| SPATIAL AND TEMPORAL PATTERNS IN LARVAL COMMUNITY STRUCTURE AND SETTLEMENT OF RED DRUM SCIAENOPS OCELLATUS IN A GULF OF MEXICO SEAGRASS MEADOW |
| FENCIL, M.C., Holt, S.A. and Holt G.J., University of Texas at Austin Marine Science Institute; 750 Channel View Drive; Port Aransas TX 78373; U.S.A., fencil@utmsi.utexas.edu. |
| Accurate recruitment models depend upon input of environmentally realistic numbers of young fish. While a large amount of work has been done to determine how abundances of fish larvae vary between distinct habitat types, relatively little work has focused on variability in abundance and community structure within seemingly homogenous habitats particularly at small spatial and temporal scales. 18,731 larval and early juvenile fishes representing 32 species were collected from a Gulf of Mexico seagrass meadow between 2 October and 20 November 2003. The community was numerically dominated by darter goby Ctenogobius boleosoma (43%), gulf pipefish Syngnathus scovelli (18%), red drum Sciaenops ocellatus (12%), and code goby Gobiosoma robustum (11%). ANOSIM analysis indicated significant differences in species dissimilarity between sampling units on both the spatial and temporal scale of this study. Samples that were collected near each other in time and space were more similar (Bray-Curtis) than sites that were spatially or temporally distant. To determine the degree to which dissimilarities between sampling units were based on environmental variables, both biotic variables (seagrass blade length, blades per shoot, shoots per core) and abiotic variables (temperature, salinity, depth, dissolved oxygen) were invoked in the BIO-ENV procedure. Seagrass blade length was the variable that best explained sampling unit dissimilarity, although the correlation was low. Seemingly “homogenous” habitats may support larval assemblages whose composition is considerably variable even at small temporal and/or spatial scales. |
| back |
|
