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Bass Biology
Spawning Again!
By Wayne Gustaveson

January/February 1998

Hey! It happens every spring, thank goodness. The snow finally melts. The ice breaks on the pond. The days get longer and it is time to do some serious fishing. What a relief to get out of the house on that first warm day and just enjoy being OUT once more.

While you are on the boat or pond bank enjoying the therapeutic solar rays, the bass down below are doing exactly the same thing. They jerk off their winter coats and blink as they emerge from the dark hole they have been hiding in all winter and head for the shallows. Fish are much more attuned to the seasonal change in weather patterns than humans. Their comfort is derived directly from their surroundings so even the most subtle change is detected.

Fish first become aware of impending spring by the changing angle of the sun as the seasons change, bringing first a few more minutes and then a few more hours of daylight. Sometimes Phil, the weather guy, has the weather so fouled up that we think it is the dead of winter in early March. But our finny friends the fish know that the strength of the sun is increasing and longer days mean it will soon be time to spawn.

Fish spawning behavior is hormone driven. Flowing juices cause different behavior in male and female bass. Males are nest builders. They need a place to entertain before they can even think about scoring with a great green fish lady. The big green mommas are not nearly as retentive about the whole scene. They are content to move near the spawning shallows while still eating tasty small sunfish in the brush or crayfish on the rocks. Males cannot really be bothered with eating because first they have to find the perfect spot to build. Then there’s nest construction, and then nest maintenance following windy turbulence and WOW, before you know it, it’s time to spawn.

The actual spawning event is temperature driven. Bass are really adept at finding even the slightest change in temperature. It’s not brain surgery. You may recall swimming in really brisk water and then encountering a warm pocket that allows half of the goose bumps to melt. Same thing for bass. They can feel the warmer temperatures. Bass males seek out a shallow, rocky area that is warmed by direct sun rays for the biggest part of the day. Some areas are really prime, pent-house, executive suite type locations. Guess who gets first choice? It is not the freckled faced two year old. Big, dominant males are there first and get first choice of the spots. Smaller males are then allowed to take what’s left. The size of the male determines how much space he needs in his personal comfort zone. An extremely aggressive male may guard a 20 foot radius around the pad, or nest. Average sized males usually require 12 feet to feel comfortable. Maybe that first year male is happy just to have a rock to call his own and not be chased.

Rapid warming causes a flurry of nest building. Ideally, water temperatures will break out of the 50’s and warm to the 60’s on a calm spring day. The dominant male with the warmest nest spot spawns first but his contemporaries reap the same environmental rewards and get with the program within a day or two. Continued warm, calm weather means that the first spawn of the season happens all over the pond or lake in a 3-5 day period. Males will actively spawn for two days. Then for the next week they exhibit some of the most amazing behavior seen in nature.

Nest guarding transforms the normally shy black bass into "Conan the Barbarian". After the brief day or two of spawning with any female coaxed near the nest, he suddenly bludgeons anything that enters the protective zone. For two days to a week he attacks any fish, fowl, frog or flipper that even looks like it might get near the nest. Normal defensive tactics include ramming his snout into any intruder at mach speed. Carp, sturgeon, great white sharks, 300 pound wading anglers all get the same treatment; a bass torpedo at 60 mph…WHAM! If not deterred by the first whack he backs up and smacks again. Larger fish of all kinds are cowed by this uncommon behavior and give Mr. Mom a wide berth.

Enter the angler with his arsenal of baits. The first terminal tackle thing entering the zone gets whacked, no question. Things smaller than a great white shark may get consumed just to keep them from coming back again. Surface poppers, crankbaits, worms and grubs will get torpedoed or eaten. Mr. Mom is not hard to catch. Put him back and he returns to the nest. Next time the thing with the hook comes by he hesitates and then attacks. This time, maybe by simply picking it up by the tail and dragging it off of the nest. As time passes and hormones fade, the aggression begins to fade. Baits are pushed instead of smacked. Instead of stationing himself directly over the nest he is spooked from the area more easily. He hangs near the periphery until the boat or lure goes away. If not harassed by anglers, Mr. Bass stays with the fry near the nest for two or three weeks.

If conditions are less than ideal and an ugly spring storm causes temperatures to drop back into the 50’s the day after spawning, Mr. Mom loses interest. Conan regains consciousness and retreats to deep water and does his normal every day bass thing again. He swims and eats and sleeps. Then when the next warming period comes, the hormone surge causes him to go on back, tidy up the nest, find another lady, make bass fry and start whacking intruders once more. In a hatchery situation where fry are removed from the nest every week, I have witnessed one male that nested 8 different times and was responsible for caring for 24,000 bass fry (that’s a lot of TLC).

What about the big old hog female bass that is revered as the source of all future generations of bass? She is a nice fish but not all that important in the overall scheme of things. Males actively seek out many of the interchangeable spawning partners and drive them to the prepared nest. If not approached by a male the female will not spawn. As part of the courtship ritual he rams his chosen mate in the side (to start the eggs flowing) and then fertilizes her complement of 500-2,000 eggs. When she is done, the male finds another female and adds even more eggs to the nest. Females are able to spawn only a few of the total eggs they carry at any one time. They have to ration the available eggs over the whole two month spawning period. The ovary is never completely evacuated. In fact, females will always have a sack full of developing eggs, even in the fall. Females grow larger than males but without the battle scarred, skinny and over-protective male parent, there would be no survival of the year class of bass which provide the fish for the future. It’s a boy thing.

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