Postsettlement Patterns of Habitat Use by Sciaenid Fishes in Subtropical Seagrass Meadows

Abstract

Spatial and temporal patterns of distribution and abundance were examined for postsettlement sciaenids collected from seagrass meadows in the Aransas Estuary, Texas. Overall, 5443 sciaenid larvae and early juveniles were identified from biweekly epibenthic sled collections taken from August 1994 to August 1995. Eight species were present in seagrass meadows, with five accounting for over 99.9% of sciaenids collected: silver perch (Bairdiella chrysoura), spotted seatrout (Cynoscion nebulosus), spot (Leiostomus xanthurus), Atlantic croaker (Micropogonias undulatus), and red drum (Sciaenops ocellatus). Settlement to seagrass meadows was partitioned temporally with little overlap among the five species. Postsettlers from inshore spawners (B. chrysoura, C. nebulosus, S. ocellatus) inhabited seagrass meadows during the spring and summer, while individuals from offshore spawners (L. xanthurus, M. undulatus) were present in the late fall and winter. Densities ofB. chrysoura, C. nebulosus, S. ocellatus were highest for small individuals (4–8 mm SL) and these taxa remained in seagrass sites through the early juvenile stage. Conversely,L. xanthurus andM. undulatus maintained longer pelagic periods and generally entered seagrass meadows at larger sizes (10–14 mm SL). Moreover, these taxa were only temporary residents of selected seagrass meadows, apparently migrating to alternative habitats shortly after arrival. During peak settlement, mean and maximum densities among species ranged from 0.1 m−2 to 0.8 m−2 and 0.7 m−2 to 23.8 m−2, respectively. Density and mean size of possettlement sciaenids differed significantly between seagrass species (Halodule wrightii, Thalassia testudinum) and among sites within the estuary.