24 
Abstract — Sand seatrout ( Cynoscion 
arenarius ) and silver seatrout (C. 
nothus) are both found within the 
immediate offshore areas of the Gulf 
of Mexico, especially around Texas; 
however information is limited on how 
much distributional overlap really 
occurs between these species. In order 
to investigate spatial and seasonal 
differences between species, we ana- 
lyzed twenty years of bay and offshore 
trawl data collected by biologists of 
the Coastal Fisheries Division, Texas 
Parks and Wildlife Department. Sand 
seatrout and silver seatrout were dis- 
tributed differently among offshore 
sampling areas, and salinity and 
water depth appeared to correlate 
with their distribution. Additionally, 
within the northernmost sampling 
area of the gulf waters, water depth 
correlated significantly with the pres- 
ence of silver seatrout, which were 
found at deeper depths than sand 
seatrout. There was also an overall 
significant decrease in silver seat- 
rout abundance during the summer 
season, when temperatures were at 
their highest, and this decrease may 
have indicated a migration farther off- 
shore. Sand seatrout abundance had 
an inverse relationship with salinity 
and water depth offshore. In addition, 
sand seatrout abundance was highest 
in bays with direct passes to the gulf 
and correlated with corresponding 
abundance in offshore areas. These 
data highlight the seasonal and spa- 
tial differences in abundance between 
sand and silver seatrout and relate 
these differences to the hydrological 
and geological features found along 
the Texas coastline. 
Manuscript submitted 24 April 2008. 
Manuscript accepted 22 August 2008. 
Fish. Bull. 107:24-35 (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. 
Spatial and seasonal abundance of sand seatrout 
( Cynoscion arenarius ) and silver seatrout 
(C. nothus) off the coast of Texas, 
determined with twenty years of data (1987-2006) 
Dusty L. McDonald (contact author ) 1 
Joel D. Anderson 1 
Britt W. Buniguardner 1 
Fernando Martinez-Andrade 2 
Josh O. Harper 3 
Email address for contact author: Dusty.Mcdonald@tpwd. state. tx. us 
1 Perry R. Bass Marine Fisheries Research Station 
Texas Parks and Wildlife Department 
HC02 Box 385 
Palacios, Texas 77465 
2 Corpus Christi Field Office 
Texas Parks and Wildlife Department 
5200 Ocean Dr. 
Corpus Christi, Texas 78412 
3 Palacios Field Office 
Texas Parks and Wildlife Department 
2200 Harrison St. 
Palacios, Texas 77465 
The sand seatrout ( Cynoscion are- 
narius) and the silver seatrout (C. 
nothus) from the family Sciaenidae 
are sympatric species that co-occur 
within the Gulf of Mexico (GOM). In 
the literature, the co-occurrence and 
distribution of these species has been 
noted, particularly in offshore areas 
where feeding grounds overlap (Miller, 
1965; Chittenden and McEachran, 
1976). These studies, in concert with 
previous life history data from Texas 
(Shlossman and Chittenden, 1981; 
DeVries and Chittenden, 1982) have 
provided some insight into when and 
why any distributional variation 
occurs in the western GOM. Never- 
theless, most studies of the abundance 
of these species have been limited on a 
spatial and temporal scale. Addition- 
ally, the spatial and temporal abun- 
dance of these species in relation to 
hydrological characteristics such as 
water temperature, salinity, depth, 
and bay access to the gulf through 
a channel or pass has not been thor- 
oughly investigated. 
Sand seatrout use inshore waters 
extensively but also move offshore 
seasonally to evade the temperature 
extremes of the inshore bays and to 
spawn (Shlossman and Chittenden, 
1981; Vetter, 1982). In contrast silver 
seatrout, although on occasion they 
can be collected inshore, live their 
entire lives offshore (Gunter, 1945; 
Miller, 1965). In addition to their 
distributional difference, differences 
exist in their hydrological prefer- 
ence, particularly in salinity and wa- 
ter depth, adding to the complexity 
of the distributional preferences of 
these two species (Chittenden and 
McEachran, 1976). However, a great 
deal of distributional overlap of these 
species occurs within the immediate 
offshore area, year-round (Gunter, 
1938; Sheridan et al., 1984), although 
the spatial and temporal dynamics of 
this overlap are poorly understood. 
Furthermore, information is lim- 
ited on whether the distribution of 
sand seatrout offshore correlates with 
what is found inshore (bays) (Shloss- 
man and Chittenden, 1981). Each of 
the bays along the Texas coastline 
is unique in their geological and hy- 
drological characteristics, giving rise 
to differences in species assemblages 
between the bays (Blackburn, 2004). 
