In case you missed the current affairs program, Four Corners delved into the issues related to mass scale near-shore salmon farming in Tasmania -- primarily the spike of water temperature and dangerous drops in water oxygen levels in Macquarie Harbour this year, where companies Tassal, Petuna Seafoods and Huon Aquaculture are intensively farming salmon.
These are issues which will not go away. In fact, if we don't address the problems inherent to salmon farming, we're not addressing our environment's needs and something bad is going to happen -- if it hasn't already. To get a deeper understanding about salmon farming in Australia, its effects and what solutions we can implement to ensure long-term sustainability, The Huffington Post Australia spoke to three sustainability and aquaculture experts.
The feed which is fed to salmon is one of the main issues of farming affecting the environment due to two reasons: Getty Images Young salmon break the water's surface as they rush for fish meal pellets fired from an air gun. Port Temperance, Dover, Tasmania, Australia. In the wild, adult salmon eat other fish, squid, eels and prawns. According to associate professor Kathy Schuller, who researches omega-3 fatty acid metabolism and oxidative stability in aquaculture species at Flinders University, a salmon's diet is what produces the quality of salmon we eat.
But farmed salmon aren't being fed a diet mostly of other marine animals -- and depending on your viewpoint, this is both a good and bad thing. And those ingredients are partially replacing ingredients that would originally have come from small fish in the marine environment," Schuller told The Huffington Post Australia. By changing the diets that are fed to the farmed fish, we can reduce the pressure on, for example, sardines that are normally caught to feed larger fish. This change in feed to reduce the impact on the marine environment is a great change, said Graham Mair, professor and director of Marine Sciences at Flinders University, who specialises in aquaculture and genetic breeding programs.
Peter Hendrie Salmon and trout cages in Macquarie Harbour, Tasmania, which is an area for concern, experts say. For example, fish meal that might come from Peruvian anchovies. Now it's only about 30 percent. So the rest of it is coming mostly from plants and sometimes by-products of livestock industries, which are already being harvested so they're more sustainable sources. Mair also highlights that the amount of salmon feed needed for one kilogram of salmon is much less than needed for other animal proteins.
Whereas most other forms of primary product are much higher than that. Bloomberg via Getty Images Salmon pass through a shower of fresh water, a process for preventing amoebic gill disease, at Huon Aquaculture Co. While a mixed fish feed of plant and land animal by-products is reducing the need for other fish like sardines and anchovies, Schuller said this diet can compromise the nutritional profile of salmon, which are a 'super food' for their long chain omega 3 fatty acids. Sardines, for example, are very rich in long chain omega 3 fatty acids.
Whereas canola oil, which has been used as a replacement for fish oil in feeds for farmed fish, doesn't contain those long chain marine-type omega 3 fatty acids," Schuller said. That's why it's recommend that people eat more seafood, because they get the long chain omega 3 fatty acids.
Everything You Should Know About Salmon Farming
By using canola oil, there is a reduction in these marine type fatty acids in the edible part of a farmed fish, Schuller explains. So you can boost the levels of these long chain omega 3 fatty acids in the flesh of the farmed fish. Then comes the issue of farmed salmon's flesh colour, which is actually grey if the salmon is not fed feed which includes astaxanthin, the supplement that makes the salmon flesh red. In Tasmania, the astaxanthin in the salmon feed comes in the form of chemically synthesised astaxanthin, which Schuller said is "exactly identical to what would be found in the food chain in the wild".
The consumer expects their salmon to be red, and that's why the salmon farmers include the astaxanthin in the feed for the farmed salmon," Schuller said. Some studies also suggest that salmon farming increases mercury contamination in wild fish. The second part of the feed issue is when excess salmon feed and excrement settles to the bottom of the sea pens and seafloor, which can negatively affect the water oxygen levels, leading to mass fish deaths.
And when you add salmon all defecating, not only does it kill the salmon but it really makes a mess of our waterway. It's a beautiful place otherwise. Philip Game Uneaten feed and faecal matter settles on the bottom of the cages and seafloor, which can create low oxygen water. I know sea pens are very economical for them and they're able to make huge profit, but I'm very concerned about the collateral damage of sea pens on the environment.
Salmon do not thrive in warm water, hence why they are farmed in the coolest part of Australia. Even still, the Tasmanian waters are too warm for salmon, which is why they have been modified to suit the climate. It's almost worth more than the entire rest of the Australian fishing fleet. And what is it? It's an introduced species that's come into Australia which has been farmed in a situation where it's in our lakes and rivers -- it's not onshore in a completely contained system, it's in these pens," Booth said.
We rank around 56th in the world in terms of wild fish catch. New Zealand is around seventh. Through selective breeding, it's possible to choose advantageous traits and breed salmon which suit Tasmanian conditions. Four Corners also reported that Tassal, through intensive breeding, can manipulate salmon so they carry both testicles and ovaries. Of course the reason they have the salmon is Tasmania is it's the coldest part of Australia but it isn't cold enough. I've spent time in Canada and there are many species of salmon that wouldn't survive in Australia, it's too warm.
My guess is the industry will naturally die off as the ocean warms, in Australia anyway. Salmonids particularly salmon and rainbow trout , along with carp , and tilapia are the three most important fish species in aquaculture. Chinook salmon and rainbow trout are the most commonly farmed salmonids for recreational and subsistence fishing through the National Fish Hatchery System.
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Salmonid aquaculture production grew over ten-fold during the 25 years from to In , the leading producers of salmonids were Norway, Chile, Scotland and Canada. Much controversy exists about the ecological and health impacts of intensive salmonids aquaculture. Of particular concern are the impacts on wild salmon and other marine life. Some of this controversy is part of a major commercial competitive fight for market share and price between Alaska commercial salmonid fishermen and the rapidly evolving salmonid aquaculture industry. The aquaculture or farming of salmonids can be contrasted with capturing wild salmonids using commercial fishing techniques.
However, the concept of "wild" salmon as used by the Alaska Seafood Marketing Institute includes stock enhancement fish produced in hatcheries that have historically been considered ocean ranching. The percentage of the Alaska salmon harvest resulting from ocean ranching depends upon the species of salmon and location.
Methods of salmonid aquaculture originated in late 18th-century fertilization trials in Europe. In the late 19th century, salmon hatcheries were used in Europe and North America. The contemporary technique using floating sea cages originated in Norway in the late s. Salmonids are usually farmed in two stages and in some places maybe more. First, the salmon are hatched from eggs and raised on land in freshwater tanks. Increasing the accumulated thermal units of water during incubation reduces time to hatching. This farming in a marine environment is known as mariculture.
There they are fed pelleted feed for another 12 to 24 months, when they are harvested. Chile is close to large forage fisheries which supply fish meal for salmon aquaculture. Scotland and Canada are also significant producers. Modern salmonid farming systems are intensive. Their ownership is often under the control of huge agribusiness corporations, operating mechanized assembly lines on an industrial scale.
Modern commercial hatcheries for supplying salmon smolts to aquaculture net pens have been shifting to recirculating aquaculture systems RAS s where the water is recycled within the hatchery. This allows location of the hatchery to be independent of a significant fresh water supply and allows economical temperature control to both speed up and slow down the growth rate to match the needs of the net pens. Conventional hatchery systems operate flow-through, where spring water or other water sources flow into the hatchery.
The eggs are then hatched in trays and the salmon smolts are produced in raceways. The waste products from the growing salmon fry and the feed are usually discharged into the local river. An alternative method to hatching in freshwater tanks is to use spawning channels. These are artificial streams, usually parallel to an existing stream with concrete or rip-rap sides and gravel bottoms. Water from the adjacent stream is piped into the top of the channel, sometimes via a header pond to settle out sediment.
Spawning success is often much better in channels than in adjacent streams due to the control of floods which in some years can wash out the natural redds. Because of the lack of floods, spawning channels must sometimes be cleaned out to remove accumulated sediment. The same floods which destroy natural redds also clean them out. Spawning channels preserve the natural selection of natural streams as no temptation exists, as in hatcheries, to use prophylactic chemicals to control diseases.
However, exposing fish to wild parasites and pathogens using uncontrolled water supplies, combined with the high cost of spawning channels, makes this technology unsuitable for salmon aquaculture businesses. This type of technology is only useful for stock enhancement programs. Sea cages, also called sea pens or net pens, are usually made of mesh framed with steel or plastic.
A large sea cage can contain up to 90, fish. They are usually placed side by side to form a system called a seafarm or seasite, with a floating wharf and walkways along the net boundaries. Additional nets can also surround the seafarm to keep out predatory marine mammals. In contrast to closed or recirculating systems, the open net cages of salmonid farming lower production costs, but provide no effective barrier to the discharge of wastes, parasites, and disease into the surrounding coastal waters.
An emerging wave in aquaculture is applying the same farming methods used for salmonids to other carnivorous finfish species, such as cod, bluefin tuna, halibut, and snapper.
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However, this is likely to have the same environmental drawbacks as salmon farming. A second emerging wave in aquaculture is the development of copper alloys as netting materials. Copper alloys have become important netting materials because they are antimicrobial i. By inhibiting microbial growth, copper alloy aquaculture cages avoid costly net changes that are necessary with other materials. The resistance of organism growth on copper alloy nets also provides a cleaner and healthier environment for farmed fish to grow and thrive. Salmonids are carnivorous and are currently being fed compound fish feeds containing fish meal and other feed ingredients, ranging from wheat byproducts to soybean meal and feather meal.
Being aquatic carnivores , salmonids do not tolerate or properly metabolize many plant-based carbohydrates and use fats instead of carbohydrates as a primary energy source. Work continues on substituting vegetable proteins and protein concentrates for fish meal in the salmonid diet. For example, a planned closed-containment salmon fish farm in Scotland uses ragworms , algae, and amino acids as feed. However, when vegetable oil is used in the growing diet as an energy source and a different finishing diet containing high omega-3 content fatty acids from either fish oil, algae oils, or some vegetable oils are used a few months before harvest, this problem is eliminated.
Now, more than half of the world fish oil production is fed to farmed salmonids. Farm raised salmonids are also fed the carotenoids astaxanthin and canthaxanthin , so their flesh colour matches wild salmon, which also contain the same carotenoid pigments from their diet in the wild. The difference between the two numbers is related to farmed salmon feed containing other ingredients beyond fish meal and because farmed fish do not expend energy hunting.
These methods studied macronutrient profiles of fish feed based upon geography and season. Using RAPID feed, salmon farms reduced the time to maturity of salmon to about 15 months, in a period one-fifth faster than usual. Modern harvesting methods are shifting towards using wet-well ships to transport live salmon to the processing plant.
This allows the fish to be killed, bled, and filleted before rigor has occurred. This results in superior product quality to the customer, along with more humane processing. To obtain maximum quality, minimizing the level of stress is necessary in the live salmon until actually being electrically and percussively killed and the gills slit for bleeding.
An older method of harvesting is to use a sweep net, which operates a bit like a purse seine net. The sweep net is a big net with weights along the bottom edge. It is stretched across the pen with the bottom edge extending to the bottom of the pen. Lines attached to the bottom corners are raised, herding some fish into the purse, where they are netted.
Before killing, the fish are usually rendered unconscious in water saturated in carbon dioxide, although this practice is being phased out in some countries due to ethical and product quality concerns.
Salmon Farming | Living Oceans
More advanced systems use a percussive-stun harvest system that kills the fish instantly and humanely with a blow to the head from a pneumatic piston. They are then bled by cutting the gill arches and immediately immersing them in iced water. Harvesting and killing methods are designed to minimize scale loss, and avoid the fish releasing stress hormones, which negatively affect flesh quality.
Wild salmonids are captured from wild habitats using commercial fishing techniques. Most wild salmonids are caught in North American, Japanese, and Russian fisheries. The following table shows the changes in production of wild salmonids and farmed salmonids over a period of 25 years, as reported by the FAO. The resulting fish hatchery fish are defined as "wild" for FAO and marketing purposes. Currently, much controversy exists about the ecological and health impacts of intensive salmonid aquaculture.
Of particular concern are the impacts on wild salmonids and other marine life and on the incomes of commercial salmonid fishermen. Such debate and positions were central to a 'halt' in the re-certification of Alaska salmon fisheries by the Marine Stewardship Council MSC in In , Gyrodactylus , a monogenean parasite, was introduced with live trout and salmon from Sweden Baltic stocks are resistant to it into government-operated hatcheries in Norway.
From the hatcheries, infected eggs, smolt, and fry were implanted in many rivers with the goal to strengthen the wild salmon stocks, but caused instead devastation to some of the wild salmon populations affected. Eighty percent of the fish in the outbreak died.
ISAv, a viral disease, is now a major threat to the viability of Atlantic salmon farming. Amongst other measures, this requires the total eradication of the entire fish stock should an outbreak of the disease be confirmed on any farm. ISAv seriously affects salmon farms in Chile , Norway , Scotland , and Canada , causing major economic losses to infected farms. Unlike mammals, the red blood cells of fish have DNA, and can become infected with viruses.
The fish develop pale gills , and may swim close to the water surface, gulping for air. However, the disease can also develop without the fish showing any external signs of illness, the fish maintain a normal appetite, and then they suddenly die.
It is also a threat to the dwindling stocks of wild salmon. Management strategies include developing a vaccine and improving genetic resistance to the disease. In the wild, diseases and parasites are normally at low levels, and kept in check by natural predation on weakened individuals. In crowded net pens, they can become epidemics. Diseases and parasites also transfer from farmed to wild salmon populations.
A recent study in British Columbia links the spread of parasitic sea lice from river salmon farms to wild pink salmon in the same river. In , Scottish salmon farming introduced the use of farmed wrasse for the purpose of cleaning farmed salmon of ectoparasites. The problem is growing worldwide, with lice being far more resistant than the industry thought. Don Staniford, the former scientist turned activist and investigator, says that diseases are rife on fish farms, waste is out of control, and the use of chemicals is growing fast.
According to him, the fish-farming industry is now close to destroying itself. Salmonid farms are typically sited in marine ecosystems with good water quality, high water exchange rates, current speeds fast enough to prevent pollution of the bottom but slow enough to prevent pen damage, protection from major storms, reasonable water depth, and a reasonable distance from major infrastructure such as ports, processing plants, and logistical facilities such as airports.
Logistical considerations are significant, and feed and maintenance labor must be transported to the facility and the product returned. Siting decisions are complicated by complex, politically driven permitting problems in many countries that prevents optimal locations for the farms. In sites without adequate currents, heavy metals can accumulate on the benthos seafloor near the salmon farms, particularly copper and zinc. Contaminants are commonly found in the flesh of farmed and wild salmon. A study, reported in Science , analysed farmed and wild salmon for organochlorine contaminants.
They found the contaminants were higher in farmed salmon. Within the farmed salmon, European particularly Scottish salmon had the highest levels, and Chilean salmon the lowest. For this reason, current methods for this type of analysis take into consideration the lipid content of the sample in question. PCBs specifically are lipophyllic, so are found in higher concentrations in fattier fish in general, [51] thus the higher level of PCB in the farmed fish is in relation to the higher content of beneficial n—3 and n—6 lipids they contain.
Wild chum salmon can be consumed safely as often as once a week, pink salmon, Sockeye and Coho about twice a month and Chinook just under once a month.
Salmon Farming
In , Russia banned importing chilled fish from Norway, after samples of Norwegian farmed fish showed high levels of heavy metals. According to the Russian Minister of Agriculture Aleksey Gordeyev, levels of lead in the fish were 10 to 18 times higher than Russian safety standards and cadmium levels were almost four times higher. In , eight Norwegian salmon producers were caught in unauthorized and unlabeled use of nitrite in smoked and cured salmon.
Norway applies EU regulations on food additives, according to which nitrite is allowed as a food additive in certain types of meat, but not fish. Fresh salmon was not affected. Current Canadian dietary guidelines state recommend eating at least two Food Guide servings of fish each week and choosing fish such as char, herring, mackerel, salmon, sardines, and trout.
The US in their dietary guidelines for recommends eating 8 ounces per week of a variety of seafood and 12 ounces for lactating mothers, with no upper limits set and no restrictions on eating farmed or wild salmon. Kurt Oddekalv, leader of the Green Warriors of Norway , argues that the scale of fish farming in Norway is unsustainable. Huge volumes of uneaten feed and fish excrement pollute the seabed, while chemicals designed to fight sea lice find their way into the food chain. The use of the toxic drug emamectin is rising fast. The levels of chemicals used to kill sea lice have breached environmental safety limits more than times in the last 10 years.
Farmed salmonids can, and often do, escape from sea cages. If the farmed salmonid is not native, it can compete with native wild species for food and habitat. Such interbreeding can reduce genetic diversity, disease resistance, and adaptability. Around Scotland, , salmon were released during storms.
At one stage, in the Faroe Islands , 20 to 40 percent of all fish caught were escaped farm salmon. Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including C. Scientific Evidence Fails to Support the Extinction Hypothesis " [72] The time since these studies has shown a general increase in abundance of Pink Salmon in the Broughton Archipelago.
And in relation to the Krkosek extinction theory: A meta-analysis of available data shows that salmonid farming reduces the survival of associated wild salmonid populations. This relationship has been shown to hold for Atlantic, steelhead, pink, chum, and coho salmon. Independent of the predictions of the failure of salmon runs in Canada indicated by these studies, the wild salmon run in was a record harvest.
A study that made the first use of sea lice count and fish production data from all salmon farms on the Broughton Archipelago found no correlation between the farm lice counts and wild salmon survival. The authors conclude that the stock collapse was not caused by the farm sea lice population. The study found that the farm sea lice population during the out-migration of juvenile pink salmon was greater in than that of , but a record salmon escapement in exonerates sea lice of the year collapse due to the absence of negative correlation.
The authors also note that initial studies had not investigated bacterial and viral causes for the event despite reports of bleeding at the base of the fins, a symptom often associated with infections, but not with sea lice exposure under laboratory conditions. Wild salmon are anadromous.
They spawn inland in fresh water and when young migrate to the ocean where they grow up. Most salmon return to the river where they were born, although some stray to other rivers.
Concern exists about of the role of genetic diversity within salmon runs. The resilience of the population depends on some fish being able to survive environmental shocks, such as unusual temperature extremes. The effect of hatchery production on the genetic diversity of salmon is also unclear. Salmon have been genetically modified in laboratories so they can grow faster. A company, Aqua Bounty Farms, has developed a modified Atlantic salmon which grows nearly twice as fast yielding a fully grown fish at 16—18 months rather than 30 , and is more disease resistant, and cold tolerant.
This was achieved using a chinook salmon gene sequence affecting growth hormones, and a promoter sequence from the ocean pout affecting antifreeze production.
The modified salmon does not switch growth hormone production off. The company first submitted the salmon for FDA approval in One study, in a laboratory setting, found that modified salmon mixed with their wild cohorts were aggressive in competing, but ultimately failed. Sea cages can attract a variety of wild predators which can sometimes become entangled in associated netting, leading to injury or death. In Tasmania , Australian salmon-farming sea cages have entangled white-bellied sea eagles.