inferences can be drawn from observations on aquar- 
ium-held fish and from the morphology of P. sciera and 
its relationships to species in which the Spawning be- 
havior is known. Aquarium-held males during late 
May and early June underwent an array of color 
changes in response to particular stimuli, including the 
proximity of females. The only sexual behavior on 
the part of males, other than metachrosis, was an 
observation of tail-beating by a male sitting directly in 
front of a large female. A pair of newly captured 
darters was placed in an aquarium on May 28, 1969, 
and within a few hours the female appeared ready to 
spawn, repeatedly swimming over the male and alighting 
in front of him. The male did not respond, and 24 
hours later the female had apparently lost interest. 
The presence of increased sexual dimorphism 
(larger size and darker color of male) in the spring 
suggests that sex recognition in the species is good. The 
xeneralized condition of a midventral row of specialized 
cales suggests that the male mounts the female and 
ligns his body with hers during fertilization and deposi- 
ion of the eggs in a manner similar to that of P. peltata 
ind P. notogramma. It is likely that spawning in P. 
ciera is no more elaborate than a free scattering of 
ggs over the gravel substrate, fertilization, and with 
hat, the spawning act is completed. 
DEVELOPMENT AND GROWTH 
development 
Observations of the development of egg, embryo, 
nd larval forms of P. sciera were made from June 8, 
969, when eggs and sperm were successfully stripped 
fom a pair of adult fishes, to June 19, when the fry 
ied. 
The eggs were transparent, spherical, and adhesive. 
hey averaged 1.5 mm in diameter and had a yellowish 
il droplet .6 mm in diameter. At 36 hours the typical 
mbryo, developing at 74-78°F, was 3.0 mm long. 
lidbrain and forebrain regions, optic vesicles, otic 
sicles, and somites in the trunk region were clearly 
efined. The heart was beating and body contractions 
ere frequent. No melanophores were visible. 
At 60 hours, the dusky darter embryo was 4.8 mm 
ag. The eye was heavily pigmented (black). A fin 
Id extended from the yolk sac ventrally to approxi- 
ately one-half of the length of the embryo dorsally. 
he number of somites ranged from 26 to 29. Melano- 
lores were scattered over the lower portion of the 
Ik sac. Unpigmented cells were visibly moving 
Tough the vitelline veins and dorsal aorta. The em- 
YO was quite active and had a heart rate of 140 beats 
rt minute. 
At 65 hours, the blood was noticeably pink, and 
elanophores were present along the ventral side of 
€ tail. At 84 hours, the eyes were metallic brown in 
lor, and fin buds had formed. 
At 74-78°F the darters began hatching at 90 hours 
9 
and had all hatched by 108 hours. Hatchlings (Fig. 
6) averaged 5.5 mm in total length. They had red 
blood, numerous melanophores on the ventral half of 
the body, and metallic gold eyes. In 2-day-old larvae 
the lower jaw was evident, rays had formed in the 
pectoral fins, and the yolk sac was small. At 3 days 
obvious breathing actions could be observed and at 
four days the fry were feeding on prepared food. At 
5 days the yolk sac was gone and numerous melano- 
phores were distributed along the myomeres. The fry 
died on the 6th day. 
Fig. 6. — Development of morphological features of Per- 
cina sciera as illustrated by a hatchling and a 2-day-old larva. 
The smallest specimen taken from the study area, a 
16-mm (standard length) male (Fig. 7) collected on 
August 4, 1967, and estimated to be about 3 weeks 
old, had body proportions essentially those of adult 
fish but with characteristics reminiscent of the larval 
form. The head and eyes were large, and the fins were 
small in proportion to those of the adult. Squamation 
was incomplete but well advanced, the scales having 
formed over the body except for the area to either side 
of the anterior dorsal fin, the nape, and the anterior 
portion of the belly. Pigmentation was poorly devel- 
oped, but the lateral blotches, the band around the 
snout, and spots of color in the fins were beginning to 
form. A short segment of the lateral line had formed 
in the region above the operculum but was absent on 
Fig. 7.— Juveniles 3 weeks (16 mm) and 5 weeks (26 
mm) of age. 
