422 
Fishery Bulletin 106(4) 
(linear regression, PcO.OOl, r 2 =0.993); estimated total 
mortality outside the AR zone was Z = 1.10/yr (linear 
regression, PcO.OOl, r 2 =0.971). Therefore, fish outside 
the AR zone were exposed to higher Z than those inside, 
but the slopes were not significantly different between 
the two catch curves (ANCOVA test for equal slopes, 
P=0.232). By subtraction, F b estimates ranged from 
0.40 to 0.44/y inside the AR zone and 0.57 to 0.61/yr 
outside the AR zone. Resultant E estimates ranged from 
0.43 to 0.47 for fish sampled inside the AR zone and 
0.52 to 0.55 for fish outside the AR zone. 
Discussion 
Inshore lizardfish were nearly ubiquitous throughout 
study areas. Fish abundance was greater in summer, 
especially for smaller individuals, possibly indicating 
that recruitment to study habitats from estuarine and 
inshore habitats occurred in summer. Small inshore 
lizardfish begin recruiting from estuaries to Campeche 
Bay in the southern GOM in June and continued to do 
so until October (Garcia-Abad et al., 1999). A similar 
pattern was observed in the present study where both 
size and inshore lizardfish age were lowest in summer. 
Overall, catch-at-age data indicated that inshore liz- 
ardfish did not fully recruit to the study sites until age 
three, but the mean age of fish sampled in summer was 
Figure 3 
Frequency histograms of total length (mm) distributions of 
inshore lizardfish ( Synodus foetens) collected within (A) study 
habitats and (B) for fish sampled opportunistically in the north 
central Gulf of Mexico during spring 2004 through spring 
2005. Sample sizes ( n ) are shown for each historgram. 
slightly less than 3 yr. Fish size, as well as age, was 
greatest in high shell habitat, but density was lowest 
there. Cruz-Escalona et al. (2005) reported that adult 
inshore lizardfish in the southern GOM preferred sand 
habitat, and our data indicated a similar trend in the 
northern GOM. However, smaller fish may avoid more 
complex habitats, such as shell rubble ridges, because 
of the presence of predators or increased competition 
for food. 
Fish were larger, on average, inside the AR zone, but 
fish density was not significantly different inside and 
outside the AR zone, which may have resulted from 
the movement of inshore lizardfish among trawled and 
untrawled habitats. No direct observations of inshore 
lizardfish movement were made in this study, but in- 
dividuals are known to move 10s of km as they recruit 
to adult habitats on the shelf from inshore estuarine 
nursery habitats (Cruz-Escalona et al., 2005). Other 
lizardfishes also move significant (10s to 100s of km) 
distances (Sweatman, 1984; Golani, 1993). Further- 
more, experimental closure of areas to bottom trawling 
in Australia’s northern prawn fishery did not yield sig- 
nificant differences in lizardfish density between areas 
open to trawling and those closed to trawling because 
fish moved into trawled areas after trawling occurred, 
thus restoring high densities there (Stobutzki et al., 
2003). Therefore, the lack of differences observed in 
inshore lizardfish density in areas exposed to trawl- 
ing and those not exposed to trawling during the 
present study may have resulted from fish moving 
between trawled and untrawled areas. 
Marginal conditional analysis confirmed that 
the timing of opaque zone formation in inshore liz- 
ardfish otoliths is similar to a range of demersal 
(e.g., black drum [Pogonias cromis] and red snap- 
per [ Lutjanus campechanus ]) and benthic (e.g., 
southern flounder [Paralichthyes lethostigma ]) fish- 
es in the northern GOM (Beckman et al., 1990; 
Patterson et al., 2001; Fischer and Thompson, 
2004) and that annual opaque zones are laid down 
from November to February. Based on counts of 
annuli, the maximum longevity observed for in- 
shore lizardfish (9 years) was similar to the maxi- 
mum longevity reported for other synodontid spe- 
cies. For example, Yoneda et al. (2002) reported 
that a Saurida species from the East China Sea 
lived to 11 years and Thresher et al. (1986) aged a 
Saurida species from the northwestern Australian 
shelf to be 7 years. 
The low regression coefficient (r 2 = 0.22) of the 
von Bertalanffy growth function computed with 
size-at-age data reflects the substantial vari- 
ability in inshore lizardfish size-at-age. Hood 
and Johnson (1999) reported vermilion snapper 
( Rhomboplites aurorubens) displayed similar vari- 
ability in size-at-age in the GOM. They indicat- 
ed vermilion snapper were difficult to age, but 
their high reader agreement indicated that the 
observed variability in size-at-age was not an 
artifact of inaccurate aging. Similarly, we infer 
