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Utilizing Technology To Maximize Rockfish Results

Rockfish Trip

Maximize Rockfish Results - Rockfish Trip“It’s so easy, it feels like cheating” is the comment a friend recently made as we discussed using today’s technology to target rockfish and after giving it some thought I couldn’t help but agree. The conversation was centered around a recent rockfish trip to an area that he’d previously fished but had lost all of his waypoints for when his old fish finder crashed. “I looked up the area on my chart and when I got out there I scanned the area and found my old spots and a couple of new ones.” While this may not seem like that big a deal, it is if you consider that he found more spots in one day than he’d found the several years he’d spent fishing the area with using outdated technology.

Let’s take a look at what’s changed. This shot shows what a rockfish area off the Coronado Islands looks like on the basic charts that come with most fish finders. While it shows different depths and contour lines, it doesn’t offer any secrets as to where to start looking for fish.fullsizerenderThis shot shows the same area using the Navionics+ Sonar Charts. The contour lines clearly show canyon edges and points that are likely to hold fish. I’ve indicated depths on the chart to illustrate the different depths and to show likely zones to investigate at each of those depths. Better yet with the ability to record and upload sonar logs to the Navionics website, these contour lines will be further refined once you’ve spent some time fishing the area. Updating your chart with your recorded sonar logs is as easy as removing the chip from your plotter following the trip and uploading the recordings to the Navionics website. Four days later, you can download the updated chart to your chip.

Maximize sonar results

The second part of the technology puzzle is using the latest and greatest fish finders to efficiently cover ground when exploring a new area. The introduction of CHIRP (Compressed High-Intensity Radiated Pulse) sonar allows fish finders to get a clearer picture of things that are farther away than ever before. I recently upgraded my fishfinder to the Raymarine eS98 with a through-hull CHIRP Down Vision transducer and a CHIRP Side Vision Transducer.

This combination allows me to cover water much more effectively than with the fish finder I was running even a couple years ago.

Rockfish captured Unlike a transom mounted transducer, the through-hull doesn’t get blown out by turbulence when the boat is on plane. This allows me to get a clear picture of the bottom at any speed. There’s really something amazing about being able to mark a rock in 350-feet of water as you drive over it at 40 MPH on your way to another spot. I don’t usually run around full speed when I’m prospecting for cod spots but it is nice to be able to run around at 15 to 20 MPH without blowing out the fish finder returns.

Once I’ve found an area that I’d like to give a thorough look, I can slow down to 5 MPH and use the CHIRP Side Vision to thoroughly scan the area. I’d been using Humminbird Side Imaging on my boat for years and loved it for shallow water fishing but it only read out to 150-feet on each side of the boat so it was pretty much useless in water over 100-feet deep. The new Raymarine CHIRP Side Vision is adjustable up to 1200-feet on either side of the boat. When cranked all the way up this allows me to cover an 800-yard wide swath of water as I drive the boat in a straight line. The other day I was fishing the 9 Mile Bank in 300-feet of water and was able to find a small pinnacle that was 600-feet off the side of the boat when I drove past it. If that doesn’t make it almost feel like cheating then I don’t know what would.

navionics - Rockfish Trip

To give you an idea of how all of this technology works to help you find rockfish, lets take a look at this screen shot from my Navionics Phone App. The area in the center of the image is the rockfish spot off Marina Del Rey known as Short Banks. As you can see this is a large fairly flat area that is surrounded by steep canyons. Based on the scale in the lower right hand corner of the image you can tell that the area is probably 4 miles long by 2 miles wide. That’s a lot of potentially good rockfish territory, but in actuality very little of it holds fish.

While this particular piece of structure is unique to the Santa Monica Bay, it has the same basic characteristics of every piece of deep water structure on the coast. Before we get into how to find the fish, we need to make a couple of assumptions. First off, rockfish usually relate to structure, even if it’s just hard bottom, and areas of sharp relief usually indicate the presence of hard bottom.

By looking at the depth marks I’ve posted on the image you can see that there is a steep drop off on the outside edges of the bank. This steep of a drop off usually indicates the presence of hard bottom along the top of the canyon. If it were soft bottom, the drop off would be much more gradual, like on the bottom edge of the bank.

rockfish at the edge of the bottom - Rockfish Trip

Now that you know where to find hard bottom, you can drive out to the edge of the canyon and start using the CHIRP Down Vision to follow that hard bottom in towards the center of the bank while using the CHIRP Side Vision to scan for any larger rocks or pinnacles off to the sides of the boat. Once the bottom changes from hard to soft you don’t need to waste any more time looking and can go check another area. With the through-hull transducer you’ll be able to still look for hard bottom while running to the next spot and if you stumble across some you can slow down and use the Side Vision to scan for structure. This new technology takes some getting used to but once you get the hang of it you’ll be fishing more effectively than ever before.

Erik Landesfeind
Erik Landesfeind is BD's Southern California Editor and has over 30 years of experience saltwater fishing for a range of species in both California an...