FRESH WATER TIDES by Steve Schaffer

How Coastal Floods Affect Saltwater Fishing

The Texas coast is prone to experiencing freshwater deluge every few years.

Last year represented some of the most epic flooding in the history of Texas with the Sabine, Neches and Trinity all pouring billions of gallons of freshwater into bay and marsh systems. Hurricanes also hit the coast periodically bringing a different kind of flood and shakeup of the ecosystem.

How do these floods impact coastal fishing?

For starters they shift speckled trout populations.

Salinity can be a factor in locating trout especially the largest ones. Researchers with the Atlantic States Marine Fisheries Commission have found that big trout tend to prefer water that is close in salinity to seawater to more brackish water.

Salinity is an important factor as the closer an area is to the Gulf, the higher the salinity, however there are some other factors that come into play with trout here. Big, incoming tides bring warmer Gulf waters onto trout friendly areas like shallow flats along channels and with them come baitfish.

A satellite photo of the Galveston area shows the impact of flooding on the clarity of the bay and Gulf.

When you have the combination of water that is more saline, a few degrees warmer than that in the upper reaches of the system on top of a high presence of mullet and other baitfish you have serious trophy trout potential about the time this issues hits readers. Looking at this research alone helps you eliminate hundreds of square miles of habitat and focus more intensely on the areas where the big trout you seek are more abundant.

However, if you have major coastal flooding even trout concentrated in those areas could be pushed into deep waters of the channel south of the bay systems.

The saltiest water is at the bottom of the water column so savvy anglers know during a normal flood situation to search out deep reefs toward the south end of a bay for trout. Often the trout will concentrate heavily in these areas and actually produce solid fishing for anglers tuned in to the phenomenon.

Locations such as Hannah’s Reef in Galveston and the big reef on the south end of Sabine Lake are key areas for spring flood fishing on the Upper Coast where freshwater influx is most prevalent.

Water clarity is an underappreciated factor that can limit fishing success and floods have a huge impact here.   

“Having two major rivers flow into Sabine Lake, one of Texas’ smallest bay systems makes it one of the most dynamic in relation to water conditions and it has taught me a lot about various water conditions and their impact on fishing,” said TF&G Editor-In-Chief Chester Moore.

Moore said when the bay itself is murky, he often hits the channel just south of the causeway and looks for “current lines”.

“There are times you will find literally a thin strip of clear water along the main current flow that produces fish. Fishing along these lines where you find mullet or other baitfish can be extremely productive for trout and flounder. You can literally cast to the clear side of the current and catch fish and the murky side and miss action altogether. The difference in clarity can be fairly subtle so you need to wear good polarized shades and move slowly when looking for places to fish,” he added.

“This is for times when you have maybe Toledo Bend releasing a bit of water or some heavy rains hit, not necessarily when we have a major flood. That changes everything.”

On a much larger scale floods that come from hurricanes can alter things in perpetuity.

According to Florida Fish and Wildlife Conservation Commission, freshwater flooding from rain or saline storm surge (hurricane) may trap fish in an inappropriate salinity. If this happens rapidly and the fish have no escape, species that are intolerant to changes in salinity may die. In addition, rising water may flood areas that normally do not contain water. After water levels recede, fish can become trapped if they are cut off from the connection to the main body of water. When the small ponds the fish have been trapped in dry up, the fish die.

According to a 1987 Texas A&M study entitled “The role of hurricanes in determining year-class strength of red drum”, the result of these storms is not all bad.

“The hurricane season in Texas coincides with the red drum spawning period. Hurricanes may impact year-class strength by increasing the numbers and/or survival of juvenile red drum recruited into the bays. Bag seine collections during the period 1962-1975 in the Laguna Madre and Galveston Bay systems are used to examine recruitments after Hurricanes Beulah (1967) and Fern (1971). Trammel net collections during the same period in the lower Laguna Madre are used to examine year-class strength through age three. Both hurricanes reduced bays salinities and the number of juvenile red drum in the Laguna Madre increased. Year-class strength may have been increased through above average transport of larvae to nutrient-rich bays and higher survival rates in intermediate salinities.”

In the long run, bay systems need the constant struggle between fresh and saltwater. In a natural setting things work out for the best but of course mankind tinkers with the environment.

The impact of the creation of dams and the sudden release of huge amounts of water as well as water control structures that allow saltwater to be trapped in areas for long periods of time after storm surge heightens any impact.

Flooding is something totally out of the control of anglers and in a normal spring it will only be a slight inconvenience or perhaps for those anglers willing to study their favorite bay systems it can be an advantage.

Dredging a deep reef with a Gulp! shrimp or soft plastic sand eel imitation might not be the funnest way to fish but it can yield huge catches even when the water is fresh enough to bass fish on the surface.

Our bays are dynamic and learning to work around freshwater flow is crucial.


—story by Steve Schaffer


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