About 50 years ago , I fished the Noosa river with a guy who worked at an abattoir and he used the spinal cord of cattle, and he caught some good ones.
My preference is mullet gut onion cut into thin slices and pounded , dipped in tuna oil and then bread crumbs.
To keep layer of sugar and then salt and place in fridge.
If drifting yabbies by a mile.
Pedro