Canadian Aquaculture R&D Review 2009

Additional project summaries

Identification of ISAV-resistant salmon broodstock families

It is now well established that many distinct Infectious salmon anaemia virus (ISAV) isolates exist in the Bay of Fundy. These isolates vary in their virulence and disease progression, but due to strict fish health management practices resulting in rapid depopulation, the true virulence and risk to the industry of the different isolates is not known.

In an attempt to better understand and characterize the virulence of ISAV isolates in the Bay of Fundy, several groups have performed in vivo challenges with different ISAV isolates. This work has corroborated many of the anecdotal field reports of varying virulence for the different isolates, and has shed some light on the dynamics of ISAV infection in vivo. It has also supported field observations that some fish become infected with ISAV (and test positive with routine diagnostics) but do not succumb to disease. This finding, once further characterized, may lead to identification of families of fish which are ISAV resistant, and can withstand the effects of ISAV infection in the field. Working closely with the industry, this study will provide information on the genetic susceptibility of different families to ISAV and will further our understanding of the virulence of different ISAV isolates. The ultimate goal of this project is to compare the response of different family groups to ISAV isolates of differing virulence, and compare the utility of diagnostic techniques to detect the different ISAV variants in clinical and sub-clinical fish.

Duration: Jan ‘08 – Oct ‘08
Funded by: DFO-ACRDP 
Project team: Brian Glebe (DFO) 
For information contact: Brian Glebe ( Brian.Glebe@dfo-mpo.gc.ca)

The effect of rearing density on stress and welfare of farm reared Atlantic Salmon (Salmo slar) over an entire production cycle

To remain competitive in the global market salmon producers must continually strive to reduce the cost of production. Fish rearing densities are critical in determining cost of production due to the capital cost of cages, feeding equipment and staff. However, there is always a potential conflict between maximizing stocking density thus reducing the cost of production while still maintaining optimal animal health and welfare.

Despite the need to establish limits on stocking densities that are based on sound scientific data, this has not been possible for two reasons. First, the type of stress associated with the gradual increase in stocking density as fish increase in size is chronic and as such, difficult to measure. Second, in the past, commercial aquaculture companies have been unwilling to stock fish at different densities necessary to carry out a controlled experiment capable of assessing the effect of stocking densities on fish stress. Marine Harvest Canada has made an unprecedented commitment to this project allowing fish to be reared at three different stocking densities over an entire production cycle. This project represents a multi-disciplinary approach, including molecular genetics, functional immunology and fish welfare, for identifying measures of chronic stress.

Duration: Apr ‘07 – Mar ’09. 
Funded by: DFO-ACRDP. Co-funded by: Marine Harvest Canada. 
Project team: Kristi Miller (DFO), Marine Harvest Canada
For information contact: Kristi Miller ( MillerK@pac.dfo-mpo.gc.ca)

Development of integrated management methods for soft-shell clam harvesting, seeding and culture activities at a clam culture site located in the St. Lawrence Estuary

Development of integrated management methods for soft-shell clam harvesting, seeding and culture activities at a clam culture site located in the St. Lawrence Estuary

Various spat supply approaches have been explored in recent years to meet clam producers’ requirements. Studies on spat collection (benthic and pelagic) have provided concrete results in various maritime regions. The results obtained demonstrate that it is possible to collect young clams for farming purposes. However, the experimental seedings carried out in the Magdalen Islands, on the Gaspé Peninsula and on the North Shore show that the dispersal rate is often high for small clams.

One potential method that can be used by clam culture operations to counter the negative effects of dispersal is to implement an integrated management strategy for the clam culture site. This strategy would involve installing collection, seeding and culture facilities in order to promote spat settlement as well as the retention of natural and seeded clams. It is proposed that research be conducted aimed at gaining a better understanding of clam recruitment and dispersal mechanisms. Management strategies will be tested in order to more effectively control these variables. This request involves five projects, namely: 1) to develop integrated harvesting, collection and culture strategies (literature review and consultation); 2) to inventory the available biomass and recruitment; 3) to carry out harvesting and sell the harvest; 4) to carry out seedings and estimate clam dispersal by size; and 5) to estimate collection success.

Duration: Apr ‘07 –Mar ‘10
Funded by: DFO-ACRDP Co-funded by: SODIM, DFO-Fisheries Science Collaborative Program, Coopérative de solidarité des produits de la Côte
Project team: Sylvie Brulotte (DFO), Michel Giguère (DFO), Jean-Marie Belisle, Isable Calderón (DFO), Marie-France Dréan, Bernard Tramblay 
For information contact: Sylvie Brulotte ( Sylvie.Brulotte@dfo-mpo.gc.ca)

Synthesis and analysis of environmental performance data for salmon farming industry in southwestern New Brunswick

The NB salmon farming industry has been operating in the Bay of Fundy since the late 1970’s. A stringent environmental monitoring program was established to quantify the impacts of individual farms on the surrounding environment. This program was developed with the expertise of scientists, and has been revised as newer information becomes available.

Since 2002, the salmon farming industry in New Brunswick has been striving to implement an environmental performance based standards (PBS) system for the management and regulation of marine cage-based salmon aquaculture in southwest NB. This program is based on maintenance of environmental quality with operational flexibility, application of a risk-based and science-supported environmental management and regulatory process, multi-jurisdictional inter-government and government-industry cooperation, and public accountability and transparency.

The proposed work will help address the needs of the SWNB industry to demonstrate its environmental responsibility to regulators and the public and will help improve the PBS framework. It will also provide an initial foray into the development of an ongoing regular review of the industries environmental performance and the knowledge gained will be useful in considerations of mitigation and remediation.

Duration: July ‘08 – Apr ‘10
Funded by: DFO-ACRDP Co-funded by: New Brunswick Salmon Growers Association, Cooke Aquaculture Inc., AquaFish Farms 
Project team: Fred Page (DFO), Blythe Chang (DFO), Randy Losier (DFO), Paul McCurdy (DFO), John Reid (DFO), Andrew Cooper (DFO), Caroline Graham (NBSGA), Jamie Smith (working in conjunction with provincial and federal regulatory colleagues)
For information contact: Fred Page ( Fred.Page@dfo-mpo.gc.ca)

Tracking the food source of mussels from Integrated Multi-Trophic Aquaculture (IMTA) sites using stable isotopes

Typically, the utilization of food sources by mussels has been evaluated via direct gut content analysis. Alternatively, we have been using stable isotope analyses as a tracer mechanism to reveal dietary sources in mussel tissue, based on the assumption that autochthonous and allochthonous organic particles taken up by the mussel will exhibit different isotopic ratios, which can be reflected in the mussels themselves.

Our studies indicate that fish feed and algae exhibit completely different 13C/12C and 15N/14N ratio signatures. Furthermore, isotopic signatures of mussel body tissue fed solely on either food source will change to closely resemble that of the source within weeks, whereas mussels fed a mixed diet of algae and salmon food exhibited intermediate C and N ratios over the same time period. This has proven that mussels can assimilate both in situ organic matter (algae) as well as salmon food as a given proportion of their biomass, proving their potential as recyclers within the fish farm. We have now expanded the use of food tracing techniques in order to test the relative importance of available food sources to the mussels both in field based settings and over seasonal cycles.

Duration: Dec ‘06 – Mar ‘09
Funded by: DFO-ACRDP Co-funded by: Cooke Aquaculture Inc., ACOA-AIF 
Project team: Terralynn Lander (DFO), Shawn Robinson (DFO), Tammy Blair (DFO), Gregor Reid (DFO), Jim Martin (DFO), Fernando Salazar 
For information contact: Shawn Robinson ( Shawn.Robinson@dfo-mpo.gc.ca)

Utility of continuous light and triploidy to control sexual maturation of Atlantic cod in the Bay of Fundy

Early maturation in pre-market Atlantic Cod affects almost 100% of fish in sea cages, and this problem is not isolated to the Bay of Fundy. Preliminary results from 24 h light treatment (six 400 W submerged lights) in a 70 m polar circle cage holding 2004 year-class cod support the hypothesis that continuous light delays onset of sexual maturity, in this case by about 4-5 months, with females subsequently retaining the state of ripeness for another 4 months.
The current project will explore two approaches to impede sexual maturation: (i) continued experimentation with light level and wavelength and (ii) induction of sterility by triploidy.
This study has a number of objectives:

1. To further evaluate on-going light treatments and test the use of new light technology to inhibit sexual maturation of Atlantic cod.
2. To examine the degree of suppression of maturation in both sexes in 0+ group, pre-market and market fish exposed to 24 h light.
3. To develop protocols for the pressure-induced production and early identification of triploid cod.
4. To monitor seasonal sex-specific growth of immature and mature cod (derived from light treatments and triploidy) as well as incidence of deformities and mortality.

Duration: May ‘07 – Apr ‘10
Funded by: DFO-ACRDP 
Project team: Edward Trippel (DFO) 
For information contact: Edward Trippel ( Edward.Trippel@dfo-mpo.gc.ca)

Data collection in support of zone of impact modeling for Lake Huron cage farms

The project will begin, but not complete, the collection of data required to initiate waste deposition modeling and zone of impact delineation at commercial cage sites in Lake Huron. Fine-scale bathymetric data as well as current speed and direction data will be collected at three of nine commercial fish farm sites in Lake Huron. This data is required for DEPOMOD, which is a deposition modelling tool developed for and in use in the marine environment. Central & Arctic wishes to test if this tool provides accurate prediction of deposition in the freshwater environment and to modify or seek a new tool if it does not. Such a tool would permit applicants and regulators to assess the potential production capacity of a site within the assimilative capacity if the local environment.

Duration: Sept ‘08 – Mar ‘09
Funded by: DFO-PARR 
Project team: Cheryl Podemski (DFO), Doug Geiling (DFO), David Ross (DFO) 
For information contact: Cheryl Podemski ( Cheryl.Podemski@dfo-mpo.gc.ca) or Doug Geiling ( Doug.Geiling@dfo-mpo.gc.ca)

Carrying capacity modelling for bivalve aquaculture: Biodeposition

Numerical modelling provides an effective means to evaluate the interactions between aquaculture activities and the ecosystem. Our work with the particle dispersion model DEPOMOD to predict carbon loading resulting from increased biodeposition from suspended bivalve culture has shown that we can predict benthic community changes in some cases. Failures with the model may result from not including biodeposition from the fouling organisms associated with mussels in culture. These may represent a considerable biomass and, in the case of tunicates, may have a biomass several times that of the mussels they are attached to.

To improve our models, we are measuring biodeposit (faeces) production and sinking speeds for the dominant fouling communities, invasive tunicates. We thus constructed small mussel socks with and without 2 species of tunicates. We compared biodeposit production from these to that from similar control socks (mussels only, tunicates only, inert controls). Biodeposition production was evaluated over a 2 week period in September/October. Faecal pellet sinking rates were measured concurrently. These data will be used to refine the existing DEPOMOD model. This will ultimately allow for better predictions for aquaculture management within an ecosystem-based management framework for sustainable aquaculture.

Duration: Sept ‘08 – Mar ‘09
Funded by: DFO-PARR Co-funded by: CIAS, CAISN, DFO (Quebec)
Project team: Chris McKindsey (DFO), Andrea Weise (DFO), Mathieu Huot (DFO), Mayi Lecuona (DFO) 
For information contact: Chris McKindsey ( Chris.McKindsey@dfo-mpo.gc.ca)

Evaluation of ecosystem-level effects of intertidal bivalve culture: Gaspé

A regional priority in Québec is to better understand the functional relationship between increased organic sedimentation due to suspended bivalve aquaculture and benthic responses to better predict the benthic ecological carrying capacity of sites for suspended bivalve aquaculture. One of the main culture sites is baie de Gaspé. However, there is currently no information available on the impact of bivalve farming in the bay.

This project constitutes a scoping study in the baie de Gaspé to evaluate the impact of current aquaculture practices on the benthic environment. As a first step in a larger future research programme, this work is limited to infaunal and sediment samples to evaluate if patterns relating to mussel farming exist. We thus sampled the benthic communities within the bay at different spatial scales with multiple sites sampled within and outside of the farms, both directly below and between longlines. Thus, this work will specifically address the habitat management considerations for site evaluations. This research will also contribute globally towards addressing the knowledge gap of the impact of bivalve aquaculture on benthic diversity and productivity and allow us to better plan for future work to be done in the area on carrying capacity.

Duration: Sept ‘08 – Mar ‘09
Funded by: DFO-PARR Co-funded by: DFO (Quebec) 
Project team: Chris McKindsey (DFO), Nathalie Simard (DFO) 
For information contact: Chris McKindsey ( Chris.McKindsey@dfo-mpo.gc.ca)

Investigating efficiencies of open water Integrated Multi-Trophic Aquaculture (IMTA)

The IMTA concept involves the re-cycling of energy from fed components of an aquaculture site through a series of extractive organisms (both plants and animals), known as biofilters. A variety of co-culture species are projected to be grown adjacent to Atlantic Salmon cages to foster augmented growth and nutrient recovery. Measures of efficiency; accessing, consuming, absorbing/digesting and retaining nutrients loaded from the fed trophic level (i.e., Atlantic Salmon) in IMTA systems, is necessary for management and measures of sustainability. Models and metrics are presently being developed to quantify these efficiencies and identify knowledge gaps where they exist. The information generated from these models is being used to guide further IMTA research and to proactively develop new management models with regulators for the constantly evolving aquaculture industry in Canada.

Duration: Jun ‘06 – Dec ‘14
Funded by: ACOA-AIF Co-funded by: Cooke Aquaculture Inc., Acadian Seaplants Limited 
Project team: Gregor K. Reid (DFO), Shawn Robinson (DFO), Thierry Chopin (USNBJ), Bruce MacDonald (DFO), Fred Page (DFO), Les Burridge (DFO)
For information contact: Gregor K. Reid ( Gregor.Reid@dfo-mpo.gc.ca)