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Fishery Bulletin 1 10(3) 
surveys, coupled with fishery-dependent sampling in 
state waters, provide a means by which to calculate age 
composition, length frequency, and condition of ncGOM 
red drum. This combination of fishery-dependent and 
fishery-independent techniques allows an assessment 
of a population whose spawning stock is largely under 
a harvest moratorium. 
Monthly red drum CPUE showed a bimodal dis- 
tribution with peak catch rates occurring in spring 
(March to April) and fall (November). These peaks in 
catch may reflect the preferred temperature range of 
this species. Red drum CPUE dropped precipitously 
from May through September, during which time mean 
monthly water temperature averaged 28°C (±0.18SE). 
During the spring (March-April) and fall (November) 
peaks in CPUE, mean bottom temperature was 21 
(±0.31SE) and 20 (±0.39 SE) °C, respectively. These da- 
ta indicate that the distribution of red drum in coastal 
waters may be temperature dependent. Under labora- 
tory conditions, greatest metabolic capacity was shown 
for red drum when exposed to near-optimum thermal 
regimes (Fontaine et ah, 2007). Equally plausible, sea- 
sonal patterns in red drum CPUE may be linked to 
temporal changes in prey availability, as demonstrated 
for red drum in Texas (Scharf and Schlicht, 2000), 
although we lack the data to further examine this 
hypothesis. Regardless of the mechanism, the bimodal 
peak in distribution determined with the current sam- 
pling scheme has implications for designing monitoring 
programs. Our data indicate the benefit of monthly 
sampling when possible and provide evidence that sur- 
veys sampling exclusively during summer months will 
not provide high enough catches to generate specimens 
for age determination. 
In contrast to the utility of bottom longlines, high 
variability in water clarity and sea conditions limited 
data from the aerial surveys. The aerial surveys were 
most useful in providing spatial distribution data. Ide- 
ally, abundances of red drum could be calculated from 
the aerial survey images; however, these abundances 
would only represent fish on the surface and not those 
found at depth within the school. Also, during the aerial 
survey, high variability in water clarity and sea state 
made it difficult to enumerate fish. Therefore, number 
of schools was the best descriptor of abundance. School 
size (area coverage) could be calculated from images 
where the lens size and altitude were known; however, 
lens angle is a significant covariate that is difficult to 
control. Logistic difficulties with aerial surveys and 
the fact that the survey produced no length or age es- 
timates lead us to question the utility of these surveys 
in generating long term abundance indices. 
Age composition of the red drum collected by fishery- 
independent sampling indicated that older age classes of 
red drum are present in the offshore population of Ala- 
bama and Mississippi. Red drum younger than 24 years 
old were present in much higher frequency than 25 + 
year-old fish. The age frequency distributions of 6-24 
year-old fish was relatively constant with an average of 
4.0 (±1.3%, 1 standard error) in each age class. In con- 
trast, fish older than 26 years were present in low fre- 
quencies (0.7 [±0.4%]) per age class. Fish 25 years old 
at time of capture would be assigned to annual cohorts 
between 1983 and 1985 and therefore subject to fishing 
pressure prior to the federal moratorium (1987). Our 
findings agree with previous work conducted in Florida, 
where the distribution of adult red drum sampled with 
purse seines showed that fish before the 1984 year class 
were rare (Murphy and Crabtree, 2001). 
Further evidence for the effectiveness of the mora- 
torium was provided by the elevated frequencies of 
the 1991 and 1992 year classes. Red drum recruit to 
the offshore population between the ages of 3 and 6; 
therefore, the year classes in 1991 and 1992 would 
have been the first to recruit to the offshore popula- 
tion after the 1987 federal fishing moratorium. Data 
for the fish in year classes from 1987 through 1992 
therefore provide evidence that the moratorium was 
effective in increasing recruitment to the offshore 
fishery. Using similar techniques, Murphy and Crab- 
tree (2001) reported strong red drum year classes in 
1986 and 1989. The authors attribute the persistence 
of these year classes to periods of low exploitation 
after state management actions. These studies show 
how the effectiveness of management measures can 
be tested by fishery-independent monitoring of year- 
class strength. 
Our fishery-independent collections also allowed eval- 
uation of individual fish condition and provide insight 
into timing of red drum spawning. Condition indices for 
longline-collected fish were relatively high, with the ex- 
ception of the period after spawning. Our data suggest 
that those energy reserves stored as intraperitoneal 
fat are consumed during the energetically demanding 
red drum spawning period. In a concurrent survey of 
ichthyoplankton (January-December, 2006-10), Her- 
nandez et al. (2010) reported red drum larvae only in 
September and October. This period of larval occur- 
rence coincides with the highest GSI and lowest IPF 
indices and is consistent with a late September to early 
October spawning period. 
Although a contrast between the fishery-independent 
and fishery-dependent collections is limited because 
the ADSFR collection was not a random sampling of 
all anglers in the region, contrasting the fisheries in- 
dependent and dependent collections does provide a 
snapshot of the data that would be generated from 
future recreational surveys of red drum above the slot 
limit (i.e., fish within an allowable minimum and maxi- 
mum length for harvest, 16-26 inches in AL). The com- 
parison highlights potential differences and biases that 
are germane to monitoring a stock under the current 
federal harvest moratorium. The offshore population of 
red drum that serves as the spawning stock straddles 
the boundary between state and federal waters south 
of Alabama, Mississippi, and Louisiana (three miles 
from shore). From interviews with the 176 anglers that 
provided fish to the ADSFR, most anglers caught red 
drum in the higher salinity areas of Mobile Bay and 
Mississippi Sound and areas within a mile from shore 
