Tolan and Fisher: Biological response of Lutjanus griseus to climate patterns in Texas bays and estuaries 
41 
during recent years when unusual climate 
trends have been reported and major events 
have affected living resources and fisheries 
management (Rebstock, 2003; Woehrling et al., 
2005). The uninterrupted, 30+ year record of 
systematic monitoring within every estuary on 
the Texas Gulf coast is almost unprecedented 
in terms of both spatial and temporal coverage. 
These collections encompass a scale sufficient to 
document ecosystem-level responses to climate 
variation and may provide insight into any 
biological responses that are revealed. Analyses 
of proxy-based reconstructions of temperatures, 
with particular emphasis on the Atlantic Coast 
region during the past millennium, have shown 
patterns of multidecadal variation in sea sur- 
face temperature with a distinct oscillatory 
mode of variation at an approximate time scale 
of 70 years (Delworth and Mann, 2000; Cronin 
et al., 2003). Embedded within this climate 
signal is an overall warming trend on the order 
of 0.16°C to 0.21°C per decade (Preston, 2004). 
Some researchers have reported that this warm- 
ing trend accelerated during the latter half of 
the 20 th century (Hoerling et al., 2004; Zee- 
burg et al., 2008). A general trend of increasing 
water temperature was also found along the 
Texas coast, but this increase was not season- 
ally consistent. Maximum water temperatures 
during summer months were relatively stable 
over the study period, whereas increases in 
winter minimum temperatures were seen to 
drive this mean increase. Seasonally nonlinear 
temperature patterns have also been reported 
in other estuarine systems (Nixon et al., 2004; 
Hare and Able, 2007), along with the common 
feature of warming winter surface waters. 
A link between large-scale climate drivers 
and biotic variability in the Gulf of Mexico 
has been attempted in only a few studies. To- 
lan (2006), however, did find a connection be- 
tween short-phase NAO-AO forcing and Texas 
estuarine salinity patterns, and the greatest 
influence was found in three mid- and north- 
ern coast estuaries (Guadalupe, Lavaca-Colo- 
rado, and Sabine-Neches). An abrupt transi- 
tion to positive phases of the NAO-AO index 
(wetter, warmer winters along the eastern 
U.S. coasts; Rajagopalan et al., 1998) occurred 
during the late 1970s, and the atmosphere 
generally remained in this positive mode through the 
2005 winter season. During this 25 year interval, 
substantial negative phases of this pattern appeared 
only four times (1985, 1987, 1996, and 2001). The 
height of the current positive phase of the NAO-AO 
index (values from 1989 through 1995 represent some 
of the largest positive values ever recorded) tempo- 
rally corresponds to the onset of the increase in gray 
snapper populations along the Texas coast. Zeeburg 
et al. (2008) identified a similar NAO-AO linked bi- 
ological response in mid-1990s in the east central 
Atlantic Ocean off Africa. Their study showed that 
the response of Spanish sardine ( Sardinella aurita) 
to changes in surface water temperatures (namely a 
surge in population numbers) began in 1995, around 
the same time that the temperature-mediated biologi- 
cal effects on gray snapper were seen in western Gulf 
of Mexico estuaries. 
Recent increases in gray snapper appear to follow 
the “thermal opening of the estuary” theory that Hare 
