The Coastal Flood Effect - Texas Fish & Game - March 2013 The Coastal Flood Effect - March 2013 When Heavy Rains Dump Freshwater into a Bay, Is It Good, or Bad for Fishing? By Chester Moore
In the mid 1990s the Sabine Lake area had massive rain in the months of February and March. On top of the rain there, it also poured in East Texas so the floodgates and Toledo Bend reservoir were open sending billions of gallons of water downstream into the ecosystem.
"The fishing is going to be terrible."
"The floods ruin the fishing."
Complaints ran rampant except with an in-the-know contingent of anglers who understood something that was not obvious.
When floodwaters move onto the lake (actually a bay) in the spring, it concentrates speckled trout on the deep oyster reef on the extreme south end between Mesquite and Blue Buck Points.
Instead of complaints these anglers were saying things like, "It’s like shooting fish in a barrel" and "This is the best trout fishing I have ever seen."
The saltiest water stays at the bottom. That area is deeper than much of the bay, as it is linked to the Sabine-Neches Waterway and only a short way from the Gulf. Saltwater will hold there, and so will the trout--thousands of trout.
And yes, at times it is almost like shooting fish in a barrel.
The popularity of the then rising Internet and the writing of a few outdoor writers (yes, I am guilty) let the cat out of the bag and that phenomenon is no longer a secret.
Coastal flooding has a big impact on saltwater fishing and it is not always a negative one.
Sure if you have been catching tons of trout at the north end of a bay at the mouth of a river and floodwaters come, those will move but they can usually be found and sometimes in great numbers.
Coastal anglers should be aware that water boards and various entities will use coastal flooding to sell interbasin water transfers. That is where water is sold from one basin to another to fill the burgeoning demands of cities like Dallas, San Antonio, Houston and Austin.
High-water release from Lake Whitney on the Brazos River. Photo: Army corps of engineers
Texas Parks & Wildlife Department biologist Coastal Fisheries Biologist Jim Tolan explains the impact in a report called "An Estuary’s Need for Freshwater Flow."
"The most immediate result of large inflows is the displacement of saltwater fish, in seeking their preferred salinity, they shift their location within the bay. Some species, which can withstand low salinity, tend remain in the same locations until conditions change back."
"Both red drum and pinfish are species that can be caught in the saltiest parts of Laguna Madre or in the freshest parts of many tidal rivers. Another option for immobile species like oysters is to close up and remain isolated from unfavorable conditions."
"Although oysters can close up tightly and stay that way for some time, warm summertime temperatures combined with low salinities for long periods can be quite detrimental."
The report goes on to say displacement of species also applies in a positive way to the larvae and juveniles that are seeking out the nursery grounds of the estuary.
"Instead of concentrating large numbers of larvae only in the upper portions of the bay, species seeking lower salinities have a much larger nursery-ground habitat. This can lead to increased larval rearing, better growth, and ultimately better survival for estuarine-dependent species. And this applies also to the forage fish that make up most of the food base for the sport-fish. Species like gobies, anchovies, and silversides all respond well to increases in freshwater inflow, especially when timed with their spawning periods."
Bays were made to have freshwater inflow and it is vitally important to the health of these ecosystems.
The fact that floods do impact fishing opportunities and have an undeserved bad reputation, which can be exploited by water boards and other entities looking to promote the sale of water through interbasin water transfers.
There are designs on the water from virtually every basin, with the Sabine and Trinity being two that are being looked at extremely closely
According to the National Wildlife Federation’s (NWF) "Bays in Peril" report, it is important for people to be informed on the importance of rainfall and flooding to bays.
"Even if humans were not using any water, the estuaries would not always receive enough freshwater inflows to satisfy these two criteria. Rainfall varies from year to year and the fish and wildlife that depend on estuaries are adapted to these naturally varying conditions."
The challenge is to avoid patterns of water use (and reuse) that push inflows below one or both criteria so often that fish and wildlife can no longer cope.
The results of the NWF analysis show troubling trends, with five estuaries
receiving a ’danger’ ranking. These are Sabine, Galveston, Matagorda, Corpus Christi and San Antonio.
"During dry times, four of Texas’ seven major estuaries would face serious problems under the ’future use’ scenario, with sustained periods of very low flows happening much more frequently than under ’naturalized conditions.’ During these low flow periods, many species are on life-support and are
just able to survive."
"If they are on life-support too often or for too long, they may be unable to recover quickly, or at all, when inflows increase with wetter times. The key spring and early summer inflow pulses needed to support strong productivity would not be impacted as heavily."
Water is already the largest battleground issue pertaining to the Texas environment.
Coastal flooding can and does have an impact on catching speckled trout and other species but a lack of flooding could have an even greater impact.
As these issues come up, look into what is best for our bays and in turn best for the fisheries and fishermen.
At the end of the day those wanting to take water from the bays are probably going to win but perhaps with some education and persuasion it can be done in such a way that gives our bays a fighting chance.
