Locating fish and determining their size using the Deeper PRO / PRO+ / CHIRP models.

Ah the moment, there are 2 ways you can detect fish and determine their size using the Deeper Sonar PRO / PRO+ / CHIRP models: Fish Icons or Detailed sonar screen mode (Fish icons OFF).

Using Fish Icons method

Fish Icons option is considered to be the easiest way to locate fishes, and something that can be used if you don't have experience in reading the sonar screen.

When Fish Icons are enabled, special algorithms will analyze the sonar screen and mark ultrasound reflections from fish with fish icons. There will be 3 different sized fish icons according to the discovered fish sizes. If you choose to use this option, here are the best-suited settings of your Deeper sonar:

- Sonar display: Detailed
- Wide beam (47°/55°) is good for quickly scanning larger areas and getting general information on fishes, depth and bottom structure, but the accuracy and detail will be lower. You will not be able to accurately determine the size of the fish using Wide beam, but due to a large area covered by the beam you'll be able to locate the presence of fishes faster (for example, if you're looking for schools of bait fish). Wide beam scanning is best suited for shallower waters.
- Narrow beam (7°/15°/16°) is much more accurate when determining the size of the fish, so if you see a thick arc or line when using this beam - the fish is definitely big. Narrow beams cover a smaller area, so it may be harder to locate the general presence of fish.
Fish Icons: ON
Sensitivity: 70-90%, but can be reduced if the water is murky, or if you're targeting big fishes only.

Please note that it is impossible to determine the exact size of the fish using any kind of sonar technology - this is related to how all sonars work and ultra-sound physics. So, you should look at different size of fish icons as an approximate evaluation of the size of the fish, but not as exact measurement. It is impossible to say that Big fish icon means that the fish underneath is more than 20 or 35 cm long. But when you see a big fish icon - there is a very good chance that the fish is actually big.

 

Analyzing raw sonar display (Recommended)

Second option is to disable Fish icons and look at the real sonar readings, which is considered to be a more advanced method, but more accurate at the same time. If you'll turn Fish Icons off, you'll see that fish in sonar readings are displayed like arch or lines. The thickness of those lines/arches is the indication of how big the fish is.

You can learn more about this here:

How to read a Deeper CHIRP+ sonar screen.
How to read a Deeper PRO/PRO+ sonar screen.

 

Recommended sonar settings for locating fish when Fish icons are OFF:

- Sonar display: Detailed
- Wide beam (47°/55°) is good for quickly scanning larger areas and getting general information on fishes, depth and bottom structure, but the accuracy and detail will be lower. You will not be able to accurately determine the size of the fish using Wide beam, but due to a large area covered by the beam you'll be able to locate the presence of fishes faster (for example, if you're looking for schools of bait fish). Wide beam scanning is best suited for shallower waters.
- Narrow beam (7°/15°/16°) is much more accurate when determining the size of the fish, so if you see a thick arc or line when using this beam - the fish is definitely big. Narrow beams cover a smaller area, so it may be harder to locate the general presence of fish.
-Fish Icons: OFF
-Sensitivity: 70-90%, but can be reduced if the water is murky, or if you're targeting big fishes only.

ⓘ When locating fish, use the Wide beam first to find the general location of fish, then switch to a Narrow beam and scan that area a few times to get the exact location and the size of fish.
ⓘ When using Wide beam, fish arches/lines will look much thicker, compared to when you use a Narrow beam. It is better to use Narrow beam for a more precise evaluation of the fish size.

 

Some important things to remember about fish arches:

  1. You’ll only get arches from moving fish (or if your sonar is moving over them).
  2. If your sonar and the fish are both stationary, you will see a line, not an arch.
  3. You’ll only get a full arch if the fish moves through the full sonar cone.
  4. If a fish swims through part of your cone, it will show as a half-arch or a thick dash – look out for these.
  5. Longer lines can indicate a more active fish that moves rapidly under the sonar cone, while shorter arches may indicate that fishes are less active.

Choosing the right color palette

Deeper PRO and CHIRP model series allow to choose between 3 different color palettes (Classic / Day / Night). Choosing the right color palette can help you with interpreting fish size and bottom features like hardness of weeds. Colors you see on the screen are important in understanding how strongly underwater objects reflect the sonar signal, which is a key factor in determining their size and thickness.

ⓘ For best interpretation of fish size and bottom features, please use Narrow beam setting (PRO models) or Mid/Narrow beam setting of Deeper CHIRP. Wide beams are less accurate when determining fish size or bottom structure.

Day color palette (recommended)

This color palette is used in traditional boat sonars, and is generally considered the best one to use. It allows you to get the most accurate understanding of underwater object size and bottom hardness. The way of interpreting colors is quite simple: the intensity of the color equals to how strongly the ultrasound signal was reflected from the object. Big and hard objects will reflect ultrasound in a stronger manner, so they will be displayed with more vivid and bright colors. Soft objects like muddy bottom or weeds will be displayed in darker colors.

Yellow - strongest reflection of the signal. You will see it from hard bottom, thick and hard underwater objects such as boulders, as well as big fishes. Sometimes you can see this color in areas with very dense vegetation.
Red - medium reflection of the signal. You will see if from bottoms of medium hardness, as well as fishes of medium size. You might also see such colors from very thick weeds.
Blue - weak reflection. Small fishes, bait-fish and individual bushes of vegetation will appear in blue. Very soft, muddy bottoms will be seen as layer of blue colors that mix with red or yellow.

Classic color palette



This color palette contains special algorithms that interpret weeds and fishes, and mark weeds with green color and fishes with yellow. It is easier to understand for beginner users, but considering that the interpretation is done by an algorithm - inaccuracies can be expected.  Other than that, understanding colors of this color mode is very similar to the Day color palette. The intensity of the color equals to how strongly the ultrasound signal was reflected from the object. Big and hard objects will reflect ultrasound in a stronger manner, so they will be displayed with more vivid and bright colors.

White - strongest reflection of the signal. You will see it from hard bottom, thick and hard underwater objects such as boulders, as well as really big fishes. Sometimes you can see these colors in areas with very dense vegetation.
Red - strong reflection of the signal. You will see it from very dense vegetation as well as big fishes.
Yellow - medium reflection of the signal. You will see if from bottoms of medium hardness, as well as fishes of medium sizes. You might also see such colors from thick vegetation.
Green- vegetation. You might also see green colors as a horizontal line going across the bottom - this means the bottom is very soft, possibly mud or muck.
Orange colors - weak reflection. This color will be seen on soft bottoms. 

Night color palette

Choose this color palette in poor lightning conditions.
For Deeper CHIRP models, colors used in Night color palette are inverted colors of the Day color palette, and logic of interpreting them is the same.
For Deeper PRO models, colors of Night color palette are similar to Classic color palette, except that they are dimmer.