Salmon farmers make big claim
Nova-Austral, a Chilean salmon farming business, is claiming to now be raising antibiotic-free salmon.
If the claim is true, it would put the company one up on Alaska ocean farmers still reliant on antibiotics.
Antibiotic use in Alaska hatcheries is one of the state’s unmentioned salmon “ranching” issues, along with the use of net pens to fatten young fish and the pollution beneath those pens as a result of uneaten food and waste accumulating on the seabed.
The commercial fishermen who now control the largely state-funded salmon hatcheries have opposed monitoring seabed pollution as a costly government imposition and would prefer to avoid the mention of antibiotics as they try to distinguish their form of salmon farming from that in Chile, Norway, Scotland and elsewhere.
But the use of antibiotics in Alaska hatcheries came up in September of last year when the state responded to an investigation being conducted by the National Oceanic and Atmospheric Administration (NOAA) to determine whether Gulf of Alaska (GOA) Chinook salmon should be listed as threatened or endangered under the U.S. Endangered Species Act.
NOAA’s action was sparked by a petition from the Washington-state-based Wild Fish Conservancy. One of the concerns raised by the Conservancy was that pen-raised Chinook sent to sea by Alaska hatcheries could spread disease to wild Chinook spawned in streams and rivers along the Pacific Rim of North America from California to the Unalakleet River drainage of the Bering Sea.
In response to NOAA, the Alaska Department of Fish and Game on Sept. 6, 2024, sent the federal agency a 264-page missive that, among other things, promised Alaska hatchery Chinook, the fish most Alaskans call ”king salmon,” were being treated with antibiotics to ensure they didn’t spread disease.
The state letter also noted that Furunculosis, a disease caused by a bacterial pathogen, “is one of the most encountered bacterial diseases in cultured salmonids and many other non-salmonid species of fish in both marine and freshwater reported in North America, Europe, Asia and Africa. Therefore, this bacterial organism is ubiquitous in other host species in both fresh and saltwater environments encountered by GOA Chinook salmon, so healthy hatchery
released salmonids are unlikely to be a significant source of potential exposure.
“(And) the bacterial organism is controlled in Alaska hatcheries by disinfecting eggs, reducing or eliminating hatchery water supplies, and recognizing the disease early for culling of dead and moribund fish followed by veterinary-prescribed antibiotic therapy (emphasis added) before major epizootic outbreaks occur.”
The letter also noted the use of antibiotics to treat a variety of bacterial gill diseases caused “by various opportunistic bacteria but primarily (by) various flavobacteria that commonly occur in the environment and infect fish when water quality is poor and/or fish are stressed.
“Occasionally the infection can become systemic as in Coldwater Disease caused by F. psychrophilum, which requires antibiotic therapy (emphasis added). When detected
early, external treatments with various approved drugs such as formalin, chloramine-T, or hydrogen peroxide will generally resolve the infection. All salmonids are susceptible, but juveniles more so than adults, and the disease is found worldwide. Again, healthy juvenile salmonids released from Alaska hatcheries are not a significant source of exposure to this disease for stocks of GOA Chinook salmon.”
Over the years, Fish and Game has endorsed a variety of Food and Drug Administration (FDA)-approved antibiotic drugs for use in Alaska hatcheries, and some remain in regular use.
“Unfortunately,” said a former hatchery employee who wished to remain anonymous, “holding penned saltwater and trough freshwater salmon at high densities requires antibiotics added to feed because if they catch something, the whole lot will die. Vibriosis, furunculosus, bacterial kidney disease, IHNV (infectious hematopoietic necrosis virus)….
“Like an ant farmer you try to salvage your crops.”
The former employee added that the state’s monitoring of hatcheries is minimal and said it is unclear exactly how large antibiotic use is in Alaska. The former worker also questioned whether all diseased hatchery fish are treated or destroyed as required by law.
Business forces
At least one state hatchery operator, the Cook Inlet Aquaculture Association (CIAA), a private business entity, is in huge financial trouble. This could create a significant incentive to send diseased fish to sea instead of killing them in the hope that at least some would survive to return and help fuel so-called “cost-recovery” harvests.
“Remote hatcheries (present) unlimited opportunities,” the source said. “(It’s) like having a desperate employee with access to the cash register.”
Hatcheries are required to report any disease outbreaks in Alaska, but the state regulations themselves carry something of a disincentive for the state’s open-ocean farming businesses.
“An affected facility may be required to remain dry or out of production for one year and be certified free of the disease pathogen before continued production of fish….”
Being forced to shut a hatchery down for a year would not be good for cost recovery.
As to whether it is truly bad to treat farmed salmon – whether net-pen or ranched – with antibiotics is a subject of some debate. There are those who contend the push against antibiotics is as much or more about marketing than about environmental health.
“Our most fundamental and recognized commitment concerns animal welfare,” the report says. “All our salmon is raised without the use of antibiotics or hormones throughout its life
cycle, from egg to harvest. This practice responds to a growing consumer demand for healthier, more natural foods and reflects our preventive farming philosophy and high standards of animal welfare.
“Our strategy of zero antibiotic use is a fundamental pillar. We maintain this commitment through strict biosecurity protocols, vaccination, immunostimulant diets and constant monitoring of fish health.”
The Alaska Seafood Marketing Institute, which promotes Alaska “wild-caught salmon,” the blend of ocean-farmed and wild fish delivered to Alaska processing plants, has taken a somewhat different approach to the issue. ASMI in 2017 told National Fishermen, a trade publication, that consumers simply shouldn’t be worried about antibiotics in Alaska hatchery fish.
That is not quite true. One of the antibiotics regularly used in Alaska – oxytetracycline, which offers protection against a number of bacterial pathogens – has long been used as a marker for hatchery salmon because it is readily detected, and since 2008, the U.S. Fish and Wildlife Service has been conducting a long-term study of oxytetracycline fortified feed to examine whether the use of that antibiotic-laced feed should be increased.
The study is due to end next year. The study protocol says researchers want to “determine the efficacy of Terramycin® 200 for Fish (a patented version of oxytetracyline) when fed as a
medicated feed to 1) control mortality caused by bacterial diseases in a variety of freshwater
and marine fish species; and 2) mark skeletal tissue in a variety of freshwater and marine fish
species.
“Terramycin® 200 for Fish is currently approved in the United States for treatment of ulcer
disease, furunculosis, bacterial hemorrhagic septicemia, or pseudomonas disease in salmonids….In addition to the use patterns listed on the current label, Oxytetracycline historically has often been the drug of choice when diagnostic evidence shows salmonids to have enteric redmouth (ERM) caused by Yersinia ruckeri; flavobacteriosis caused by Flavobacter columnaris, Flavobacter psychrophilus, or closely related yellow pigmented gliding bacteria….
“In recent years, studies have shown evidence that Oxytetracycline may be effective in
controlling bacterial kidney disease (BKD) caused by Renibacterium salmoninarum. Additional clinical field trials are needed to follow up on this lead.”
Problems past and future
Wikimedia Commons
The Trail Lakes Hatchery, which the state built near Moose Pass on the Kenai Peninsula before turning the operation over to the commercial-fishermen-controlled CIAA, has struggled against BKD since it opened its doors, and the struggle continues.
Erythromycin is a government-regulated macrolide antibiotic. In people, it is used to treat “respiratory tract infections, skin infections, diphtheria, intestinal amebiasis, acute pelvic inflammatory disease, Legionnaire’s disease, pertussis, and syphilis,” and as an alternative to penicillin or sulfa drugs in people allergic to those medications, according to the Mayo Clinic.
A number of other Alaska hatcheries have also struggled to deal with both BKD and the infectious hematopoietic necrosis virus (IHNV), but state investigators in 2018 reported that at that time “the existing statewide disease history database has shown no increasing trend in the prevalence of these indicator pathogens (in wild salmon) due to hatchery interactions.
“Although modest increases have occurred in the prevalence of IHNV – 31 percent versus 38 percent – and in the percentages of sockeye salmon with high virus titers – 30 percent versus 48 percent – over the last 30 years, there is no evidence that these increases are correlated with hatchery practices. This is further supported by the temporally low genetic diversity maintained by INHV in Alaska and indications that hatchery practices have not caused the virus to adapt to other fish species beyond the natural sockeye salmon host, as has
occurred in other areas of the Pacific Northwest.”
Antibiotic drugs have been widely used in animal husbandry – of which salmon farming, whether via net pens or the Alaska ”ranches” is a part – since the 1940s to control disease, but the drugs have become a hot-button issue in recent years.
The major concern is not so much with potential exposures to antibiotic residues in the flesh of animals or fish treated with antibiotics, although there are concerns there, or the troubling signs of the development of antibiotic resistance to infections among farm workers exposed to antibiotic-laced feed, but with the broader environmental consequences.
“Between 2018 and 2023, antibiotic resistance rose in over 40 percent of the pathogen-antibiotic combinations monitored, with an average annual increase of 5 to 15 percent.”
The extent of antibiotic use in Alaska hatcheries today is unclear. The Alaska Department of Environmental Conservation (DEC) requires hatcheries to obtain water discharge permits, but does not require them track the volume of antibiotics discharged.
“All facilities are required to control solids through efficient feed management, adhere to proper operation and maintenance procedures, use only Food and Drug Administration (FDA) or Environmental Protection Agency (EPA)-approved disease control chemicals, and implement a plan to reduce polychlorinated biphenyls (PCBs) in the facility discharge,” the DEC regulations say.
But the hatcheries are given pretty broad latitude in the use of these “disease control chemicals.”
“The general permit authorizes the use of certain disease control chemicals, including Investigational New Animal Drugs (INADs) and Low Regulatory Priority (LRP) compounds, provided they have been approved by the FDA and/or EPA for use in aquaculture applications. The permit also authorizes extralabel drug use when prescribed by a licensed veterinarian. Permittees must apply all drugs, pesticides, and other chemicals according
to label directions or under the order of a licensed veterinarian. When drugs, pesticides, or other chemicals are used, permittees must document the use and the proper disposal of all spent materials,” according to the regulations.
There are no set limits on antibiotic use.
