Eggs and larvae were reared in fresh water after stripping and fertilizing ripe ova from known brood fish found spawning in April and May in tidal fresh water. The early developmental stages and transforming postlarvae and very young fish were also identified in ichthyoplankton taken in tidal fresh and slightly brackish water up to 8%. salinity.
The eggs are spherical (except for those with an attachment disk), markedly adhesive, transparent to translucent, relatively small, demersal, and undergo meroblastic cleavage. Average diameters and ranges were: (a) unfertilized egg, 0.79 mm (0.70–0.89); (b) fertilized and water-hardened egg, 0.92 mm (0.75–1.09); (c) yolk mass, 0.70 mm (0.50–0.89); and (d) oil globule 0.32 (0.20–0.44). Nothing unusual was observed in the embryonic development of white perch eggs.
Prolarvae hatch in about 48 hours at a water temperature of about 63 F. They averaged 2.6 mm (range, 1.7–3.0) total length (T.L.), and are transparent and relatively undeveloped, lack a mouth opening, have non-pigmented eyes, and display a greatly enlarged yolk sac and oil globule beneath the head. Early postlarvae occur when the yolk and oil globule are absorbed at about 3.8 mm T.L., at which size a visibly toothless mouth is developed, and the eyes become pigmented. Sparse pigmentation occurs on the head, oil globule, posterior yolk sac, and edges of the dorsum, ventrum, and hind-gut. All larvae hatched in the laboratory died at a size between 4.0 and 5.5 mm T.L. before transformation took place. Transforming postlarvae at the critical stage between 6.0 and 8.0 mm T.L. have not been reared in the laboratory or identified in the plankton.
Late-stage postlarvae, identified from plankton samples, transform to very young fish between 7.0 and 9.0 mm T.L. The heterocercal tail with projecting urostyle assumes a homocercal outline and lepidotrichia are evident in the fins between 10 and 12 mm T.L. Preanal (12) and postanal (13) myotomes correspond to the adult number of vertebrae. As metamorphosis proceeds, the fish become less transparent, pigmentation is more profuse, and they assume an early serranid shape.
Very young fish are relatively short, with a deep caudal peduncle, and usually lack preopercular spines. The third anal spine develops from the first terminally-segmented softray between 20 and 30 mm T.L.; at smaller sizes they possess two anal spines and can be misidentified as a percid fish. Squamation begins between 20 and 25 mm T.L. after which size most of the adult meristic numbers are attained The profuse but uniform dorsolateral pigmentation is developed at this size interval.
The early stages of white perch were compared critically with those of the striped bass, which is larger at similar stages of development. Important differences in the eggs, prolarvae, postlarvae, and very young fish were found between them. Further data is given that will allow separation of these two species from the early developmental stages of other species that may occur in ichthyoplankton samples collected in the upper estuaries of the Chesapeake system.
A historical review of sporadic large-scale artificial propagation and stocking of yolk-sac fry of white perch from 1875 to 1936, largely in northern Chesapeake Bay, suggested that no perceptible benefits took place in the commercial catches three to six years later when they would have become 6 to 8 inches long and exploitable.