How to Read a Contour Map for Fishing

May 1, 2017

The amount of fishing gear available to anglers today is larger than ever before. And granted, the advancements made in gear may help put a fish or two in the boat more often, but one of the most important aspects of catching more fish is understanding where to find them. A great place to begin is with a contour map that shows you the depths of the waterway you’re fishing on. How you interpret these wavy lines on the map can put you in the right spots, at the right time, more often than not.

Here are some tips to get you started:

Visualizing Changes in Depth
Besides the displayed gradient depths (usually marked in 5-10 ft. intervals), the space between contour lines is the key to understanding how shallow or deep you are fishing. Contour lines spaced narrowly between one another indicate areas of steep transition - meaning the depth of the water column changes from shallow to deep (or vice versa) quickly within a short distance. You’ll often hear anglers talk about fishing “drop-offs” or “points” when targeting certain species of fish - they’re referring to these same closely-spaced contour line areas on a fishing map.

Example of drop-offs located on a Fishidy map.
Example of drop-offs located on a Fishidy map.

On the other hand, when you see contour lines spaced far apart, it’s just the opposite. These are areas of gradual transition where the depth of the water column is changing from shallow to deep (or vice versa) slowly over a long distance. Anglers who talk about fishing the “flats” or “shallow” are referring to these same areas on a fishing map with contour lines spaced widely apart.

Example of flats located on a Fishidy map.
Example of flats located on a Fishidy map.

Understanding Behavior and Habitat
Find peak fishing times on Fishidy.
Once you’ve mastered how to interpret changes in depth on your map, the next step is understanding the behavior and prefered habitat of the species of fish you’re trying to catch. Coldwater and warmwater species of fish have different preferences that dictate when they move, where they move, and for how long they’ll be there. These behaviors are often influenced by a variety of factors including light, weather, water temperature, food sources, and reproduction. Oftentimes fish behavior is closely aligned with underwater habitat or structure, and this is where your knowledge of depth comes into play.

For example, if you’re targeting largemouth bassin early spring, you’ll most likely want to seek out shallow areas containing emerging weeds and vegetation. For crappie in the middle of the summer, you’ll most likely start your approach in deep water basins alongside drop-offs, or on offshore flats with structure such as flooded timber or artificial fish cribs. The better you understand the fish you’re targeting, the more you’ll know what to look for on a fishing map with contour lines.

Focusing on Fishing Hot Spots
The last step in this process is wrapping together what you know from both of the previous steps, and keying in on the specific areas on your waterway where depth, structure, and fish behavior all intersect. Fish migrate on specific travel routes within the course of a given season. Once you have the knowledge of where these areas exist, and you’re able to identify these "fishing hot spots" on your map, you will drastically increase your chances of catching more (and maybe bigger) fish more often.

Access fishing hot spots as a premium subscriber on Fishidy.
Access fishing hot spots as a premium subscriber on Fishidy.

Hopefully these tips will help the next time you’re looking at a fishing map. Best of luck with your next on-the-water adventure.

Related Products

NewHumminbird Helix 7 Chirp Mega DI GPS Fish Finder
Humminbird Helix 7 Chirp Mega DI GP...
Become versed in the underwater world and what lurks directly under your boat with the Humminbird Helix 7 Chirp Mega DI GPS Fish Finder. With MEGA Down Imaging and dual Spectrum Chirp, you get the clarity the competition wishes they could give you! With three times more output than the standard sonar, you'll see well-defined fish arches and a clear view of structures and the bottom. Create real-time maps of your fishing adventure for up to 8 hours with the AutoChart Live feature! Now you'll neve...
$599.99
NewHumminbird PiranhaMAX 4 Fish Finder
Humminbird PiranhaMAX 4 Fish Finder
If you're searching for the best fish finder for the money, look no further than the Humminbird PiranhaMAX 4 Fish Finder. Featuring a 4.3 in. color LCD display with an easy-use interface, you'll have a clean, bright look of fish, structures, and contours under your boat. Dual beam sonar lets you choose a narrow beam for great detail or a wide beam for a large coverage area. With Fish ID+ and fish alarms, you'll never miss what species you are targeting! The technological punch of the Humminbird ...
$99.99
NewHumminbird Solix 15 CHIRP Mega SI+ GPS Fish Finder
Humminbird Solix 15 CHIRP Mega SI+ ...
Strike fear into the hearts of fish everywhere when you have the Solix 15 CHIRP Mega SI+ GPS Fish Finder installed on your boat! Featuring a massive 15.4 in. touchscreen display, with leading proprietary technologies, you'll be able to easily distinguish fish from structures, see the direction fish are facing, and target individual species. With MEGA side and down imaging, you'll experience crystal clear images with a 200 ft. range on either side of your boat as well as beneath your boat. Precis...
$3,699.99
NewLowrance Elite Ti2 Fish Finder
Lowrance Elite Ti2 Fish Finder
We don't consider it cheating and neither should you! Research fishing hot spots and learn tournament-winning presentations with the Lowrance Elite Ti2 Fish Finder. Featuring a high resolution SolarMax display and easy-to-use touchscreen, you'll have a crystal clear view of what lurks underwater. Active Imaging is the highest quality sonar available, giving you superior clarity that is perfect for pinpointing fish holding areas like rockpiles, standing timber, weedbeds, ditches, and dropoffs. Po...
$749.99 - $1,999.99
NewLowrance HDS Live Fish Finder
Lowrance HDS Live Fish Finder
Fish like never before with the Lowrance HDS Live Fish Finder! The most popular fish finder on the professional circuit features a sleek design and incredibly fast processor to take you to a new level of fish finding performance. Active Imaging sonar provides superior clarity and the highest resolution images of fish and structure at a longer range. With LiveSight sonar, you can watch fish react to your bait so you can figure out what is working and what to do next. Turn all your fishing into si...
$1,149.00 - $4,499.00
NewLowrance Hook2 Fish Finder
Lowrance Hook2 Fish Finder
Spend more time fishing and less time messing with settings on the Lowrance Hook2 Fish Finder! Known as the world's easiest fish finder, the display is intuitive and easy to use with quick access keypad. You'll always have the best image available thanks to auto-tuning sonar, which automatically adjusts your sonar settings as water conditions change. With basic GPS navigation options, you’ll always know where you’ve been and where you’re going. The SplitShot and TripleShot models come preloaded ...
$119.99 - $799.99
Comments