I checked the regs for b.c freshwater and you will see a star beside the creek, stream etc name. that star means no fishing including the tributaries. Heck everything is a tributary of some thing then.
I'll take a stab at it.
For BC Freshwater regulations, the Region 2 tables list the water specific exceptions to the regional regulations on pg 23. If there is an asterisk, then those exceptions apply to all of that body of water's tributaries (unless those tributaries are also listed in the table in which case those apply).
For example, Capilano River has exceptions. It also has an asterisk. Therefore, all non-listed tributaries to the Cap river have the same exceptions.
Compare this to Cheakamus river. It has exceptions. But it does not have an asterisk. Therefore the exceptions for Cheakmus river do not apply to the non-listed tributaries to the Cheakamus river but they must still adhere to the Regional regulations on page 23 and Provincial regulations on page 9-11.
The original thread however pertains to the freshwater salmon regulation by DFO which is separate from the BC Freshwater regulation.
http://www.pac.dfo-mpo.gc.ca/fm-gp/rec/fresh-douce/region2-eng.htmThe first regulation states:
"Unless otherwise stated in the table, the daily limit in all water of Region 2 is zero (0). "
So if the creek/stream in question is a tributary of a body of water in this table but it is not listed in the table by name and "tributaries" is not specified under Specific Area for that body of water, then the retention is 0.
For example, Seymour River which has a retention of 1 hatchery coho. It does not specify tributaries under "Specific Area". Therefore, there is no retention of coho in the Seymour river tributaries.
Compare this to Capilano River which has a retention of 4 hatchery coho. Under "Specific Area" column, it says "including tributaries". Therefore, the tributaries of the Cap river and Cap river itself has a combined retention of 4 hatchery coho.
Compare this to non-tidal Fraser River which has 2 hatchery coho retention. Chilliwack river is a tributary to the Fraser River but it is listed in the table so you would refer to this regulation which has a 4 hatchery coho retention when fishing this Fraser River tributary. Non-listed tributaries to the Fraser River would have a retention of 0 coho.
All else aside, the answer to the original question would then be... what does the regulation say about the body of water that this creek flows into? If the body of water allows retention but it doesn't specify tributaries, then there is no retention in this creek. I know the creek that the original poster is talking about and I know the body of water that this creek flows into, so I already know the answer to this question.