Temporal and spatial spawning patterns of the atlantic butterfish, Peprilus triacanthus, in the South and Middle Atlantic bights

Three species of the stromateoid genus Peprilus have been found to occur in the northwest Atlantic: 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. Collections 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 determined with morphometric, meristic, and pigment character analyses. Specimens sampled had counts for caudal vertebrae (18-19) and ventral midline melanophores (11-16) consistent with those found for P. triacanthus in previous studies. By analyzing otoliths, we estimated larval and juvenile growth rates to be approximately 0.23 mm/day. Back calculation 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 beginning in late February and ending in late July. This study reveals that P. triacanthus 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 duration of its spawning period. This strategy is one used by other north-south migrating species and warrants further study.