Study links fish farms to spread of antibiotic resistance JOHN MCPHEE THE CHRONICLE HERALD Published September 3, 2017 - 4:09pm Last Updated September 4, 2017 - 7:02am Print
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Posted by Joan Russow
Wednesday, 06 September 2017 23:01
 

JOHN MCPHEE THE CHRONICLE HERALD 

 

September 4 2017
 

A fish farm worker inspects a salmon for sea lice. (THE CHRONICLE HERALD / File)  

A fish farm worker inspects a salmon for sea lice. (THE CHRONICLE HERALD / File) 

New research that finds a possible link between fish farms and the spread of antibiotic resistance doesn’t surprise marine biologist Inka Milewski.

“Anytime you have animals grown in very concentrated conditions in these intensive livestock operations, whether it’s pigs or chickens, or in this case, fish, you’re going to have the potential for disease problems,” Milewski said in an interview Sunday from her home in the Miramichi in New Brunswick.

“The solution to a lot of these problems is to put antibiotics into the feed. And so it should come as no surprise to anyone that they have found antibiotic resistance associated with fish farms.”

The study released last week by Jing Wang of Dalian University of Technology in China concluded that genes for antibiotic resistance are getting into ocean sediments through fish food.

Millions of tonnes of fishmeal are used in fish farms every year, much of it sinking uneaten to the ocean floor, a news release on the study said.

Wang and colleagues analyzed commercially available fish meal and found 132 antibiotic resistance genes, some of which could potentially pass on resistance to common antibiotics, as well as antibiotics of last resort such as vancomycin.

These genes change the makeup of bacteria species, including human pathogenic bacteria that contribute to food-borne illnesses worldwide, the news release said.

“The medical community has identified increasing bacteria resistance to antibiotics,” said Milewski, a former science adviser to the New Brunswick Conservation Council. “It’s now been linked to the high degree of use of antibiotics in our food systems, whether it’s chicken or beef or any livestock product including fish.

“So the finding that fish farms could be contributing to bacteria resistance to antibiotics . . . and ending up with humans being exposed to bacteria that are now resistant to antibiotics of a whole range, is very concerning.”

The conclusions reinforce the need for increased aquacultural monitoring, she said, and more transparency about the amount and type of pesticides and antibiotics being used and the incidence of disease.

It’s particularly difficult to get such information in Nova Scotia, Milewski said, but the New Brunswick government will provide information about disease incidence at fish farms upon request.

She contrasted that situation to countries such as Norway, where detailed information on the use of pesticides at fish farms is posted online.

“It’s very transparent. That’s not the case here.”

Milewski has studied the effect of fish farms on the environment in Nova Scotia. For example, in 2011, she used underwater cameras to examine decommissioned fish farm sites in Shelburne Harbour. She found large mats of bubbling white Beggiatoa bacteria, along with worms, covering the ocean bottom under the sites.

The Aquaculture Association of Nova Scotia could not be reached for comment Sunday.

In the past, fish farm operators have said aquacultural operations must deal with the risk of disease in their stock like any farming operation.

That may be the case, Milewski said, but drugs in fish meal eaten by farmed salmon remain in excretions that fall to the ocean floor.

“The farmer who’s got 30,000 chickens — it’s contained, the farmer is responsible for cleaning up the feed and it’s not spread outside of that containment area,” she said. “But in the case of open net-pen aquaculture, these compounds get into the environment and affect other species, that’s the problem.”

 

A fish farm worker inspects a salmon for sea lice. (THE CHRONICLE HERALD / File) 

 

A fish farm worker inspects a salmon for sea lice. (THE CHRONICLE HERALD / File)  

New research that finds a possible link between fish farms and the spread of antibiotic resistance doesn’t surprise marine biologist Inka Milewski.

“Anytime you have animals grown in very concentrated conditions in these intensive livestock operations, whether it’s pigs or chickens, or in this case, fish, you’re going to have the potential for disease problems,” Milewski said in an interview Sunday from her home in the Miramichi in New Brunswick.

“The solution to a lot of these problems is to put antibiotics into the feed. And so it should come as no surprise to anyone that they have found antibiotic resistance associated with fish farms.”

The study released last week by Jing Wang of Dalian University of Technology in China concluded that genes for antibiotic resistance are getting into ocean sediments through fish food.

Millions of tonnes of fishmeal are used in fish farms every year, much of it sinking uneaten to the ocean floor, a news release on the study said.

Wang and colleagues analyzed commercially available fish meal and found 132 antibiotic resistance genes, some of which could potentially pass on resistance to common antibiotics, as well as antibiotics of last resort such as vancomycin.

These genes change the makeup of bacteria species, including human pathogenic bacteria that contribute to food-borne illnesses worldwide, the news release said.

“The medical community has identified increasing bacteria resistance to antibiotics,” said Milewski, a former science adviser to the New Brunswick Conservation Council. “It’s now been linked to the high degree of use of antibiotics in our food systems, whether it’s chicken or beef or any livestock product including fish.

“So the finding that fish farms could be contributing to bacteria resistance to antibiotics . . . and ending up with humans being exposed to bacteria that are now resistant to antibiotics of a whole range, is very concerning.”

The conclusions reinforce the need for increased aquacultural monitoring, she said, and more transparency about the amount and type of pesticides and antibiotics being used and the incidence of disease.

It’s particularly difficult to get such information in Nova Scotia, Milewski said, but the New Brunswick government will provide information about disease incidence at fish farms upon request.

She contrasted that situation to countries such as Norway, where detailed information on the use of pesticides at fish farms is posted online.

“It’s very transparent. That’s not the case here.”

Milewski has studied the effect of fish farms on the environment in Nova Scotia. For example, in 2011, she used underwater cameras to examine decommissioned fish farm sites in Shelburne Harbour. She found large mats of bubbling white Beggiatoa bacteria, along with worms, covering the ocean bottom under the sites.

The Aquaculture Association of Nova Scotia could not be reached for comment Sunday.

In the past, fish farm operators have said aquacultural operations must deal with the risk of disease in their stock like any farming operation.

That may be the case, Milewski said, but drugs in fish meal eaten by farmed salmon remain in excretions that fall to the ocean floor.

“The farmer who’s got 30,000 chickens — it’s contained, the farmer is responsible for cleaning up the feed and it’s not spread outside of that containment area,” she said. “But in the case of open net-pen aquaculture, these compounds get into the environment and affect other species, that’s the problem.”

Last Updated on Friday, 08 September 2017 19:07