Latin writers used to name "Bistonian" the land facing Troy and therefore adopted the Greek Bistonis, an adjective applied to Bistones (Hdt. 7.110), a Thracian people inhabiting Abdera. As during Roman domination Thracian sailors named themselves "Bessi", from the tribe of Bessi which became the ethnicon for "Thracian", "Bistones" were the people living on the coast beyond the Strait and more generally "Thracians".
"Bistonis" can be considered the equivalent of "Bissonis", according to a variation that can be observed in many toponyms such as Carystos/Lycastos/Geraestos together with Caryssos/Lycassos/Geraessos and Oppian seems to indulge in some sort of paretymology when he comments about the name of bisons: «There is a terrible breed of deadly Bulls which they call Bisons, since they are natives of Bistonian Thrace» ( Cynegetica 2.159-161). The Cilician writer, born in Anazarbos, was certainly aware of the equivalence between "Bissonis" and "Bistonis", but his remark may rely on his Anatolian linguistic background which allows to explain "bison" as *Bisa + -wani-, a Luvic suffix used to form ethnonyms. Those Thracian bulls were then named "bisons" according to their origin from *Bisa, probably Thracia.
The above consideration is valid also for our river, Pishon, which can be interpreted as "of the Thracians", given that Anatolian languages are usually indifferent to the opposition p/b. Naming a trait of sea as a river would not be unheard of, if we resort to Babylonian and Assyrian geography that consider Lydia as a region in marratu, that is "bitter sea", the northern part of the Ocean surrounding the ecumene in the Babylonian map (Horowitz 1988; Horowitz 1998).
Pishon surrounds the land of Havilah and maybe Abydos, a supposition that would make sense if we accepted what was common among ancient writers, who called "Thracian" that trait of sea (Lipinski 2004: 160-161; Bunnens 1979: 358-366), the most northern part of the Aegean Sea, certainly stretching from Thasos to the Thracian Chersonese (Columba 1918: 13).