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Canadian Aquaculture R&D Review 2017

Shellfish: Mussels

Effects of Husbandry Practices and Mitigation Treatments on the Long-Term Control of Tunicate Infestation in PEI Mussel Farms

Tunicate infestations have severely impacted the shellfish aquaculture industry in Atlantic Canada, particularly the mussel aquaculture industry in PEI. Floating or submerged substrates such as shellfish aquaculture structures, gear, and mussel lines provide ideal surfaces for the colonization of invasive tunicates. While current mitigation practices (e.g., pressure washing) address the immediate removal of tunicates from mussel lines and substrate, they do not prevent re-infestation. Past research has focused primarily on the timing, frequency, and ecological sustainability of these practices; however, there have been no long-term assessments of these treatments or of alternative measures. Examining the role of bay-wide mussel stocking densities and related effects on tunicate recruitment could provide insights into alternative options for managing tunicates on shellfish farms.

In the case of tunicates, it is recognized that unused space or substrate availability facilitates the settling of these invasive species in a new environment. This project investigates the relationship between available recruitment space and levels of infestation by the invasive Vase Tunicate, Ciona intestinalis, on PEI mussel culture sites. The study will be conducted at the scale of a typical mussel aquaculture site, and will entail multi-year simulations to assess the overwintering potential of tunicates. The effect of different mussel stocking densities on infestation levels will be assessed, and numerical models developed to simulate the effects of fallowing of culture leases. The results from this study are intended to inform long-term tunicate management strategies at both farm and bay-scale levels.

Date: APR. 2014–MAR. 2017

Funded by: DFO–Program for Aquaculture Regulatory Research (DFO–PARR)

Project Leads: Thomas Landry, Thomas Guyondet (DFO)

Collaborators: Aaron Ramsay (DFARD); Jeffrey Davidson, Thitiwan Patanasatienkul (UPEI–AVC)



Assessing the Effect of Climate-Change-Related Summer Heat Wave on the Condition and Physiology of the Cultured Blue Mussel (Mytilus edulis) and Monitoring of the Carbonate System within Prince Edward Island Bays

Climate change is an issue that will impact the shellfish aquaculture industry in Atlantic Canada. There are a number of questions related to the impact of the physical effects of climate change on the environment (such as ocean acidification) in which the shellfish aquaculture industry operates, which would consequently affect the health and health management of farmed animals.

This project will quantify the physiological stress (shellfish health impact) associated with increased water temperature for extended periods of time. In relation to ocean acidification, parameters of the carbonate system will be measured within the shellfish aquaculture environment to assess current levels. Results from this project will offer guidance on maintaining healthy mussel populations in the face of climate change and sustainable management of shellfish aquaculture in the present and future.

Start Date: APR. 2015–JUN. 2018

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: Prince Edward Island Aquaculture Alliance

Project Lead: Carla Hicks (DFO)

Project Team: Luc Comeau, Kumiko Azetsu-Scott (DFO); Aaron Ramsay [PEI–Department of Fisheries, Aquaculture and Rural Development (PEI-DFARD)]; Sarah Stewart-Clark (Dalhousie U) Collaborators: Peter Warris (PEIAA)



Blue Mussels. Photo: DFO

Identification of Mussel Spat Supply Strategies in the Magdalen Islands

For more than 20 years, Magdalen Islands mussel farmers have collected most of their mussel spat in Bassin du Havre Aubert (BHA), where the stock is more resistant to episodes of summer mortality than stocks in other water bodies. However, the space available for collecting spat is limited in BHA, and it is essential that the potential supply in other Magdalen Island water bodies be assessed to ensure active and future supply. The main objective of this project is to identify the various strategies for Blue Mussel (Mytilus edulis) spat supply in the Magdalen Islands. The project contains two specific components and sub-objectives: 1) collection yield at three other sites; and 2) performance (survival and growth) of stocks from these sites (stock site design).

Preliminary results indicate that, although alternative stocks appear to be more resilient than in the 1990s, the BHA stock is still the most resilient. Genetic analyses will be performed to study the basis of this adaptation. Stock performance (survival and growth) differs among grow-out sites, reflecting a variation in local conditions. Correlation analyses will be performed with environmental parameters to identify the most important parameters.

The outcome of the project will profile alternative collection scenarios, enabling current and future companies to meet their production and profitability targets. The proposed strategies will support the proposals made at the end of the marine aquaculture fisheries project (Merinov) and mariculture development approaches in the Magdalen Islands.

Date: APR. 2014–DEC. 2017

Funded by: Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ)

Co-Funded by: MITACS; Merinov

Project Lead: Nicolas Toupoint (Merinov)

Project Team: Carole Cyr, Jean-François Laplante (Merinov); François Bourque (MAPAQ); Réjean Tremblay (ISMER)

Collaborators: UQAR; Moules de Cultures des Îles inc.; Grande-Entrée Aquaculture inc.



Collection yield–collector analysis. Photo: Nicolas Toupoint (Merinov)

Stock performance–in situ measurement process. Photo: Nicolas Toupoint (Merinov)

A Study of the Reproductive Patterns of Blue Mussel, Mytilus edulis, Grown in Deep and Shallow Water Sites in Notre Dame Bay, Newfoundland and Labrador

Notre Dame Bay, Newfoundland and Labrador, traditionally uses shallow water sites for mussel aquaculture, but changing spawning patterns have had a direct effect on sustainability. Offshore and deeper sites may provide a more stable deep water environment that might help to reduce physical and environmental stresses. This can include mitigating temperature and salinity changes, less mechanical disturbance due to wave action, or different concentrations of phytoplankton, all of which are thought to influence the frequency of spawning events. Offshore sites would also have lesser impacts on the benthic environment, enabling enhanced environmental sustainability.

Preliminary results have suggested that: 1) Blue Mussels from deep water sites can show improved conditions versus shallow water sites; 2) spawning events are more infrequent and predictable; and 3) meat yield is maintained.

This project will document, characterize, and compare the gonadal development in mussels cultured in deep vs. shallow water sites to determine differences in spawning frequency. The project will also monitor environmental factors that might affect gonadal development in Blue Mussels.

Results from this project will assist the mussel industry to enhance environmentally responsible operations by optimizing the utilization of resources on leases. Industry will be provided with important information on the reproductive condition and patterns of farmed mussels, leading to better overall management. The success of this project would also help reduce the impact of mussel farming in the near-shore environment.

Date: SEP. 2015–JUN. 2018

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: Norlantic Processors Ltd.

Project Lead: Harry Murray (DFO)

Project Team: Sharon Kenny, Dwight Drover (DFO)

Collaborators: Terry Mills (Norlantic Processors Ltd.)



Assessment of Strategies to Prevent Farmed Mussel Predation by Sea Ducks

Predation by wild ducks has affected the mussel industry for several years and causes considerable damage at some production sites. The various scaring techniques tested to date (e.g., chasing by boat, sound recordings, etc.) have been unsuccessful because they require a lot of energy and sometimes become ineffective in harsh weather conditions or when the birds become habituated.

In the Magdalen Islands, Grande-Entrée lagoon is a Quebec mussel site that is greatly affected by this problem. In order to protect mussels from predation, Merinov installed vertical nets that surround production lines and cover the entire water column to keep ducks from landing near the lines. Unfortunately, some environmental conditions prevented the netting from staying in its optimal position.

Other Merinov initiatives included transferring young mussel socks at different high densities to two sites currently not visited by ducks: a lagoon and an open environment. When the mussels reached a size less favoured by eiders and scoter ducks, they were returned to the producer’s site to continue growing to commercial size. The inter-site transfers worked well. The results demonstrate that high-density socking is an option under certain conditions. Analysis of the economic data will be completed in the winter of 2016–2017 and will help determine the real effectiveness of these transfer scenarios.

The purpose of this research project is to prevent predation of mussels by sea ducks and protect mussel farmers’ production.

Date: OCT. 2013–DEC. 2016

Co-Funded by: Merinov; Grande-Entrée Aquaculture Inc.; Culti-mer Inc.; Biomer

Project Lead: Lise Chevarie (Merinov)

Collaborators: Grande-Entrée Aquaculture Inc.; Culti-mer Inc.; Biomer



Buoy system, installed around the mussel lines, to keep protective netting out of the water. Photo: Lise Chevarie (Merinov)

High-density mussel sock when transferred to a wild duck-free environment. Photo: Lise Chevarie (Merinov)

Mussel Stock Structure and Density in Longline Culture

With the proposed increase in mussel production in Malpeque Bay, PEI, there is a need to determine the amount of aquaculture production that can be supported by the aquatic environment without causing permanent changes in ecosystem function, species populations, communities, or habitats; this is also known as the Ecological Carrying Capacity (ECC). ECC is typically estimated using mathematical models which combine and describe complex interactions among shellfish aquaculture, natural shellfish populations, and the environment (e.g., currents, water exchange, nutrient dynamics, etc.). For example, the size and density of cultured mussels will determine the amount of phytoplankton being removed from the water column which, in turn, influences the overall ability of the system to sustainably support both cultured and natural shellfish populations. In PEI, leaseholders provide stock information to DFO on an annual basis, which is useful for assessing whether or not leases are used, but has little value in informing the estimate of ECC. To address this gap, a survey of the PEI Blue Mussel (Mytilus edulis) longline system will be carried out to generate information on mussel lease use. Specifically, the survey will focus on seasonal trends in stock composition, densities, and the degree of fouling by invasive tunicates. Characteristics such as size and weight will also be recorded and used to calculate rates of filtration and waste production (i.e., biodeposition). This new information will contribute to improving the accuracy of model simulations and predictions of the overall capacity of an area to support changes in shellfish aquaculture production.

Date: APR. 2015–MAR. 2017

Funded by: DFO–Program for Aquaculture Regulatory Research (DFO–PARR)

Project Lead: Luc Comeau (DFO)

Project Team: Peter Warris (PEIAA); André Nadeau, John Davidson (DFO); Jonathan Hill (UPEI)

Collaborators: Jeffrey Davidson (UPEI)



Serial Knots in Mussel Culture Ropes Increase Spat Collection and Reduce Duck-Related Mortality

Predation by sea ducks is a threat to mussel culture in many sites. In many natural situations, however, mussel survivorship is enhanced by crevices and substrate features because predators have reduced access to their prey. We mimicked the effect of crevices by using loosely knotted spat collector ropes. The knots used were the chain sinnet and variants thereof. These are serial knots which can be knotted easily for spat collection and socking, and undone easily at harvest.

The knots were tested against regular unknotted ropes for their efficiency at collecting spat and providing anti-duck refuges in Cascapédia Bay, Quebec. Two suspended culture variants were used, the standard autocollector method used in Cascapédia Bay in 2015 and U-shaped collectors hanging from long lines in 2016.

In the 2015 experiment, control ropes collected about 2700 individual spat per 30.5 cm (October 2015; mussels smaller than 0.5 cm not included). Knotted ropes collected roughly 4000 individual spat per 30.5 cm. This is a 1.5-fold increase as compared to controls. Survivorship in June 2016 was roughly 10-15% in knotted ropes but was less than 5% on control ropes. Survivors and spat smaller than 0.5 cm in spring provided a residual population which grew during the summer and reached about 1500 individuals per 30.5 cm in Oct. 2016 (versus roughly 400  on control ropes). Size-related effects on survivorship will be examined in June 2017.

In the 2016 experiment, control ropes collected about 1300 individual spat per 30.5 cm. The chain sinnet and its variants collected 2900 and roughly 5900 individuals per 30.5 cm, respectively, with slight differences between variants. This is a two to four-fold increase as compared to controls.

Adding serial knots in spat collectors ropes increases spat collection, which is useful wherever spat are in short supply. Survivorship also increases, thus providing a potential method for reducing duck predation.

Start Date: JUN. 2013–DEC. 2017

Funded by: R-D Mytis Ltée

Co-Funded by: La Ferme Maricole du Grand Large

Project Lead: Marcel Fréchette (R-D Mytis Ltée)

Collaborators: Éric Bujold (La Ferme Maricole du Grand Large)


Comparison of the Health and Condition of Cultured Mussels from Deep and Shallow Water Sites in Newfoundland with Reference to Environmental Conditions, Condition Index, Physiological Stress, and Lipid Biochemistry

Mussels are typically cultured in sheltered nearshore areas. Traditional shallow water coastal areas (estuaries, harbours, and shallow bays) can be affected by land runoff and contaminants, especially during precipitation. Increased pressure for lease space in these areas has raised concerns regarding carrying capacity (maximum population without affecting the environment) and thus sustainability.

Industry has recently begun to develop offshore and deep water bivalve culture in Newfoundland’s Notre Dame Bay region. However, little is understood about how deep water environments affect mussel health and condition. This project characterizes and compares seasonal changes in environmental conditions between shallow versus deep sites, and investigates potential correlations between environment and mussel condition, physiological stress, and lipid biochemistry. This information will help industry make decisions regarding whether expanding production to deep water sites will add increased sustainability for Newfoundland mussel culture.

Specifically, the following results were found:

  • Mussels grown in deep sites demonstrate higher Omega-3 and essential fatty acids, which are key factors contributing to food quality in mussels and seafood.
  • Deep water sites in Notre Dame Bay generally demonstrated increased overall condition after 12 months when compared to shallow sites.
  • Under temperate conditions, mussels grown in shallow sites do as well or slightly better than those grown in deep water sites. However, under extreme environmental and surface weather conditions (i.e., abnormally cold water, wind, and ice), mussels have better overall condition over long term in deeper water, which offers more stable environmental conditions compared to shallow sites.

It is recommended that farmers in the Notre Dame Bay region take advantage of the benefits of growing in both deep and shallow water sites within a bay or lease to maintain consistent accessibility to high quality product regardless of the weather conditions.

Date: JUL. 2012–JUN. 2015

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: Norlantic Processors Ltd.

Project Lead: Harry Murray (DFO)

Project Team: Kim Hobbs, Sharon Kenny (DFO)

Collaborators: Terry Mills (Norlantic Processors Ltd.)



Deep water mussel site near Pleasantview, Notre Dame Bay, NL. Photo: Harry Murray (DFO)

Passive Protection of Mussel Production Through Use of Exclusion Cages to Prevent Duck Predation in the Gaspé, Quebec

Migrating ducks that feed on farmed mussels cause significant economic losses for the mussel aquaculture industry and current deterrent systems are becoming increasingly ineffective at keeping the ducks away. The aquaculture industry in Chaleur Bay, Québec, normally uses self-regulating mussel collector techniques. It is believed that mussels grown in this way would be best protected from diving ducks by deploying a passive, physical deterrent system of underwater duck exclusion cages around the mussels.

The project aims to develop protective cage prototypes made with common and locally-available materials to keep costs as low as possible. It will determine the optimal type of netting to prevent duck bycatch and biofouling, while measuring the effectiveness of the exclusion cages in preventing duck predation compared to the traditional methods used for self-regulating mussel collectors.

The results of this project will increase the knowledge surrounding diving duck predation on mussel farms in Québec (and elsewhere) and how this impact may be responsibly mitigated while adhering to the Migratory Birds Convention Act (1994). The results will also improve the economic situation of the Québec mussel industry and provide the industry and authorized management bodies with effective and conservation-oriented mitigation tools. This will benefit the mussel aquaculture industry as a whole by allowing it to better understand and mitigate potential wild-farmed interactions concerning duck predation to improve the sustainability of the shellfish culture industry.

Date: MAY 2015–DEC. 2016

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: La Ferme Maricole du Grand Large; Moules Tracadigash Inc.

Project Lead: Chris McKindsey (DFO)

Project Team: Annick Drouin, Marie-France Lavoie, Paul Robichaud, François Roy, Anne-Sara Sean, Émilie Simard, Andréa Weise (DFO); Élisabeth Varennes (UQAR)

Collaborators: Éric Bujold (La Ferme Maricole du Grand Large); Manon Deslauriers (Moules Tracadigash Inc.)



Deployment of a cage structure to protect the mussels on the lines within it from diving ducks. Photo: Paul Robichaud (DFO)

Retrieval of mussel lines that had been deployed to collect mussel spat (juvenile mussels) for grow-out for aquaculture. Photo: Paul Robichaud (DFO)

Monitoring Variability of Environmental Factors Impacting Tunicate Infestation on Coastal Shellfish Farms in Nova Scotia

Vase Tunicate (Ciona intestinalis) is an invasive species negatively impacting mussel farm productivity in Nova Scotia and Prince Edward Island. They grow in dense groups on mussel ropes, nets, and the mussels themselves, competing for resources and resulting in crop losses. They are difficult to remove and remain persistent even after pressure washing, brine dips, liming, UV treatment, and electric shocks.

The spatial distribution of tunicates is highly heterogeneous and could be the result of variation in environmental factors among sites. This study examines the effect of variability of environmental factors (salinity, temperature, pH, and water movement) on the establishment and proliferation of tunicates. Research results may suggest an environmental factor as an indicator to assess aquaculture sites (either current or future proposed sites) for their risk of tunicate infestation and inform siting decisions by the government. This study may also help reduce further spread of tunicates and the need for control treatments through the identification of sites less vulnerable to infestation.

This project supports the DFO objective of environmental performance. Specifically, the following results were found:

  • Of the four environmental factors considered (i.e., salinity, temperature, pH, and water movement), temperature and salinity have the most influence on Vase Tunicate population dynamics. This suggests that coastal sites with generally cooler water or with greater or more frequent freshwater inputs may be less susceptible to heavy tunicate fouling. At cooler sites, initial tunicate settlement may be delayed and growth may be slower throughout the season, resulting in smaller populations, while their abundance can be reduced further if salinity is lower.
  • Predictive NMLE (non-linear mixed effects) model is under development to aid in future aquaculture siting and management decisions.

Date: JUN. 2013–JUN. 2015

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: Aquaculture Association of Nova Scotia (AANS)

Project Lead: Dawn Sephton (DFO)

Project Team: Danielle Goodfellow, Bruce Hancock (AANS); Benedikte Vercaemer (DFO); Cory Bishop, Russell Wyeth (StFX)

Collaborators: Danielle Goodfellow (AANS)



Characterization of Lobster Habitat and Fishery’s Spatial Use in Relation to Shellfish Aquaculture Leases in Malpeque Bay, PEI

Shellfish aquaculture is an important economic activity for coastal communities in Atlantic Canada. The Blue Mussel industry emerged on the east coast during the 1970s and expanded rapidly in PEI during the 1990s. Today, Blue Mussels are the nation’s leading cultured shellfish species by weight and value. In 2013, Fisheries and Oceans Canada (DFO) identified the need to develop a detailed spatial plan to accommodate a possible increase in leases for mussel aquaculture in Malpeque Bay, PEI. In addition to considering the scale of shellfish aquaculture that can be sustainably cultured in Malpeque Bay, there also remain questions related to interactions between lobster and cultured mussels. In making decisions or proposing potential increases in the number of leases in Malpeque Bay, aquaculture managers have to consider complex coastal zone management issues, including the potential for habitat overlap between lobsters and aquaculture mussel leases.

This project addresses management questions related to the interactions between lobster and cultured mussels by investigating the potential overlap between proposed mussel aquaculture sites with lobster rearing grounds and fishing activities in Malpeque Bay. The outcomes of this study will inform departmental and provincial decision-makers in their marine spatial planning processes and contribute to a sustainable aquaculture industry.

Date: APR. 2015–MAR. 2017

Funded by: DFO–Program for Aquaculture Regulatory Research (DFO–PARR)

Project Lead: Marc Ouellette (DFO)

Project Team: Michel Comeau, Denis Gagnon, Angeline LeBlanc, Bruno Comeau, Deryck Mills (DFO)



Develop Diagnostic Markers to Assess Mussel Population Health in Response to Environmental Stress

This project is focused on generating better tools to enable industry to determine and analyse the stressors that impact cultured Blue Mussels and what effects these can have on their condition and health. This project aims to be proactive in managing health issues that may arise for cultured shellfish species in relation to climate change (water temperature and pH), tunicate treatment (high pressure water spray and hydrated lime) and other environmental stressors (food availability, hypoxia and salinity).

This project will identify genetic markers that can be used: 1) to investigate the causes of stress within underperforming mussel populations; and 2) to develop mitigating strategies to minimize the impacts of the underlying environmental/mechanical stressors on the long term viability of the mussel aquaculture industry in PEI.

The stress response (heartbeat, lysosomal destabilization) in mussel populations after an event challenge (food availability, hypoxia, salinity, thermal, pH, tunicate (Ciona intestinalis) recruitment/removal) will be evaluated. At the same time, transcriptomic data will be collected to develop molecular markers related to a specific stressor. We plan on using RT-qPCR markers identified via RNA-Seq to evaluate stress responses.

Start Date: OCT. 2016–MAR. 2020

Funded by: DFO–Aquaculture Collaborative Research and Development Program (DFO–ACRDP)

Co-Funded by: Prince Edward Island Aquaculture Alliance (PEIAA)

Project Lead: Denise Méthé (DFO)

Project Team: Sarah Stewart-Clark, Stephanie Hall (Dalhousie U); Carla Hicks (DFO); Fraser Clark (Mount Allison U)

Collaborators: PEIAA



Left to right: Sarah Stewart-Clark (Dalhousie U), Denise Méthé (DFO), and Stephanie Hall (Dalhousie U). Photo: Scott Jeffrey (Dalhousie U)

Sub-Lethal Biological Effects on the Blue Mussel (Mytilus edulis) from Chronic Exposure to Three Types of Conventional and Unconventional Oil under Ice Cover in Winter

Western Canada has huge bitumen deposits, a source of unconventional oil. Once diluted, it is easily exported, which suggests it will be a leading component of future Canadian exports. The Estuary and Gulf of St. Lawrence are highly coveted shipping points given their adequate port infrastructure and strategic access to foreign markets. In addition to its extreme winter weather conditions, the St. Lawrence supports vital economic operations such as shellfish farming in outlying areas. Dilbit’s (diluted bitumen) behaviour and biological effects are still unknown in the event of a spill occurring in winter under ice cover in the marine environment, not to mention the adverse economic repercussions if a spill were to occur near aquaculture facilities. We quantified the immediate and delayed biological effects by reproducing such a scenario and exposing commercial size mussels Mytilus edulis to dilbit and conventional crude oil for seven days. After a 72-hour exposure, bioaccumulation of the hydrocarbons as well as cellular and physiological stress were observed. A depuration period was observed after exposure during which the mussels eliminated the accumulated hydrocarbons. Several months after winter exposure and despite the depuration period, negative effects on spring spawning were evident mainly in larval survival and development. Our experiments revealed immediate toxicity (bioaccumulation, cellular and physiological stress) in addition to delayed toxicity (reproductive success). A more pronounced biological response to exposure to unconventional crude oil was also demonstrated.

This study investigated the consequences of an oil spill in the cold northern marine environment on the Mytilus edulis farmed mussel.

Date: AUG. 2015–AUG. 2017

Funded by: DFO–National Contaminants Advisory Group (NCAG)

Co-Funded by: Fonds de Recherche du Québec en Nature et Technologies (FRQNT)

Project Lead: Anthony Schmutz (UQAR-ISMER)

Project Team: Richard St-Louis (UQAR); Réjean Tremblay, Céline Audet, Jean-Pierre Gagné; Émilien Pelletier, Mickaël Barthe (UQAR-ISMER)

Collaborators: Richard St-Louis (UQAR), Réjean Tremblay, Céline Audet, Jean-Pierre Gagné, Émilien Pelletier, Mickaël Barthe (UQAR-ISMER)


Photograph of larval production (day two) in adults exposed to the control treatment. Photo: Anthony Schmutz (UQAR-ISMER)

Photograph of larval production (day two) in adults exposed to unconventional oil treatment. Photo: Anthony Schmutz (UQAR-ISMER)

Photograph of larval production (day two) in adults exposed to conventional oil treatment. Photo: Anthony Schmutz (UQAR-ISMER)

Characterization of Interactions Between Mussel Aquaculture and Adult American Lobsters

Understanding the influence of mussel culture sites on the distribution and condition of lobsters is an important question for managers who evaluate requests for new mussel farms as there is limited scientific information on the subject. Additionally, it is widely perceived by lobster fishers that lobsters that congregate around aquaculture sites may become sedentary and are therefore less available to the lobster fishery. Known environmental interactions between mussel (and other shellfish) aquaculture include water column-related effects on plankton and nutrients due to mussel filter-feeding, as well as localized effects on infaunal (benthic) communities from increased organic loading on the seafloor. In the case of suspended mussel culture, organic loading comes from faeces, pseudofaeces (biodeposits), and from large quantities of farmed mussels (and the organisms that grow on them) that fall from the suspended culture structures as the mussels grow. The physical structures of aquaculture equipment also provide potential habitat for organisms that need solid substrate to grow, which may attract a variety of predatory and scavenging species. As a result, there may be ecological effects because of changes in the productivity, distribution, or catchability of target (fishery) species.

The goal of this project is to describe the extent and effect of interactions between mussel aquaculture activities and adult American Lobsters, including the spatial distribution and movement of lobsters within and around mussel aquaculture sites, and their availability to the fishery. The influence of mussel aquaculture on the condition of lobsters and their diet will also be evaluated. The results of the study will help Fisheries and Oceans Canada (DFO) aquaculture managers make scientifically sound decisions in support of ecologically and economically sustainable aquaculture.

Date: APR. 2015–MAR. 2018

Funded by: DFO–Program for Aquaculture Regulatory Research (DFO–PARR)

Project Lead: Chris McKindsey (DFO)

Project Team: Rénald Belley, Luc Comeau, Catherine Couillard, John Davidson, Annick Drouin, Jonathan Hill, Marie-France Lavoie, Domynick Maltais, François Roy, Paul Robichaud, Émilie Simard, Anne-Sara Sean (DFO)

Collaborators: Ocean Tracking Network (OTN); Philippe Archambault (ISMER); Jeffrey Davidson (UPEI)



Annick Drouin and Marie-France Lavoie (DFO) take tissue samples of a lobster to determine its condition in a study on the influence of mussel farms on lobster condition and movement. Photo: Chris McKindsey (DFO)

Mussel socks with a hydro-acoustic receiver used to detect ultrasonic signals emitted by acoustic transmitters affixed to lobsters and crabs in Malpeque Bay. Photo: Chris McKindsey (DFO)

Map of arrays of acoustic receivers (blue points) deployed around mussel farms in Richmond Bay (left, 0.9 km2 coverage) and Marchwater (right, 2.0 km2 coverage) to detect lobster movements inside and outside of mussel farms (orange polygons) in Malpeque Bay, Prince Edward Island.

Impact of Mussel Culture on Infauna and Sediment Biogeochemistry

Interactions between bivalve aquaculture and the environment are complex. In suspended mussel culture, great quantities of waste (digested and undigested planktonic food, or biodeposists) may fall from culture structures and this may impact benthic communities, particularly those living in bottom sediments. Different biogeochemical methods have been developed as proxies to monitor the health of benthic communities. While some work has examined dose (biodeposition) – response (benthic conditions) relationships, these studies often suffer from procedural issues or have been done over limited levels of biodeposition and mechanisms have not been evaluated, making the determination of benthic ecological carrying capacity difficult. This study evaluates the dose-response relationship between mussel biodeposition and benthic conditions over a wide range of deposition levels and over more than one year. Measurements will be taken to determine the processes by which bottom sediments and communities are impacted with the aim of determining the ecological carrying capacity of the benthic environment of Malpeque Bay, PEI, for mussel aquaculture.

Combining the results of this study with ongoing organic loading models for bivalve aquaculture will inform managers on how many mussels may be farmed in an area while protecting the benthic environment.

Date: APR. 2016–MAR. 2019

Funded by: DFO–Program for Aquaculture Regulatory Research (DFO–PARR)

Project Lead: Chris McKindsey (DFO)

Project Team: Luc Comeau, Annick Drouin, Nathalie Forget, Frédéric Hartog, Élise Lacoste, Marie-France Lavoie, François Roy, Émilie Simard, Anne-Sara Sean, Andrea Weise (DFO)



A diver examines a benthic mesocosm to evaluate benthic respiration and nutrient fluxes around mussel lines in Havre-aux-Maisons Lagoon, îles-de-la-Madeleine. Photo: Anne-Sara Sean (DFO)

Marie-France Lavoie and François Roy (DFO) prepare sediment traps and sample jars to evaluate sedimentation around mussel lines in îles-de-la-Madeleine. Photo: Andrea Weise (DFO)

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