Every angler who has fished the south-west corner of Western Australia knows the feeling of standing on a river mouth and not being sure which rulebook applies. The river behind you is fresh, the inlet in front of you is salt, and the fish moving through the gap belong to both.
The fisheries authority's answer is a map. Its South West recreational fishing region is a coastal and marine polygon: it runs along the shore and across the estuaries, and it stops at the coast. It does not cover the inland length of the south-west rivers. So the same river can sit under coastal rules at its mouth and inland rules a kilometre upstream, and the advice for one does not carry across the line.
That is why this page exists, and why it is a boundary note rather than a guide to the fishing. The Blackwood, the longest river in the south-west, has exactly one mapped reach inside the coastal region, the last one at the mouth, and it is the only water grouped here. This guide holds no reviewed angling coverage for the inland rivers yet. When it does, those pages will sit under an inland region, not this one.
Read the coastal rules for the mouth and the inland rules for the river, check local closures and protected areas, and let the land manager and the tide decide access rather than the polygon.
What this region means
South West is one of eleven polygons in the department's recreational fishing regions dataset, its geography for monitoring, assessment and management. The captured polygon is coastal and marine. It catches the estuaries and the river mouths of the south-west coast and does not extend up the rivers. That distinction matters when you are planning a trip: the same river can sit under coastal reporting at its mouth and inland reporting a kilometre upstream.
Waters in this guide
The Blackwood River mouth boundary reach is where the mapped river meets the coastal South West polygon, and it is the one Blackwood reach grouped here. The inland Blackwood is not, because the boundary does not contain it. This guide holds no reviewed angling coverage for the south-west rivers yet; when it does, the inland pages will sit under an inland region, not this one.
Rules and access
Check the current WA recreational fishing rules for the exact water, species, method and date before fishing, and check local closures and protected areas as well: this reporting boundary is a geography, not a rule lookup, and the rules for the coastal region differ from the inland ones. Estuary and river-mouth access is set by the land manager and the tide, not by the polygon.