Do you love big bluegill?
Which Jacksonville are you referring to? I used to live in Jax, FL and fished all over the place. Just about anywhere you went there was water and some place to fish. It was heaven, in that regard.
I distinctly recall the biggest danged crappie I ever caught was under the I-295, where it passed over a small creek at Blanding Blvd.
Seriously, I fished in any place I could reach with my car. Roadside creeks, ponds, golf course ponds, ditches - you name it. The fishing was everywhere. Every little backwater was a potential fishing spot and I pulled some big fish out of the smallest of places... without a boat. I occasionally snagged a canoe from NAVY recreational services, but that was more for the fun of canoeing.
You just have to be creative and think like a fish. It's the out of the way places, with deeper water nearby, that you wanna find. My nephew still lives in Orange Park, and he kills 'em in storm drain runoff ponds!
If youre at Mayport, there are lots of little ponds on the map. That close to the ocean, you'll have to stick to ponds as creeks will probably be too brackish, even for for sunfish. Here are a few "quick and dirty tips" for you.
Buy a small bag of cheap pellet type dog food. Soak it a small, plastic container with a small amount of water, until soft. Then mix in about 1/3 as much of sand to make a "chum mix" about the consistency of biscuit dough. Keep this stuff with you and when you find a likely spot with lots of weeds and cover, toss dime-sized bits of this into the water on the deep side of the cover. Remember that - the deeper side.
Feed regularly - every few minute - and just this small amount. This creates a chum cloud that turns the fish on to feeding and keeps them in "your" spot.... but it doesn't fill them up. Every third or fourth toss, add a tiny bit of your hook bait to the chum button before tossing it out. More on hook bait in a minute.
This time of year, many of the brim are still bedding there in Florida. Some have also moved off to other areas. But they haven't moved to their deepest, summer water haunts. Morning and late day are the best times, although in spring that is flexible.
Since you're on foot from the shore, find the longest telescoping pole you can, 13-15 foot or longer. WalMart sells a 13' Shakespeare. Also buy the smallest thinnest floats you can find, tiny split shot and #10 or smaller hooks long-shank hooks. 2-6 lb test line is fine; you'll probably find Wally World doesn't carry 2lb, so get the 4. Crickets or worms will be the likeliest baits you will find for brim, so use those.
Also at Walmart are some panfish jig sets - get the smallest ones they have: 1/32 ounce heads with 1-1.5" soft bodies (chartreuse, black, yellow, combo colors). They also sell some of the Berkely Gulp! panfish soft baits - Fish fry, Earthworms, Asticots/Maggots, etc. Try one of those.This stuff should cost no more than about 30$, total.
Wrap 30' of the line around the line stay on the pole and then run the line up and tie it on your pole a foot back from the tip. Finally thread 15' of line line through the tip-top and tie it there. Rig up with your chosen tackle.
Now comes the fun. Use the long pole to reach out to the areas around weeds and cover - on the far side, nearer to deep water. If you can determine where they are bedding, so much the better. Present your bait there by dropping it right in, as close to vertical as possible. You want to be about 12-18" off bottom. The deep side is crucial, though, as that is where the bigger brim will hold.
See, large males will often wait off-bed in deeper water for females and then run off the smaller males when they find a mate, taking over their nest.
The long pole will also allow you to remain well back so as not to spook the fish, but still make it possible to fish the deep side of weeds and structure (anything in the fishes environment of wood or rock where they might find cover). Again, drop your bait right in, vertically, or as close as possible to it. Seek out pockets and holes in the weeds, and fish right in tight to structure, always closer to the deep water side.
Then, not only can you present your bait right in front of their noses, but you can lift them right out when you hook up.
This method is also way more sensitive to bites and serves the shore angler who wants to go on the hunt for the fish - instead of just sitting there.
Just keep on the look out and keep moving. You'll find some fish.