’t just your ordinary farmed fish—it’s a hybrid created to grow much faster than its non-GM counterparts.

But how exactly is this done? Let’s dive into the science.

The Genetic Recipe

At its core, the genetic modification of AquaAdvantage Salmon involves inserting specific genes from other fish species into the genome of an Atlantic salmon. Here’s how it works:

1. Chinook Salmon Growth Hormone Gene: A gene from the Chinook salmon, the largest species of Pacific salmon, is introduced into the Atlantic salmon's DNA. This gene is responsible for producing growth hormone.

2. Ocean Pout Promoter Gene: To ensure that the growth hormone gene is active all year round, a promoter sequence from the ocean pout (a type of eel-like fish that lives in cold waters) is added. This promoter ensures that the salmon grows continuously, unlike regular Atlantic salmon that only grow during warmer months.

By combining these two genes, scientists create a fish that can grow year-round at a much faster rate than conventional salmon. Normally, Atlantic salmon reach market size (about 4-6 kg) in about 36 months. AquaAdvantage Salmon can reach the same size in just 18 months—cutting the growing time in half.

Why Does GM Salmon Grow Faster?

So, why exactly does this genetically modified salmon grow faster? The answer lies in the growth hormone.

In non-GM salmon, growth hormone is produced naturally but only during the warmer months of the year when the water temperature is optimal. In colder months, salmon growth slows down significantly or even stops altogether. This is a survival mechanism in wild salmon, as it helps them conserve energy during the harsh winters.

However, for farmed fish, this slowdown isn’t necessary—and that’s where the GM modifications come in.

By adding the Chinook salmon growth hormone gene and the ocean pout promoter, AquaAdvantage Salmon continues producing growth hormone throughout the year, even in colder temperatures. As a result, the fish experiences continuous growth rather than seasonal fluctuations. Essentially, GM salmon skips the natural pauses in growth that its wild cousins experience.

The Data: How Much Faster Does GM Salmon Really Grow?

The claim that GM salmon grows faster is not just a marketing pitch—it’s backed by solid data. According to AquaBounty, AquaAdvantage Salmon grows to market size in 18 months, compared to the typical 36 months for non-GM Atlantic salmon.

Here’s a breakdown of how much time AquaAdvantage saves:

• Non-GM Salmon: 36 months to reach market size (about 10 pounds)
• GM Salmon: 18 months to reach market size (about 10 pounds)

This acceleration in growth time means that fish farmers can produce more salmon in a shorter period, theoretically lowering costs, reducing resource consumption, and making the production process more efficient.

The Benefits of Genetically Modified Salmon

The rapid growth of GM salmon brings several potential benefits, both for the industry and the environment.

1. Increased Food Production

One of the most pressing global issues is how to sustainably feed a growing population. With world population estimates reaching 9.7 billion by 2050, the demand for high-protein, sustainable food sources will only increase. GM salmon offers a faster, more efficient way to produce high-quality protein without overburdening the world’s already strained wild fish populations.

2. Reduced Pressure on Wild Fish Stocks

Wild salmon populations are under immense pressure from overfishing, habitat destruction, and climate change. By creating a faster-growing alternative, GM salmon could help alleviate some of the demand for wild-caught fish. This would give wild populations time to recover and reduce the impact of overfishing on marine ecosystems.

3. Lower Environmental Impact of Fish Farming

Fish farming, or aquaculture, has faced criticism for its environmental impacts, particularly water pollution, disease transmission, and habitat destruction. By producing more fish in less time, GM salmon could potentially reduce the environmental footprint of aquaculture. With shorter production cycles, fish farms could use fewer resources like water, feed, and energy, making the entire process more sustainable.

Public Concerns: Are There Risks Involved?

Despite its potential benefits, genetically modified salmon has sparked a debate among scientists, environmentalists, and the general public. Let’s explore some of the concerns.

1. Environmental Risk: What If GM Salmon Escapes?

One of the major concerns surrounding GM salmon is the possibility of it escaping from fish farms and interbreeding with wild populations. Although AquaBounty has taken precautions, such as raising the fish in inland tanks and sterilizing the majority of GM salmon to prevent breeding, critics argue that no system is foolproof.

If GM salmon were to escape into the wild and reproduce, they could potentially outcompete native species for resources due to their faster growth rate. This could disrupt local ecosystems and threaten biodiversity.

What the Data Says: AquaBounty’s tests indicate that less than 1% of their salmon are fertile, significantly reducing the risk of crossbreeding with wild populations. Additionally, raising the fish in inland tanks rather than ocean-based farms further minimizes the risk of escape.

2. Health Concerns: Is GM Salmon Safe to Eat?

The safety of genetically modified organisms (GMOs) in our food supply has been a hot topic for years. So, is GM salmon safe to eat? According to the U.S. Food and Drug Administration (FDA), AquaAdvantage Salmon is “as safe to eat as non-GE (genetically engineered) Atlantic salmon.”

The FDA’s approval in 2015 was based on a comprehensive analysis of the nutritional profile, allergenicity, and safety of the salmon, concluding that there are no meaningful differences between GM salmon and its non-GM counterpart.

3. Labeling Controversy: Should Consumers Be Informed?

Another major concern revolves around labeling. Many consumers believe they should be informed if the salmon they’re purchasing has been genetically modified. Although the FDA ruled that GM salmon does not require a special label since it is nutritionally equivalent to regular salmon, this has sparked a wave of debate. Some argue that transparency is critical in giving consumers the freedom to choose what they eat.

As of now, some retailers have voluntarily chosen to label GM salmon, while others have refused to sell it altogether. In 2019, the U.S. Department of Agriculture (USDA) established a mandatory labeling requirement for bioengineered foods, which includes genetically modified salmon, but it remains a controversial topic.

The Future of Genetically Modified Salmon: What’s Next?

AquaAdvantage Salmon was officially approved for commercial sale in the United States and Canada, with the first batches hitting U.S. markets in 2021. While this marks a significant step forward for genetic engineering in aquaculture, it’s still just the beginning.

The success of AquaAdvantage could pave the way for other genetically modified fish species, potentially transforming the entire seafood industry. As we move into the future, the key question will be how we balance the potential benefits of GM fish with environmental concerns and public sentiment.

Conclusion: Innovation or Risk?

The science behind genetically modified salmon is impressive. By using genetic engineering to create a faster-growing fish, scientists have potentially revolutionized the future of seafood production. AquaAdvantage Salmon has the potential to meet growing food demands, ease pressure on wild populations, and reduce the environmental footprint of aquaculture.

However, like all technological innovations, GM salmon comes with its share of challenges—environmental risks, health concerns, and transparency issues. As consumers and regulators continue to navigate the murky waters of genetic engineering, it will be crucial to strike a balance between innovation and caution.

For now, the rapid growth of GM salmon stands as a testament to how science can shape the future of food. The only question is, are we ready to embrace it?