Tuesday, January 19, 2010

Sea Change for Salmon Husbandry

This is extremely promising for the aquaculture industry.  Fundamentally, everyone has assumed that salmon need to spend their life in the ocean.  Now it turns out that that is not true at all.  The consequences are huge.


We still have the issue of feed.  I am aware of work on replacing part of the feed with grains and I assume that will continue.  They are suggesting here that they can approach 1.1 to 1, except I heard that tale two decades ago.


I think though that we may have a far better option available.  It is expensive to raise fish in tanks.  So raise them in the lakes of the boreal forest.  These lakes have often been fished out and are forced through a serious die off every winter that decimates populations.  These salmon can in fact live in these lakes.  The lakes themselves are easily closed off to restrain migration if the fish are released only after they are properly sized.


The fish can be initially raised and fed in lakeside pens until they are so sized.


Far more important, small lakes are covered during the summer with mosquito and black fly larvae which should augment the feeding regime and perhaps keep the local environment somewhat more livable.  The reason this food supply is so substantial is that the winter die off has wiped out their predators.  Thus introducing a huge supply of active predators into the lake means that the natural food supply can be used.


The fish population will still need to be fed over the next winter, but that can be planned for and perhaps may be a mostly grain based diet.  After all we are simply carrying them over the winter until spring brings back the insect larvae again.


Winter feeding through the ice should not be difficult since we presently do ice fishing anyway.  In fact I suspect that the fishermen will help since it helps their sport.


I am sure these methods can be applied to other fish species, but we are most experienced with Coho at present since it happens to be ready for harvest inside of two years.


Sea Change: Environmental Group Gives First-Time Nod to Sustainable Salmon-Farming Method


An aquaculture company devises a new, sustainable process that raises Pacific Coho salmon in freshwater


SALMON SOLUTION: A new farming technique for Pacific coho salmon has received approval from a consumer education group that advocates for sustainable fisheries

Farm-raised salmon has long been the poster child of unsustainable aquaculture practices. Issues of escape, pollution and inefficiency have plunged it deeply into the "avoid" territory of environmental groups—until now.

In a report released January 14, the Monterey Bay Aquarium's Seafood Watch program is taking the unprecedented step of approving a particular method for farming Pacific coho salmon that is currently employed exclusively by the Rochester, Wash.–based AquaSeed Corp. The sustainability nod from the consumer education group means that these salmon also will be assigned a green "Best Choice" rating on Seafood Watch's Web site. The approval follows several months of intensive site visits by Seafood Watch scientists and reviews of the company's production facility, feed ratios, fish contaminant and pollution discharge levels, and more.

The salmon, to be sold under the SweetSpring label, have also been shown to contain high levels of omega-3 fatty acids, placing the salmon on Seafood Watch's newly created Super Green List, which denotes that the fish is good for human health without causing harm to the ocean. To appear on the Super Green List, the salmon must provide the daily minimum of omega-3s (at least 250 milligrams per day) based on 28 grams of fish, and have PCB (polychlorinated biphenyl) levels under 11 parts per billion (ppb). AquaSeed came in at 335 milligrams per day of omega-3s and had a PCB level of 10.4 ppb.

"This is the first farmed salmon we've ever talked about as a good source [for food, since the program's inception in 1999]," said Geoffrey Shester, senior science manager for Seafood Watch. "This is extremely exciting. It's not an experimental science project. It is mature to the point where there is real potential to scale it up."

The farming method

The AquaSeed Pacific coho salmon are raised in a freshwater, closed containment system, which is not how salmon are conventionally farmed. Salmon in the wild live primarily in saltwater but swim to freshwater every year to spawn. Traditionally raised farm salmon are grown in open-net ocean pens. This has led to problems such as nonnative species escaping into the wild and pollution as well as sea lice infestation and disease, because there is no barrier between captive salmon and the wild version in surrounding waters. Plus, traditionally raised farmed salmon require as much as five pounds (2.3 kilograms) of meal made from smaller fish caught in the wild for every pound (half kilogram) of salmon meat, a level that is considered unsustainable by environmental groups.

AquaSeed's salmon are grown in land-based, freshwater tanks ranging in size from 60 centimeters to 15 meters wide depending on the salmon's developmental stage. Containment tanks prevent escapes and problems with sea lice infestation that have plagued open-net ocean pen operations. Also, a high-end salmon feed and selective breeding has helped minimize fishmeal use, reducing the ratio of pounds of wild feed fish to produce pounds of farmed fish to 1.1 to one—a number AquaSeed owner Per Heggelund says he expects to whittle further.

"What's interesting about this is this is they've taken salmon back millions of years evolutionarily, to the point where they're freshwater again," Shester says.

Now on their 17th generation of pedigree breeding, the egg-to-plate operation is in the process of providing the salmon with a DNA fingerprint to help thwart any unauthorized breeding. AquaSeed's core business is selling "eyed" salmon eggs (eggs that have developed to the point that their eyes are visible) under the Domsea label to salmon farms in Japan, China and other countries. They've also been working to conserve endangered wild Pacific salmon stocks by maintaining an isolation and breeding facility operation, protecting 40 distinct families of salmon.

"We didn't set out to be in a food fish program in a land-based facility," Heggelund says. "That wasn't our goal. We were more focused on the genetics—the livestock breeding of salmon for the normal traits of survival at certain stages of the life cycle, productive growth and feed conversion, and egg production."

Producing 90,700 kilograms of salmon a year, Heggelund is preparing to rapidly expand production on his 20-hectare farm, and is already working closely with large purchasers such as Compass Group and Whole Foods as well as Mashiko, a Seattle-based sustainable sushi restaurant.

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