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Fishery Bulletin 107(4) 
by conventional tagging were places where residence 
time was short, fishing effort was low, and catchability 
was reduced. We could not compare conventional tagging 
data with ultrasonic telemetry data in our study be- 
cause the spatial distribution data from the conventional 
tags and the ultrasonic telemetry tags did not overlap. 
However, we believe movement data from conventional 
tagging were generally robust except for fish tagged 
in the NPR. A large number of fish were convention- 
ally tagged in conjunction with commercial pound-net 
operations in the Pamlico River, and many were recov- 
ered within a few days in the same or nearby pound 
nets. Such intense localized fishing pressure adjacent to 
major tagging operations likely biased NPR movement 
data, resulting in shorter mean distances moved and 
days at large than mean distances and days at large 
from other regions where fish were not tagged from 
pound nets. In light of the unusual pound-net tagging 
in the Pamlico River, movement data from NPR should 
be viewed cautiously. Most recoveries of fish tagged in 
WPS occurred in EPS, but this result is not surprising 
given that the primary WPS tagging location was near 
the dividing line between the two regions. Based on 
available information, WPS has a similar level of fishing 
activity as that of other areas of North Carolina. 
Our analyses could have been improved if fishing- 
effort data across coastal North Carolina had been 
available. Because heterogeneous fishing effort may 
influence movement results, tag recoveries have been 
standardized by regionally variable fishing effort in 
recent movement analyses (e.g., Wang et al., 2007). 
Building upon the pioneering work of Hilborn (1990), 
McGarvey and Feenstra (2002) went further and de- 
veloped a movement model that uses fishing effort or 
mortality data across space in a maximum likelihood 
framework to estimate the probability parameters of 
movement. Accurate fishing-effort data could be useful 
for future red drum tagging analyses and may improve 
both movement and mortality modeling. 
The addition of an ultrasonic telemetry method in 
this study to examine small-scale movement patterns 
of subadult red drum complements large-scale analy- 
ses that use conventional tagging. When they could be 
compared, the two different methods provided similar 
movement patterns. For instance, the high emigra- 
tion rate of age-2 transmitter-tracked red drum from 
Hancock Creek in fall months corresponded with the 
season when conventionally tagged age-2 fish moved at 
the highest rate. The direction of movement during fall 
months was also consistent for the two methods. From 
data from additional submersible receivers deployed 
both upstream and downstream of Hancock Creek (see 
Bacheler et al. [2009a] for description), we determined 
that most transmitter-tracked red drum (87%) emi- 
grating during fall months moved downstream in the 
direction of the coast (senior author, unpubl. data). 
Likewise, conventionally tagged fish in NPR also moved 
downstream toward the coast during fall months. 
Ultrasonic telemetry could also be used to relate 
smaller-scale movement patterns to environmental vari- 
ability. Because the salinity in Hancock Creek (0-10 
psu) is near the lower tolerance limit for red drum 
(Crocker et al., 1983; Forsberg et al., 1997), upstream 
and downstream movements of transmitter-tracked red 
drum may have been a physiological response to fluc- 
tuating salinities. In laboratory experiments, estuarine 
organisms have been shown to respond to changes in 
salinity with increased swimming speed and respiration 
(von Oertzen, 1984). Alternatively, transmitter-tracked 
red drum may have been following the movements of 
prey species (Bacheler et al., 2009b) that had their 
own physiological constraints. Regardless, transmitter- 
tracked red drum appeared to remain in salinities 
around 4-5 psu (Bacheler et al., 2009b), following this 
gradient up and down the creek with fluctuations in 
salinity. Our results contrast with those of Dresser 
and Kneib (2007), who showed that subadult red drum 
movement patterns in a coastal Georgia saltmarsh were 
primarily influenced by tide and time of day. The lack 
of lunar tides in Hancock Creek, in addition to much 
lower salinities, may explain this discrepancy. 
We developed a conceptual diagram to highlight the 
ways in which our conventional tagging and ultrasonic 
telemetry data helped elucidate several critical aspects 
of red drum life history and ontogeny (Fig. 8). Spawn- 
ing occurs in late summer (Barrios, 2004; Luczkovich 
et al., 2008), and fertilized eggs are advected upstream 
where they eventually hatch into pelagic larvae and 
settle to benthic nursery habitats during fall (Bacheler 
et al., 2008b). Age-0 to age-3 red drum are found in 
upper estuarine environments, but we have shown that 
each fall a portion of both age-1 and age-2 cohorts move 
to high-salinity coastal waters (Fig. 8). It appears that 
some red drum remain in upper estuary habitats until 
age 3, the age at which the last remaining red drum 
move to coastal environments. Subadult red drum in 
coastal environments join the adult population after 
maturity at age 3 or 4 (Ross et al., 1995). We have 
also shown that adults overwinter on the continental 
shelf and some move westward into North Carolina 
estuaries, whereas others move northward to the lower 
Chesapeake Bay or coastal Virginia and Maryland dur- 
ing spring, and back east or south during fall months. 
The large proportion of conventionally tagged adults 
recovered near their tagging location in summer months 
indicates a return to specific spawning areas each year. 
We could not eliminate the possibility that some adult 
red drum remain in continental shelf waters year-round 
and spawn on the shelf or in passes or inlets, as has 
been observed in another study (Murphy and Taylor, 
1990). Therefore, the arrows in our conceptual diagram 
highlighting the seasonal movements of adult red drum 
into the estuary were dotted to acknowledge this un- 
certainty. Taken together, these movement results have 
direct implications for the use of temporal and spatial 
management tools and also for the scale at which man- 
agement and assessment should take place. 
Assessment of North Carolina and Virginia red drum 
together as one stock is justified by tagging data. Sub- 
adult red drum tagged with conventional tags in North 
