Tides are primarily caused by the gravitational pull of the moon on the oceans. The tide is stronger on the side facing the moon because that is the shortest distance between the two bodies. It is easy to visualize the moon pulling water away from the earth causing a bulge of water, but the water is also rising on the opposite side of Earth, causing a tide there. This happens because the Earth moves slightly toward the moon, which in turn pulls the earth away from the surface of the water on the opposite side from the moon resulting in another bulge of water.
The strongest tides will always be during a new moon or a full moon. When the Earth, moon and the sun align the largest tides are created because the sun and moon can both pull on the oceans.
On the other hand, during a quarter moon or a three-quarter moon, the sun’s gravitational pull is at right angles to the moon’s, resulting in weaker tides known as neap tides.
For all these reasons, it is not difficult for scientists to predict when and how large tides will be anywhere on Earth. Of course, wind can locally change the tide strength as I’m sure you have experienced when a strong falling tide and a strong north wind leaves us plowing through mud in the marsh.
How does the tide affect marine life?
Do tides have an impact on marine life? You bet they do. Here are some reasons why.
- Tides can create new habitats where aquatic life will thrive. Tides can also destroy habitat by exposing areas to harsh conditions, but tides are a net positive to the marine ecosystem.
- Tides play a crucial role in the reproductive cycles of many marine species. Speckled trout release their eggs into the water during tidal movement so that the eggs will be carried to suitable habitats. Many types of fish larva depend on tides to transport them to areas with favorable conditions.
- Tides can influence the migration patterns of marine animals. For instance, without tides, Louisiana would not have the abundance of shrimp. Shrimp are heavily dependent on migration through tidal movement. The larva travel into the marsh from the Gulf on tides, and the juvenile shrimp move out to the Gulf on opposite tides.
- Tides increase the interactions between predators and prey. The moving water stimulates our gamefish to feed because, among many things, it changes the visibility of the predators, concentrates bait, and pushes bait into areas with better access for predators. The tides are also beneficial for the bait because they are able to better feed on smaller organisms moved by the tide.
How does the tide affect fishing spots?
There are many spots where I will fish based on the direction and strength of the tide. For instance, I prefer:
- The MRGO rock dam on a falling tide.
- The guillotine gate on Bayou Bienvenue on a medium falling tide.
- The Lake Pontchartrain Trestle on any medium tide.
- The Hospital Wall and nearby pilings in Lake Pontchartrain on a falling tide.
- The beaches between Port Fourchon and Caminada Pass on a rising tide.
Is strong tidal flow necessary?
In pursuit of larger trout, I have over the years drifted away from fishing only pinch points with strong tidal current and moved toward fishing more open water structure which has less flow velocity. This could be shorelines of large bodies of water, inshore rigs in bays, island shorelines, and other such areas which are not typically thought of as pinch points. While you won’t see ripping current in these spots, the tide is still critical. The tide-driven flow velocity of the water doesn’t have to be high in order to arrange the conditions to make for excellent trout feeding areas. Slower moving water will still transport shrimp and move the smaller organisms that the fin-fish feed on.
The impact of tide when fishing beaches
In my experience, beach fishing for trout is highly dependent on tides. Unfortunately, beach fishing is also guarded by wind conditions, because heavy surf driven by big winds slams the door on beach fishing. Calm conditions are generally the result of north wind or light breezes but I have seen days with perfect winds and still the Gulf swell was high enough to surf on.
When you manage to find the right surf conditions, you also need good tide movement. I prefer fishing an incoming tide on beaches. The rising water allows the bait to move onto newly submerged beach and the trout follow the bait up to the waterline. Bull redfish and sharks will also feed there, so expect an occasional drag screaming battle. An outgoing tide can also be productive, but I normally find that the trout will move off of the waterline in this condition and can be caught in the first trough.
Tidal flow and changing techniques
Tides are the major force dictating the velocity of moving water in coastal marshes. A weak tide generally depresses the trout bite but a strong tide can also do the same. Ideally, I like tides in the 0.8 foot to 1.2 foot range. In this range I can fish my preferred techniques, which are jerkbaits, topwater, light jigs and large plastic swimbaits with unweighted hooks. When the tide is strong, I am forced to fish with heavy jigs, such as ½-ounce to ¾-ounce, drop shots, or a heavy jigging lure like a Nomad Design Vertrex. Of course, whether tides are weak or strong, I can generally find spots that either channel the water to increase the flow or reduce the flow by widening the flow path. So for instance, on a weak tide I could fish the downstream side of a coastal protection gate or on a strong tide I could fish a shoreline of a large lake or bay.
Fishing in a coastal environment means we need to adjust our techniques to align with the tidal conditions. I will fish certain spots at certain tide conditions. For instance, around the MRGO rock dam near Hopedale I prefer to fish the south side of the dam on a falling tide, because the water flows through the upper part of the dam and sets up favorable conditions for trout to feed.
With stronger tides where the water velocity is fast, I like to cast up current and let the bait float back to me. In this arrangement I may be able to successfully fish light jigs, such as ¼-ounce or 3/8-ounce, or a sinking hard-bait like a Paul Brown. If for some reason I need to cast down current, then I am forced to fish heavy jigs, drop shots, or heavy sinking lures.
