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Salmon Aquaculture in Atlantic Canada

After the wild Atlantic salmon population spiralled out of control and collapsed in 1985, the salmon aquaculture industry grew across coastal regions in Canada, particularly in the Atlantic provinces. Seemingly within the blink of an eye, the commercial fishery was padlocked, and aquaculture sites helped supply the local and international demand for this high-valued species. Over the years, the industry continues to develop but remains a controversial subject across the country due to a lack of public knowledge on how salmon aquaculture works, and the benefits and downfalls of the industry. My hope is that this blog article helps to provide clarification and valuable insight for the future of salmon aquaculture in Canada.

Aquaculture is a complicated industry but can be broken down into key steps to better understand how it functions. Selective breeding of mature salmon is used to promote genetic diversity and to pass desirable traits onto the next generation, thereby increasing profit. After several months of development in a freshwater hatchery, the salmon are tagged and relocated to open-net pens in marine areas that provide suitable temperature, water conditions and security for salmon growth. Between 16 and 24 months of feeding and growth, the salmon reach market size, where they are slaughtered and processed, before reaching your kitchen table.

When it was determined that the commercial salmon fishery wasn’t a viable option, salmon farming offered an opportunity to meet the largescale demand while facilitating the recuperation of wild salmon stocks. The industry also drives economic development and employment to coastal regions of Atlantic Canada, bringing jobs and revenue to rural and aboriginal communities. There may be benefits to welcoming aquaculture in our area, but what are the costs?

When uneaten food pellets and salmon feces sink to the ocean floor, the area surrounding the cages often becomes deprived or completely stripped of oxygen due to oxygen-hungry bacteria decomposing the organic matter. The loss of oxygen results in damage to the sediment quality and nearby vegetation, creating ‘dead zones’ below sea cages. This occurrence has led to the common practice of incorporating fallowing periods into the aquaculture industry, meaning cages remain empty for several weeks to allow for the recovery of the vegetation along the ocean floor.

Salmon farming sites are hotspots for parasites and disease as the crowded environments increase transmission. Vaccines and chemical treatments are often used to decrease the amount of harm or mortality rates of captive fish due to these infections. In a previous post, I explained the effects of sea lice, but other local diseases include infectious salmon anaemia and furunculosis, which have all been identified in Atlantic Canada aquaculture sites. Not only does this effect the wellbeing of farmed fish but can also be spread to threatened wild salmon during their migratory period.

One of the last impacts of salmon aquaculture I will highlight is the consequences of cage infrastructure failure. Although open net pens have evolved greatly over the years, natural disasters often cause these pens to fall apart, scattering debris across the coast and releasing the captive fish. It’s important to note that farmed salmon are genetically very different compared to the wild population and pose a great threat if they are to escape. Escapees create competition for resources and can lower the success and survival of the wild population if mating was to occur. Farmed salmon are bred to be successful under very different circumstances than their wild counterparts . Interaction between these two population can result in poor genetics and overall survival.

Without undercutting the benefits aquaculture has provided on wild Atlantic salmon conservation and the economic opportunities for coastal communities, there is still a long road ahead. New policies in Canada’s Aquaculture Act are being developed across Canada to promote enhanced environmental protection, incentives for moving away from open-net pen systems and proper site selection for future development.

In response to aquaculture waste management, the best option would be converting to land-based sites, which would allow the outflow water to be treated and would also eliminate the risk of salmon escapes, but this option is expensive and would require plenty of resources to have the same success as marine systems. Another option is the use of integrated multi-trophic aquaculture (IMTA), which is currently being trialed in Atlantic Canada. This system uses several species in which all would have marketable value, and the waste of one species, becomes the nutrients of another. IMTA would reduce the amount of excess organic matter and increase revenue by producing native species along with Atlantic salmon, such as shellfish or seaweeds.

In open-pen systems, it’s unlikely that we will never be able to eliminate farmed fish escapes, but we may be able to reduce the associated risks. The manipulation of salmon eggs before sexual differentiation can be done and led to sterile or single-sex populations (triploidy), therefore there would be little to no risk of armed salmon breeding with wild populations. This method is not currently used in our area, but research is being conducted in laboratory settings and is showing positive results in the fish quality, growth, and survival.

As stated early, salmon aquaculture is a vast industry, and this post was only to give a general summary of the salmon farming practices, costs, benefits, and potential changes for aquaculture in Atlantic Canada. Feel free to follow the links to learn more about some of the topics I discussed on salmon population decline, aquaculture development in New Brunswick, breeding practices, organic waste & treatment and salmon disease.

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Energetic Burden of Sea Lice on Atlantic Salmon

In the north Atlantic Ocean, the presence of Atlantic salmon aquaculture sites is growing. These sites have opened the door for high concentrations of an ectoparasite that feeds on the mucus, skin and blood of Atlantic salmon known as sea lice. The sites are typically stationed in areas typically traveled by the wild salmon population during migration, therefore becoming infected by the larval parasites as they disperse from the open-water cages. As the lice develop from larvae to adults, they become mobile, moving across the surface of the salmon as they feed and reproduce. The effects of skin damage from sea lice feeding behaviours have been well documented, but a recently published paper has explored the energetic costs that sea lice infections inflict on Atlantic salmon, which has never previously been studied.

Salmon have a limited energy budget for their daily functions. The standard metabolic rate (SMR) refers to the minimum amount of energy needed for physiological functions, such as temperature regulation. The maximum metabolic rate (MMR) is reserved for high energy events such as predator avoidance or migration. Researchers in Norway believed that the SMR of Atlantic salmon would increase due to the energy required to induce an immune response and that the MMR would decrease because of the energy drainage from coping with the parasite.

To understand the energetic costs, sea lice infested juvenile salmon underwent a period of exhaustive activity and then given a rest period. During both phases, respirometers were placed in the tanks to measure oxygen uptake to quantify energy consumption. Contrary to the original assumption, researchers discovered that the SMR and the MMR of infected salmon were both elevated, indicating that the species may be able to shift their energy budget to accommodate for the burden of sea lice infection.

If you weren’t originally interested in learning more about this parasitic relationship but it’s beginning to grow on you, you can follow the link here!

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They'll Be Dammed

Water systems are the only means of transportation for aquatic animals. The Saint John River (Wolastoq) is the main ‘aquatic highway’ in New Brunswick spanning from the northern areas of the province to the Bay of Fundy. Atlantic Salmon migrate along this main waterway to feed, grow and spawn in several branches of rivers and streams. With their lifecycle requiring both freshwater and marine environments, salmon migration acts like a boomerang, leaving the freshwater habitat to enter the ocean and traveling back to the freshwater source they originated from. This is only possible if the fish can successfully pass through the Saint John River’s biggest barriers: dams.

Atlantic Salmon rely on directional cues from flowing water as part of the transition between the salt water and freshwater stages of their life. This species is born in freshwater rivers and stream, and after several years of growth and biological changes they develop into smolts where they acquire the impulse to travel to the ocean where they can feed and develop. Once they mature into adults, they then travel back to their original freshwater source to spawn but there is only a short window of time for this migration. If delays occur within these transition windows, there is an increased risk of predation, decline of their reserved energy, disorientation due to changes in water conditions. These impacts can often result in higher chance of harm or death to the migrant fish.

In 1968, the Mactaquac Generating Station (MGS) began fully functioning as the largest energy producing dam on the Saint John River system. This dam was designed with a system that allowed for upstream fish passage, where fish are collected, separated, and counted. The only downstream passage is through controlled releases of reservoir water (spillways) or by passing through the hydraulic propellers (turbines). Currently, the MSG upstream passage mainly facilitates the movement of Atlantic Salmon, Alewife and Blueback Herring.

When adult Atlantic Salmon swim upstream to spawn and reach the MGS, pumps are used to create a flow that attracts the fish into collection chambers. These chambers have a series of mobile bottoms that move fish into a sorting facility, with one special tank designed to attract salmon. The salmon, as well as any other species that may have snuck into the tank, are loaded onto a water tanker truck, and moved to a nearby secondary sorting facility as the Mactaquac Biodiversity Facility (MBF). Here, the salmon are released into a new tank, where workers must handle them to collect important data to assess the population before they are placed into the truck once again to be transported and released above the dam in multiple undisclosed locations along the river. Although this system is elaborate, risks are still present.

When Atlantic Salmon reach such large barriers, such as dam, and are unable to complete their very important task of moving upstream to spawn, it may seem like they’ve reached a point of no return to their original freshwater source. The system and timing of upstream passage is completely left in the hands of humans, leading to stress and exhaustion while in search of a quicker route upstream as well as crowding in the collection chambers. Even small variations in water condition such as water flow, temperature, or dissolved oxygen, can also be fatal if the fish are not supplied with a period to adjust, otherwise known as acclimation. In 1968, about 200 adult salmon being held below the dam for upstream passage died of gas bubble disease due to an overabundance of gases as air was forced through the turbines and into the water. Nitrogen and oxygen were trapped in the turbines during a period of low generation creating pressure in a process known as cavitation, and when the water was released, the fish below were exposed to the high gas levels. As salmon are transported and released, it’s important that water temperature and gas levels must be controlled, or the entire population exposed will die. Monitoring during transport can be done with the use of compressed oxygen and a multi-sensor device that is placed in the tank and supervised from within the vehicle. After their battle with short-term captivity, extensive handling, and transportation, we can only hope that the stress endured from their upstream passage will not affect their mating success when released.

The downstream passage of post-spawning adults and young salmon smolt can occur by soaring down the spillway gates, which are only operational during peak water levels, or passing through the turbines. Either options could result in injury, disorientation, or death - talk about being stuck between a rock and a hard place. If they can successfully reach the foot of the dam, they must be able to avoid predatory species, such as bass and birds that have learned to gather at common discharge points with a greater chance of capturing harmed or stunned Salmon. A study done by MacEachern at a nearby and similar dam concluded that smolts had a 23.7% of morality by passing through the turbines, not accounting for predation. Research conducted in rivers connected to the Baltic Sea indicates the mortality percentage to be about 6 times greater compared to undammed rivers. The lucky number of smolts that survived the daring escape from above the dam can now move to the ocean, to hopefully return as mature adults and challenge the dam once again to breed.

By 2030, the Mactaquac Generating Station was estimated reach the end of its life, therefore it needed to be decided whether to remove or update the existing structure. It was concluded that the dams life would be extended until 2068 with updates to the existing structure. With this decision, efforts should be made to create less invasive passages for migrating Atlantic Salmon. The current methods alter the natural river flow, increase predation, and often result in stress, injury and mortality thereby lowering the overall success of an already endangered species.

Fish passage is an issue across the globe, therefore new innovations are being created and studied. The Bonneville Dam in Washington is currently testing a new fish passage technology by Whooshh Innovations, which is a free-swimming system that can sort, count , photograph and move fish above barriers. This system would allow for less migratory delay, removal of invasive species and lessen the stress of handling. This system is one of many different fish passage technologies that could be explored in our area.

The current efforts to help the declining salmon population involve exposing the species to stress, and we need to decide how much harm we are doing while trying to help. When it comes to the weakened population of Atlantic Salmon returning to the Saint John River system to spawn, the species is dammed if they do, and damned if they don’t.

For more information on the methods of fish passage of three common generating stations along the Saint John River and its effect on Atlantic Salmon:

https://unbscholar.lib.unb.ca/islandora/object/unbscholar%3A10320/datastream/PDF/view

https://unbscholar.lib.unb.ca/islandora/object/unbscholar%3A10328/datastream/PDF/view

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Hopeless to Hopeful: A Program to Save Atlantic Salmon

Under the Species at Risk Act, the inner Bay of Fundy (iBoF) population of Atlantic Salmon were categorized as endangered in 2001. Over the past 20 years since this announcement, New Brunswick is continuing to take drastic steps to avoid the total extinction of this fish, which is ecologically, economically, and culturally of high importance in Atlantic Canada.

I’ve chosen to share a link to a video produced by the Fundy Salmon Recovery Project which highlights the significance of the iBoF Atlantic Salmon population, and the countless interventions being done in New Brunswick with the help of several partnerships and collaborations in our area. Despite being such a large movement in our province which is the first of this kind, I believe it is still highly unrecognized in our communities.

Although original conservation initiatives showed little progress, there has been a steady increase in the amount of spawning salmon returning to our rivers since the implementation of the Fundy Salmon Recovery Project. Having a first-hand opportunity to participate in the collection, care, and release of this species, I believe human intervention is our last chance to the save the small population that remains, and I am hopeful that one day they will become prosperous and flourishing in future years. I hope this video helps to share the initiatives being done in our area but also provide a basis to future, more depth topics I will cover on the threats and mediations to save our Atlantic Salmon.

Follow this link to check out the moving project by the Fundy Salmon Recovery Program: https://www.fundysalmonrecovery.com/our-project/

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Look Who the Fisherman Reeled in!

Hi there,

I believe certain people are simply born as talented writers. My name is Jodi, and rest assured; I am not one of these people. Instead, I’m more like your typical introvert that enjoys reading, keeping up with my favourite shows and lounging about my house with both my dog and a coffee close by. I’ve completed almost four years of my biology degree at the University of New Brunswick, and I can confidently say I spent the better part of those years wondering what I would do with my degree once it was time to graduate.

The summer of 2021, I took an internship that involved travelling to several rivers and streams to assess the dwindling Atlantic Salmon populations. Whether I was snorkeling along a river where cell phone reception couldn’t dare reach, or visiting local wild salmon sanctuaries, I found myself excited to participate each day. Thanks to my peers, I became more familiar with the alarming status and details of this species and like a moth drawn toward a flame, I discovered what I wanted to do with my degree.

How can a population that was once thriving and integral in Atlantic Canada become an endangered species requiring a live gene-banking program to help mitigate their anticipated extirpation? What does the future of Atlantic Salmon look like in our area? How can we help? These are questions that many people have, but no one has a simple answer for, including myself. My hope for this platform is to help bring awareness and share current knowledge on Atlantic Salmon and its importance to the Bay of Fundy.

Although my sole experience with blogging has been scrolling through cooking websites desperately trying to find the ingredient list for banana bread, I hope I can captivate you with at least one interesting point that will leave you wanting to learn more about some fishy business.

Thank you for reading and I can’t wait to explore what you will be sharing in the coming weeks, Jodi.