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Archived – Stress effects in shellfish investigated three ways

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Responding to an industry-wide need for more efficient ways to evaluate and monitor health states in shellfish, three research teams across Canada have been looking at different aspects of the problem.

Seedstock differences in Newfoundland



DFO’s Dr. Randy Penney, based in St. John’s, Newfoundland, is interested in the reported variability in performance of different mussel seedstocks, some of which comprise two species (Mytilus edulis and Mytilus trossulus), when confronted with stresses related to temperature and salinity. At DFO, Dr. Penney, Dr. Dounia Hamoutene and their team are comparing physiological stress responses (primarily “heat shock protein” Hsp) of several indigenous seedstocks from the Notre Dame Bay area. The team is currently working out some standardized testing protocols for Hsp and other stress proteins in the hopes of developing a quantitative way to identify “hardy” strains that can be used for inter-site transfers, and which may be expected to perform favourably compared to local mixed-species stocks. They hope to provide recommendations to the industry regarding the most desirable stocks for commercial development, and to begin comparative work on stress response in scallops (Placopecten magellanicus).

Behavioural indicators in Quebec

Mussels were also involved in a recently-completed study at the University of Quebec at Rimouski. Noting the difficulties in determining the state of health of individual shellfish outside obvious indicators such as very slow closing of the valves in already-moribund animals, Dr. Rejean Tremblay, Rachel Picard and Bruno Myrand have been seeking a simple, behavioural indicator that could be quantified for intermediate levels of stress between robust health and deep morbidity. They tested the time required for softshell clams (Mya arenaria) to bury themselves, and assessed the strength of attachment and number of byssus threads produced by mussels (Mytilus edulis), after removal from the water for more than three days at 100% humidity. The researchers reported that the behavioural indicators selected were not able to discern various levels of stress in test animals.

A Genome-based model in BC

Dr. Helen Gurney-Smith

Dr. Helen Gurney-Smith

A research program (Myt-OME) on the West Coast funded by Genome British Columbia and the BC Innovation Council has taken a different approach to the challenge of quantifying stress responses in shellfish. Led by Dr. Helen Gurney-Smith of Vancouver Island University’s Centre for Shellfish Research and Dr. Stewart Johnson of the DFO Pacific Biological Station, a team of international collaborators is attempting to identify the genes involved in the expression of stress responses.

According to Dr. Gurney-Smith, “Most people have heard the expression ‘happy as a clam’, but the truth is we do not have any tools to determine if a clam is happy (healthy). Genomic science can provide the necessary tools”.

In 2008 an investment of more than $400,000 by the Government of Canada through Western Economic Diversification Canada helped to establish a Shellfish Genomics Laboratory at Vancouver Island University in Nanaimo, BC, where research tools will be developed to diagnose various factors related to transportation, pollution and environment in hatchery-reared larvae and adult shellfish.

In recognition of the many possible overlapping sources of stress arising through environmental conditions, human activities and biological influences such as disease, Dr. Gurney-Smith and her team have launched a major program to develop a genomics tool for use with mussels (Mytilus spp.), a known ecosystem bio-indicator genus. They hope to devise an accurate way to measure the activity of specific genes that are up- and down- regulated in response to a variety of stressors. Once they can measure accurately the genomic biomarkers that respond to multiple-stressing conditions in the marine environment, they will be able to correlate levels of stress with environmental conditions, and to understand what ultimately determines a fatal response. With a sensitive genomics tool applied to a number of “keystone species”, scientists should be able to perform far more accurate and timely health assessments of individual shellfish. This would facilitate assessments of ecosystems in various coastal zones and stocks in aquaculture operations, as well as monitoring of environmental changes and their effects.

Newfoundland study:
Duration: Nov ’08 - Ongoing
Project team: Randy Penney (DFO), Dounia Hamoutene (DFO), Juan Perez Casanova (DFO), Sean Macneill (DFO), Marsha Clarke (DFO).
Funded by: DFO.
For information contact: Randy Penney (Randy.Penney@dfo-mpo.gc.ca)

Quebec study:
Duration: 2005 – 2008
Project team: Rejean Tremblay (ISMER-UQAR), Rachel Piquard (ISMER-UQAR), Bruno Myrand (CEMIM-MAPAQ).
Funded by MAPAQ.
For information contact: Rejean Tremblay (Rejean_tremblay@uqar.qc.ca)

British Columbia study:
Duration: Jan ‘09 – Mar ’10
Report submitted by: Genome British Columbia.
Project team: Helen Gurney-Smith(CSR-VIU), Stewart Johnson (DFO), Ben Koop (UVIC), Antonio Figueras (CSIS-IIM, Spanish Ref. Lab. For Mollusc Diseases, Spain), Crain Newton (ATG Genetics).
For information contact: Helen Gurney-Smith (Gurneysmh@viu.ca)

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