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Transcription

1 R A I N O A S T Oc\ oovsrn 4_/v\cAo: -U VlL*- x 1 <L OLTVN \ < > "V C<>^ i c RAINCOAST RESEARCH SIMOOM SOUND BRITISH COLUMBIA CANADA VOP iso (604) 9

2 October 30, 1994 Dr. Carl Folke Dept. of Systems Ecology Stockholm University S Stockholm Sweden Dear Dr. Carl Folke: I just read your paper on "The Costs of Eutrophication from Salmon Farming". I am writing to request your comments on related events here on the west coast of Canada and research I feel needs to be done. I have been conducting research on killer whales.in a remote archipelago for 10 years. During that time 25 salmon farms have been established in the area. I have become very concerned about the impact these farms appear to be having on a wide range of species from whales to larval organisms. I have recorded declines in many species and an increase in the occurrence of diseased salmon. At this point I believe this archipelago ecosystem maybe near the point of collapse, due to the pressures applied by the presence of millions of farmed salmon. The greatest concern is increase in disease. Before salmon farms arrived a small coho enhancement hatchery here had no difficulty holding broodstock and had never heard of the disease furunculosis. Now it is very difficult to keep broodstock alive due to this disease. '~J»'. In several farmsites were stocked with salmon that had.*%." '"'"^been infected with furunculosis before entering the saltwater. -'The farms reportedly lost about 60% of these fish during growout, despite prolonged use of antibiotics. That same year, for the first time, the coho hatchery lost many of its wild broodstock to furunculosis. Oxytetracycline was successfully used to combat the disease in the hatchery. In 1993 Scanmar, another company, stocked several sites with fish infected with a strain of furunculosis that was resistant to all -three antibiotics approved in Canada for salmon; OTC, Rornet and Tribrissen. The disease spread to fish belonging to a third company (BC Packers), in a matter of days. The rapid spread, virulence and resistance of the disease alarmed all parties The Department of Fisheries and Oceans (DFO) was called in to assist and they released Erythromycin for use on these farms. This drug is restricted in Canada and is not approved for use in fish to be consumed by humans. B.C. Packers initiated a lawsuit against Scanmar.

3 Three months later the coho captured as broodstock had a strain of furunculosis that was resistant to OTC. DFO told me this was a coincidence. In the summer of 1994 approximately 30,000 of ^Scanmar's fish (now owned by BC Packers) escaped due to heavy growth accumulated on the nets. The farm was torn apart by a big tide. This fall the coho in the hatchery are again dying of furunculosis, many of them have it their brains, according to DFO patholegists, and are succumbing quickly without exhibiting external symptoms. This strain of furunculosis is resistant to two antibiotics. I believe the events on the farms and in the hatchery are related, but the DFO says they are not. Do you have an opinion on this or know of someone who is looking into this problem? Officials here tell^me not to worry because furunculosis is a ^.naturally occurring disease. However, I believe the farms are v functioning as a haven and dispersal mechanism for disease. In < addition, I am concerned that as farmed fish travel the coast i_f rom hatcheries, to hardening sites, to rearing pens and then into live transport vessels to processing plants that strains of furunculosis are being moved around and introduced into naive fish populations with devastating results. Currently wild fish are unable to migrate into these waters j without passing close to several farms. One farmsite is noted as ' being permanently infected with furunculosis. When vaccinated fish are raised there, they contract the disease as soon as the vaccine wears off, just weeks before harvest. As a result the farmers have actually fallowed this site for a significant amount of time, which is a very rare practice here. They are guessing that the disease maybe existing in the barnacles or mussels. We have experienced a sharp decline in the population of wild chinook salmon which over-winter here. Some of the farms infected with furunculosis are situated in areas recognized by DFO as nursery areas for chinook. People who worked on those farms have told me that when they fished for wild salmon from the pens, the wild fish had the same open sores as the farmed salmon. I reported this to DFO, but they did not respond on this point. In regards to toxic algal blooms, this area experienced its first recorded Heterosigma bloom this year, 7 years after the.first farm arrived. Densities were as high as 269 million cells per litre and at least 150 tonnes of farmed salmon died. The farmers deserted a location further south (Sechelt Inlet) because of problems with Heterosigma. This year there was no bloom in Sechelt despite the same warm, calm conditions as here. Do you know of any research on Heterosigma*s relationship to salmon farms? If so would it be possible to forward copies of the papers to me or references? Another problem is the disappearance of prawn stocks in the vicinity of salmon pens. Prawn fishermen have lost productive

4 fishing sites after salmon farms began operation over a kilometre away. Instead of catching prawns and other benthie organisms, they say the traps are empty and the ground lines stained with a greyish matter. The government will only examine areas directly beneath the pens and when they find sediment, they say it is transient and will clear up when the farms are gone. They have ignored the capacity of tidal currents to carry and deposit farm sediment. I have asked about the effect of habitat loss on particular stocks of prawns and they reply that their disappearance is merely a "quirk of prawn biology". We are also concerned about the use of very bright lights on farms at night. These lights attract small fish and larval stage organisms which can swim through the nets and enter the pens. Local fishermen visited a farmsite at night and found the pens "teeming with life". A study done on this coast reported that upto 58.3% of farmed * fish at some sites contained invertebrate larvae in their stomachs (Gill is et al. 1991). These invertebrates included crab zoea and larval euphausiids. Also found were pelagic eggs and fish larvae. This study did not examine farms using lights, but made it clear that farmed fish do prey on wild organisms. The lights may exacerbate this problem. This feeding behaviour represents an unregulated harvest of commercially important species. Farmers have reported that they did not need to feed their fish when a type of smelt larvae (eulachon) migrated through their pens. The eulachon population has plummeted to the point of near extinction and despite strong conservation measures the area has experienced its first prawn fishing closures over the last two years. Despite this DFO allows the farmers to use the lights. I have brought all of the above and more to the attention of the Minister of Fisheries, but he refuses to act. I think that the current Minister of Fisheries is a good man, but he is being poorly advised. He has said that it is up to me to bring him proof of a disease problem. I study whales, I am not a fish pathologist and time is running out. I remain hopeful that if I can collect and present research from other areas that I might convince him to remove the farms from wild salmon migration routes, until valid research has been conducted. However, if not the research must get done. From what little I know, I am hoping that antibiotic resistance profiles of the various strains of furunculosis could be used to trace the direction and spread of disease. I would like to convince the government to impose mandatory, detailed reporting of any disease outbreak which causes a 10% or higher rate of mortality on any farm. Currently there are very few diseases which have to be reported.... *,*»*>'.*+ r ^,, ^. v J, **.<jf,«'**,--''''.-*- *&<*-. ; - -^ fab-'*,,.- V,. <=#,' * ''* -I '-' ' --./-^ ' Vf - " - -' " : '" -- If the history of disease on each farm was known, wild fish could be tested for disease near farms, distant from farms, in pristine areas and in the rivers, to examine the degree of

5 relationship between farm and wild fish pathogens. Antibiotic resistance patterns, plasmid profiles and DMA fingerprinting could be used to define and inventory each strain in maximum detail In this way we could map the effect of placing diseased fish in pens We could also determine the rate of infection from wild to farmed salmon and wether that vector reverses direction during the course of extended antibiotic treatment. Antibiotic resistant profiles could act as indicators of the direction of infection. We could also determine the affect of farm salmon diseases on non-salmonid species. Can you comment on the validity of this approach? Due to my extremely limited knowledge of this subject I am sure this is an over simplistic approach. If the government ever agrees to study the transmission of disease from farmed salmon to wild fish I would like to be able to comment on how -it could be done. I am not confident in some of the government research underway. A current government study on sedimentation beneath salmon farms was designed in a way that it is going to produce ambiguous results. It is essential that any research on disease be as definitive as possible. In addition if the government won't study the disease problem perhaps I can raise the funds and organize the project myself Your comments would be very appreciated, as well as, the names of any other people who might be able to assist me in designing this study. Thank you for your time and consideration Sincerely, Alexandra Morton cc. Nils Kautsky Max Treoll Meg Thorburn Kjetil Hindar