Reprinted from Seafood for the Future Blog http://seafoodforthefuture.org/2010/07/marine-harvest-visit-part-one/
Andrew and I spent the better part of last week in Canada visiting salmon farming facilities in British Columbia, starting with the Skretting feed mill in Vancouver and ending with a hatchery in Campbell River. It was our hope that a firsthand view would give us greater insight into the practices of British Columbian salmon farming.
From the beginning, it is clear that this trip will not be a formal investigation. We have been invited to Campbell River as guests of Marine Harvest, and it is not our intent to validate BC salmon farming practices by going on a guided tour. However, much can be learned simply through observation; Andrew can walk through any commercial kitchen and tell you how well it is run from the subtle clues that only an experienced chef would recognize. Based on my experience, I can usually say the same of fish farms and the facilities that support them. The type of equipment we see, the condition of the facilities, and the proficiency of the technicians will tell us far more than the official tour.
Clare Backman, Director of Sustainability for Marine Harvest, picks us up on the Canadian side of customs and will be our guide for the duration of the trip. He is determined to give us an experience that is as objective as possible. “I’m not going to sugar coat anything for you,” he states soberly. In spite of this, Backman is genuinely excited to visit some of the sites with us, not often having an excuse to visit facilities like the feed mill. It’s one of the places we’ve specifically asked to visit in order to better answer questions about the content of the feed.
Located in Vancouver, the Skretting feed mill is the primary producer of feed for Marine Harvest. Skretting world wide produces around 1 million tons of feed annually. Interestingly, Skretting also provides feed to salmon hatcheries that grow fish for enhancement of wild salmon stocks here in the US.
Chris Oikawa, nutritional specialist for Skretting, meets us at the reception desk and invites us into the conference room to answer questions. Oikawa started his career in the husbandry department of the Vancouver Aquarium, and we chat amiably about public aquariums and their similarities with fish farms. After a brief presentation on the nutritional requirements of fish and the history of technology employed by the mill, we’re ready to get see the actual process of making feed.
The smell of fresh feed permeates the whole facility, but quickly fades into the background as we become accustomed to it. We put on the required lab coats and safety gear as Wayne the technician extruder (pellet making machine) operator describes the flow of materials through the mill and how the process is controlled from a central command station. The status of each machine can been seen at a glance on the monitors in this room. “Let’s go into the mill itself,” Wayne suggests, watching me squint at the screen, “then you’ll have a better idea of what you’re looking at here.”
We step out of the control room into the mill, where the abrasive thrumming of the machines is deafening. In spite of the noise, I keep my earplugs in my hand so I can hear Wayne’s description of each step. Wayne stops at the extruder – arguably the heart of the mill – to explain the machine that creates pellets from a doughy mixture. The extruder is like a giant Play-doh spaghetti maker, with an auger that pushes the dough through a pellet die. The size of the holes in the pellet die determines the diameter of the pellet, which is different for each size of fish according to the size of its mouth. The smallest size is barely larger than a grain of sugar. Today, Wayne is making 12mm pellets, the largest pellet made for salmon.
Truthfully, there is not much new here in terms of the handling of the ingredients; this is the same extrusion technology used to produce certain kinds of breakfast cereals. The advantage of this technology is that not only can the pellet size and content be tightly controlled, but also its buoyancy. A steam jacket surrounding the barrel of the extruder controls the temperature of the auger, barrel, and pellet mix. Controlling the temperature of the jacket results in more air in the mix and breakfast cereal or fish pellets that float. For salmon, a slow-sinking pellet is desirable in order to give the fish enough time to strike the pellet.
Wayne takes us to each station in turn to ensure that we see the whole process. It’s a bit confusing, since we’re not going in order: we start at the step closest to the control room, winding through a maze of catwalks whose layout is partly governed by use of gravity to move the ingredients. Each time we pass the extruder – some five times in the course of the tour – Wayne opens a panel and deftly removes a sample of brand new pellets. Correct texture, color, and shape can be seen by eye by an experienced technician long before the formal quality control procedures, and Wayne takes a second to examine each sample before herding us along.
Those formal quality tests happen in the mill’s laboratory, where Wayne and the other technicians examine each batch of pellets for their physical qualities, nutritional content, and a metric known as pellet durability. Durability is a characteristic that must be tailored to each species and its needs. Shrimp, being slow-eating bottom dwellers, require a sinking pellet that is highly durable so they can take their time eating it. For salmon, the degree of pellet durability is determined by the automated feeding system that shoots the pellets out to the fish pens. If the pellet has insufficient durability, it will break into pieces and be wasted. With feed representing 60% of the cost of raising fish, farmers have a strong incentive to ensure that maximum feed efficiency begins with the pellet itself.
Examining the pellets as they exit the durability tester, another unique characteristic of the feed is apparent. The pellets are harder than dog food (the closest equivalent that comes to mind), but nowhere near as gritty. Like pellet fragments, any dust or grit (technically known as “fines”) would be lost in the water and unavailable to fish. Thus, the finished pellets are necessarily uniform and almost clean-looking.
At this point, Oikawa hands me a small tub of one of the ingredients being tested. It is a dried substance that resembles ground herbs or seeds. “It’s poultry meal,” says Oikawa, smiling. “Smell it. It’s like peanut butter.” Sure enough, it has a clean, sweet scent that makes me momentarily desire some complementary jam and bread. It’s surprisingly far from what I had imagined poultry meal to be like, so I press Oikawa for details.
It turns out that farmed salmon do not have to fulfill their nutrient requirements from any particular source. That is, while salmon require protein and lipids, they are perfectly capable of using less expensive and more sustainable vegetable or animal meal instead of fishmeal and fish oil (though complete replacement is not yet possible). However, fishmeal and fish oil used in salmon feeds are included not only for the sake of the fish. These ingredients are used so that the salmon will have a nutritional profile that is suitable for human consumption, particularly with respect to omega-3 fatty acids. In this case, Marine Harvest requires Skretting to include enough fishmeal and fish oil in the feed to produce salmon that match the fatty acid profile of wild Pacific salmon (roughly 2.8g per 100g edible portion).
Later on the trip, Backman would show me an email he’d just received on his Blackberry from [a large, well-known retail chain] regarding the omega-3 content of Marine Harvest products. The retailer performs its own testing for omega-3 levels and requires Marine Harvest to produce salmon with the nutritional profile they have agreed upon. In effect, the retailer and Marine Harvest have created a standard for the nutritional benefits of farmed salmon on behalf of their customers.
Considering that there is no government requirement for omega-3 content in any salmon, I find this to be an interesting example of corporate responsibility.
Apart from protein and lipids, what else is in the feed? Carbohydrates make up the next major component, followed by minerals, moisture, and vitamins/pigments. Carbohydrates are not as big a part of salmon diets as they are for many other land farm animals, since there aren’t very many starchy or sugary food sources available in the ocean. Consequently, fish really don’t use carbs for fuel.
20 – 38% lipids: fish oil, vegetable oil (e.g. canola oil)
10-13% carbohydrate (includes fiber)
37% – 50% protein – fish meal, corn gluten, wheat, soya meal, poultry meal
10% minerals (e.g. potassium, known as pot-ash)
7% moisture
<1% vitamins (B, C, E) and pigments
Pigments have been cited as a major concern for consumers even though they make up a small percentage of the diet, so we linger on this topic for a bit before leaving the feed mill. It turns out that what is sometimes referred to as “dye” or “paint” is a naturally-occurring pigment found in many red, orange, and yellow vegetables (think bell peppers). This group of colorants, known as carotenoids, is named for the fact that they make carrots orange. Like the beta-carotene found in carrots, the carotenoid pigment used in salmon feed (astaxanthin) is a powerful anti-oxidant that is quite good for you. It’s surprising how often we hear the nutritional advice to eat more vibrantly colored natural foods (Chef Ann Cooper adds her own caveat that gummy bears do not count), but we do not often recognize that salmon falls within this category.
Finally, I ask Oikawa about the use of antibiotics, since they are not on the ingredient list. Only a few have been legally approved, he says, and both the US and Canada explicitly require the supervision of a veterinarian for their use. Despite popular belief, fish farms cannot use antibiotics to promote growth or prevent disease – only as a treatment prescribed by a vet. Consequently, their usefulness is limited.
If you want to find out more about formulated feeds for salmon, see the FAO document entitled Nutrition of Fish and Crustaceans: a Laboratory Manual.
Andrew Gruel manages 