I'm fairly positive, whether by accident or design, aberrant salmon can not be fished. I built an enclosed fishing boat so I could safely fish for blueprints (hopefully saddles for abblerrant creatures) in the caves (the only place salmon it exist on the map) and after letting the game sit idle fishing for hours I have not gotten one bite.
Tamable using fish baskets from aberration. They seem to flee from the baskets once placed. It is a good strategy to pen then in with fence foundations and walls, or kite them to a pen. Place your basket on the other side of the wall and catch.