Here is some more info from SRAC.

SRAC Publication No. 200

Largemouth Bass

Biology and Life History



Spawning

Largemouth bass in the South

will usually spawn when 1 year

old, if they are at least 10 inches

long. Males select a nest site in

the spring after the water temperature

has stabilized above 60o F.

Bass normally spawn at temperatures

of 65 to 75oF in water

depths of 1 to 4 feet near shore,

but nesting has been observed as

deep as 20 feet in clear water.

There are some data, based on

induced spawning trials, that

indicate spawning is also affected

by photoperiod or day length.

The male constructs a shallow,

circular nest, about twice the

male’s body length in diameter,

by sweeping away debris. Hard

substrates such as sand or gravel

are preferred and if cover or any

form of structure is available, this

will be the area of choice. Males

normally guard the area about 6

feet around the nest. If there is an

obstruction, males will often nest

closer together than 12 feet because

they are unable to see one

another.

After the nest is completed the

male is often observed swimming

in the vicinity of the nest searching

for a compliant (ripe) female.

When a ripe female joins the male,

they slowly circle the nest, side by

side. Spawning occurs with both

fish tilted laterally so their vents

are close together. Both fish shudder

as eggs and sperm are

released simultaneously. The male

may turn and check on each

release of eggs before resuming

the spawning position.

Spawning with multiple females

is common. Females normally

release about one-half of their

eggs during the first spawn and

half of the remaining during the

second spawn. A third spawn up

to 1 month later is common.

Females average about 4,000 eggs

per pound of body weight, but the

number can be quite variable.

Reports of up to 80,000 eggs from

one female have been reported

but the average is much smaller.

Larger fish tend to have larger

eggs and therefore larger fry but

fewer eggs per pound of body

weight. Usually at spawning the

weight of eggs in females will be

10 percent or more of her body

weight. During the spawning season

the male does not eat and

many males die each year due to

their poor body condition prior to

the spawning period.

Males attempt to guard the nest

and fan the silt away from the

eggs until they hatch. If he is successful,

eggs hatch in 2 to 4 days

in the southern U.S., depending

on water temperature. The male

will continue to guard the fry

until they disperse, which may be

a period of 2 weeks or more

depending on temperatures. In

nature, most nests are lost to sunfish

predation.

Nesting success is also reduced if

the temperature drops below 60o

F. This temperature usually causes

the male to leave the nest.

Without parental care the eggs

will not hatch and predation will

be increased. The fry feed on the

yolk sac of the egg for the first

few days. At 68o F they will

develop mouthparts in about 190

hours. Fry swim up when they are

about 8 days old and begin feeding

on zooplankton (cladocerans,

rotifers, copepods). They remain

in a school, guarded by the male,

for 2 to 7 more days before dispersing.

They continue to feed on

zooplankton and add insect larvae

and fish to their diet when about

2 inches long.

Normally fry feed about every

three hours as this is the length of

time necessary for food to pass

through the gut. Adult bass are

often observed to feed after about

14 to 24 hours depending on the

size of prey devoured.

Studies have found that largemouth

bass tend to move toward

warm water in the colder months,

although this may be affected by

prey availability. In addition, most

bass will move less frequently

when water temperatures are

below 50 or above 80o F. Largemouth

bass apparently do not

learn quickly. There are some

bass in every population that are

non-learners. This may make up

the majority of the harvestable

surplus.