Diagram of a fish trap used by Indigenous Australians. Image courtesy of https://www.questacon.edu.au/discover/burarra-gathering/extra-information/fish-trap

The trap was anchored to the river bottom, with a fence or weir like structure built in the river to direct fish into the trap entrance. Once inside, most fish could not get out of the small inner opening of the funnel.

We do not know for certain. It is possible they were removed from the back end of the trap.  Unfortunately, that part no longer exists for us to study. We can study the funnel end, and the lashings there indicate the funnel was permanently attached. In the middle of one side, there are tool marks and rope cordage that suggest the trap may have had a small door. 

Dolly Varden trout and several kinds of salmon were known to use this stream. Apparently, eulachon and king salmon did not.

Standards for How did the Trap Work?