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Tides and Currents: Their Effect on Fishing
By Capt. Ken Roy
Lots of folks use "Tide" and "Current" interchangeably but there is
a difference. Tide is defined as "the vertical movement of water."
This is caused by the gravitational pull of the moon and to a lesser
extent, the sun. Currents may be defined as horizontal movement of
water. Some currents (not all) are caused by this vertical movement of
the tide.
When the tide increases in height, it moves inshore as a simple
response to water seeking it’s own level. Tidal water fills all of the
low spots, so to speak. The shoreward movement of water creates a
tidal current, the "incoming" tide. The "outgoing" tide is exactly the
reverse of the process, water flows seaward as the tide falls.
There are other factors
that create currents. Wind driven currents occur when the friction of
wind movement forces water ahead of it. When wind and tide are in the
same direction, much higher and much lower tides can result. With lots
of wind, it is entirely possible to have a low tide higher than the
preceding high tide. An additional factor that can create current flow
is barometric pressure. A low barometric pressure can ! result in
higher tides and a higher barometric pressure can result in lower
tides. Perhaps some of the feeding frenzies that we have experienced
as a front approaches can be somehow related to the additional current
speed generated by falling barometric pressure.
Tides and currents created by
tides are of utmost importance inshore. Fish feed into the current,
simple as that. They face into the current to maintain position and to
intercept food washed by the current. This is especially true on the
falling tide.
Fish that feed on the
flats are more affected by water depth (tide height) than by the
current flow. If there isn’t any water on the flat, the only fish ther!
e will be dead ones. As the water level drops with a falling tide, the
fish leave the flats and take up positions along channel edges to
ambush critters that also have to leave the flat.
Fast tides work better for me
offshore whereas slower tides are better (for me) inshore. Fast
inshore tides can create a lot of turbidity. With reduced visibility,
it may be advisable to switch to natural bait with smell or to a noisy
lure.
Slow tide days offshore can be slow fishing days but there are a
few techniques that work for me. On slow tide days, I fish the highest
rocks and wrecks. The higher profile bottom sort of "compresses" the
flow over it thus increasing the speed across it a little.
A change in the species targeted
can produce much faster fishing also. Cobia, Mackerel, Kingfish,
Trippletail, Spadefish, and Sheepshead bite fine on slow tide.
Spadefish seem to bite best at absolute slack tide, unusual for most
fish.
Chumming on very slow tide days will help your bottom fish catch.
Grouper and Snapper will respond just fine whereas on fast tide days
your chum may drift too far away from the boat to ever get to the
level where they find it.
I use this little formula to
determine the tidal speed during a tide. I found it in Chapman’s a
long time ago. Simply put, the tidal current speed increases and
decreases about 8% the first hour, 16% the second hour, 24% hours 3
and 4, decreasing to 16% the fifth hour and 8% the sixth hour. Easier
to remember is 1-2-3-3-2-1 with 1 being minimum current speed. Feeding
picks up as current speed picks up and begins to slow down with lower
current velocity.
Take a look at the tide table for
your area. The table on "Fishing Around the Bend" is as good as they
come. The greater the height difference between high and low tides,
the faster the tidal current. Just another point of trivia is outgoing
tides flow faster than incoming tides. As the tide rises and moves
shoreward, it "stacks up" or compresses against increasing land
height, thus a resistance. When it begins to fall, the water is
flowing "down hill" and you can get some mighty fast movement. When
you have a fast outgoing tide moving against a strong wind from
offshore you can have a nasty chop.
Get familiar with tide tables and you! will have much more
predictable fishing
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