Understanding Fish Behavior
Dale Thorburn and Stan Kulak
Facts by U.S Fish and Wildlife Fishery Biologist
Quotes by accomplished anglers
D Keating , C Porter , E Lantiagene
Studies by a number of Universities
Quotes by lakeporttexas.com
Fish have a brain the size of grass seed if not smaller. We have a huge brain and try and out-think a fish and mess it all up.
We are going to try and put the facts as simple as possible.
During the fall and winter there is no thermocline once the surface water get below 45 degrees. So the big fish and little fish have to work for scattered bait fish and smaller fish to feed on.
Simply put, the thermocline is a thin layer of water in a lake which is sandwiched between the upper layer of water ( the epilimnion ) and the lower, colder layer of water ( hypolimnion ) . During the summer months, surface water is heated by the sun and the surface temp could be 80 degrees or more. The floats over a layer of colder more denser water called the hypolimnion. Now between these 2 layers you have a thin layer in which the water temp drops fair substantially. This will be the thermocline. The temp at this level may be high 60s and up in about the middle of spring.
The main thing to remember is when stratification is evident the fish will be found in greater concentrations within the thermocline. This is because the upper layer has too much light penetration to be comfortable for the fish, andnd the hypolimnion is usually void of oxygen. This leaves the thermocline where the light is just right and the oxygen is comfortable for the fish.
But once the surface water starts to warm the thermocline starts to form, this is where the plankton and algae is located which draws lake shrimp to feed and then the shad or other shrimp feeders come to feed. Then the chain of events start. the aggressive big fish are there to feed and will hang 10 or 15 ' above the thermocline and below.
Picture a big fat guy, he will not fenture far from the refrigerator and that is the same with big fish. Fish will come out of their comfort zone to feed but just like the big fat guy they retreat back to their comfort zone.
Another author once stated that you only have to fish the top 40' of water in the am and late pm, thats were the bait fish are. Well it's true in parts. Not all the bait fish have come up, only the ones that are being chased by jaws have come up and try and walk on water, I am sure a number of you have seen this.
Winter there is usually no stratification on most lakes. As a result the water will undergo a temporary oxygenation process.Strong winds, feeder streams feed the lake with spring rains and plant growth begins. So under normal conditions the deeper end of a water body will be quiet saturated with oxygen. Since the lower layer is much colder than the surface ( average 10 to 25 degrees difference the deeper portions can retain the oxygen molecules sent it's way during the pre- stratification.
You will always better your chance of catching quality fish by, fishing 10 to 15 feet above and below the thermo. Now in that thermocline there are several comfort zones, for different species of fish. As follows
King Salmon----------------------42-48 degrees this is there active range
Coho salmon --------------------45-58 " " " " "
Rainbow -------------------------42-61 " " " " "
Mac's ---------------------------- 42-48 " " " " "
Mr. Brown -----------------------47-65 " " " " "
Kokanee -------------------------48-56 " " " " "
How you approach the lake will determine how many fish you catch. Always approach the water with a goal in mind. Clearly understand the behavior of your target species.
Of all the species in a lake the Rainbow Trout is the most nomadic and unpredictable. They maybe in one area for several days and then disappearing over night.
There general migration patterns and timetables can be followed by experienced fisherman. But you must realize that of all the fish, they will determine when and where the game will be played.
Rainbow Trout have a wide range of temperature preferance. Their preferred range is wide, from 42-61 degrees. During the spring months 42-44 degree water is the strike zone.
Then in the summer months they may be caught in the upper portion of the thermocline 56-62 degree water.
For you Lake Oroville fisherman, the Coho is the number one table salmon. And to categorize the ideal game fish for it's fighting ability, abundance and catchability. This guy is the finalist.
The Coho is very forgiving of the angler error and his technique. They are aggressive feeders and easy to fool into striking. The Coho is a highly social fish, chances you have one then there is a school close by.
Coho seek 48-54 degree water. They will move to the upper layers of the water column. They will be found in warmer water than the KING.
Spring Coho tend to follow the surface layers and can be found in the top 20' of water. During the summer months. They will descend with the thermocline. You will find them in and feeding just below the thermocline. They will suspend in the summer months 40-80' over deeper water 100' plus.
Some schools will follow parallel to the shoreline, seeking to stay in the bottom layers where cold water intersects the bottom.They will follow a similar pattern year after year.
Using Lures that have a lot of flash, zip and bang will draw the most strikes. Historically flies such as the Grand Slambuck tails and dodgers are the top producers.
Orange and silver Needlefish, green and pink hootchies and Kokanee Killers all will catch Coho's.
Kokanee Salmon KING Salmon
The Kokanee is probably the most sought-after fish in California. Anglers spend thousands of dollars on boats, rods and reels to catch the smallest of the salmon family. The Kokanee demands respect for it's size, and is ranked with the Coho salmon. In as much as quality, abundance, catchability. They are not only sought-after by anglers but also by the predators of many lakes, such as the Browns ,Mac's and the King Salmon. For it's size there is no better fighting fish per-ounce. Once you hook the soft mouth Kokanee and he see's the boat , he will be like the little engine that thought he could. The biggest mistake anglers make on him is to try and horse him in.
Kokanee find thier comfort zone in the 48-56 degree water of the thermocline. He is a filter feeder and feeds on lake shrimp and plankton. The Kokanee is a midwater dweller, following the thermocline for his dinner. They are a very social fish and school in numbers and size. You will find him 5 to 10' below the thermocline.
Tackle for the Kokanee will not put you in the poor house. Lures for Kokanee run the gamete from needle fish, bugs, wedding rings, hochies , apaxes, squid, to worms and corn. Dodgers water melon or pink uv. 4 to 6 ". Color choice will vary with the time of day and the depth the fish will sink to.
Be sure not to forget your shoe-peg corn. Most anglers buy scents to soak their corn in. But the simplest and fastest is maple syrup. Be sure to put a couple of kernels on the hook.
Kokanee have very soft mouths and your fishing equipment should allow for this. A limber fishing rod a light drag on your reel and a rubber snubber can make the big difference over the number of boated fish. If you are having a day where there are too many LDR's (long distance releases), you need to evaluate these three things. Six pound line is the preferred for Kokanee although in Lakes where larger species of fish like Mackinaw exists, I would step up to eight pound test. It is common to take a hit from larger fish on a Kokanee lure.
The mighty King Salmon, he is one of the hardest fighting fish in fresh water. Fights with the King can go on as long as fifteen minutes, on light line. He has incredible endurance. The thrill of the fight is unmatched. With his dorsal fin cutting the surface of the water, the angler prays he will not take another run.
The King salmon with thier huge metabolism, needs a large food source to survive. They are a very aggressive predator who prefer much deeper and colder water. Ther peak feeding range is a chilly 42-46 degrees.
During low light periods some kings will move up into the thermocline to feed. As light penetration increases, the kings will usually drop back to the colder water. Kings along with MacKinaw will be the deepest in the water coumn.
Water temperature is the dominant key to locating and catching Kings. Kings are a school fish and will school by size. They will mix with other species of fish. They spend much of their lives roaming deep open water, most of the year. They will be found suspended from 50-150' over 180-500' of water. Kings love structure, the back of a underwater hill , a shallow spot in the bottom of the lake.
Mature Kings spawn between Sept and Nov, a month or two prior to entering their spawning location they will stage off shore of their stocking site.
Brown Trout (also known as German Brown)
Is the fish of legends. They are highly efficient predators and will grow vary large. The brown is a highley regarded trophy amongst anglers. There are several strains of browns.They are a shallow water fish that spend the majority of their time, close proximity to the shore line.
They have a higher temperature tolerance and will aggressively feed in warm water more than other species. Browns tend to be homebodies and less migratory than other species. Locations that produce browns will usually be productive year after year. There are exceptions though. There are Ocean run Browns in Oregon and on the East Coast regions. It is a rare occurrence and the fish are sometimes caught when the come back to spawn.
Like their cousins the Rainbow Trout, Brown Trout can tolerate a broad range of temperatures. Brown Trout are vary structure oriented. Successful anglers know you must fish near bottom to consistenlly locate fish. Studies suggest that browns perfer 47-65 degree water, and there peak feeding range 54-62 degrees.They are opportunistic feeders and will venture out of temperature to feed.
If you want to catch big browns, you must fish for them. They are not commonly found in the same water as other species.
One key to success in the spring is to use light line for clear baits. Locating pockets of warmer water will lead you to success.
As the lakes warm , in the summer months browns will move down to 54-62 degree water were it intersects bottom.
During the pre-spawn period they will move in and hold in the vicinity of their spawning destinations. They will begin staging for their spawning runs earlier than other species.
Browns are said to be light sensitive and that they will feed in the dark of the early morning or at sunset hours. The truth is that you can catch browns at most any hour of the day if you know where to find them. Early morning they do move in to the shoreline and forage before the sun starts to warm the shallow water. That's where long line trolling a lure 200 to 300 feet behind the boat and in close to the shoreline can pay off. A planer board can be a huge asset fishing the shoreline because it won't spook the fish as much as the boat will. The speed of your troll should be somewhere between 2.8 mph and 3.4 mph. You need to have your rod in hand and pull the lure toward you and then ease it back out and then repeat this motion over and over. This is called ripping. It causes the fish to aggressively give chase. The rip of the lure triggers the strike. With your fishing rod in hand you increase your odds for catching dramatically compared to fishing from a rod holder.
Later in the morning the browns will move to deeper water. Usually between 30 and 40 feet where they will find cover in rocks and tree stumps or falls. This is where your lead core, divers and downriggers and deep diving baits will come into play. Your lure should be set to be skimming right along the bottom. Bumping bottom is what the bill of your Lure should be doing. Yes! You will get snagged and yes you will lose a lure now and then. It's frustrating but this is the price of catching big browns.
Many is the time the shore angler can be brown productive with a bobber and a suspended inflated worm. Walking the shoreline and casting lures with a spinning outfit can also be very productive. Especially just before sundown. I favor spoons like crocodiles, kastmasters, Thomas boyants and goldfish.
Boat motors will spook fish because they make noise, create cavitation and send out vibrations. Stealth is mucho importante when fishing for Browns. The electrical displacement your boat puts out should also be checked. If the voltage is high, you should clean your zinc anodes and retest. I've found that a mixture of Alumiprep and water cleans them with just a spray from the bottle. Correcting excessive electrical leakage will help to improve your catch results.
Your Minn Kota Electric trolling Motor is the best stealth propulsion system you can have for shoreline trolling. It eliminates almost all the deficiencies listed above.
I like to call the Brown Trout the freshwater Barracuda. Their teeth are like razors and can do a lot of damage. Use care when removing the hook. One bit my thumb a few years ago and I am very cautious with them now.
The kamloop trout ( 100,000 ) are stocked in a number of California lakes. The water temp they love is 48 to 53 degrees. Most anglers who hook up a Kamloop think they are Rainbow Trout.
(Oncorhynchus mykiss kamloops)
Kamloops trout have bright silver bellies and sides and are either blue or green on top. Coloring can vary depending on habitat variables, such as water temperature. They have small and v-shaped spots everywhere but the belly and head, with a few rounded spots on the top of the head and behind the eyes. The chin and lower jaw are usually black. They are the largest of non-migratory rainbow trout and have muscular, elongated bodies. Their heads are longer and wider than other types of rainbow trout.
Kamloops trout are native to lakes in the southern interior of the British Columbia. They have been transplanted widely, with the greatest success occurring at sites with similar conditions to their native lakes and streams such as Idaho, Montana, Pennsylvania, California, Oregon, and Colorado.
Kamloops trout prefer the still water of lakes and reproduce in the lakes' feeder streams. They can survive in a large range of temperatures, from the frigid water of icebound lakes in winter, when they virtually hibernate, to the warmer waters of summer. Like all rainbow trout, they prefer clear, clean water.
Kamloops trout predominately eat invertebrates, fresh water varieties of shrimp, snails, worms, and leeches. They eat tail up, rooting around in the weed bottom, leaving small depressions behind in the chara weeds and marl patches. They feed most often at dawn and dusk, but they are opportunistic and will feed at any time if presented with easy prey.
Kamloops trout breed in the spring. At three to four years old, the fish make their way up the feeder streams of the lakes they occupy as adults. Female Kamloops trout release their eggs at the same time the male fertilizes them, in beds of loose gravel. In most cases, adults die after spawning, but not always.
The spawning streams in south central British Columbia used by the Kamloops are about 9 F cooler than most other spawning streams around the rest of the world. Although the eggs may be raised in slightly warmer temperatures, studies show these cooler waters are responsible for the physical characteristics of the fish.
Mackinaw Trout (Salvelinus namaycush)
Most people from the North East call it a Lake Trout. Californians call it a MacKinaw Trout. No matter what he is called , he is the mythical trout from lakes of Canada and the Northern United States . This colorful monster of the deep, has had anglers dreaming for years. With imaginations running wild, of how to land him. He has an almost fictional existence , rarely seeing the light of day.
Self-sustaining populations of lake trout are present in Lake Tahoe, Fallen Leaf Lake, Stony Ridge Lake, and Donner Lake, all of which are in the Truckee River drainage.
Mackinaw have recently been introduced into other waters like Stampede Reservoir, Bullards Bar Reservoir, Folsom Lake, Bucks Lake, Hell Hole, Caples, Jenkinson and Oroville.
They were brought here from Michigan in 1894. It has not been widely distributed because of its tendency to feed upon other trout. It is sometimes blamed for the disappearance of the Lahontan cutthroat from Lake Tahoe.
The State Record: 37 pounds 6 ounces (Lake Tahoe, 1974)
(World Record - 72 pounds 4 ounces)
The Lake Trout is easily identified by its forked tail and the white spots on the upper part of its body. Its belly is white.
MacKinaw do grow to a massive size . They are slower at growing than other species but their life span is longer. They have been known to live up to 25 years. MacKinaw prefer cold water and their ideal feeding range is 44-48 degree water.
When the water is cold from the top to the bottom during the spring and fall. You can find him anywhere from the surface to the bottom. Once the lake starts to warm MacKinaw will usually be one of the deepest gamefish in the water column. They are structure oriented fish. Bottom structure such as drop-offs , humps , rocky hills will often be the place to locate both suspended and bottom hugging fish.
MacKinaw will spawn in the fall and they will drop their eggs in the gravel and rocky crevices. There are several different strains of MacKinaw. During the spring months, some of the biggest MacKinaw of the year will be caught from the surface. They are known to retreat to waters below the thermocline and suspend over deep open water as well as orient themselves tightly to the bottom.
Todays color fish finders can make Macks lying on the bottom stand out while other Macks will look like they are standing on their tails with their nose almost vertical as they watch for prey to swim by. They are fierce eaters and when caught they have been found with 3 and 4 fish in their gut. Once they have gorged themselves they will descend to the colder bottom waters where they will rest and digest for days. That's not to say that they are to full to not strike at your Lure. In Lake Tahoe Macks will be found at 190 to 200 feet but they have been recorded as deep as 1300 feet. To fish Tahoe your downrigger should have 400 feet of 150 lb. test cable on it.
Suspended and bottom oriented Mackinaw can be caught with downriggers, wire line and vertical jigging. Some tackle to use is dodgers and flies ,spoons, stick baits, and jointed Rapalas. J-Plugs and large Flat Fish or Quick Fish do well also. Most pro's will recommend using a fish scent but the best bait is the live minnow behind a Dodger. That's legal only in Tahoe, Donner and Fallen Leaf Lakes. The minnows have to be caught and used in the same Lake you are fishing.