785 
Abstract .—Three species of the 
stromateoid genus Peprilus have been 
found to occur in the northwest Atlan- 
tic: P. triacanthus (butterfish), P. burti 
(gulf butterfish), and P. alepidotus 
(harvestfish). Peprilus triacanthus and 
P. alepidotus reportedly spawn from 
May through August and June through 
July, respectively. Peprilus burti spawns 
twice yearly: February through May and 
September through November. Collec- 
tions of larvae and juveniles of Peprilus 
spp. from the northern South Atlantic 
(SAB) and Mid- Atlantic (MAB) Bights 
during both the spring and summer of 
1988 and 1989 suggest that either a 
combination of species was spawning 
or that reported spawning dates were 
suspect. Species identification of 
Peprilus in these collections was deter- 
mined with morphometric, meristic, 
and pigment character analyses. Speci- 
mens sampled had counts for caudal 
vertebrae (18-19) and ventral midline 
melanophores (11-16) consistent with 
those found for P. triacanthus in previ- 
ous studies. By analyzing otoliths, we 
estimated larval and juvenile growth 
rates to be approximately 0.23 mm/day. 
Backcalculation of hatch dates suggests 
either two spawning events for P. 
triacanthus , February through mid- 
April and mid-May through late July, 
or one extended spawning period begin- 
ning in late February and ending in late 
July. This study reveals that P. tria- 
canthus spawns for a much longer period 
than previously thought. It is possible 
that P. triacanthus spawns during the 
spring in the SAB and summer in the 
MAB as a strategy to extend the dura- 
tion of its spawning period. This strat- 
egy is one used by other north-south 
migrating species and warrants further 
study. 
Manuscript accepted 7 March 1997. 
Fishery Bulletin 95:785-799 (1997). 
Temporal and spatial spawning 
patterns of the Atlantic butterfish, 
Peprilus triacanthus, in the South 
and Middle Atlantic Bights* 
Teresa Rotunno 
Robert K. Cowen 
Marine Sciences Research Center 
State University of New York 
Stony Brook, New York 1 1 794-5000 
E-mail address (for T Rotunno): trotunno@ccmaifsunysb.edu 
Three species of the stromateoid 
genus Peprilus (order: Perciformes) 
are reported to occur in the west- 
ern North Atlantic: butterfish, P 
triacanthus (Peck), gulf butterfish, 
P burti (Fowler), and harvestfish, 
P. alepidotus (Linnaeus). Although 
the ranges of all three species ex- 
tend along the eastern coast of 
North America and the West Indies, 
there is some question as to which 
species of Peprilus are regular resi- 
dents in the South Atlantic Bight 
(SAB) and Mid-Atlantic Bight 
(MAB) regions (Caldwell, 1961; 
Haedrich, 1967; Horn, 1970; Persch- 
bacher et al., 1979). This question 
is extended by the suggestion of 
possible hybridization between P. 
triacanthus and P. burti in the 
northern portion of the SAB (Horn, 
1970; Perschbacher et al., 1979). 
Reproduction in P. triacanthus 
and P burti is seasonal and appar- 
ently associated with annual migra- 
tion patterns (Horn, 1970). In the 
summer and fall, P. triacanthus 
migrates northward and inshore, 
where it reportedly spawns from 
late May through August, with a 
peak in June (Horn, 1970). During 
winter, P triacanthus migrates off- 
shore and becomes horizontally re- 
stricted (Horn, 1970). Movement by 
P burti is somewhat opposite to that 
ofP. triacanthus. Peprilus burti mi- 
grates offshore during late spring 
through early fall, then onshore to- 
wards shallow bays and inlets dur- 
ing the winter and early spring 
(Horn, 1970). Spawning by P. burti 
is reported to occur during two dis- 
tinct periods, February through May 
and September through November 
(Murphy, 1981). Unlike these other 
two species, P. alepidotus does not 
exhibit seasonal migration patterns, 
remaining in shallow waters 
throughout the year where it spawns 
during June and July (Horn, 1970). 
During the spring and summer 
seasons of 1988 and 1989, we con- 
sistently collected larval and juve- 
nile Peprilus from the South Atlan- 
tic and Mid-Atlantic Bights. The 
combination of their location and 
dates of capture raised the question 
as to which species were present in 
our samples. Although most abun- 
dant within the MAB region, P. 
triacanthus is reported to spawn 
during the summer only (Horn, 
1970). According to time of capture, 
the spring-collected larvae in our 
SAB samples should have been P 
burti because they were collected be- 
fore P triacanthus and P. alepidotus 
supposedly begin to spawn (Horn, 
1970; Murphy, 1981). However, their 
occurrence within the South Atlantic 
and Mid-Atlantic Bights suggests 
that they were either P. alepidotus or 
P. triacanthus. Thus, the overall aim 
of this study was to identify the spe- 
cies in our samples and to back- 
* Contribution 1061 of the Marine Sciences 
Research Center, State University of New 
York, Stony Brook, New York 11794-5000. 
