Observations on the Life History of Diplectrum pacificum and D. macropoma (Pisces, Serranidae) from the Bay of Panama

Abstract

Diplectrum pacificum and D. macropoma were collected in abundance from January through February 1973 at a depth of 20-30 m in the Bay of Panama. Juvenile D. pacificum apparently occur in shallow water (less than 2 m). The substrate where adults of both species occur sympatrically is fine sand and silt bottom with some shell. Both species display nearly identical negative allometric growth. Diplectrum pacificum reaches a maximum size of 219 mm standard length. The oldest specimens were from age-group 6. Diplectrum macropoma attains a maximum size of 130 mm standard length. The oldest specimens were from age-group 4. Both species tend to aggregate in definite size groups. Both species feed predominately on small shrimp and other crustaceans. Diplectrum pacificum tends to select larger shrimp than does D. macropoma. Reproductively, both species are synchronous hermaphrodites. Testicular tissue is restricted to a morphologically distinct, species-specific area. Mature eggs pass into an ovarian sinus before being deposited. Sperm and ovarian ducts exit separately. No evidence was found of internal self-fertilization in either species. Behaviorly, both species show an affinity for the substrate and display color patterns that are similar to the active-inactive color pattern described for another related species, D. formosum.