Many factors, but mainly weather and water temperature, affect the movement of largemouth bass to spawning areas and the sequence of behaviors that follow. One challenge to a fuller understanding of this process is that most scientific data on spawning come from hatcheries where conditions are often more stable and controlled than in natural environments

The time between commencement of nest building and egg laying can vary considerably—from a day or two to a couple of weeks. Drops in water temperature after nest building delay egg laying. The male may remain on his nest, apparently convinced it’s the “right” spot, or may abandon it and build a new one after the cold snap passes.

Egg laying can be completed in just a few hours, or it may last up to 48 hours, largely depending on the ripeness of the female, her size, and her ability to release eggs quickly. A female with a large number of eggs may take longer, or she may be able to extrude more per pass. This depends on the female’s condition, based on her diet and nutrition the previous fall and winter.

Nest Guarding

Females may help guard the nest during and immediately after the egg-laying process, but may soon leave. The male is boss and bullies the female, trying to make her lay more eggs. As a result, the female may depart to protect herself. If she is still carrying eggs, she may spawn with a different male, or occasionally the same one, within 15 or 30 days when more eggs ripen.

While they’re engaged in actual laying, it’s generally difficult to interest either fish in lures. Males defend the nest before and after. Females seem most vulnerable to fishing soon after egg -laying before they depart.

The duration eggs remain in the nest under guard also varies. Sunlight and warm water at nest depth hasten the process since embryos develop faster when warmer. Eggs are normally laid between 60° and 68°F, but subsequent temperature drops can extend the hatching process.

Time between laying and fry swim-up ranges from 5 to 17 days. Nests generally have failed if there’s no production after about 15 days. But last spring I watched a 5-pound male guard his nest for 15 days before fry were evident.

The male then guards fry until his hormonally based inclination not to eat the fry wears off. Data on this aspect of the spawn are weak since hatcheries usually don’t leave males with fry, to maximize production. Field observations have seldom been specific enough to identify the behaviors of many individual males.

In our pond in central Texas, I’ve watched males escorting fry until they reached about 3/8  to 1/2 inch long. I’ve also seen 3/8-inch fry without apparent escorts (perhaps having been caught). I suspect that once a male is separated from his fry he may be unable or disinterested in returning as that motive has been steadily waning. That 5-pound male stayed with his fry for 4 days before moving from sight. This duration may depend upon both the male’s hormones and availability of planktonic food for fry to eat.

Moon Effects

Moon phase seems to affect timing of the bass spawn as well. The first major spawn typically begins just before and during the first full moon, when water temperature at nest depth exceeds 60°F. I’ve then seen additional nesting near the subsequent dark (new) moon as well as the next full moon. This sequence may then continue for another month. As water temperatures reach the 70°F range, the relationship to moon phase appears to weaken.

The main concern of late-spawning fish is finding a suitable partner, as most bass have finished this task for the year. Late-spawning males must sit on a barren nest longer while awaiting the approach of a ripe female. Or he may need to search widely for a suitable mate.

Food availability also plays a role. Bass with inadequate food supplies in fall and winter may spawn late or not at all. If springtime prey are abundant (usually not the case), a spring feeding binge may bulk up late spawners.

Ralph Manns, Rockwall, Texas, is an astute observer of bass behavior and a long-time contributor to In-Fisherman publications.