The truth about farmed salmon 'colouring': Are salmon dyed and are they safe to eat?

By Katherine Scott On Nov 30th, 2016

​People still baulk at the notion of synthetically coloured salmon, but are we missing the point?

The salmon lovers of our nation were left reeling after ABC's Four Corners revealed a widespread use of chemical colouring in the Tasmanian salmon industry. Footage of lead investigator Caro Meldrum-Hanna holding up a commercial salmon pigment chart that they'd "managed to get [their] hands on"—the gradient colour swatch used by salmon companies—became the unofficial poster of the salmon dyeing debate.

Following the report, there was an outpouring of fury from the Australian public, with concerns over the chemicals used and a general feeling of deception about the practice's existence.

​But while many consumers and consumer groups, including Choice, are shouting for more transparency in the industry around the labelling of synthetically coloured salmon, the question remains: is coloured salmon actually bad for us to eat? And should we be encouraging the industry to abandon the practice in place of a chemical-free farmed salmon—one with a decidedly less appealing white-ish-grey flesh?

9Kitchen spoke with Huon Salmon's group technical manager David Whyte and leading dietitian and creator of the Shape Me Kickstart program Susie Burrell to get their take on the controversial colouring agents and how they're affecting the salmon—and, by default, the humans—who consume it.

Do farmers dye their fish to make them look fresher?
While many food experts and manufacturers, including Huon Salmon, would argue that the practice of artificial salmon colouring is hardly the "closely guarded industry secret" Four Corners spoke of in their exposé, there's no denying that many Australians remain unwittingly oblivious to the practice—a fact that became patently obvious in the ABC report aftermath.

The chemical in question, interestingly, can be found in nature. "Astaxanthin is a naturally occurring antioxidant, meaning that it helps to protect cells from damage," Burrell tells 9Kitchen. "The functionality [of synthetic astaxanthin] is the same—a synthetic compound will have exactly the same effect in the body as naturally occurring.

"Salmon as a species metabolises this compound which gives the fish its rich pink colour. It is a natural process which occurs when fish consume a diet of algae and krill, which is simply mimicked with farm fish so they are receiving the same nutrients they would in nature, and their body is metabolising astaxanthin as it would in nature."

But does the practice go beyond cultivating a fish with visual appeal? According to Whyte, it's linked directly to the health of the farmed fish, which in turn effects the salmon's colour, taste and texture.

"Astaxanthin is essential to the salmon natural reproductive cycle and functions as a provitamin, being converted to vitamin A. Salmon are unable to make astaxanthin themselves, needing a dietary supply for these vital functions. It just happens to have a pink pigmentation to it, which in turn impacts the salmon flesh," Whyte says.

Are we better off leaving out the colouring agent (astaxanthin)?
Superficial concerns aside, is there a benefit to scrapping the chemical added to salmon feed altogether? In short, no—in fact, ditching it could actually have a disproportionately adverse effect on the fish according to Whyte, who manages the company's feeding systems. "Given its health benefits in salmon feed, it is poor practice to make feeds for this species without astaxanthin, and it is not natural for salmon to be depleted of this nutrient," Whyte says, adding salmon are not naturally white fleshed and thus farmed salmon are not naturally white fleshed.

Is wild salmon better for you?
Wild-caught Australian salmon is available—it's not as readily available or sustainable as its farmed contemporary, but if you have a good fish monger and are willing to only devour it in small amounts, the option is there. But are there any differences from a nutritional perspective?

"Nutritionally, not a lot [of difference between wild-caught and farmed], simply because farmed salmon is fed a diet that seeks to maximise the fish's natural nutrition and mimic what they would be fed in a wild scenario," Burrell says.

"In the same way the fatty acid profile differs in the beef we eat depending on diet, so too does the fatty acid profile differ depending on diet, and major farmers will give their fish a diet that keeps their fatty acids as similar to that of wild salmon as possible."

Why not use a naturally derived astaxanthin in salmon feed?
With the recent announcement of Australia's largest producer Tassal Salmon making the switch to a naturally derived source of astaxanthin by 2017, it begs the question: are there benefits to going natural over synthetic?

Tassal cited "a growing consumer preference" for a natural feed source, rather than any nutritional advantages, adding that sourcing a sustainable and reliable natural source had been a complex task for the company. 
Burrell's take on synthetic versions of the nutrient is that not only are they absolutely safe for human consumption (both directly, via supplements, and indirectly, via eating salmon), but they're necessary due to "availability and environmental sustainability"—large scale aquaculture farms rely on these nature-identical versions of the compound.
Whyte says that while Huon Salmon also recognises a customer and consumer preference for a natural, algae-derived version, algal cultivation can be a water-intensive process and not, in his opinion, as sustainable as the current method.

"The ability to make an identical version of this nutrient increases the ability of the industry to sustainably grow without impacting other industries or depleting naturally occurring, but limited, resources.

"Apart from the smaller carbon footprint [as a result of using a synthetic version], the salmon doesn't care where the astaxanthin comes from, so there is no biological benefit from one source versus another. The same is true of most animals, for example–the vitamin C that we might take in supplements is fully synthetic, it's not extracted from oranges or other fruit, but our bodies will use it regardless."

Source: http://kitchen.nine.com.au/2016/11/30/16/10/the-truth-about-farmed-salmon-colouring