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John Childs

John is a full time fishing guide in Oregon, guiding from the Columbia to the Oregon Coast. John also is a writer and photographer about all things to do with fishing.

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July 24, 2013

How to Find Tuna

by John Childs

Finding fish offshore can be the hardest part of catching tuna regularly. Yes, you do need to have good fishing technique, and some understanding of your quarry, but just finding them in the big blue expanse we regularly fish can be a daunting task. This is especially true in the Pacific Northwest because our deep, cold water doesn't lend itself to fishing bottom topography the way many other tuna destinations do. Often the offshore tuna angler is fishing in water anywhere from 3,000 to 6,000 feet deep. The captain/angler who consistently makes good catches, is one who has learned to fish conditions. They have figured out how to take all the information at hand and make a quality prediction about where they might find fish and then once they get on the water are able to follow through with a plan and physically track the tuna down.

Sunrise over 80 Wides!

Many new captains just follow the fleet out, and while this can be a good way to begin finding fish, in the long run it will pay large dividends to learn how to predict where the fish might be using the tools at your disposal, and then putting these plans into action. It can feel a bit nerve racking the first few times you try this, and you can end up second guessing yourself, but again, put in the time and effort and with some resolve you should be able to begin finding fish on your own. The benefit to this is many pronged, but in my opinion the best part is you can often get away from other anglers and find some seclusion. Having a small section of ocean all to yourself can often reward you with bigger catches since you won't have the issues of other anglers trying to encroach on your hard won stops. The less the fish are driven over by other boats the more likely they are to come and bite at the back of your boat, and they are even more likely to stay with your boat if you don't have other boats buzzing by you trying to troll them up and unknowingly put your hard won stop down.

Where do you find this information, and how do you put a plan together about where to look? There are a couple of ways to find this information, and one of the first you should use is the internet. Also, meeting other captains and anglers in your port who you share information with is another great way to start assembling plans. The more you fish around certain areas, and the better you get to know other people in your port, the better the information you receive will be. Finally, learn to trust your gut when searching for this information. There are always little tendrils of truth in most everything you hear, but there will always be some intel which isn't very good, so string multiple ideas together and then trust your instincts on which path to follow.

Hooked up in the rod holder!!

Today's anglers are truly blessed by the plethora of information the Internet can bring. While it is a blessing, it can sometimes be a curse too. There are many wonderful sources of fantastic information floating around in cyberspace, but as in any pursuit, the internet does breed some individuals who are wonderful arm chair anglers, but may not give the kind of quality intel you are looking for. Regardless, if you stay with reliable sources and read the on-line chat rooms with an eye towards taking most everything with a grain of salt, the internet can be a wealth of great information.

When beginning your search for tuna on the Internet, one of the first things you should look at are SST charts. An SST is an acronym for Sea Surface Temperature Charts. These are pictures of the ocean taken from a satellite that's able to read the water with thermal imagery cameras and determine the temperatures on the surface of the sea. Since Albacore need at least 60 degrees of water temperature to thrive, this can be a major factor in where you begin your search for tuna. In the Northwest this is of major importance, and can be the limiting and defining factor on where the tuna might be, so in years where there is a lot of cold water close to the beach, finding the line where the water warms to over 60 degrees is vital. Some years, the water temperatures are above 60 degrees over much of our fishing area, and temperature breaks can become the most important factor. Temperature breaks are defined as an area where the water temperatures change at least a ½ a degree or so within a very short distance. The larger the temperature change over a fairly short distance, the more a temperature break becomes important in finding fish. SST's can be a wonderful tool in locating these breaks. In the picture below (an SST shot from Terrafin, a paid subscription service) notice the area at the 45 50, 124 50 location. (see note below ** for description of latitude and longitude numbers) It looks like within a mile or so the water temperature changes close to 3 degrees. Generally, you can find fish in temperature breaks as little as a ½ degree change, but when I'm looking on the internet I look for a 1 degree change or more as a starting point.

Terrafin Sea Surface Temperature shot of Northern Oregon

Another set of charts worth looking at, are Chlorophyll charts. These charts show how much chlorophyll is suspended in the water, which lets you know if you're looking at dirty green water, clean green water, green/blue, or blue water. While I've caught albacore in all the water- colors listed, I would always prefer finding clean water, whether it be green or blue. What I really want to see though, is a color change overlaying a temperature break.

Terrafin Chlorophyll shot of Northern Oregon

As I mentioned earlier in this article, we aren't fishing physical structure like bottom contours the way you can in areas where the fish come into fairly shallow water. Since we don't have fishable bottom structure, we have to find structure formed at the surface, and color changes and temperature breaks represent surface structure. Often, color and temperature changes indicate where two currents collide, which form current rips. This structure is important because it often pins bait at the rip itself. Baitfish can't swim against a current any faster than 1mph, so they get swept along, and when two currents meet forming a rip, the bait is pinned in between the currents. Color and temperature changes often overlay these areas, forming a virtual dinning room for the tuna. This is why finding temperature and color breaks is so important. Have you ever noticed when you're offshore and you find a color change, that you often find floating debris along this line? This is visual clue that you are looking at current break, and often the fish will be right there.

You can find free charts on the NOAA Coastwatch site, but these charts are very low resolution since you are looking at a much larger area of water. There are also pay sites like www.terrafin.com and www.ripcharts.com which have subscriptions services that give you the same information as Coastwatch, but with a much more defined area, so it's easier to find the temperature and color changes.

A side note should be added hear about bottom structure. As I've alluded to, we aren't fishing bottom structure in the way many of our East Coast brethren do since we are in such deep water. (They are often fishing in water between 100 to 500 feet deep, and occasionally in 1,000 feet.) We do occasionally have the bottom structure help us though through upwellings. If the ocean currents are flowing against some prominent bottom structure, currents can sometimes be deflected off the bottom and pushed towards the surface. When this occurs, you'll often find a steep temperature and color change, which can often be a hot spot in terms of finding fish. Whenever I find a strong temperature change over prominent bottom structure, I select this as my starting point for the following day.

I also like to check the internet chat rooms like ifish.net to see if there are any recent reports for the water I'm fishing. While GPS numbers are always a nice thing to have, just knowing that a boat was on fish NW from my port at 40 miles is all the intel I really need, especially if I have a satellite shot to look at in conjunction with the report. There are often tuna schools spread out over vast amounts of water, sometimes it's just a matter of finding the distance offshore of where they happen to be.

Have you ever noticed how the commercial trollers are all trolling back and forth North to South or vice-versa? This is because they've found there are concentrations of fish at a certain Longitude, so they concentrate along that line. It's often just a matter of finding this line, and then concentrating your search there.

It's also a good idea to start to make friends with other people that run from the same port. When you develop a good core group of guys who fish the same area, you can often start to get exact locations of where the fish have been lately. This is the best sort of intel when a friend you can trust tells you EXACTLY where they found fish over the last couple of days. Again, if you can overlay this information with a current SST or Chlorophyll shot, you've often just found where the fish are. This also plays out well on the ocean itself once your fishing, because these same friends can help spread out and look for fish and you can narrow down the search much faster with multiple boats working together to find them.

This is good time to discuss etiquette on the tuna grounds. It used to be that GPS numbers were given out freely to others out chasing tuna, but as more and more people started chasing fish, and as many of the boats had started to find ways to have live bait, GPS numbers started to be harder to come by. This happened because often someone would hear that another boat was absolutely whacking on the fish, so they drove straight to the GPS numbers called out on the radio. These boats would often troll within a long cast of the boat on a live bait stop. This will put the fish down almost immediately, and of course will not help in making friends with the boat who just had their fish disappear. The thing to realize is that all the tuna in the Northwest aren't under the one boat who is doing well. There's often fish all over the area, you just need to get into the ballpark to start catching them yourself.

Nice albacore caught off of Garibaldi

Another thing I've noticed, especially latter in the season, is that guys start struggling because they are still trying to troll tuna clones (7 Strand Clones, Eat Me Lures Lolo's, Williamson Tuna Catchers, etc.), while the boats who are doing well are fishing live bait, or they are working stops using a plethora of iron, swim baits and vertical jigs. Even without live bait you can often develop a pretty good stop by using small baitfish type lures while chumming with dead bait, while the guys trying to troll clones hardly get bit at all. This often happens because the tuna are no longer feeding primarily on squid, but have switched their diets to fin bait (anchovies, sauries, hake and a mixture of bottom fish fry), consuming mostly baits in the 2-4 inch category. They wrongly assume that the boat on the stop has all the fish under them, when in fact it's what they are using that's causing them to fail.

For these reasons it's considered incredibly impolite offshore to come any closer than several hundred yards, unless you know the boat you're approaching, and if they've invited you to come closer. Otherwise, it's imperative to stay a long way off from them.

A couple years back I was having one of those frustrating days we can all have where I was struggling to find the fish. It was late season, so the troll game was virtually over. I was trolling swim baits, but the water on the surface was cool, so I was having a hard time locating them. A friend called me into a bite he had going. I got within a ½ mile of him and shut down my motors and started vertical jigging and immediately hooked up. We ended up with a great day because I had some help, but we never even got close enough for my friends to realize I had run to their numbers. They asked me at the dock that afternoon why I hadn't come in on their stop, and I relayed that I had got close enough and had immediately started hooking fish. So with this in mind, if you hear about someone doing well, try to get there east/west number, and that's often all it takes to starting finding the fish.

So I've covered the things I do preceding a day on the water, but how do you find the fish once you've actually left the dock?

First, I have a game plan I've assembled from my earlier recon. Over the last decade the one thing I've had hammered home more often than any other factor is to trust my gut, and to stick to a plan! If you change your mind constantly, you're going to end up chasing your own tail, so resist the temptation and follow the plan!

The things I'm looking for offshore are water temp, color changes, current rips and slicks, floating debris, life (i.e. birds, whales, dolphins, etc.) and finally, the tuna themselves. I look for them in the order I've given, and when I have 2-3 line up together, it's usually time to start fishing.

The first thing I'm searching for offshore is water temp. Here I want to mention that most water temp gauges have a plus or minus of 3 degrees, so your gauge could read 2-3 degrees different than mine. I can't tell you how many times I'm catching tuna in 60 degree water, and I hear someone on the radio mention they are in 58 degree water at the same east/west number I'm at and don't think the fish are there, so they are going to keep trolling west. The fish probably are there, but they are worried the waters the wrong temp. Calibrate your gauge with a hand held temp gauge, or check with a buddy boat, and you can get a sense of how far off your machine might be reading. I've also caught fish in 56-degree water, so if there's life around, but the water seems a bit cold, don't automatically discount the spot!

When I'm running towards the spot I've determined to be my starting point, I start really paying attention to the conditions around me as soon as I've hit 58 degree water. At this point I start searching for temp/color changes, floating debris and life. I ask my crew to start actively looking as well, and we often see the fish themselves, which eliminates the need to continue looking!

Debris and life are the next two things I really want to find when looking for tuna. Early in the season, you will often catch fish without a lot of attending life above on the surface. Often when the fish first arrive, their main forage base is squid, which aren't pushed to the surface the way baitfish are, so often you won't find bird life in the area, or at least large masses of birds the way you'll find them latter in the season. For this reason, if I find floating debris or a color change, all with the right temperature, it's often enough to get me to start fishing.

I often hear people talking about how important water color is. This is something I have found to be of little importance. I've caught tuna in incredibly dirty green looking water, as well as blue water. It really doesn't matter what the water color is, as long as it's warm enough (58-60 degrees) and has bait. If those two contingencies are met, the tuna are likely there, so don't get caught up in finding clean blue water.

Bird life is another key to finding fish. This is especially true from mid-August thru the end of our tuna season. During these periods the tuna are primarily eating baitfish, which they push to the surface where birds can get at them. For this reason there is often a lot of bird activity in areas where the fish are. The two most important birds to watch for are terns and shearwaters. To really tell if the fish are present, you have to watch the body language of the birds. If you see a tern flying in a straight line, with their head up they probably aren't following fish. If you see a tern flying with their head down and excited wing beats, he's probably following tuna. If you see this same tern wheel around reel quick then dive you definitely have tuna under him. If you ever see terns diving offshore you have just found tuna.

Shearwaters are sometimes called liar birds, but they still give good clues about tuna. If you come upon a large raft of shearwaters sitting on the water and they are calm and just sitting there, there probably aren't any tuna underneath them, but they probably were there not to long ago. The tighter these aggregations of shearwaters are, the more it indicates tuna were recently in the area. When you find a tight flock of shearwaters when they are squawking and actively diving there are tuna under them. Sometimes shearwaters walk on the water. They get up on their hind feet and flap their wings as they look down. This as sure a sign as any they have tuna under them. These are often things you'll notice when the tuna are puddling on the top, but not actually jumping. The shearwaters can often help you find the tuna when they aren't necessarily breaking the surface.

Finding floating debris, especially if you've found a trash line, can be a great spot to start fishing. Whenever you find lots of debris in one area, and especially if it's formed up in a line, you've found a current seam. Often this same area will correlate with a color or temperature break as well. These are areas that deserve a good look. It's common to also only find fish on one side of these types of breaks. They'll be on the side of the break where the bait is trapped, so pay attention to where you're getting bit so you can maximize your time over the fish.

Finally, just pay attention when you're offshore. The fish themselves will often tell you where they are by jumping, puddling and showing signs on the surface. The more you watch, the more you begin to see.

Comments (7)

SharkAttack wrote 6 years ago

This is a most excellent writeup, thank you John!

onstep wrote 6 years ago

A guy can save a ton of gas by reading this over and over. Another great blog John!

capttuna wrote 6 years ago

Smart guy, for a sporty. You've got most of it figured out. why are you wasteing time guiding? Buy a tuna boat and join the pros.

crackshothillbilly wrote 6 years ago

That was super John! Thank You!

Mike-n-sons wrote 6 years ago

Thanks for the excellent post and very well done. I believe it is the same basic rules we "try" to use here in the deep waters off the Island of Hawaii.

clipfin wrote 5 years ago

Great blog, just bought my first offshore boat have been fishing with friends for years and was gathering info for next season

wildwinds wrote 2 years ago

This is a good read...thanks for the post!
Can't believe I've never read it!

This will be our 4th year of chasing tuna. We are mostly "Troll" fishers, but late in the year need more options.
When we find tuna we toss chum, circle back through. We toss chum every hook up.
Usually bang a bunch with this tactic.
We have dabbled with jigging, throwing swim-baits and such, with minor success. This year we will be making more of a concentrated effort that direction. Especially from, lets say late August on.
I have a question: on Bait Stops do you think it is necessary to shut the engine down? Or, can we let it just idle down? My boat has a nice quite low rumble when idled down & we have seen many tuna right along side & under her while gaffing hooked up Charlie.
It seems to me shutting down my main 50 miles out may not be the most prudent option if it isn't absolutely required.
I love my boat, a 2601 Striper I/O
She has never NOT fired up & runs like a champ. Still I consider a lot of things :)

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