Factory Fish Farming Woes: OSU Researchers Reel In Warning Signs

Natural fisheries have long sustained coastal populations, but with ever more people consuming fish, natural fisheries have begun to be supplemented, and in some cases replaced, by Aquaculture production.

fishJust as in the farms housing thousands of cows and chickens, rates of disease are more prevalent in Aquaculture. In fact millions of dollars every year are lost by Salmon fisheries because of Saprolegnia parasitica, an oomycete  pathogen that causes visible grey or white patches of fungal like masses on the skin and fins of the salmon.

As the disease worsens the mass penetrates the muscles and blood vessels of the fish eventually leading to death. Tens of millions of dollars are lost every year to this affliction, and it has been suggested that the pathogen may be migrating from human fisheries to natural ones.

In order to better understand this disease, OSU researchers, in work published in the journal PLOS Genetics, used rapid sequencing machines to build and compare the genome of this parasite to other plant and animal pathogens.

They found that the genome of this oomycete encodes for numerous enzymes that enable it to rapidly adapt to changing and varied environments, as well as to help it override the immune system of its hosts. They also found that, while it lacks many of the genes found in similar “true” plant fungi, it contains numerous animal genes suggesting horizontal gene transfer during the infection of salmon.

Fortunately the researchers did discover that 1% of the cell wall is made up of chitin. This makes it vulnerable to anti-microbials that work by preventing the synthesis of chitin in the cell. More work is necessary to help combat this pathogen, but the work done by OSU researchers lays the groundwork necessary for others to develop drugs or new farming practices to combat the spread of disease.

By William Tatum

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