My co-worker and I were hunched over a laminated Captain Segull’s Chart, doing a little Monday-morning quarterbacking. Over the weekend, we’d fished for fluke, but weren’t thrilled with our results. Relying on our fishfinder to reveal bottom structure and find new fishing areas, we managed to find plenty of fluke but no keepers, and we returned to the dock with an empty cooler. The need to find less-pressured structure and deeper holes that would hold bigger fluke led to our fit of chart-reading the following Monday and a plan to get familiar with a new chartplotter before the next trip.
A good chart will contain all the information an angler could hope to procure about a specific area, and today’s digital charts are describing the ocean floor in never-before-seen detail. While these advances have made the modern chartplotter an incredible tool for anglers, it’s still necessary to understand the basics to take full advantage of its power.
Where Does the Information Come From?
Prior to 1807, with the exception of the Long Island Sound and North Carolina, there had been no surveys made of the Atlantic or Gulf coasts. Thomas Jefferson signed on February 10th of that year “an act to provide for surveying coasts of the United States.”
Since then, the creation of up-to-date coastal charts has been the responsibility of the National Oceanographic and Atmospheric Administration (NOAA) Office of Coast Survey. With information provided by the Coast Guard, Army Corps of Engineers, Naval Oceanographic Office and several other groups, the charts are constantly updated to allow for the safest navigation possible.
These charts are the starting point for products more familiar to fishermen such as the charts sold by Captain Segull’s, Navionics and Jeppesen.
The old, reliable paper chart is still a good option when looking for a new fishing spot. It is beneficial in that it provides a detailed look over a wider area without the scrolling needed to look over large areas of electronic chart on a computer screen. And in the event your electronics fail, a paper chart (and a compass) can help you get back to port safely. However, such charts take up space on your boat, and multiple charts are often needed.
Homeport and Captain Segull both make detailed laminated charts. These companies take the navigation charts provided by NOAA and add valuable local knowledge about the general location and GPS coordinates for wrecks and other popular fishing areas.
More anglers now rely on electronic charts for their navigation. Electronic charts can be perused on your home computer, chartplotter, tablet or smartphone. With them, fishermen can investigate larger areas in more detail than ever before.
Most chartplotters come pre-loaded with a navigational chart. In most cases, this is a very basic chart, providing information needed for safe navigation and little more. While it is fine for the pleasure boater, it is often not enough for the serious fisherman.
Companies like Jeppesen and Navionics offer charts with greater detail and in-depth information available on chips that can used with your chartplotter. These companies take the information provided by NOAA and augment it with their own surveys to provide better charts for fishermen. For example, Navionics Gold charts provide seamless depth and structure information for the entire continent, while showing detail down to a resolution of 3 feet. This will show you a depression where monster fluke might be sitting or a large submerged boulder where a big striper could be lurking.
Regular updates are another benefit of electronic charts. Theoretically, every paper chart is out of date by the time the ink dries, but some electronic charts are constantly updated. With their Freshest Data add-on, Navionics improves their maps using the latest satellite imagery, airborne laser and sonar, and Notices to Mariners. Anglers can then update their own charts online whenever they want. This keeps up with the ever-changing ocean, getting the most accurate information even as sandbars shift and new submerged structures are discovered.
Electronic charts can be further enhanced by community or personal data with tools like Navionics SonarCharts and Simrad Insight Genesis. The Simrad Insight Genesis allows users to create their own maps. This Tool uses sonar recordings taken from Broadband Sounder and StructureScan transducers connected to Simrad NSS Sport Multifunction Displays to create detailed maps. Whether mapping previously uncharted waters, seeking greater detail or additional layers of information, Insight Genesis delivers a new level of chart detail for fishermen.
Navionics takes a community approach to their map generation tool. Through sonar logs uploaded by Navionics Community users, the SonarCharts layer provides incredible detail of areas including one-foot depth contours and submerged structures that have never been mapped before.
Another feature of electronic charts is the three-dimensional chart view. The Jeppesen C-Map 4D shows a 3D image of the bottom structure, providing fishermen with a fish-eye view of the seafloor.
The Power of Chartplotters
To unleash the true power of electronic nautical charts onboard your boat, you’ll need to learn how to use a chartplotter. Chartplotters not only give you a way to view electronic charts, they use GPS to allow you to track your exact location and where you’ve been. Long gone are the days of grease pencils and handwritten coordinates. Now, exact waypoints can be marked and stored with the touch of a button, and trolling routes and drifts can be covered with precision.
Most chartplotters are integrated with fishfinders, and a growing trend in these combo units is features that allow interaction between the two. For example, some units allow anglers to make note of structure or fish marked on a fishfinder and create waypoints on their chart. Lowrance’s TrackBack feature even allows you to go back through your sonar history, mark something you previously passed over, and create a waypoint that marks exactly where your boat was at that moment.
Think for a moment about how you can use all this technology to improve your fishing. For instance, say you are fishing for fluke. You set up a long drift along a shoal in 30 feet of water, a depth that has treated you well in the past. On the first pass, you find that one particular part of the drift is producing all the bites. So, you set a waypoint, shorten your drift and continue to work over that mark until the bites stop. Now you know the depth that was producing fish because of your fishfinder. By examining the exact location on your digital chart, you can decipher what it might be about that particular location that was holding fish. Perhaps it was close to an edge of the shoal, where the bottom drops off to deeper water. Perhaps it was near in an area marked “rocky” on the chart. Now, zoom out and look for other locations with similar features, and see if you can replicate your success.
This is just one example of the many ways that being chart-fluent can help you use new digital chart technology to catch more fish. This season, brush up on your chart-reading skills and start strategizing ways to use nautical charts to uncover your own hotspots.
Chart Reading 101
Rk, rky… Rock, Rocky
Locating underwater depth changes that denote gamefish-holding structure such as humps, ledges, flats and drop-offs is one of the most important ways fishermen can benefit from being able to read a chart. These depth changes are denoted by the contour lines scrawled across the chart.
Being able to visualize the structure represented by contour lines is a vital skill. Some fishermen misinterpret contour lines, thinking that each parallel line marks an abrupt change in depth, perhaps seeing the bottom like a staircase, when in reality the bottom is a smooth slope.
It is the amount of spacing between contour lines that provides the most significant information. Contour lines stacked closely together indicate a sharp change in depth, while widely spaced contour lines indicate a gradual decline. It’s important to learn how to visualize the structure represented by the contour lines in order to discern which areas will hold fish.
Charts provide information about the buoys you’ll come across while on the water. Simply by clicking on the buoy marker on an electronic chart, you’ll get everything you need to know—its name, its color, whether it flashes or not, and the interval between flashes. On a paper chart, this information is condensed into abbreviations, for example, on the Captain Segull’s Sportfishing Chart, the buoy outside Fire Island Inlet on Long Island is labeled RW “FI” Mo (A) WHISTLE. This means the buoy is red and white, is named “FI,” has a Morse Code flashing light and a whistle as a fog signal. The areas around buoys are often popular fishing areas. If you hear that the tuna bite is hot at the BB buoy, you’ll want to be able to recognize it on a chart so you can navigate to the hotspot.
Shipwrecks are shown with a few different symbols on nautical charts, indicating their position and whether or not they pose a hazard to boaters. The information accompanying wrecks on nautical charts includes the depth and GPS coordinates, and on paper charts, the name.
Not all wrecks will produce fish. Some have deteriorated so much over time that they barely provide enough structure to attract fish. Some have been sanded over completely. Information available through NOAA’s Automated Wreck and Obstruction Information System (AWOIS) will provide more information about the wrecks, including but not limited to the vessel name, date it sunk and survey depth.
Knowing what kind of bottom lies below your boat is critical to fishing success. While species like bluefish that feed in the upper levels of the water column may not pay much attention to the bottom substrate, benthic fish like fluke, sea bass, cod and blackfish will.
Most good charts will tell you the nature of the seabed in addition to the depth. Identifying the bottom substrate is essential to finding fish. Many predators such as fluke and stripers will patrol the areas where the bottom changes from hard to soft.