A paper about the exploitation of Guadiana river resources in the enclosure of Perdigões was recently published (and it is available here). It is a paper about a unique decoration inside a pot.
To interpret this decoration two hypothesis were suggested. It could be a representation of a river raft (similar to present reed rafts of the Southwest coast of Portugal) or it could be a representation of a fishing trap (my first bet).
In favour of this last possibility the presence of fish bones of river species in Perdigões was underlined, revealing the exploitation of Guadiana river resources by the communities that circulated in the enclosure.
This paper has already generated some comments from colleagues and one of them (Gabriel Martinez, from Granada University) alerted me for this evidence: a Neolithic fishing trap recovered in Russia that seems to be very similar to the ethnographic ones presented above, reinforcing the possibility that the image from Perdigões is evoking the importance of the river Guadiana to these communities.
Fishing trap from the Neolithic site of Zamostje (Russia). Taken from here