Hi ronragus,
It's an interesting thread.
Yr basic questions were – (i) is fish/crustacean/shellfish storage segregation required in Canada ?, (ii) is changeover process cleaning of equipment required where single line in use for 2 or more of 3 entities in (i) ?
A few comments -
(a) I am unclear as to Canadian Jurisdictional (ie Federal/State) scenario for Seafood Process industry. (cf USA where USFDA, afaik, totally Rules Seafood Processing).
(b) I am unclear as to whether any relevant Canadian Regulatory rules consider the occurrence of fish/crustaceans/shellfish) as ONE allergen (ie Seafood [fish, crustacean or shellfish]) from a Processing POV. This is so far unresolved (to me) from viewing CFIA website although links in Post3 seem to support this (Labelling) opinion.
© I am unclear with respect to Canadian Labelling whether “blanket” Precautionary Style labelling is accepted. Scampi’s previous post suggests Yes and similarly this (cynical?) file (2016) –
May Contain Traces of Allergen Precautionary Statements and Allergen Management.pdf 1.49MB
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Yr allergen queries have occurred in different ways many times on this Forum although rarely (if ever) relating to Canadian Seafood Industry. A number of “analogous” threads (eg multi-“allergens” within "allergen X” ) are here -
http://www.ifsqn.com...ain-processing/
http://www.ifsqn.com...in-the-factory/
http://www.ifsqn.com...ilemmaquestion/
http://www.ifsqn.com...eling-concerns/
The typical (Process) conclusion to the above threads is “non-definite”.
If “Seafood” is designated as the allergen, segregation and changeover cleaning are IMO unlikely to be a Regulatory demand where fish and shellfish are stored together and processed on the same line. Recommendations for seg./cleaning may of course exist, eg this quote from link in Post 3 -
The CFIA enforces Canada's labelling laws and works with associations, distributors, food manufacturers and importers to ensure complete and appropriate labelling of all foods. The CFIA recommends that food companies establish effective allergen controls to prevent the occurrence of undeclared allergens and cross-contamination. The CFIA has developed guidelines and tools to aid them in developing these controls.
Some input from a Canadian seafood processor of appropriate products would be nice. 
PS - Just as a contrast to above manouevres, here is a quite neat Canadian example of a more purist / haccp-friendly Allergen Control Plan -
ALLERGENS CONTROL.doc 46KB
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