Good comments and observations everyone!
As far as faecal coliforms go - all warm-blooded animals - birds, dogs, humans, livestock, etc - have them in their guts. Humans test for these organisms in public waters where humans may contact them through breaks in the skin by swimming, or ingest them by swallowing water. Improperly treated sewerage (raw, or only primary treatment) from residences would also be a major source of faecal coliforms.
The reason these bacteria are "of concern" is twofold: 1/ Getting too many coliforms on the wrong side of our digestive system can cause our liver to fail and other internal issues, and 2/ They are an indicator that other "bad bugs" (e.g.. Hepatitis, giardiasis, cryptosporidiosis, Salmonella, E. coli, Vibiro, Cholera, etc.) may also be present in the sewerage that contaminated our water, giving us the faecal coliform levels.
In addition to concerns over health issues - in restricted waters with limited flow, turn-over and volume - excessive nutrients in sewage can cause an increase in algal growth, which in turn can cause a decrease in dissolved oxygen, making it difficult for marine life to flourish. These zones are called "dead" zones, and Saanich inlet is an example:
https://microbewiki.kenyon.edu/index.php/Saanich_inlet
So there are different criteria (
http://www.hc-sc.gc.ca/ewh-semt/alt...res_recom/sum_guide-res_recom_2014-10_eng.pdf) developed to assess ambient faecal coliform levels for determining safety of the water dependent upon whether the water is used to drink, swim in and/or provide shellfish for us to eat. Environment Canada is ultimately responsible to ensure the water is tested for faecal coliforms.
In the case of the marine-based boaters - contamination of shellfish beds would be the most likely risk from raw sewerage:
https://www.ec.gc.ca/marine/default.asp?lang=En&n=4DFAFB15-1
However, in many harbours esp. Prince Rupert and Victoria - raw sewerage is still pumped directly into the harbour. Those shore-based residents would likely outnumber the boaters by many thousands of bums.
Since 2012 - Transport Canada now wants all boats to have holding tanks for sewerage to be pumped-out for treatment; or discharged into the marine environment only if greater than 3 nautical miles from land (ships less than 400 tons), or more than 12 miles from land (ships larger than 400 tons). Anything else is now banned (
https://www.tc.gc.ca/eng/marinesafety/tp-tp1332-appendix2-1582.htm), although Transport Canada has ruled that porta-potties and composting toilets can qualify as "temporary storage devices" as long as the vessel is less than 15 gross tons and carries fewer than 15 people.
Were these regulations developed in order to protect shellfish beds? Were the distances developed by looking at plumes and contamination effects? Doubt it.
http://www.pac.dfo-mpo.gc.ca/fm-gp/contamination/sani/index-eng.html
What about cruise ships with thousands of people onboard? Looks like they are exempt along with all the traffic to/from Alaska:
http://laws-lois.justice.gc.ca/eng/regulations/SOR-2012-69/page-14.html
Discharges of Sewage or Sewage Sludge
94 This Subdivision does not apply in respect of (a)
vessels in a shipping safety control zone; or (b)
pleasure craft that are not Canadian vessels and that are in waters in the exclusive economic zone of Canada.
BUT....Where are those pump-out stations? Not enough for sure:
https://georgiastrait.org/work/cleanmarinebc/pumpouts/
Pump-out stations - even if they existed - would be less than redundant at this time in Rupert and Victoria. Pumping sewerage uphill in a pipe - to be then dumped again downhill in a different pipe in the harbour does not solve the issue.