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Fishery Bulletin 110(1) 
been tagged and released by the other study during that 
same month. Additionally, three additional loggerheads 
that were previously tagged and released by Van Dolah 
and Maier (1993) were also recaptured in September 
1991 by Dickerson et al. 1 In contrast, only eight (3.6%) 
of 220 loggerheads tagged after collection in the ship- 
ping channel during 2004-07 were recaptured during 
this study, four of which were recaptured within the 
same 2—10 day sampling period. During 2004-07, re- 
captures of loggerheads tagged in a previous year oc- 
curred in spring when total loggerhead catch was also 
greatest, similar to trends reported by Van Dolah and 
Maier (1993) and Dickerson et al. 1 
Significant variables accounted for 45% of model devi- 
ance, of which sampling period (outlier) and sampling 
block within the channel were most strongly associated 
with loggerhead catch. Loggerhead catch rates were 
greatest in the “D” sampling block (farthest offshore) 
and least in the “A” block (closest inshore). A clustered 
distribution with increasing catch farther seaward in 
the channel was consistent with aggregation of logger- 
heads in the “D” block throughout the Van Dolah and 
Maier (1993) survey; however, Dickerson et al. 1 did not 
report spatial clustering of catch during monthly trawl 
surveys in this channel between September 1991 and 
November 1992. Lack of spatial influence on catch re- 
ported by Dickerson et al. 1 may stem from sampling the 
center of the channel to avoid “edge effects,” whereas 
channel edges were sampled by Van Dolah and Maier 
(1993) and the present study (2004-07). Dickerson et 
al. 1 also sampled fewer (3) and longer (3 km vs. 1.5 
km) stations than Van Dolah and Maier (1993) and the 
present study; thus, fine-scale habitat differences may 
have been less discernible owing to overlap in station 
boundaries. 
Among environmental variables, only barometric 
pressure was significantly associated with loggerhead 
catch rates, notably due to higher barometric pressure 
during May 2004. Barometric pressure in May 2004 
was statistically similar to May 2007 when loggerhead 
catch rates were much lower despite targeted trawling 
in May 2007 at stations associated with high catch 
rates during the previous three years. Although some 
loggerheads foraging in oceanic habitats are reported 
to respond to changes in sea level height (Eckert et al., 
2008), contrasting catch rates under similar barometric 
pressures between May 2004 and May 2007 suggest 
that higher barometric pressures in May 2004 were 
simply autocorrelated with anomalously high catch 
rates in May 2004. High loggerhead catch in May 2004 
was more likely related to concurrent catches of horse- 
shoe crabs, a known prey item (Plotkin et al., 1993; 
Seney and Musick, 2007), which was a marginally non- 
significant model term but that also occurred at high 
and potentially under reported levels because of high 
loggerhead catch (J. Byrd, personal observ.). 
Intensive trawling in the Charleston shipping chan- 
nel during a four-month window associated with peak 
annual catch (Van Dolah and Maier, 1993) revealed 
a consistent decline in catch rate between May and 
August, but there was no interannual change except 
for catch rate in May 2004, which was an outlier. Rela- 
tively stable catch rates during the present study may 
explain why most variables were deemed nonsignifi- 
cant in (or were dropped from) the final GLM equa- 
tion. In contrast, significant increases in catch rates 
were reported for juvenile loggerheads in estuarine 
study sites in Florida (Ehrhart et al., 2007) and North 
Carolina (Epperly et al., 2007) during the first half 
of the same decade. Catch rate increases in Florida 
and North Carolina were attributed to smaller (and 
presumably younger) loggerheads than those captured 
during the present study and are noteworthy for at 
least two reasons. First, annual survival (Conant et 
al., 2009) systematically reduces cohort abundance with 
age. Second, given compensatory growth in the pelagic 
phase (Bjorndal et al., 2003) and initial neritic settle- 
ment at a fairly consistent size and age (Conant et ah, 
2009), younger cohorts should provide a more direct 
reflection of nesting success than older cohorts with 
greater exposure to natural and anthropogenic sources 
of mortality. As such, increases in catch rates in Florida 
and North Carolina during the early 2000s likely reflect 
strong year classes hatched between 1989 and 2000 
( Witherington et al., 2009), with larger loggerheads 
sampled in the present survey representing older (and 
initially less abundant) cohorts whose abundance was 
further reduced with time. Therefore, increased catch 
rates for similar sizes (and presumably similar ages) of 
loggerheads in the present study between 1991-92 and 
2004-07 suggest great potential for sustained increases 
in nesting in the region during the next 10-20 years, 
assuming stable survival rates. However, we caution 
that indefinite increases are unrealistic, given multi- 
decadal fluctuations in Northwest Atlantic loggerhead 
nesting which may be climate induced (Van Houtan and 
Halley, 2011). 
Ninety-one percent of all loggerheads possessed one 
of two dominant haplotypes, consistent with previous 
genetic studies with loggerheads captured from our 
study location (Sears et al., 1995) and elsewhere along 
the U.S. East Coast (Rankin-Baransky et al., 2001; 
Bass et al., 2004; Roberts et al., 2005). Three distinct 
nesting “populations” in the southeast United States 
are also dominated by these two haplotypes (Encalada 
et al., 1998), but with different relative distributions 
of CC-A01 and CC-A02 between northeast Florida and 
North Carolina (0.79; 0.09), south Florida (0.44; 0.48), 
and northwest Florida (0.93; 0.06). In the present study 
only juvenile loggerheads <75.0 cm SCLnt possessed 
haplotypes other than CC-A01 or CC-A02 and were 
predominantly observed in May and June 2004, when 
greatest catch rates also occurred. Concentration of 
six rare (and one new) haplotypes in June 2004 was 
statistically unique, but given the time of year and the 
rare occurrence of these haplotypes from nesting beach 
and foraging ground surveys throughout the Northwest 
Atlantic (Bowen et al., 2004), high catch rates in May 
and June 2004 did not likely result from an influx of 
transients (Sasso et al., 2006). Instead, we suggest that 
