Learn The Delta with a Depth Finder

I thought I'd write this article with the idea of expanding upon my previous article, Delta Ledge Fishing, by focusing on the use of your depth finder. I've found that most novice to intermediate fisherman don't even use their depth finders while their fishing the Delta. The most important tool on your boat is the depth finder. Use it to find the fish and rod and reel to catch them.

Ever find yourself thinking, “Where should the fish be for this time of year?” What you should be asking yourself is “What depth should the fish be at his time of year?”

The bulk of the fish in the Delta feed somewhere between 4 and 10 feet, depending on what time of year it is and what they’re feeding upon. What I have seen and observed, is the average fisherman will position his boat too close to properly pitch or flip the bank. The boat may be in good position for the 25 yards of a 100-yard bank, but what of the other 75 yards? If you’re too close to the bank the fish are likely behind you or beneath you.

You’ve got to watch your depth finder at all times, especially at low tide.

The Delta levees are man made. The Delta itself is natural, man and machine just changed and controlled the flow and direction of it. Take a straight looking levee that is say half mile long. The levee looks straight but the channel itself in most cases is not. This is where the average fisherman makes his mistakes if he’s not watching his depth finder. Sharp corner's or turns are usually where you’ll find the deepest section of a river. The straightness of it can be misleading and this is where your depth finder is the most important tool you've got on board. The old rule of thumb on fishing the Delta is “if you have 10 feet under your boat and are 10 feet from shore; fish it.”

The new rule of thumb is put 12-15 feet under the boat and 15-20 feet from shore and then watch that depth finder to maintain your depth.

The reason for this is because of the grass that has taken over the Delta since the late 1980's. For most of the west side of the San Joaquin, the grass grows down to 8-9 feet, and then becomes baron with occasional patches at 12-14 feet. On the east side of the Delta the grass grows down little bit deeper because of the water clarity is better.

Take your favorite area, one that you have confidence in and that you’re familiar with, and start by going into a shape corner watching your depth finder. It’s deep, as it should be, and you catch a fish. Now, ask yourself how deep was that fish you just caught? 4 feet? 6 feet? 8 feet? And why was it there? Is it because of low tide? What was it feeding on? The depth finder with today’s technology will tell you. Is there a ledge? Likely. Is there any other structure or features that are keys to holding fish?

Say its low tide and you caught the fish at 6 feet and the ledge is at 8 feet. Now what do you do with the rest of the bank! It’s all the same!!!!. Keep your boat going down the bank at 12 feet . That 100-yard bank may have 2 or 3 shallow flats on it with a ledge further out. By watching the depth finder you will notice that your getting further from the levee, with the ledge going out towards the center of the channel. Your metering shad or baitfish next to it, bingo you caught another fish and you’re only 10 yards from the first fish. You go a little further down and the ledge cuts in and, bang, you catch another one. You have three fish now by watching your depth finder. If you were the guy not watching his depth, you would only have one fish in the boat at best. The other fish are behind you and never would have been caught.

Flooded Islands

Most of the islands on the Delta that are flooded have say an average depth of 10 feet with a minor amount that maybe deeper. Okay, you go in at high tide and you whack them in 2 – 3 feet of water. The next weekend its low tide and the fish aren’t there.

What do I do?

Back off and place your boat in at least 5 feet of water and throw to 3 – 4 feet and look for grass beds or anything that may hold a fish. A one to two foot difference a lot of the time can make or break a limit.


First you deal with depth, then speed and lastly color. Buck Perry developed the phase back in the late 40's or early 50's with his book “Spoonplugging”. In those days there wasn't anything but crank baits and spoons. So let’s bring this up to date. With today’s new and innovative baits we have a lot of ways to catch bass. We have innovative crank baits that cover every depth down to 20 feet. Spinner baits, buzz baits and know chatter baits in every color, and now swim baits. All the above are classified has reaction baits and all can be controlled with speed. Most jigs and plastics today are classified as subtle baits and can be worked in a known fashion to create a strike. Color is the last thing you need to think about but can be narrowed down seasonally or depending on watercolor and clarity.

I hope this will help the new bass fisherman that come to the Delta and maybe help put a bigger limit live well. Just remember when your out on the Delta, Think Depth.


While driving through the Delta, watch your console depth finder. Recommended speed of 25 miles an hour or less. Come to an area that you enjoy fishing and slow down and meter it in a way that you feel confortable with, then go in slowly with your trolling motor and watch the front depth finder. You may be surprised in what you will find and learn of why the fish are where they are during the year.

Rich Thiel is a working bass guide on the California Delta, Clear Lake and Berryessa. For more information on his guiding service please go to: