October 25, 2020

Locate Grass Beds In Lake Pontchartrain Using Sonar

Beds of eel grass make for prime speckled trout fishing in Lake Pontchartrain. But how do you know where they are? Here's a few tips.


Fall fishing in Lake Pontchartrain can be really good, and while most people tend to think of the bridges when they think of the lake's legendary fishing, the various grass beds are another hot item as well.

Why are Lake Pontchartrain's grass beds so good?

When speckled trout are spawning during the summer they do so "outside" of the marsh where there's saltier water.

This is why we don't really find a lot of speckled trout in Lake Pontchartrain during the summer months, because her salinity is too low.

Maps like the one produced by Hydrocoast show just how salty she is (or isn't).

lake pontchartrain salinity  grass beds speckled trout

But, once the spawn is over, salinity is no longer a requirement and speckled trout head "inside" the marsh to feed in preparation for winter.

Once they do, you can expect them to populate bait-laden hot spots, with grass beds being one of them.

How good can fishing the grass beds be?

Pretty darned good! See for yourself in this video:

But not just any grass...

There are many types of aquatic grass we find throughout Louisiana's coast, with the more common type being milfoil and widgeon grass.

These types of grass tend to choke out the entire water column like what you see in redfish ponds, but not eel grass.

Eel grass, also called turtle grass or shoal grass, does not grow to the water's surface, leaving plenty of real estate for speckled trout to prowl looking for bait like mullet, mehaden (aka "pogies) and – an absolute favorite – shrimp!

How can we find beds of eel grass in Lake Pontchartrain?

There are more ways than one: First, there's experience, meaning you must get out there and look in the water for yourself.

While this works, it's time consuming and not nearly as effective as other methods.

That and it's difficult to see underwater, even with polarized lenses and good light conditions.

Google Earth Pro is an option, as its historical satellite imagery can you show you where grass beds (of any type) are most likely to be found in the marsh.

Sonar Is An Excellent Tool

Google Earth Pro can get you close, but sonar will zero you in.

After all, any imagery you find on the Internet is old news.

But, if you use sonar while you are fishing you can see exactly where the grass beds are located, revealing where you need to be casting to catch a decent box of speckled trout.

Conventional 2D sonar works to this end, but it's not the best because it only covers a narrow cone directly under your boat.

2d sonar speckled trout grass beds

But, side imaging sonar reveals much more, since it spreads over a wider fan.

side imaging sonar speckled trout grass beds lake pontchartrain

How wide of a fan?

On my Helix 12 I can easily punch out to beyond one hundred feet!

However, side imaging 40-70 feet off each side of the boat is a more practical setting.

What do you think?

I hope you enjoyed this fishing tip and, if you'd like more, then you really ought to subscribe to my newsletter or on YouTube.

Sonar is a great tool that I personally believe is highly underrated amongst inshore anglers and only utilized by a handful.

Do you use sonar? What brand do you carry? Would you recommend it?

I look forward to seeing your answer in the comments below!

Captain Devin

About the Author

Devin is a former fishing guide and lifelong inshore angler. He founded Louisiana Fishing Blog in 2012 to share his ideas as a charter captain and still writes in it today. Since then he's created a fishing university — LAFB Elite — where he teaches inshore anglers how to safely navigate Louisiana's coast and catch more fish.

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  • Yes captain I agree sonar is very important to me I have a Garmin and it helps me a lot to zero in on some awesome spots once I learned how to use it

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