Predicting tides is an exact science that isn’t exactly exact.
If you’re an angler who likes to spend your off days shrouded by green wire grass, with a rod in your hand and your foot on a the trolling-motor control, you’ve probably cursed us a time or two.
Go ahead and admit it: You’ve muttered under your breath about the good-for-nothing so-and-soes at Louisiana Sportsman and their worthless tide charts.
It’s O.K.; we forgive you. At least you were kind enough to keep your comments to yourself rather than calling us and giving us an earful — like many of your fellow anglers have done.
Actually, we don’t mind. We know how you feel. We’ve cursed the tide charts ourselves a time or two.
We’ve had days in which we knew we could catch a limit of trout over a particular oyster reef as long as the tide was rising. We checked the trusty tide charts to discover when the tide would be rising, and scheduled our trip accordingly, only to find upon arrival that the tide was still falling when it was supposed to be rising.
Hours later, it was still falling.
So what gives? Why would Louisiana Sportsman publish tide charts that are so frequently incorrect?
Well, the answer’s simple: Because they’re not incorrect. They are absolutely correct 100 percent of the time.
So why is there a variance?
Because the tide times we run in the Sportsman are based on the moon and, to a lesser extent, the sun, and the effects those heavenly bodies have on the world’s oceans and seas.
Scientists can pinpoint to the exact minute the times when the tides will peak and valley at any point on the entire globe based upon lunar and solar influence.
But what they cannot do to any similar level of precision is predict what impact atmospheric conditions will have on the tides at a given location.
To illustrate the point, let’s consider an example.
Say a mutual friend of ours knows he can catch fish at Manila Village on a rising tide, so he checks the tide chart and discovers that the water should bottom out at 8:06 a.m. on Friday.
That’s perfect; it’ll be rising most of the day. So he calls three buddies, and tells them to meet him in Lafitte in the pre-dawn hours on Friday for some sure-fire speckled trout action.
On Thursday night, however, a late-spring cool front moves through, bringing strong north winds with it. Undaunted, he meets his buddies at the launch early Friday morning, and then motors to Manila Village to find the tide low and falling.
At noon, it’s still falling, and his ice chest is still empty. Finally at 2 p.m., he gets disgusted and throws in the towel.
The tide didn’t come anywhere close to doing what the Sportsman tide chart said it was going to do, and our good friend is tempted on his way home to make a stop at the magazine’s office in Boutte and wring a certain editor’s neck.
O.K., well that’s an easy one. Most any angler who’s been fishing the Louisiana coast for more than a day knows that a strong north or northwest wind will blow the water to Cuba.
But what about the days when you’re out there and winds are calm. Shouldn’t the tide then do exactly what the tide chart says?
Well, not necessarily.
What many anglers don’t consider is what the atmospheric conditions were like on the days leading up to their trip.
Let’s continue with the above scenario. Say our friend gets home from his ill-fated trip, and now he’s got a serious yearning to catch some fish. So he decides to forget about the trout and chase some redfish. He knows he can catch some reds on a falling tide in a favorite pond just north of Manila Village.
So he checks the tide charts for that Sunday. Low tide is at 10:18 a.m. That’s not ideal, but at least he’ll have four hours between sunrise and the bottoming out of the tide. That’s plenty enough time to catch a limit of reds.
But our buddy has wised up. This time he checks the forecast as well, and Margaret Orr assures him that winds will be light and variable on Sunday. Perfect! He can’t lose.
He pulls his cell phone out of his pocket, and calls his three buddies again. This time he promises them action. They somewhat reluctantly agree to meet him at the Lafitte launch on Sunday morning before the chickens are even stirring.
That morning, winds are non-existent. There’s even a wisp or two of fog hovering over the surface of the water. Our buddy’s got ants in his pants. He can’t wait to be sitting at his favorite trenasse mouth throwing live cocahoes to schools of marauding redfish.
But lo and behold, he pulls into his favorite pond to find the water is rising.
Six hours later, he returns to the launch with a sunburned neck, a lone sheepshead in the cooler and a catfish sting on his ring finger. He spends the car ride home carefully choosing the words he’s going to use in his post on louisianasportsman.com telling anyone who’ll read it how worthless the Sportsman’s tide charts are. His friends spend the car ride home carefully choosing the words they’ll use the next time our buddy calls to invite them fishing.
But actually the tide charts weren’t wrong at all. The moon and sun were doing their best to pull the water from our buddy’s pond all the way until 10:18 — or at least a couple of minutes thereafter (more on that in a moment) — but the atmospheric conditions wouldn’t allow it.
But how can that be? Weren’t the winds negligible?
Indeed they were, but they were anything but on the two days leading up to our buddy’s trip. The strong north winds had blown a significant amount of the water out of the Barataria Basin. The tide didn’t rise for two days.
Then when the winds relented, the water level began to equalize. All that water that had been blown into the Gulf slowly returned to the “vacuum” that existed in the basin. Although the tide was supposed to fall at Manila Village until 10:18 a.m., it actually bottomed out much earlier, and it didn’t stop rising for 36 hours.
Why our snake-bitten buddy didn’t abandon the reds and go try the Manila Village trout on the rising tide, we don’t know. Some people are just that way. They couldn’t catch fish with a dip net in a pet-store aquarium.
So it’s obvious that winds have a profound impact on our tides, but they’re not the only atmospheric conditions that affect when our waters fall and rise. High- and low-pressure systems also serve to push and pull tides, depending upon where they’re located.
A high-pressure system over the Gulf, for instance, will put pressure on the water’s surface there, which will cause tides to rise — or, at least, not fall as substantially — along the Louisiana coast.
A low-pressure system will have the opposite effect. As Katrina and Rita demonstrated on an extreme scale, a low-pressure system raises the water level under it. If the low-pressure system is located over our marsh, then the tides will be higher than they would have been without it. If, on the other hand, it’s located out in the Gulf, our tides will be lower because the water will be “sucked” into the low.
All of these atmospheric conditions are at play every day to some degree, and their impacts on our tides range from negligible to profound. And they obviously can’t be predicted by any chart.
Choke points make tides unreliable
Complicating matters further is the fact that Louisiana’s coast is among the most intricate in the world. Every bay is connected to a lake that’s connected to a bayou that’s connected to a pond that’s connected to a canal that’s connected to a trenasse, and all of those choke points constrict water movement, which makes the tides exponentially more vulnerable to the impacts of the atmosphere.
That means the tide charts are much less reliable at an inland area like the Paris Road Bridge than they are at a point much nearer the Gulf, like Bayou Rigaud.
The water has to pass so many choke points on its way in and out of the marsh that anything can happen, and any change in the atmosphere will alter that tidal flow in some way.
So are the tide charts worthless? Certainly not. We at the Sportsman check them before scheduling any fishing trip. But we use them as a general guide, and we try to guess how recent atmospheric conditions — winds especially — have impacted the tides, and how that might alter what we find when we’re out on the water.
Sometimes our calculations are right; other times we go home scratching our heads wondering where we erred in our “educated” guesses.
We’ll never be right 100 percent of the time, but isn’t that what makes fishing fun? If an angler had everything figured out, and all of his plans always worked, he’d find a new hobby.
And if you ever think you get this whole tide thing mastered, spend a few days on Lake Pontchartrain with a watch and a tide chart.
Humbling, ain’t it?