Yes, you’re right about your hypothesis. This study with a similar concept mentions that Aboriginal stone-walled fish traps were designed to be most effective in enclosing water at mid-tide, which indicates that fishes are funnelled to that space and become trapped.
Check this specific resource uploaded on the Challenge website: Resources>Information Boards>Yirgganydji Sea Country (scroll to 5th slide), which describes how the Yirgganydji people engage in spearfishing. Woven baskets are likely used with the fish traps as they must be close enough to the shore to retrieve them.
I hope this helps clarify things for you.
EWB Australia acknowledges the traditional custodians of country throughout Australia and recognise their continuing connection to land, waters and community. We pay our respects to them, their cultures and their land; to Elders both past and present; and to emerging leaders. We recognise that the Aboriginal & Torres Strait Islander people never ceded sovereignty of what we call Australia.