Basic Florida Seagrass Facts

A primer on the favorite flats habitat.

A red found on shoal grass.

They say Inuit people can identify seven different kinds of snow. There are almost that many kinds of seagrass on Florida’s flats, but if you can tell the difference between just three varieties, it’s likely to make you a considerably better angler. Here are a few basic Florida seagrass facts.

The one that we all know, turtle grass Thalassia testudinum is probably the most important to anglers; it’s widespread, found in a variety of depths from barely awash to 20 feet (in very clear water), and wherever it grows, it forms a nursery for a variety of shrimp, crabs, minnows and other critters that are of interest to grazing gamefish, and thus interesting to fisherpersons. It’s abundant from Cape Canaveral southward on the Atlantic Coast, and throughout the Gulf of Mexico except in areas of high turbidity like the waters around the mouth of the Mississippi.

Find turtle grass and you can bet that you’re not far from seatrout, redfish, snook and other inshore species; it’s by far the largest habitat feature throughout most productive inshore Florida waters. It’s easily identified by long, waving leaves that look somewhat like flat green ribbons or eels.

Turtle grass, shown here, grows in deeper water than shoal grass. Where these and other grasses intersect, you'll often find redfish and other gamefish.

Some turtle grass meadows are far more productive than others. Why? Only the fish know, but observation shows several likely indicators:

1. Broken grass with holes, edges and outcroppings is more productive than broad, thick stands without breaks. Maybe it makes for easier predation, but it’s often the case that you’ll catch zip as you drift over thick, tall grass, then suddenly be covered up with fish when you hit the edge of the growth or a “white hole” where grass is sparse.

2.Grass in slightly murky water is better than that in crystal clear or in muddy water. Water that’s slightly green offers gamefish some cover, but still allows them to spot prey. Muddy water shuts down fishing completely most of the time in Florida waters where turtle grass is found. (Not so in Louisiana, I know, where they catch reds and trout by the ton from water thick enough to plow, but in most Florida waters, mud is a dud.)

3.Areas where turtle grass mixes with other types of grass is often productive; as in hunting wildlife ashore, “edge” cover is often productive.

The second most important grass to anglers is manatee grass, Syringodium filiformes. Manatee grass often grows in shallower water than turtle grass, but scientists say it’s limited by spring low tides; if a flat gets exposed on these lowest tides, manatee grass won’t be found there. So, if you find a good stand of manatee grass in an area otherwise surrounded by shoal grass (see below), you can bet that spot is going to remain wet on a spring low, and just might be stacked up with reds, snook and trout at certain times of the year.

Shoal grass, Halodule wrightii can grow in fairly murky water, and can stand some exposure to air, thus it grows on bars and nearshore areas. Where you find lots of it but not the other grasses, spring lows may cause the area to go dry, which will force fish into surrounding channels—and these cuts are likely to be marked by turtle grass mixed with manatee grass. I’ve also occasionally run into snook and reds plowing around in shoal grass, sucking in minnows and baby shrimp. Sometimes these fish have their entire backs exposed. They’re tough to catch but throw a small swim bait, about 2 inches long, into the cover and “rip” it back through, snatching it hard enough that the hook stays clear, and you’ll connect. I’ve caught snook to 30 inches with this tactic on Tampa Bay’s east shore on full-moon low tides.

An edge where any of the three seagrasses stops abruptly is likely to indicate a change in bottom makeup, and often there’s a slight washout along that line. This slightly deeper edge right up against the grass is a favorite hiding area of big seatrout.

Needless to say, because the grasses are so closely woven into the pattern of life on the flats, damaging them is both a moral and pragmatic mistake; anything which results in less grass has a bad affect on the overall productivity—including the fishing opportunities—so we all have to do our best to see that this doesn’t happen on our watch. This means no operation where the prop touches grasses, and no high-speed running where the prop wash might blow out grass roots—the roots can take years to regrow, though the blades of grass can restore themselves quickly on a healthy root system. - FS

First Published Florida Sportsman May 2010.

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