Stephen et at: Comparison of life history parameters for landed and discarded fish off the southeastern United States 
293 
tality on faster-growing phenotypes that reach the 
minimum size limit at a young age. Size limits protect 
all small fish of all ages, and over time small fish of 
all ages may dominate the population, because they 
have more opportunities to reproduce before removal 
from the population. Size at age and size at matura- 
tion may decrease in response to a higher proportion of 
slower growing phenotypes in the population (Pitcher 
and Hart, 1982). Such changes may result in decreased 
population abundance and biomass (Kuparinen and 
Merila, 2007). 
All current indications of phenotypic shifts for reef 
species off the coast of the southeastern United States 
have been derived solely from fishery-independent 
research surveys (Harris and McGovern, 1997; Zhao 
et al., 1997; Harris et al., 2002). Yet for many reef 
species in this region, there is not enough fishery- 
independent data to make this determination. When a 
lack of such data occurs, there are only fishery-depen- 
dent data sources available to determine if phenotypic 
shifts are occurring. To the authors’ knowledge no 
one has used fishery-dependent data from commer- 
cial or recreational harvests to confirm whether or 
not the selective harvest of fast growing phenotypes 
is creating a phenotypic shift in fished populations. 
By comparing the life history parameters of landed 
(legal size) fish to those of regulatory (sublegal size) 
discards, one can determine if the minimum size limit 
is an appropriate management technique for a given 
species. If a phenotypic shift towards small, slow grow- 
ing fish is occurring, then the discarded portion of the 
catch when compared to the landed portion should 
show similar age ranges, smaller size at age, smaller 
size at maturity, and smaller size at sexual transition 
for hermaphroditic species. Alternatively, if no pheno- 
typic shift is occurring, then the discarded portion of 
the catch would consist almost exclusively of young, 
immature fish (although maturity stage would vary 
depending on the minimum size limit and species be- 
ing investigated). 
The South Atlantic Fisheries Management Council 
(SAFMC) is responsible for managing stocks in fed- 
eral waters from North Carolina to Key West, Florida. 
Size limits (supplemented by seasonal closures for 
some species) have been the preferred regulatory 
control measure of the SAFMC since the development 
of the Fishery Management Plan for the snapper 
grouper fishery of the South Atlantic Region in 1983 
(SAFMC, 1983). We investigated whether minimum 
size limits are contributing to a phenotypic shift 
towards small, slow growing phenotypes for three 
managed species of the snapper-grouper complex at 
different levels of exploitation: vermilion snapper 
( Rhomboplites aurorubens), currently experiencing 
overfishing with a fishing mortality rate (F) of 0.49 
(SEDAR, 2008); red porgy ( Pagrus pagrus), currently 
considered overfished, with predicted F of 0.095 (SE- 
DAR, 2006); and scamp (Mycteroperca phenax), last 
classified as experiencing overfishing in 1998 (Ma- 
nooch et al., 1998). 
Table 1 
The total number of days when samples of fish were col- 
lected by commercial fishermen off the coast of southeast- 
ern United States for each month within each year. 
Month 
2005 
2006 
2007 
Total 
January 
10 
5 
15 
February 
10 
10 
20 
March 
12 
8 
20 
April 
7 
8 
15 
May 
16 
14 
30 
June 
3 
8 
11 
July 
10 
8 
6 
24 
August 
9 
13 
4 
26 
September 
13 
14 
7 
34 
October 
11 
13 
24 
November 
6 
11 
17 
December 
8 
2 
10 
Materials and methods 
Sampling took place on a South Carolina commercial 
snapper-grouper fishing vessel from July 2005 through 
September 2007 and consisted of 52 trips (246 sampled 
days) across all months (Table 1). The vessel captain 
dedicated the last few days of each trip (trips ranged 
between five and nine days) to collecting samples, when 
he would retain all legal and sublegal size fish of ver- 
milion snapper, red porgy, and scamp. The sampling 
locations were selected by the captain as part of his 
normal fishing routine. Fishing locations were situated 
from 30°16.558'N to 33°36.795'N, and most locations 
were along the shelf-break (Fig. 1). Sampling depths 
ranged between 20 and 128 m. Three bandit-reels, 
with terminal tackle consisting of two 4/0 J-hooks 
and baited with mackerel ( Sarda sarda ), were fished 
simultaneously by three crew members, and all fishing 
took place from sunrise to sunset. For each location, the 
captain recorded the position (latitude and longitude) 
and depth. Fish were tagged with a numbered t-bar tag 
(Floy Tag, Inc., Seattle, WA) and immediately placed 
on ice to preserve reproductive tissue in samples. Up 
to 90 sublegal and legal size fish of each species were 
kept from each trip, for up to 500 fish per species for 
each of two size categories (legal and sublegal) per year 
of the study. All fish were immediately collected from 
the captain upon returning to port and transported to 
the laboratory. 
In the laboratory individual weight (g) and lengths 
(total [TL], fork [FL], and standard length [SL] ; mm) 
were measured for each fish sampled. Both sagittal 
otoliths were removed and stored dry in coin enve- 
lopes. A posterior section of each gonad was removed 
and stored in 10% buffered seawater formalin. Al- 
though the sampling period was limited to one expe- 
rienced commercial fisherman’s catch over multiple 
