I assume you mean freshwater fishing. All the creeks off the river even past downtown toward the ocean have freshwater fish, esp. the further back up in the creek you go. Ive never caught a freshwater fish past the arlington river because its too salty. But between there and way south down the river you will catch fresh and saltwater fish as it is brackish. Ive caught mullet way up in crescent lake.
The further south= more freshwater fish. The closer to the ocean= more saltwater fish.
I might be wrong, but I believe FWC considers the buckman bridge to be the dividing line for salt and freshwater licensing. So Drs lake is just into whats considered freshwater .
There is a lot of fish to catch. If you are dock fishing in Drs, Id use multiple baits, especially natural baits, cut bait, worms, live and dead shrimp, live shiners, etc. Youll catch more fish.
I caught most of my fish in there in the tournament on red shad culprit worms fished slow. I caught nearly all the fish near eel grass . I dont know if theres much of it left there anymore...
If you have a boat , and just want to catch something, fish deep holes or pilings in the river with dead shrimp. You can catch some nice bream fishing worms under docks in Drs lake too.