Kb. Gido et Wj. Matthews, Dynamics of the offshore fish assemblage in a southwestern reservoir (LakeTexoma, Oklahoma-Texas), COPEIA, (4), 2000, pp. 917-930
Reservoirs are relatively new ecosystems with fish assemblages that include
both native and introduced species, Spatial and temporal variability in su
ch fish assemblages is difficult to predict from ecological theory. We char
acterized the dynamics of an offshore fish assemblage of Lake Texoma by sam
pling multiple fixed sites fortnightly with gill nets from 1981 to 1984 (40
2 net-nights). Univariate and multi-variate analyses were used to quantify
(1) variation of the fish assemblage in space and time, (2) spatial and tem
poral independence of samples, (3) persistence of species associations, and
(4) correlations between the dynamics of the fish assemblage and environme
ntal conditions. Overall, depth and season accounted for the greatest amoun
t of variation in the fish assemblage in our study area. Much of this varia
tion was the result of spatial and temporal fluctuation in the abundance of
various age classes of Dorosoma cepedianum (Gizzard Shad), Morone saxatili
s (Striped Bass), and Aplodinotus grunniens (Freshwater Drum). With the exc
eption of a winter kill of the nonnative Dorosoma petenense (Threadfin Shad
), the reservoir fish assemblage differed little among years. Species assoc
iations were constant across years during the warm season but not in cold s
easons, Overall, the fish assemblage in our study area remained relatively
consistent, in spite of considerable variability in reservoir volume, turbi
dity, and temperature.