36 
Abstract — The increase in the abun- 
dance of gray snapper ( Lutjanus gri- 
seus) in Texas bays and estuaries 
over the past 30 years is correlated 
to increased wintertime surface water 
temperatures. Trends in the relative 
abundance of gray snapper are evalu- 
ated by using monthly fishery-inde- 
pendent monitoring data from each of 
the seven major estuaries along the 
Texas coast from 1978 through 2006. 
Environmental conditions during 
this period demonstrated increas- 
ing annual sea surface temperatures, 
although this increase was not season- 
ally uniform. The largest proportion of 
temperature increases was attributed 
to higher winter temperature mini- 
mums since 1993. Positive phases of 
the North Atlantic Oscillation, result- 
ing in wetter, warmer winters in the 
eastern United States have occurred 
nearly uninterrupted since the late 
1970s, and unprecedented positive 
index values occurred between 1989 
and 1995. Increases in water tempera- 
ture in Texas estuaries, beginning 
in the early 1990s, are postulated to 
provide both favorable over-winter- 
ing conditions for the newly settled 
juveniles and increased recruitment 
success. In the absence of cold win- 
ters, this species has established 
semipermanent estuarine popula- 
tions across the entire Texas coast. 
A shift to negative phases of the North 
Atlantic Oscillation will likely result 
in returns to colder winter tempera- 
ture minimums that could reverse 
any recent population gains. 
Manuscript submitted 21 March 2008. 
Manuscript accepted 5 September 2008. 
Fish. Bull. 107:36-44(2009). 
The views and opinions expressed 
or implied in this article are those 
of the author and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Biological response to changes in climate patterns: 
population increases of gray snapper 
( Lutjanus griseus ) in Texas bays and estuaries 
James M. Tolan (contact author ) 1 
Mark Fisher 2 
Email address for contact author: james.tolan@tpwd. state. tx. us 
1 Texas Parks and Wildlife Department, Coastal Fisheries Division 
6300 Ocean Dr., Natural Resources Center, Suite 2501, Unit 5846 
Corpus Christi, Texas 78412 
2 Texas Parks and Wildlife Department, Coastal Fisheries Division 
Rockport Marine Science Laboratory 
Rockport, Texas 78382 
Decadal and multidecadal climate 
variability in the eastern United 
States and North Atlantic Ocean are 
sensitive to natural climate variabil- 
ity associated with the North Atlantic 
Oscillation-Arctic Oscillation (NAO- 
AO; Okumura et al., 2001). Ocean- 
atmosphere interactions between 
sea-level atmospheric pressure and 
sea surface temperature have resulted 
in periods of intensified climate vari- 
ability at 50-80 year cycles (Enfield et 
al., 2001; Cronin et al., 2003). Inter- 
annual fluctuations in fishery catches 
that are linked to climate variabil- 
ity occur in many marine systems; 
the best examples are found in the 
North Pacific Ocean and Bering Sea 
(reviewed in Roessig et al., 2004, but 
also see Perry et al., 2005; Zeeburg et 
al., 2008). Huge increases in fish pop- 
ulations in the North Atlantic Ocean 
(“fish outbursts” in Hare and Able 
[2007]) have been linked to decadal- 
scale fluctuations in both atmospheric 
pressure gradients and water temper- 
atures. Examples include dramatic 
fluctuations in gadoids (Sirabella et 
al., 2001), sciaenids (Hare and Able, 
2007), pleuronectids (Sullivan et al., 
2005), and in the size of fish assem- 
blages — the latter caused by changes 
to the estuarine ecosystem (Attrill 
and Power, 2002). Changes in fish 
populations along the west coast of 
the Americas have also been related 
to shorter time-scale climate varia- 
tion associated with El Nino patterns 
(Arcos et al., 2001; Smith and Moser, 
2003). Few studies have examined 
the link between ecosystem struc- 
ture, fisheries production, and cli- 
matic forcing along the southeastern 
coasts of the United States (includ- 
ing “the Gulf” of Mexico, hereafter 
referred to as “the gulf”), but those 
that have (Parker and Dixon, 1998; 
Sullivan et al., 2005) generally iden- 
tify warmer winter temperatures as 
the cause of distributional changes in 
fish populations (Oviatt, 2004; Pres- 
ton, 2004). 
The gray snapper (Lutjanus gri- 
seus) is a temperate and tropical reef 
fish, commonly found in marine and 
estuarine waters in the western At- 
lantic Ocean from Florida through 
Brazil, including Bermuda, the Carib- 
bean, and the northern Gulf (Ran- 
dall, 1968; Rutherford et al., 1989a). 
Although the young of this species 
have been collected as far north as 
Cape Cod, Massachusetts (Denit and 
Sponaugle, 2004), they are most prev- 
alent in continental and island shelf 
waters in the vicinity of south Flori- 
da, Cuba, and Venezuela (Allman and 
Grimes, 2002). Larvae and juvenile 
fish are common inshore in seagrass 
and mangrove nursery areas and 
have been even found in freshwater 
estuaries. Adults are usually associ- 
ated with complex structures (such as 
rocky areas, coral reefs, pilings, and 
docks) and mangrove sloughs (gain- 
ing them the often-used local name 
