40 
Fishery Bulletin 107(1) 
Figure 3 
Amplitudes of the spatial empirical orthogonal function, mode 1. Lower panel is the 
seasonal signal, upper panel is the seasonally detrended signal. Dashed line within the 
upper panel is the slope derived independently for the period before 1993 and after 1993. 
Amplitudes are nondimensional. 
Table 3 
Separate variance t-test results from a comparison of the mean size and standard deviation (SD) of gray snapper (Lutjanus 
griseus) collected with bag seines, otter trawls, and gill nets (before and after 1993) from Texas estuaries, pooled by sampling 
gear and time period. Effective degrees of freedom (df) for each test were approximated with the Welch- Satterthwaite equation; 
therefore degrees of freedom (df) are not reported as whole numbers. 
Bag seine 
Otter trawl 
Gill net 
Before After 
Before After 
Before After 
Mean size (mm) 
50.1 
61.4 
110.7 
138.9 
268.8 
308.0 
SD 
19.2 
22.8 
44.3 
49.1 
59.0 
36.3 
t-test value 
2.77 
2.24 
9.62 
df 
38.5 
16.7 
230.6 
P value 
0.008 
0.039 
<0.001 
recruitment (as evidenced by the young-of-the-year 
abundance estimates determined from the bag-seine 
collections), as well as limit the survival of over-winter- 
ing juveniles. An absence of cold winters has allowed 
for dramatic increases in the abundance of gray snap- 
per in nearly every estuary along Texas gulf coast. 
Accompanying these increases there has been a con- 
comitant increase in the mean size of gray snapper 
collected with all gear types. Separate variance t-tests 
revealed that coast-wide post-1993 collections of gray 
snapper were significantly greater in numbers (for all 
gear types) than the pre-1993 collections (Table 3). 
The exponential increase in estuarine abundance of 
gray snapper in Texas, as recorded with the fisheries- 
independent gill nets, has been confirmed with fishery- 
dependent data of population trends from nearby loca- 
tions. A time series of state-wide recreational landings 
from both Texas (primarily bay and estuary landings) 
and Louisiana (primarily nearshore continental shelf 
landings) virtually mirrors the exponential increase in 
abundance recorded with the gill nets (Fig. 5). 
Discussion 
Time series have become increasingly important in 
the studies of climate influences on biological patterns 
(Reid et al., 2001; Edwards et ah, 2002), especially 
