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Marine biologist with 30 yrs extensive industry experience speaks out against seapen salmon farming

MUST READ: A letter written by retired Marine biologist and Mahone Bay resident, David Aggett who sent this to Stephen M'cNeil, Keith Colwell, Hugh MacKay and Suzanne Lohnes-Croft regarding proposed seapen salmon farm expansion in Nova Scotia.


About David Aggett:

"I served as a founding Director of the Aquaculture Associations of Canada and of Newfoundland, and as an active member of the Aquaculture Association of Nova Scotia and the World Mariculture/Aquaculture Society. Later in my career I oversaw federal environmental law enforcement operations encompassing, among other industries, salmon farms in New Brunswick."


Dear Mr. McNeil:


I have been watching, with interest, recent developments surrounding proposals to establish seapen salmon farms in Nova Scotia's coastal waters. Thank you for your role in attracting this much-needed potential investment to our province. I would like to take this opportunity to express to you my thoughts on the matter. Firstly, I must clarify that I do not have a knee-jerk antipathy to aquaculture so often encountered in these debates. My comments below reflect my experiences accrued during 30 years of work in the fields of aquaculture and environmental law enforcement.


Although now retired, my career started in the mid 1970s as a marine biologist, developing new technologies for the establishment of aquaculture in Newfoundland. In my capacity at Memorial University of Newfoundland and later at the Newfoundland Department of Fisheries and at the Newfoundland Ocean Research and Development Corporation, I assisted with the establishment and operations of a number of experimental and commercial enterprises including Blue Mussel, Sea Scallop, Rainbow Trout, Pacific Pink Salmon, Atlantic Salmon, and Arctic Charr. I served as a founding Director of the Aquaculture Associations of Canada and of Newfoundland, and as an active member of the Aquaculture Association of Nova Scotia and the World Mariculture/Aquaculture Society. Later in my career I oversaw federal environmental law enforcement operations encompassing, among other industries, salmon farms in New Brunswick.


Having been involved in virtually all aspects of salmonid aquaculture over the years, I have come to the conclusion that seapen salmonid aquaculture is not the best use of our common-property coastal marine resources. Although upfront capital and some operating costs associated with land-based aquaculture are higher, the long term advantages and protections afforded the farm operator and the environment more than offset these costs. Here are some examples of the advantages of land-based farms:


Arguably the most objectionable problem associated with seapen aquaculture relates to the waste food and fish faeces that rain down from the seapens. I am very familiar with video surveys conducted under active seapens in New Brunswick's area of the Bay of Fundy. Despite the massive flows of tidal currents and exchange of water, the seafloor under all seapens was virtually devoid of natural life. The biodiversity was reduced to anaerobic bacteria and mats of white fungus. The worst sites were those where fish were hand fed. However, there was only a marginal improvement under farms which employed very expensive (>$1,000,000) computer controlled hydraulic feeders. I think it would be reasonable to assume that Nova Scotia's south shore tidal range would be even less effective at mitigating this environmental degradation.


Salmonids under culture in Atlantic Canada are subject to a host of bacterial, viral and parasitic diseases. Veterinary treatment of stock in seapen operations, especially treatment of ectoparasites, typically involves surrounding the affected seapen with an impermeable bag, then dosing the pen with Cypermethrin or some other pesticide. Once the treatment is complete, the operator is left with a seapen full of pesticide-contaminated seawater, for which the usual practicable disposal option is to evert the bag and allow the pesticide to disperse in the ocean environment. Unfortunately, it does not disperse as one might expect. Experiments conducted a number of year ago demonstrated that a measurable bolus of pesticide, at concentrations well in excess of those toxic to bottom-dwelling crustaceans (lobster, crabs, shrimp, barnacles, etc.) were present and migrating with tidal currents for at least 24 hours and for distances as far as 10 km post-release. This bolus of pesticide from salmon farms has been the cause of at least two very large die-offs of lobsters in commercial pounds in New Brunswick and the wide scale extermination of crustacean life at an unquantifiable scale in those locales. Food-based treatments, such as Slice, have lost their effectiveness over time due to the development of resistance by the target organisms. Land-based farming would allow the sequestering of affected stocks in their tanks, effective treatments, collection and appropriate disposal of the pesticide after use, and greatly simplify compliance inspections.


In order to minimize the common parasite infestations mentioned above, land-based operations could largely limit exposure of their stock to parasite larvae by either filtering incoming water, treating the incoming water (UV light, ozone, or sand filter) or, during high risk periods, extracting their seawater from deeper in the ocean where the parasites are typically less common.


Seapen culture requires the removal and replacement of net enclosures on a regular basis for both maintenance and removal of fouling material. Common practice to remove fouling organisms is to spread the nets out on open areas to let the sun and rain kill algae and epizootics and to wash away debris. Folks living in or visiting communities near seapen fish farms always know when pens are being changed out by the pungent odour of decaying detritus. Land-bases operations avoid this serious nuisance.


Seapen operations are prone to losses of stock due to seal and raptor intrusions. Also, eels foraging on waste food lying on the floors of pens often cause abrasion holes in the seapen floor. Shell ice migration leads to displacement and slicing of seapen walls and the sun's ultraviolet radiation degrades pen netting resulting in failure. Inadvertent releases of stock dilute already threatened natural popultions of salmon in our rivers and spread parasites. Finally, theft of stock and sabotage are also risks. Some of the losses associated with the risks outlined above can be significant. Land-based operations avoid or significantly reduce all of these problems.


Seapen operations are often viewed as an eyesore. While I personally don't object to the appearance of these operations, for those who do, the seapens are a constant reminder of the loss of "their" common-property environment so that profits can accrue to offshore (Japanese and Norwegian) investors. The creation of jobs associated with the farms will not likely offset this sentiment. Nova Scotia has a long history with land-based facilities integral to our marine fisheries and industrial heritage such as fish plants, boat yards, marine fabrication shops and ship repair facilities. Appropriately-located land-based fish farms would be another example of the positive evolution of our south shore rural communities.


It will likely be argued that most of the aforementioned risks can be mitigated or eliminated through judicious use of regulations or terms and conditions in licences, permits and certificates of approval. Compliance inspections and enforcement on floating structures, the access to which is often closely controlled by operators, are very expensive and difficult to conduct effectively. Contraventions always occur, either inadvertently or as a result of questionable practices aimed at reducing costs. These contraventions, especially if they entail visible environmental damage or loss to other users of the environment, typically have two outcomes: i. In the case of a successful enforcement action, the permitting authority (ie. the provincial government) will be blamed by the public for failing to prevent the damage or; ii. In the case where a responsible party cannot be identified or the evidence is insufficient to support enforcement action, the permitting authority will be blamed for failing to take firm action.


I appreciate the opportunity to express to you my views on this subject. The development of a healthy finfish aquaculture industry in Nova Scotia should be a welcome addition to our communities, provided that it is conducted in such a way as to not jeopardize the environment, property values and quality of life.


Land-based farming of salmonids, in my opinion, should be the only option considered, even if it means that government financial incentives are necessary to make it happen.


Most respectfully,

David Aggett

254 Mader's cove Rd.,

Mahone Bay, Nova Scotia

B0J 2E0


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