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Fishery Bulletin 1 12(2-3) 
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Figure 4 
The mean (dashed line), median (solid line), 5-95% percentiles (box), 10 th 
and 90 th percentiles (whiskers), and outliers (dots) of gonadosomatic index 
(GSI) values for Hickory Shad (Alosa mediocris) collected during the pre- 
spawning and spawning periods during February-May 1996: (A) females and 
(B) males sampled from the Albemarle Sound as part of the North Carolina 
Divison of Marine Fisheries Independent Gill Net Survey and (C) females 
and (D) males from the Roanoke River sampled as part of a gillnet survey in 
the Roanoke River National Wildlife Refuge and from a recreational fishery 
at sites near the city of Weldon, North Carolina. 
Age analysis, otolith back calculations, and mortality 
estimates 
The 57% agreement between scale and otolith ages in 
our study in the Albemarle Sound-Roanoke River wa- 
tershed is similar to results reported by Harris et al. 
(2007), who found a 57.3% agreement for fish from St. 
Johns River; 96% of the ages were in agreement of one 
year. Our study found no more than 2 years disagree- 
ment for any given fish. Kornegay (1977) reported a 
similar agreement for Alewife from Albemarle Sound, 
but for Blueback Herring his agreement was approxi- 
mately 68%. Kornegay’s (1977) Alewife scale ages never 
deviated by more than 2 years from otolith ages, but, 
for 2 Blueback Herring, scale ages deviated by up to 3 
years from otolith ages. 
A difference of 1 or 2 years between scale age and 
otolith age is a relatively large de- 
viation for a fish with a lifespan 
of only 7 or 8 years. Likewise, the 
agreement level of 57% between 
scale and otolith ages is low. Alosa 
scales are commonly regenerated, 
and spawning marks sometimes 
obscure annuli near the scale mar- 
gin. The first annulus is sometimes 
confused with the freshwater zone, 
which is a false annulus formed 
when juvenile Alosa first enter the 
marine environment, and the first 
annulus is not always visible on 
the scale (Cating, 1953; Judy, 1961; 
Kornegay, 1977). In addition, the 
Hickory Shad, among Alosa spe- 
cies, has scales considered to be the 
most difficult to use for age analysis 
(Richkus and DiNardo 1 ). Therefore, 
otoliths should be used whenever 
possible for aging Hickory Shad. 
The few published studies on age 
composition of Hickory Shad and 
other Alosa species generally show 
1-3 dominant year classes (Street 
and Adams 15 ; Pate, 1972; Street et 
al. 4 ; Kornegay, 1977; Winslow 19 ’ 20 ; 
NCDMF 21 ; Harris et ah, 2007). In 
our study, ages 3 and 4 were the 
dominant age classes, with male 
Hickory Shad contributing the ma- 
jority of the younger age classes 
(ages 2 and 3) and female Hickory 
Shad contributing the majority of 
the older age classes (ages 4-7) (Ta- 
ble 2). For the adjacent Neuse Riv- 
er, Murauskas and Rulifson (2011) 
reported that both sexes averaged 3 
years of age, although a larger pro- 
portion of females were in older age 
classes: 25% of females were of ages 
4, 5, and 6, whereas 14% of males were of age 4 only. 
Overlapping lengths at age made it difficult to ac- 
curately determine age structure from length fre- 
19 Winslow, S. E. 1989. North Carolina alosid fisheries man- 
agement program. Completion report for Project AFC-27, 
102 p. Division of Marine Fisheries, North Carolina Depart- 
ment of Natural Resources and Community Development, 
Morehead City, NC. 
20 Winslow, S. E. 1990. Status of American Shad, Alosa sapi- 
dissima (Wilson), in North Carolina. Completion report for 
Job 5, Project AFC-27, 94 p. + appendix. Division of Marine 
Fisheries, North Carolina Department of Natural Resources 
and Community Development, Morehead City, NC. 
21 NCDMF. 2001. North Carolina shad and river herring 
compliance report, 2000, 66 p. [Available from Division of 
Marine Fisheries, North Carolina Department of Environ- 
ment and Natural Resources, 3441 Arendell St., Morehead 
City, NC 28557.] 
