Courtenay, Walter R. Jr.

Advanced embryos, larval and early juvenile snook, Centropomus
undecimalis, are described from laboratory reared specimens. This description
includes details of advanced embryos, changes in body shape,
pigmentation, and osteological development. Eggs ranged from 0.68 to
0.73 mm in diameter with a single oil globule. Larvae were between 1.4
and 1.5 mm standard length at hatching. The yolk sac was absorbed by
2.2 mm and adult pigmentation began to appear on the head and fins by 7.0
mm. Ossification had commenced by 5.5 mm and all bones, except the
ethmoid and preyomer, had at least begun to ossify by 21.9 mm. Illustrations
of snook eggs and larvae, including details of the caudal skeleton,
are presented to show changes that occurred during development.

A seasonal sampling of fishes was collected by seine
from the sand-gravel areas of Clam Lagoon, Adak, Alaska.
The community structure was compared to the structure
of communities described from surveys of other areas.
The seasonality of the fish fauna was examined for possible
relationships with three exogenous factors; salinity,
temperature and wind velocity. Length frequency
histograms and substrate preferences are presented for
seven species. The shallow-water seasonality of 13
species is presented. The ontogenetic and seasonal diets
of seven species are discussed.

A description of Tilapia aurea based on specimens from
Florida is presented with an updated synonomy. The
Florida specimens are compared with descriptions of
specimens from Israel. It is concluded that Florida
specimens have the same range in morphological variability
as specimens from Isreal. The experimental
work completed here indicates that Tilapia aurea
does not adversely affect native fish populations.
It is speculated that Tilapia aurea may have stabilized
the experimental fish populations by a "polyculture
effect."

Five eastern Pacific species of the genus Haemulon
Cuvier are described, their color pattern and dentition
illustrated, and a key presented for their identification.
Lythrulon Jordan and Swain and Orthostoechus Gill are
synonymized with Haemulon. Haemulon scudderi Gill, Haemulon
sexfasciatum Gill, Haemulon flavigattatum Gill, and Haemulon
maculicauda (Gill) are found exclusively in the Pacific while
Haemulon steindachneri (Jordan and Gilbert) is found both
in the Atlantic and the Pacific.