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Fishery Bulletin 108(2) 
Figure I 
Location of the sampling station used during the October 2004-October 2006 ichthyo- 
plankton monitoring survey (star symbol) and the NOAA National Data Buoy Center 
oceanographic data buoy (NDBC 42007) used to determine the 10-year (1993-2003) 
mean monthly water temperature estimates for the region (diamond symbol). 
recently, Lyczkowski-Shultz et al. 1 reported on larval 
fish seasonality and distribution for the northeastern 
Gulf of Mexico. 
Although these latter studies provided information 
on multiple species, no analyses of larval fish assem- 
blages and environmental variability were presented. 
Here we report on the seasonality and concentrations 
of larval fishes in relation to water temperature based 
on data collected during an intensive two year (October 
2004-October 2006) ichthyoplankton survey conducted 
off the coast of Alabama. The objectives of this study 
were 1) to examine the seasonal variability in ichthyo- 
plankton diversity and taxon-specific abundances off 
the coast of Alabama; and 2) to examine variability 
in the relationship between larval fish assemblages 
and seasonal changes in water temperature. These 
objectives would contribute to our overall goal of un- 
derstanding the oceanographic factors that maintain 
larval fish assemblages. 
1 Lyczkowski-Shultz, J., D. S. Hanisko, K. J. Sulak, and G. 
D. Dennis III. 2004. Characterization of ichthyoplankton 
within the U.S. Geological Survey’s northeastern Gulf of 
Mexico study area — based on analysis of Southeast Area 
Monitoring and Assessment Program (SEAMAP) sampling 
surveys, 1982-1999, 136 p. NEGOM Ichthyoplankton Synop- 
sis Final Report, U.S. Dep. Interior, U.S. Geological Survey, 
USGS SIR-2004-5059. 
Materials and methods 
Data collection 
The sampling station was located on the inner continen- 
tal shelf of the northern Gulf of Mexico, approximately 
18 km south of Dauphin Island, Alabama, at a water 
depth of approximately 20 m (Fig. 1). Ichthyoplank- 
ton sampling was conducted during monthly day-time 
surveys (n=26) and quarterly diel surveys (n- 8) from 
October 2004 to October 2006 (Table 1). All samples 
were collected with a Bedford Institute of Oceanography 
Net Environmental Sampling System (BIONESS) (Open 
Seas Instrumentation, Inc., Musquodoboit Harbour, 
Nova Scotia, Canada), with a 0.25-m 2 mouth opening 
fitted with seven (during quarterly surveys) or eight 
(during monthly surveys) plankton nets. During monthly 
surveys, six depth-discrete samples (18-15 m, 15-12 
m, 12-9 m, 9-6 m, 6-3 m, and 3-1 m) and one oblique 
sample (18-1 m) were collected during eight replicate 
tows at the study site with 202-pm mesh nets. An addi- 
tional oblique sample was collected during each tow with 
a 333-pm mesh net for a nominal total of 64 samples per 
monthly cruise. All eight replicate tows were collected 
during daylight hours, generally during a single day. 
During the quarterly surveys, a set of six depth-discrete 
samples (same depth bins as monthly survey) and one 
