How to Read Water for Fishing

Fish do not spread themselves evenly through a body of water. They sit where current delivers food to them for the least effort. Find those places and you have done more for your catch rate than any lure in the box will do.

The one principle

Everything below is a variation on it: fish hold on edges, and feed when water moves.

An edge is any place where two things meet — fast water and slow, deep and shallow, weed and sand, warm and cold, clear and murky. Food gets concentrated and disoriented at edges, and a predator can sit in the easy side and ambush into the hard side.

A long, featureless, uniform stretch of water is usually the emptiest part of any venue, no matter how good it looks.

Moving water

Slack water is dead water. In tidal fishing this is the single most reliable rule: a spot that was alive an hour ago goes quiet at the turn, then wakes again when the tide moves.

Direction matters less than movement, but it does matter, and it depends on the spot:

• Marsh drains and creek mouths — best on a falling tide, when bait is flushed out of the marsh into waiting fish.
• Shallow flats — often best on a rising tide, as fish move up onto them to feed.
• Jetties, points and passes — best whenever water is being pushed hard past the structure.

In rivers the same principle uses permanent features instead of tides. Look for:

• Seams — the line between fast current and slow, where a fish sits in the slow side and picks food out of the fast side
• Behind rocks and bridge pilings — a slack pocket directly downstream
• Undercut banks on the outside of a bend
• Confluences, where a tributary enters

NOAA publishes tide predictions for US coastal stations, and for rivers our live water temperature tool pulls current USGS gauge readings — both are better inputs than a calendar.

Water clarity — and how it changes the answer

Turbidity is how much suspended material is in the water. It changes which sense a fish is hunting with, and therefore what you should throw.

In dirty water people reach for brighter colours. The more useful change is more vibration and a slower retrieve — a fish that cannot see needs time to locate a lure by feel. A fish's lateral line detects water displacement before its eyes are involved at all.

Colour still matters near the surface, but less with depth, and in a specific order — see fishing lure types for what NOAA publishes on which colours survive underwater and which do not.

A colour change in the water is itself an edge. Where muddy river water meets clean, predators hunt the line, sitting in the dirty side and ambushing anything silhouetted against the clear.

The productive environments

Estuaries — where a river meets the sea and fresh mixes with salt, producing brackish water. Among the most productive environments on earth: the mixing traps nutrients, and they serve as nurseries for juvenile fish. That is why Chesapeake Bay is the nursery and highway for East Coast striped bass, and why redfish, snook and speckled trout are estuary species.

Reefs — hard structure holding an entire food chain, from the small things living in it to the predators patrolling its edges. Fish the edges and the up-current side.

Piers and jetties — man-made structure that gives shore anglers access to deep water and current. They hold bait, they create ambush points, and they are the reason a bank angler can reach fish that otherwise need a boat.

They also come with a specific hazard.

Rip currents — the part that matters if you fish structures

This section exists because the structures anglers deliberately seek out are exactly where rip currents form.

The National Weather Service defines a rip current as "a strong, narrow and concentrated seaward flow of water that extends from close to the shoreline, through the surf zone and variable distances beyond." Channelized rip currents "typically range in width from 5 to 100 yards."

Two facts every pier and jetty angler should know:

1. They form at structures. Rip currents occur adjacent to man-made structures such as groins, jetties and piers, as well as at natural headlands and rock outcrops.
2. They do not need big surf. NWS states these "structurally-controlled rip currents are persistent in location and can occur even during small breaking wave conditions." A calm-looking day is not evidence of no rip current.

NOAA adds the speed: rip currents move "at speeds of up to eight feet per second" and "can move faster than an Olympic swimmer." They are prevalent along the East, Gulf and West coasts, and along the shores of the Great Lakes.

If you go in

NOAA's guidance, verbatim:

If caught in a rip current, don't fight it! Swim parallel to the shore and swim back to land at an angle.

NOAA notes that "panicked swimmers often try to counter a rip current by swimming straight back to shore — putting themselves at risk of drowning because of fatigue."

The current is carrying you away from shore, not under. Swimming across it is short; swimming against it is a race you lose.

Sensible precautions for fishing structures

• Wear a life jacket on jetties and rock structures. Wet rock and a heavy swell put people in the water who never intended to be there.
• Watch the water for a few minutes before climbing out. Sets come in groups.
• Never turn your back on the sea on an exposed jetty.
• Fish with someone, and tell someone where you are.
• Check the local surf and rip current forecast before you go.

Putting it together

Before you cast, spend two minutes asking:

1. Is the water moving? If not, is it about to be?
2. Where are the edges? Depth change, current seam, weed line, colour change, structure.
3. How clear is it? That decides vibration versus subtlety.
4. Where is the bait? Birds, surface disturbance, baitfish flicking. Follow it.

Those four questions beat changing lures, which is what most people do instead.

Related

• Live water temperature — current USGS gauge readings
• Spawning calendar — what is spawning, and at what temperature
• Fishing lure types — matching the lure to the water
• Fishing hook types — what to tie on once you have found the fish
• Chesapeake Bay — an estuary doing exactly what this page describes

Sources

• Rip Current Science — NOAA National Weather Service — the definition of a rip current; that channelized rip currents typically range from 5 to 100 yards wide; and that structurally-controlled rip currents near man-made structures are persistent in location and can occur even during small breaking wave conditions.
• What is a rip current? — NOAA National Ocean Service — speeds of up to eight feet per second, faster than an Olympic swimmer; prevalence along the East, Gulf and West coasts and the Great Lakes; and the instruction not to fight the current but to swim parallel to shore and return at an angle.
• Why are so many deep-sea animals red in color? — NOAA Ocean Exploration — the order in which light penetrates water: blue best, then green, yellow, orange and red.