Article by Capt. Mark Sampson
We fishermen are a diverse lot. We fish for big fish, little fish, in freshwater and salt, we troll, we cast, we drop baits to the bottom and drift. We fish from the shore or from piers, bridges or from boats, and the selections of tackle, baits and lures we use are as wide as the ocean is deep. Beside that fact that we all use (some kind) of hooks, weights and line, there’s not exactly a long list of commonalities that all fishermen possess. One trait, however that most fishermen have in common (at least those that fish around these parts) is a use of the “tides.”
Of course tides are not an issue in “non-tidal” water such as lakes, ponds and most streams, but those who fish in Delmarva’s rivers, bays and ocean waters know that the state of the tide can mean everything when it comes to catching or not catching fish. Very few fishermen these days put a line in the water without at least taking note of what the tide is doing and many will plan their entire fishing trip to coincide with favorable conditions.
Tides are the result of the gravitational pull of both the sun and moon. But since the moon is so much closer to earth, it’s the primary factor of influence. Because there's a lot of smart guys out there who can predict the moon’s rotation around the earth, tides can be very accurately forecast right down to the minute and well into the future. “Tide charts” are the products of these calculations, so if someone needs to know when the morning high tide is going to be – say on July 27th at the Ocean City inlet, all they have to do is look at a tide chart for the area and see that it will occur at (let's just say) 6:30am.
Taking all that into account, here’s a question for all you fishermen and boaters out there: If the tide is going to be high at 6:30, would it be right to say that at 6:00am the tide will be “coming in” (or flooding) until it finally “slacks” (or stops moving) at 6:30?
I’ll bet that most folks would agree with that statement and then go on to say that sometime after the “high-slack” the tide will start to go out or “ebb.” But guess what, it’s all wrong! You see (and here’s what’s going to blow even some old-timers minds) technically speaking, tides don’t “come in, flood, go out, ebb,” or even “slack.” The proper terms to use for what tides do is “rise, fall, or stand” because tides are actually a measurement of the vertical (up and down) movement of water. The horizontal (in and out) movement of water that we see rushing past a dock piling or buoy, or that carries our boat up the bay is actually not the tide, it’s the “current”, which may be affected by the tide, but not always as much as some folks might think. The proper terms that describe what currents do are “flood” (away from the ocean), “ebb” (towards the ocean), and “slack” (no movement).
Ok, so who cares about technical terms, if I call Joe on the radio and he says “the tide is coming in ” I know that means I’ll be drifting up the bay, that’s all that’s important to me. Right? Well, maybe not. At 7:00am on July 27th old Joe could still be drifting up the bay (with the current) even though the tide quit rising a half hour ago. That’s because currents are affected not just by tidal movement but also by factors such as wind, rain, and a bounce back effect from land masses. Ever wonder why the tide chart says the low tide was supposed to be hours ago and yet water is still flying out of the inlet? Imagine putting a ping-pong ball in an empty bathtub, then you start filling the tub. At first the ball will float with the “current” to the back-side of the tub, but eventually it will start to drift with the “current” back toward the incoming water. Even though the “tide” in the tub is constantly rising, the “surface current” is flowing toward the source of the incoming water.
Now, consider our back bays where for about six hours as water comes in from the ocean the tide is constantly rising, but in some parts of the bay the surface current may change direction and actually flow back toward the inlet. From his boat, Joe only notices the horizontal movement of the current taking his boat north, not the falling of the tide.
Your tide chart says that the tide started going out over an hour ago, but you ignore this and accept Joe’s assumption that the chart is wrong and the tide is still “coming in.” Consequently you try to cross a sandbar that you can only transit at high tide but “Whammo!” You end up hard aground and now have almost five hours to wait for the next high tide when you can float your boat off the bar. Now do you see why it’s good for all boaters to know the difference between tide and current?
So remember: “Tides” rise, fall, and stand. “Currents” flood, ebb, and slack, and “Joe” doesn’t know what he’s talking about! §
