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Op-Ed: Farm-raised salmon — What you don't know about your fish

By Karen Graham     Jul 27, 2015 in Food
I recently wrote a story about salmon farming practices in Chile. I focused on the horrendous amount of antibiotics used by fish farmers, and then I became curious. Why were human-use antibiotics being used at all? Here is what I found out.
Our oceans are in a heap of trouble. Tons of untreated sewage, runoff from agriculture, industrial wastes, petroleum products, and heavy metals are being dumped or allowed to run into the world's oceans. Added to pollution problem, overfishing of the ocean's fisheries saw a marked decrease in many species.
Aquaculture was born to help raise seafood to feed the world's growing population and at the same time, protect the dwindling wild fish species we had left. It sounded good at the beginning, but what I discovered is not very pretty. We are going to stick with salmon, specifically, Atlantic salmon.
Because aquaculture practices vary by region and country, Atlantic salmon raised in fish farms pose a huge threat to the environment and to public health. let's talk about Chile first. Yes, the fish farms have been accused of using 1.2 million pounds of antibiotics in 2014, according to the Digital Journal story written yesterday.
Hazorea Aquatics salmon farm  Chile.
Hazorea Aquatics salmon farm, Chile.,
Chile has a problem with coastal water pollution
Chile has a big problem with pollution of its coastal waters. Wastewater treatment is inconsistent, and rivers, lakes, and the ocean become open sewers. Added to this form of pollution are non-metropolitan industries, like agriculture, forestry, and mining that are contributing to the contamination of rivers and the sea.
Right now, Chile is the world's second largest producer of farm-raised Atlantic salmon, and the industry is expanding. But as I mentioned yesterday, Chile has a big problem with an infection called SRS, or Piscirickettsiosis. Fish farmers have been fighting this bacterial infection since before 2009, and still have not eradicated the disease.
Pesticides and chemicals used in fish farming
We can add the pesticides, used to combat fish lice, added to the net pens where the salmon are raised. Keep in mind that thousands of fish are raised in these net pens, and as one Scottish fish biologist says, a single mature salmon has an area the size of a bathtub to live in.
Sea lice and kudoa (soft-flesh syndrome) are two very virulent parasites that infect salmon farms. Sea lice, Lepeophtheirus salmonis, infestations have been reported in fish farms in Canada, Norway, Scotland, and Ireland. The lice chew on fish, leaving open lesions that alter the salmon's ability to maintain a healthy salt-to-water balance. The danger of sea lice? They can easily spread to juvenile and adult wild salmon. And the infestations can spread rapidly to other nearby fish farms.
Kudoa thyrsites (arrow) in body muscle of a yearling Atlantic salmon.

M-G G stain. X600.
Kudoa thyrsites (arrow) in body muscle of a yearling Atlantic salmon. M-G G stain. X600.
The second parasite is Kudoa thyrsites, commonly called “soft flesh syndrome.” This microscopic insect breaks down muscle fiber in fish, turning the flesh to a jelly-like consistency and making it commercially worthless. As of 2012, although detected in more than 20 fish species worldwide, this nasty parasite has only been detected in farmed salmon in British Columbia and costs the industry $30 to $40 million annually. Pacific salmon don't seem to be affected by the parasite.
Bacterial diseases in farmed salmon
Interestingly, while Chilean fish farms are fighting SRS, or Piscirickettsiosis, a gram-negative bacterial infection, Chile, Norway, Canada, Scotland, Ireland, and the U.S. have to contend with infectious salmon anemia (ISA), a viral disease that can also cause severe losses. The ISAV virus is related to the influenza virus and was first observed in 1984 in fish farms in Norway.
By June of 1988, the spread of the disease in salmon farms had become serious enough the Norwegian Ministry of Agriculture, Fisheries and Food was forced to declare it a notifiable disease. Now, it has spread around the globe.
Furunculosis is another deadly disease that has been spread around the globe because of salmon farming. This disease is caused by the bacteria Aeromonas salmonicida, and primarily affects Atlantic salmon in both the freshwater and marine stages of their lifecycle. A. salmonicida lives well in water with low oxygen concentrations, like polluted water.
This bacteria was first reported in Norwegian salmon farms in the 1980s and quickly spread around the world. The symptoms include internal and external hemorrhaging, boils, ulcers, liquefaction, and gastroenteritis. This bacteria is very difficult to eradicate because it can live in freshwater 6 to 8 months and in saltwater up to 10 days without a host. So it spreads very easily and is very costly to clean up.
The environmental impact of salmon farming
Remember the mention of A. salmonicida thriving in polluted water? Salmon net pens discharge thousands of pounds of untreated sewage, including contaminated feed containing chemicals, toxic residues, nitrogen, and phosphorus, as well as copper and zinc, into coastal ocean waters. Did I mention the diseases and parasites that are also discharged by salmon net pens?
In 2000 and 2001, nutrient discharges from aquaculture in Scotland, Denmark, Norway, and Ireland were estimated at almost 40,000 tons of nitrogen and 6,600 tons of phosphorus, according to the Seafood Watch. Let's add one more issue that is a worldwide problem. What do the farms do with all the dead fish?
When an outbreak of disease, bacterial, viral or parasitic occurs, it sometimes necessitates the destruction of thousands of salmon, and they have to be dumped someplace. In British Columbia, around 80,000 tons of salmon are produced yearly, with almost 20,000 tons of dead salmon needing to be discarded.
While the majority of the salmon are discarded in landfills, remote fish farms often use other unspecified places rather than paying at a legitimate dump site. Some salmon, diseased and full of chemicals, antibiotics, and pesticides are sometimes used by farmers as fertilizer. with even some of the dead salmon ending up as pet food.
I guess the question bothering me is this, why do we think we are doing better by creating bigger problems. Pollution, chemical contamination, the unbridled use of antibiotics intended for use on humans, and the discharge of pesticides are rampant in the industry, and it's ridiculous.
This opinion article was written by an independent writer. The opinions and views expressed herein are those of the author and are not necessarily intended to reflect those of
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