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Farmed vs Wild Salmon? - A comparison

Salmonids Economics

By David Cox, the Fish Vet Group - "You don't want to eat that - it's farmed!! How often have we heard that phrase? So-called discerning gourmets pontificating on the relative demerits, rarely (if ever) merits of farmed salmon versus the real thing.

Fish Vet Group

They wax lyrical with the romantic notion of Salmo salar - the leaper - fighting its way upstream against all the odds in pursuit of achieving immortality on the spawning redds. Some recent articles have clearly distorted and misrepresented facts, showing pictures of obviously mature fish which no self-respecting Fish farmer worth his or her salt would ever sell as a Superior-grade fish.

Let's try to have dispassionate look at just some of the contentious facts relating to the "two species".

  1. Feed and feeding
  2. Harbingers of disease
  3. Environmental polluters
  4. Freedom, from fear, from suffering
  5. Chemicals used
  6. Colouring agents
  7. Harvesting methods
  8. Flavour and texture

1. Feed and feeding

Wild salmon feed on natural food - none of your artificial feed with all its additives Farmed fish are fed on a diet based on their species requirements as found in wild fish. The difference is that the energy levels of current diets are significantly higher than that found in the diet of wild fish. Additionally most, but not all, farmed fish are increasingly fed to satiation all day , every day - unlike their wild counterparts who do not necessarily manage to eat every day.

The plus side for farmed fish is that high energy diets do allow fish to grow much faster thus making production more cost-efficient , a necessary requirement for today's fish farmer. The oils that they store belong to the health-promoting Omega class of oils - a fact that should be more widely advertised. The negative side is that farmed fish , fed to satiation, are significantly oilier than wild fish - there is no disputing this fact, no matter what feed companies might say. High flesh oils present smokers with a real challenge in producing a quality product - with free oil, textural and oxidation problems.

Fish oils along with fish meals are finite resources. Replacements for both are being actively pursued by feed manufacturer's eg substitution by soya meal - another finite resource with genetically modified organism (GMO) implications.

2. Harbingers of disease

With the introduction of very effective vaccines against furunculosis farmed fish no longer have to run the risk of contracting furunculosis from wild fish - yes wild fish - they are the carriers of this previously devastating bacterial disease. The only risk period for this disease at present is during the early stages of growth up to the point where fish can be vaccinated.

Sea lice have been , and continue to be, the Number 1 enemy of the fish farmer . As well as inflicting damage to fish they can be carriers of many other diseases such as IPN and possibly ISA. Although effective treatments have been identified through research, these are yet to become freely available. Fish farming companies are still jumping through the not inconsiderable number of hoops of the authorisation process with acquisition the consent to discharge (the holy grail). In their defence, fish farmers have made considerable progress towards co-ordinated strategies for treatment of sea lice but are severely limited by lack of availability of effective treatments.

3. Environmental polluters

Short -sighted, so-called environmentalists blame fish farms for all the recent blooms of plankton and jellyfish with graphic descriptions of uneaten feed and faeces falling through pens encouraging all manner of toxic plankton to grow exponentially.

Blooms are a world wide phenomenon and have been around long before the advent of fish farms. Their development is a lot more complicated than being simply due to fish farms - global warming is a much more likely significant factor.

4. Freedom, from fear, from suffering

Freedom from fear is an emotive term - but it could be argued that fear aka stress is a natural response to a potentially life-threatening situation and consequently a necessary evil. Fish like all animals , including man, live by their senses and it could be said that a little bit of stress is no bad thing for keeping fish in touch with the real world. However it clearly does not mean that increasing stress levels is a good thing because chronic production of stress hormones will lead to severe negative effects on growth and resistance to disease - it will even affect flesh quality following harvesting. Wild fish are beset by all manner of stressors throughout their lives including predators such as birds, seals and man and water-related problems such as declining oxygen levels with increasing water temperatures and decreasing water flows as experienced in summer time. For obvious reasons, farmed fish are a captive beast excluding recent newspaper articles reporting large numbers of escaped famed salmon.

Investigations into freedom from fear and from suffering in farmed fish are being actively pursued and encouraged by a number of organisation including the RSPCA, the Humane Slaughter Association and some of the larger Supermarket chains such as Tesco's.
This work must, and I am sure will, continue.

5. Chemical usage

Unlimited, uncontrolled chemical usage has long been laid at the Fish farmer's door when in reality intensive aquaculture is one of the most tightly controlled industries in the UK. The oft quoted assertion that all farmed fish have been fed on antibiotics all their short lives is a fallacy. Antibiotic usage has dropped to virtually nil following the introduction of very effective vaccines in the early 1990's. SEPA has done an "excellent" job of reducing chemical usage by farmers applying to use sea lice treating chemicals - these same "chemicals" have been acceptable to Norwegian authorities and widely available to Norwegian fish farmers for a number of years. Terrestrial farmer's have been discharging far more damaging chemicals onto the land and into watercourses for much longer than fish farmer's.

6. Colouring agents

A lot of hype has been generated by the anti-fish farming lobby regarding the so-called artificial colouring agents used to feed fish. The 2 main pigment used by the majority of fish farmer's are indeed artificially produced but are chemically indistinct from the natural form. Wild salmon derive pigment from the various insects, crustacea and fish that they feed upon and typically have much lower levels of pigment. Given this fact I am always surprised that farmers have to achieve such high levels of pigment in their product at no inconsiderable cost to the Farmer. If wild are perceived to be the desired product for the consumer then why not spend less on pigment. Uptake of pigment by salmon is remarkably poor, typically less than 10%, so the only person gaining financially from high flesh pigment is the pigment supplier.

7. Harvesting methods and post-harvest handling

Farmed salmon are starved for an average of 7 days before harvesting in order to clear the alimentary tract which can otherwise lead to flesh quality problems post-harvest as digestive enzymes continue to operate. This will not happen in wild caught fish which may or not contain feed. Farmed salmon may or not be narcotised using carbon dioxide or killed by a blow to the head followed by cutting the gills to remove most of the blood. Bleeding fish reduces any bloodspotting problem for Smokers' - to the best of my knowledge wild caught salmon do not have their gills severed. Farmed salmon are then immediately placed into a water / ice slurry thus ensuring very effective chilling of fish prior to gutting and possible filleting. The chilling process retards the passage of fish into rigor, slows down digestive enzymes and significantly reduces any bacterial growth and consequent spoilage. Farmed salmon are rigorously monitored through all the critical stages of the post-harvest process all the way through to the Fish processor - are wild caught salmon subject to such close scrutiny ?

8. Flavour and texture

Is farmed fish really an inferior product ? I personally do not believe this to be so. A lot of the larger Fish farming companies carry out their own taste panels on a regular basis to ensure the quality of their product. I have yet to see any properly performed trial comparing the eating quality of farmed versus wild salmon where farmed is inferior to wild.

In my opinion, the majority of farmed fish are in no way an inferior sub-species of the genus Salmo. The positive aspects of fish farming really need to be better co-ordinated and stated more strongly and more frequently. As an industry , fish farmers can no longer sit back and let the anti's throw all the mud they can - it's going to start to stick - soon we won't be able to wash it off.

Source: Fish Vet Group - November 2006