Canadian Aquaculture R&D Review 2013

SHELLFISH: MUSSELS

Proof of concept of a scalable hatchery system using modular principles to increase production and survival for commercially important Mytilus species

Mussels are one of the fastest growing aquaculture products and the market demand far exceeds the current supply. Unfortunately, the lack of appropriate mussel seed has hindered industry development.

Island Sea Farms, a BC mussel production company has designed an innovative hatchery for mussels that will increase the production of seed by 50%. The reliable supply of additional seed will be used to stabilize and expand the BC industry through joint venture and other collaborative culture arrangements with current shellfish growers and First Nations. The innovative hatchery design uses green technologies that reduces energy requirements and improves environmental performance. The increasing demand for mussels and the relatively high value of the quality-controlled Island Sea Farms product presents an opportunity to market the new technology to interested growers in the BC shellfish industry as well as to mussel producers around the world.

Island Sea Farms has calculated the innovative modular hatchery will increase the production of mussel seed by 50%. The three modules (algal production, larval production, and nursery culture) have been constructed, integrated and optimized to create greater efficiencies and enhance output. Each module was designed to be constructed separately and scaled to production requirements allowing for incremental increase as required or over time.

APR. 2011 – MAR. 2012

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Klahoose First Nation

project lead: Paul Simpson (Island Sea Farms)

Project team: Paul Simpson, Grant Hunt, Wendy Brown, Ingrid Niamath, Greg Steine (Island Sea Farms); Kathy Francis (Klahoose First Nation)

collaborators: Klahoose First Nation; World Fisheries Trust

Contact: isfhatchery@shaw.ca

Grant Hunt and the mussel larvae rearing tanks

Design, installation and assessment of an innovative duck deterrent system to reduce predation of high value aquaculture Mytilus product and minimize duck mortality

Like other mussel aquaculture growing areas of the country, British Columbia has experienced significant losses due to marine diving duck predation. Current techniques for mitigating loss from duck predation are ineffective, frequently results in death of the duck, and often becomes a safety hazard for farm workers and divers. Island Sea Farms has developed an innovative duck predator deterrent system to reduce predation of farm raised mussels and to minimize harm to ducks.

The innovative Duck Deterrent System was designed with three parts — an unique net system that envelopes groups or single rafts with protection under the rafts as well as on the sides, a specially designed net deployment and retrieval platform to efficiently handle the net envelopes, and a net maintenance and cleaning system, re-purposed from the salmon farming industry, to remove heavy bio-fouling. It is the combination of these three elements that make it possible to address all of the current problems.

Predation by diving ducks is the main problem for the mussel culture industry in BC and many other areas of Canada. The use of this innovative system will remove a constraint to sustainable production while increasing the competitiveness of the Canadian mussel industry in a healthy and productive ecosystem.

Apr. 2012 – Mar. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP)

project lead: Paul Simpson (Island Sea Farms Inc.)

Project team: Ron Francis, Linda Hiemstra (Island Sea Farms Inc.); Samantha Richman (U. Rhode Island); Erika Lok (Canadian Wildlife Service); Gregor Reid (DFO)

collaborators: Campbell River Netloft

Contact: isfhatchery@shaw.ca

www.islandscallops.com

Development of genomic health assessment tools for marine mussels (MYT-OMICS)

The BC coastline is under increasing pressure from competing coastal zone utilization and potential climate change impacts, highlighting the need for effective diagnostic tools of coastal ecosystem health and function. One of the major problems in assessing shellfish health is how to determine the organism’s response to multiple stressing agents in the natural environment such as temperature, salinity, oxygen levels and diet as well as to anthropogenic effects such as xenobiotic pollution and aquaculture husbandry methods. Unexplained shellfish mortalities in four major BC aquaculture companies accounted for $6 million in lost sales in 2007 alone. It is likely that the complex interaction of these factors is responsible for the mass mortality events seen, although it is not known to what extent each factor contributes and what combinations result in fatalities.

Marine mussels (Mytilus spp.) are dominant members of coastal and estuarine communities and are established worldwide keystone bio-indicator species and aquaculture organisms. Within this project we will develop genomic information and tools for use in the study of Mytilus spp. We will use these tools to examine the stress responses of Mytilus spp. with the goal of understanding the causes of seasonal mortality. An understanding of the factors responsible for significant mortality events can be used by the shellfish industry to develop management practices to reduce their losses. In addition genomic information and tools developed within this program will be available for use by other research groups. This project is complementary to our Genome BC project funded under the Science Opportunities Fund program.

sept. 2009 – june 2012

Funded by: DFO – Aquaculture Collaborative Research and Development Program (ACRDP) co-funded by: Taylor Shellfish Canada; Genome BC Science Opportunities Fund

project lead: Stewart.Johnson@dfo-mpo.gc.ca

Project team: Helen Gurney-Smith, Don Tillapaugh (VIU)

collaborators: Bill Taylor (Taylor Shellfish Canada)

Contact: isfhatchery@shaw.ca

Increasing vacuum packaging efficiencies in Blue Mussel processing

Allen’s Fisheries Ltd. (AFL) in partnership with Badger Bay Mussel Farms Ltd. proposes to upgrade their vacuum packaging equipment for Blue Mussels. This specific processing equipment is currently being used for European mussels, Mytilus galloprovincialis; at Allen’s the equipment will be used to process Blue Mussels, Mytilus edulis. Vacuum packaging of mussels is a way to deal with the peaks and valleys of production due to the natural inconsistencies in farm based supply.

This vacuum packaging equipment will be the first of its kind in North America. Unlike North American companies, European companies are further advanced; they spend more time and resources in research and development of processing equipment. Europe is focused on equipment efficiencies and reducing the amount of labour needed to complete a task. For instance, the debysser has a higher speed and is said to give a better product with less breakages than the North American equipment. This is an opportunity to adopt equipment from other markets to make the product competitive in international markets. Advancements in vacuum packaging equipment will lead to a better product line as a cheaper cost to the processing industry.

APR. 2011 – dec. 2012

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP)

project lead: Craig Allen (Allen’s Fisheries Ltd.)

Project team: Craig Allen, Sean Allen (Allen’s Fisheries Ltd.)

Contact: callen@allensfisheries.com

www.allensfisheries.com

Improvement of quality and productivity associated with live Blue Mussel inspection through the installation of automated sorting equipment

Allen’s Fisheries Ltd. (AFL) proposes to purchase and install an automatic sorting and defect removal system supplied by Best Sorting Systems Inc., Belgium, to improve the quality of live Blue Mussels processed at the plant and improve plant productivity. The technology does not exist in Canada and has not been used to sort mussels.

The goals/objectives of this project are to improve productivity and quality of finished mussel products and to reduce producing costs.

AFL has completed preliminary investigation into available technology and have concluded the processing advantages of incorporating new automating sorting technology. The use of automatic sorting systems will provide improved finished product quality, increased productivity and volume. The system would provide inspection capacity up to 8,000 kg per hour or double the current production level. Manual inspection processes are labour intensive, not always effective and often monotonous. The manual inspector performance is significantly reduced as the shift progresses and is influenced by employee vision, process lighting and worker fatigue.

APR. 2012 – mar. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Fisheries Technology and New Opportunities Program (DFA-FTNOP); National Research Council (NRC)

project lead: Sean Allen (Allen’s Fisheries Ltd.)

Project team: Richard Allen, Craig Allen (Allen’s Fisheries); Bob Hardy (Hardy Fish Co. Ltd.)

Contact: sallen@allendfisheries.com

www.allensfisheries.com

Arctic ice boom innovation for mussel farm protection

New ice boom technology is being developed by Sunrise Fish Farms Inc., one of the Newfoundland pioneers for cultured Blue Mussel technology for our cold Arctic waters. To meet the demand for increased production, security of existing and new growout waters is necessary. Many sites on the northeast coast of NL are at risk during the winter/spring ice conditions. Existing ice boom technology helps to control most bay ice conditions, but has limitations when winds and currents allow ice to slice under the boom to enter the site, and potentially damage floats and mussel lines.

Partners in this project include North Atlantic Marine Services Inc. in its St. John’s and Halifax fabricating facilities. Also, C-CORE, based at the Memorial University of Newfoundland, is providing engineering advice on local ice conditions, as well as potential stresses on the ice boom and shore mooring systems. North Atlantic Marine Services Inc. is leading the fabrication and breaking strength testing of the new ice boom system. The design includes a submerged skirt system that will allow bay ice to catch in the mesh, preventing the boom from lifting, and preventing ice slipping underneath as occurs for a typical surface boom. The boom will be in place before freeze-up in December 2012, allowing in-situ performance testing during the 2013 winter season.

APR. 2012 – mar. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP); National Research Council (NRC)

project lead: Laura C. Halfyard (Sunrise Fish Farms Inc.)

Project team: A. Job Halfyard, Trenton Johanson (Sunrise Fish Farms Inc.)

collaborators: North Atlantic Marine Services Inc.; C-CORE

Contact: lchalfyard@bellaliant.net

Protection from bay ice damage by the use of an ice boom

An investigation of the lipid and fatty acid composition of the Blue Mussel with reference to palatability and taste during conditions of extended holding

The Newfoundland mussel culture industry is poised to undergo a period of significant expansion in production and therefore the amount of harvested fresh product will increase. In many cases the product may be held at processing facilities awaiting transport. Unfortunately, storage of mussels over longer periods has been found to result in reduced meat yield, quality, and mortality. Recent work on a related project has indicated a significant loss in dry weight and condition index in mussels held for as little as one month during summer and fall. These types of changes in meat quality can be reflected in lipid, fatty acid, and glycogen content and hence taste and palatability. The current project will examine the variability in biochemical composition of Blue Mussels (Mytilus edulis) with a focus on lipid and fatty acid content under industrial standards for long-term holding and then, through the use of panel taste testing, determine if potential variations in lipid and glycogen content will affect product quality.

sept. 2011 – MAR. 2013

Funded by: DFO – Aquaculture Collaborative Research and Development Program (ACRDP) co-funded by: Norlantic Processors Ltd.

project lead: Harry Murray (DFO)

Project team: Lynn Hobbs, Sharon Kenny, Gehan Mabrouk (DFO)

collaborators: Terry Mills (Norlantic Processors Ltd.)

Contact: Harry.Murray@dfo-mpo.gc.ca

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

The Newfoundland mussel culture industry is poised to undergo a period of significant expansion in production due to increased utilization of existing approved culture sites as well as the development of new sites. Mussels are typically cultured in sheltered near shore areas (river mouths, estuaries, harbours, and shallow bays); however, these sites can be negatively affected by land run-off, especially during times of significant precipitation, exposing mussels to land-based contaminants. Benthic deposition (i.e., mussel drop off, faecal material, and rejected particles known as pseudo-faeces) and increased pressure for lease space in these areas has raised concerns regarding the ecological carrying capacity* and sustainability of coastal shallow water culture sites. Recent interest in the development of offshore deep water bivalve culture could potentially reduce many of the issues associated with near-shore sites. Deep water offshore sites show less benthic impacts by deposition, higher chlorophyll concentrations, and experience natural upwelling events which can bring additional nutrients and particles into the water column. Offshore sites offer a combination of a concentrated food source and potentially greater water quality which should support improved culture conditions and a corresponding decrease in animal stress, ultimately improving mussel condition and health. This project will characterize and compare seasonal changes in environmental conditions in offshore deep water and standard coastal shallow water mussel culture sites in Notre Dame Bay, Newfoundland. Researchers will investigate potential correlations with mussel condition, physiological stress indicators and lipid biochemistry to determine the environmental sustainability of each culture site.

*Ecological Carrying Capacity: is the highest stocking density that can be cultured without compromising other components of the ecosystem (for example: phytoplankton depletion)

july 2012 – MAy 2015

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

Contact: Harry.Murray@dfo-mpo.gc.ca

New and innovative equipment for mussel processing industry

In 2010, planning began for a major retooling at PEI Mussel King concentrating on modernizing its facility and increasing its capacity for value added production. The project had many parts, but the most consideration was given to finding innovative equipment solutions to automate key processes.

Specifically, the project was for the purchase of a complete line of equipment for the automated vacuum-packaging of in-shell mussels. This equipment installed is the first of its kind in the Canadian mussel industry. Generically known as a horizontal-form-fill-seal (HFFS) line, such equipment is commonly used in many packaging applications. However, the special challenge of packing whole shell mussels required a fully-customized line with one-of-a-kind innovations. The installation of this equipment has been very successful, meeting and exceeding the proponents’ expectations.

The greatest cost savings resulting from this project is in the direct labour column. Based on the same process steps pre- and post-project, Mussel King expects to realize a 75% saving. Film costs are higher, but these are offset with savings in labels. Mastering the mussel pouches at the time of production represents a yearly saving and less waste in product and packaging material.

Pressure to lower costs, a smaller and more sophisticated labour force, and the need for new production capabilities have all driven this innovative project.

apr. 2011 – MAr. 2012

Funded by: Province of Prince Edward Island co-funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP); Atlantic Canada Opportunities Agency (ACOA)

project lead: Esther Dockendorff (PEI Mussel King Inc.)

Project team: Scott Dockendorff (PEI Mussel King Inc.)

Contact: esther@peimusselking.com

www.peimusselking.com

A project to develop and introduce automated, digital imaging technology to the grading process in Canadian mussel plants

Confederation Cove Mussels Co. Ltd. developed a fully operational mussel grading system. This innovative grading system uses image acquisition and analysis using a specially designed software algorithm to grade mussels at a high speed. Mussels are fed over four grading belts and their images are acquired in real time to allow grading at a rate of 8 mussels per second per lane or 25-30 mussels per second per unit. Mussels are separated at high speed for such elements as size, shape, and meat content, while also identifying and removing any defective units.

Digital imaging technology is dependent on the object being in a consistent location and format to give a repeatable process. The greatest technical challenge was resolved in the application of the Auxiliary Handling Equipment. A great deal of energy was spent on designing mussel handling equipment that could effectively singulate and organize mussels in a consistent pattern at high speed.

This new automated grader will change the fundamentals of processing and deliver significant concrete and indirect benefits to the industry including lowering and controlling labour costs, improving both quality and food safety performance and making the whole grading process more consistent and predictable.

apr. 2011 – MAr. 2012

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Atlantic Canada Opportunities Agency (ACOA); Province of Prince Edward Island

project lead: Len Currie (Confederation Cove Mussels Co. Ltd.)

Project team: Melanie Waite (Confederation Cove Mussels Co. Ltd.)

collaborators: Lizotte Consultants; Atlantic System Manufacturing

Contact: mussels@confederationcove.pe.ca

http://confederationcove.com

Blue Mussel imaging sorter

Evaluation of Blue Mussel processing plant holding systems in PEI

As Blue Mussels become more of a commodity, processors are looking for new and improved holding systems and methods while maintaining high product quality. Current systems have shown limited holding mussel capacity (defined as the length of time live mussels can be held in wet storage). Better holding systems and/or practices would improve the industry’s ability to compete in international markets. The goal will be to develop better holding methods by evaluating water quality in holding systems, assessing time of harvest impacts and thermal shock on shelf life, and conducting a preliminary evaluation of emersion/immersion cycles on mussel shelf life.

june 2011 – MAR. 2014

Funded by: DFO – Aquaculture Collaborative Research and Development Program (ACRDP) co-funded by: PEI Mussel King (1994) Inc.

project lead: Daniel Bourque (DFO)

Project team: Luc Comeau (DFO)

collaborators: Esther Dockendorf (PEI Mussel King (1994) Inc.)

Contact: Daniel.Bourque@dfo-mpo.gc.ca

Mussel larvae production enhancement by restocking mussel beds in Bassin du Havre-Aubert, Magdalen Islands

Mussel production has been an important part of Magdalen Islands aquaculture industry for the previous thirty years. Natural mussel spat is facilitated via rope collectors set in the shallow Bassin du Havre-Aubert (BHA). This is the first crucial step in the mussel growing process on the Magdalen Islands. When grown sufficiently, juvenile mussels are socked (placed in plastic rope nets) and transferred to one of two mussel farm sites.

Since 2004, mussel growers have observed three years in which seed collection in BHA was very poor. Many reasons have been advanced in an attempt to explain this drastic decline of spat abundance. One of them focusses on mussel biomass and, through that, spat production. Mussel beds were inventoried between 2001 and 2009, and it was found that biomass had declined by 98 %. Decreased mussel biomass and wide distribution over BHA could explain observed spat declines and, therefore, mussel seed collection success.

Since 2009, Merinov-Centre des Îles has been involved in a new project on mussel bed restoration in BHA. Collectors were first installed at grower installations in the bay. The following summer, mussel seeds were removed from collectors and grown in socks for one year to contribute to the spawning effort. Finally, mussels were seeded on the bottom close to grower installations. Results from seed harvesting in the year following the first and the second restocking attempt have indicated significant success in BHA mussel restoration.

June 2011 – Mar. 2014

Funded by: MAPAQ

project lead: Carole Cyr (Merinov)

Project team: Carole Cyr, Lisandre G. Solomon, François Bourque (Merinov)

Contact: carole.cyr@merinov.ca

Technical-economic assessment of an integrated mussel post-harvest process

In shellfish culture, there are sometimes periods of faecal coliform contamination that exceed the standards set by the Canadian Shellfish Sanitation Program (CSSP). This obstacle limits structured annual aquaculture operational planning and effective commercialization. Moule de Gaspé Inc. must now handle all processing steps previously performed by a plant, from processing to marketing. The proponent intends to integrate the post-harvesting steps into one on-vessel operation and then transfer its batches of mussels in a wet holding system in a floating platform. A compact, innovative device (Kramer C700) will be used to perform post-harvest interventions in one step, which will limit handling and save space on-board the vessel, as well as time and money (i.e., elimination of the costs associated with transportation and with pumping process and treatment water). A secondary goal involves bringing the company’s batches of mussels outside the contaminated area in a floating platform during closed times so that they can purify themselves naturally. A validation of the protocol will be done in consultation with CSSP members to determine the operational parameters for depuration in the natural environment.

Apr. 2012 – mar. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Merinov

project lead: Jacques Dufresne (Les Moules de Gaspé Inc.)

Project team: Estelle Pedneault (Merinov)

Contact: dufja@hotmail.com

www.facebook.com/lesmoulesdegaspe

Floating platform used for wet holding

Genomic and physiological processes during the larval ontogeny of the Blue Mussel: impact of eicosanoid precursors

Found in many countries, Mytilus edulis is a bivalve cultivated directly in the natural environment. Therefore, survival, growth, breeding, and physiological performances depend on the environmental conditions at each aquaculture site.

The effect of two essential fatty acids (EAA and EPA) on the ontogenic pre- and post-larval development was studied by monitoring the building up of energy reserves, as well as the performances in terms of survival and larval growth. Furthermore, a functional genomic approach was then implemented using an Illumina HiSeq with high sequencing capacity. In this manner, 50,000 sequences were obtained for the various larval stages. Of these, 30,000 integrate functions in biological processes, as well as growth, localization, marking, apoptosis, stress response, and behavioural processes, etc. The results of the project show an increase in the lipidic reserves of the larvae at various ontogenic stages. The results also put into relief the fundamental role of these fatty acids in the building up of essential energy reserves, thereby providing for improved survival, immunocompetence and stress tolerance. The transcriptomics approach using DNA chips allowed for the identification of new transcripts which are potentially involved in some major biological functions, such as development and immunity, and also allowed for the global analysis of the ontogenic transcriptome of the Blue Mussel.

May 2010 – Apr. 2013

Funded by: Institut des Sciences de la Mer (ISMER); Institut universitaire européen de la mer (IUEM)

Project team: Sleiman Bassim, Réjean Tremblay (UQAR); Dario Moraga (U. Brest, France); Sophie Gauthier-Clerc (U. Montréal)

Contact: rejean_tremblay@uqar.qc.ca

The Eider Spider: Development and experimental testing of a novel method to deter sea duck predation on mussel farms

The cultivation of mussels is a growing industry worldwide, but predation by migrating sea ducks has been a challenge to mussel growers causing major financial losses. Ice coverage and the ducks’ seasonal migration patterns limit their predation activity in most areas, but with the prospect of milder winters due to global warming, losses are expected to increase in the future. Mussel growers have adopted several techniques to “scare” ducks off mussel farms which include loud recordings, pyrotechnics, shooting, chemical deterrents, or chasing with boats; all of which have had limited success and are often subject to habituation. Protective socking material has also been tested; however, results have indicated that the socking material has unfavourable effects on the growth rate and production level. Since sea ducks are protected species, any deterrent method must ensure that it follows the framework of conservation laws and regulations. Therefore, there is a need for a deterrent mechanism that will not only be beneficial to the growers but would also be conservation-friendly. The Eider Spider sea duck deterrent system will be tested in field trials in Quebec and Nova-Scotia to provide the aquaculture industry with an innovative and efficient device to deter bird predation on mussel culture.

Apr. 2012 – mar. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Société de développement de l’industrie Maricole (SODIM); Aquaculture Association of Nova-Scotia (AANS)

project lead: Priyum Koonjul (Valeo Management)

Project team: Estelle Pedneault (Merinov); André Mallet (Mallet Research Services Ltd.)

collaborators: Aquaculture Association of Nova Scotia (AANS)

Contact: priyum.koonjul@valeosec.com

Developing an innovative treatment system for Vase Tunicate fouling on cultured Blue Mussels

Somers Island Blues Inc. of Murray River, PEI, will develop and assess a prototype system designed to mitigate the impact of Vase Tunicates on the applicant’s mussel farms. The proposal is supported by a proof of concept that followed recommendations from the AIF Underwater Tunicate Treatment Trials Report. Air will be injected immediately behind the nozzle and a funnel (plastic cone — approx. 7" long) will be placed around the front of the nozzle to enable the water jet to travel from the tip of the nozzle to the treatment material at the end of the cone.

The sprayer will be mounted on a treatment platform custom designed for this project. All other equipment necessary for operating the system (e.g., motors and pumps) will be built into the frame of the platform and hydraulic, water, and air lines will be run under the deck to the sprayer assembly. This will reduce unnecessary clutter around the sprayer and make the system safer. In terms of efficiency, Somers Island Blues Inc. believes that a dedicated treatment system is the next step in managing the current tunicate infestation.

apr. 2012 – MAr. 2013

Funded by: DFO – Aquaculture Innovation and Market Access Program (AIMAP) co-funded by: Province of Prince Edward Island

project lead: Chris Somers (Somers Island Blues Inc.)

collaborators: Province of Prince Edward Island

Contact: cj.somers@pei.sympatico.ca

Impact of biotic and abiotic factors on the mechanical properties of the byssus of the Blue Mussel: a marketable biomaterial

This strategic research project focused on the production of the byssus of the Blue Mussel (Mytilus edulis). The project had two main objectives. The first objective was to identify the biotic and abiotic parameters responsible for the weakening of the byssus and the fall-off of the mussels during rearing, in order to improve the management of mussel production and promote sustainable aquaculture. The second objective was to explore the use of the byssus as an innovative and highly value-added product, notably by drawing on the unique mechanical properties of the byssal threads to develop biomaterials like nanofibres, biocompatibles, and biopolymers, etc. Our work demonstrated the impact of the rearing site (lagoon or open water), the reproductive effort (clutch size) and the metal content of the strands on the mechanical properties of the byssus. Furthermore, byssus production with a high level of stable carbon isotope (13C) and infrared analyses enabled us to understand better the structure and composition of the byssus. Finally, this project led to the development of methods for the synthesis of biopolymers using byssus hydrolysate.

Oct. 2009 – Nov. 2012

Funded by: NSERC; RAQ

project lead: Isabelle Marcotte (UQAR)

Project team: Bertrand Genard, Remy Hennebicq, Réjean Tremblay (ISMER); Frédéric Byette, Marc-Olivier Séguin Heine, Alexandre A. Arnold (UQAR), Christian Pellerin (UDEM); Bruno Myrand (Merinov)

Contact: marcotte.isabelle@uqam.ca

Mussel sock in the Gaspé

Culture density, biomass-density relationship, and self-thinning in molluscs

Aquaculture requires crucial decisions, regarding the stocking density of culture structures. Populations must be high enough to ensure profitability, but low enough to prevent overpopulation. An approach borrowed from forestry allows us to address this issue systematically. It involves studying the biomass-density relationship and self-thinning. This approach is currently little-used in aquaculture research and development. The purpose of this project is to provide examples of this theory for use in and development of mathematical models to facilitate its understanding and practical use. We previously worked with the Blue Mussel (Mytilus spp.). This work targets the Sea Scallop (Placopecten magellanicus) and the Surf Clam (Spisula solidissima). Our work suggests that self-thinning depends on, among other things, initial culture density. We have produced a mathematical model that can take this effect into consideration without multiplying the density levels studied. Also, our results indicate how mass mortality observed in scallop cultures in Asia was linked to self-thinning. In the next steps, we will examine the issue to determine whether clam dispersion can be better predicted through the biomass-density relationship.

1990 – Mar. 2012

Funded by: DFO

project lead: Marcel Fréchette (DFO)

collaborators: José Urquiza, Gaétan Daigle, Dominique Maheux (U. Laval); Marianne Alunno-Bruscia (IFREMER, France)

Contact: marcel.frechette@dfo-mpo.gc.ca

Harvesting mussels grown using a self-thinning technique

Bioenergetics and mollusc food ingestion

Bioenergetics helps us understand how environmental variables act on the growth of organisms in culture. It has applications in a variety of domains, such as support capacity, understanding environmental impacts of aquaculture, and forecasting climate change effects. Along with temperature, food ingestion is a crucial component of bioenergetics. The model species in our work is the Blue Mussel. However, our results are applicable to a wide variety of organisms. In a recent communication, we showed that the classic model describing food ingestion is inadequate. As a result, we developed a model based on a regulation by the animal’s internal state. This model successfully describes effects such as, the spatial variability of growing conditions and physiological flexibility of feed in organisms. The next steps will focus on the analysis of an experiment testing our regulation model and, if necessary, improving it. We will also examine its performance in culture situations observed in France.

apr. 2010 – Mar. 2012

Funded by: DFO

project lead: Marcel Fréchette (DFO)

collaborators: José Urquiza, Gaétan Daigle, Dominique Rioux-Gagnon (U. Laval); Marianne Alunno-Bruscia (IFREMER, France)

Contact: marcel.frechette@dfo-mpo.gc.ca

Blue Mussels