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The Difference Between Headlines and Fact

An article published this week in Environmental Science and Technology compares mercury levels in rockfish living near active salmon farms in three geographic areas of British Columbia

April 21, 2006

The Difference Between Headlines and Fact

An article published this week in Environmental Science and Technology reports on a study considering the ecosystemic effects for mercury recycling. Study authors compare mercury levels in rockfish living near active salmon farms in three geographic areas of British Columbia to those from reference sites, and explore possible mechanisms for observed differences in mercury levels among the sites.

"It is extremely important that scientific work be assessed on its methodology and findings," says Mary Ellen Walling, executive director, BC Salmon Farmers聽聽Association. "The important thing to remember is this study concludes the average of all fish tested fall within the safe consumption guidelines set by Health Canada."

聽THE FINDINGS FROM THE STUDY

聽聽聽聽聽 "Under guidelines set by Health Canada , the mercury levels we observed permit unrestricted consumption of rockfish by adult males at any site, and require only slightly restricted consumption near farms by children and women of child-bearing age." (See study line 278 - 292 "Ecosystemic Effects of Salmon Farming Increase mercury Contamination in Wild Fish")

聽聽聽聽 Fish from all sites tested below the 0.5 parts per million (ppm) safe consumption standard set by Health Canada. (See study Figure 2)

R聽聽聽聽Rockfish from six of the eight reference sites - i.e those located away from fish farms - had mercury levels the same or higher than four of the nine salmon farming sites. (See study Figure 2)

聽ADDITIONAL INFORMATION

聽聽聽聽聽 The study references 30 year old research when stating "Some sources of fish feed have been found to contain high levels of mercury" (see study line 56 - 58). Research conducted by the Canadian Food Inspection Agency in 2004 measures mercury content in fish meal and fish feed as very low, at between 0 and 0.35 ppm.

聽聽聽聽

F"聽聽 For simplicity, the fish were all assumed to be immature" (see study line 190-191). Size and age provide significant information on contaminate load, especially in rockfish, which are long lived and feed high on the food chain, and can therefore be expected to bio-accumulate mercury more than other species. Accurate information on size and age of the samples is critical to the assessment of the study results.

聽聽聽聽

T聽聽聽聽There is no evidence in the study to suggest local food supplies are harmed. In the Results and Discussion portion of the paper, study authors write "Ongoing monitoring will be required to ensure that British Columbia's First Nations communities, and coastal communities everywhere, can safely continue to consume marine foods." (see study line 294 - 297)

聽聽聽聽

The Kitasoo First Nation was one of the First Nations involved in the recent monitoring project between university researchers and three First Nations Organizations to聽 investigate the impact of salmon farms on the local food web, specifically traditional food resources. Here's what Larry Greba, fisheries director for the Kitasoo Band says about the results. "We can only comment on results from our area but overall they were reassuring. While mercury appears slightly elevated in rockfish - it remains an issue for further investigation, as for other metals such as cadmium and arsenic, results appear normal. We will continue monitoring with the continued support of our partners." To read the Kitasoo release follow this link... http://www.salmonfarmers.org/files/04_19_06_b.html

To review the study referenced above "Ecosystemic Effects of Salmon Farming Increase mercury Contamination in Wild Fish" click here...
http://www.salmonfarmers.org/pdfs/mercury_contamination.pdf

Other related links:

Mercury Your Health and the Environment
http://www.hc-sc.gc.ca/ewh-semt/pubs/contaminants/mercur/q12-q17_e.html

Siting criteria for salmon farms mandate that farms must be an appropriate distance from sensitive fish habitat, as determined by DFO and the Province. Here is a link to the siting criteria for your interest.
http://www.agf.gov.bc.ca/fisheries/Finfish/Provincial_Siting_Criteria_March_2000.pdf

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