Patterns in the utilization of the intertidal salt marsh by larvae and juveniles of Fundulus heteroclitus (Linnaeus) and Fundulus luciae (Baird)

Abstract

Larval and juvenile fishes were collected at low tide from the surface of an intertidal salt marsh on Sapelo Island, Georgia every 6 days from 25 May through 20 December 1982. Larval fishes were present in shallow puddles of tidal water on the marsh from the beginning of the sampling period until the end of October. Juveniles were present throughout the year. Fundulus heteroclitus (Linnaeus) and F. luciae (Baird) accounted for 96.3% (67.0% and 29.3%, respectively) of the 4355 fishes collected. These fishes exhibited synchronous, temporal pulses in larval abundance, suggesting that reproduction was discontinuous and controlled by the same factor(s) in both species. Larval F. heteroclitus inhabited aquatic micro-habitats near the upland edge of the intertidal marsh, but as the larvae grew to juvenile size (≈ 10 mm standard length) they moved to lower elevations near a tidal creek. Large juveniles and adults of F. heteroclitus infrequently occurred in the samples, presumably because they leave the intertidal marsh as the tide ebbs. F. luciae were rarely found in low marsh areas, but all age classes (including adults) occurred at higher elevations, supporting previous suggestions that this species prefers high marsh habitats. The vegetated, intertidal salt marsh appears to be the principal nursery habitat for both of these cyprinodontid species.