Native submerged aquatic vegetation (SAV) provides critical habitat for estuarine nekton. Relatively high nekton densities also are often associated with the nonnative, Eurasian Watermilfoil (Myriophyllum spicatum), a widely-distributed species in estuaries of the northern Gulf of Mexico. The goal of my study was to assess the habitat value of Myriophyllum with that of a common native SAV (Ruppia maritima) and SNB using two metrics (nekton density and growth of juvenile white shrimp Litopenaeus setiferus). Including estimates of vital rates such as growth together with density can give a more complete assessment. The nursery habitat provided by Myriophyllum for juvenile white shrimp appeared to match or exceed that of naturally occurring habitat types ( Ruppia and SNB) in the oligohaline study area. Juvenile white shrimp densities in Myriophyllum (2.2 ± 0.47 m–2 ) were higher than those in Ruppia (1.0 ± 0.36 m–2). Similarly, white shrimp growth rates were higher in Myriophyllum (1.0 ± 0.07 mm TL d –1, 28.2 ± 2.83 mg d–1) than in Ruppia (0.6 ± 0.09 mm TL d–1, 14.1 ± 2.51 mg d–1). Myriophyllum also supported a nekton assemblage similar to that of Ruppia. Though differences were detected between SAV species, other factors derived from differences in SAV biomass may have driven differences in white shrimp growth rates and nekton densities. My study indicates that nonnative habitat forming species like Myriophyllum can provide an alternative to native habitat, though more research is needed to fully understand the mechanisms at work.
|Advisor:||Rozas, Lawrence P.|
|Commitee:||Duke-Sylvester, Scott M., Felder, Darryl L., Leberg, Paul L.|
|School:||University of Louisiana at Lafayette|
|School Location:||United States -- Louisiana|
|Source:||MAI 58/05M(E), Masters Abstracts International|
|Keywords:||Community structure, Growth experiment, Myriophyllum spicatum, Nonnative species, Nursery habitat quality, Submerged aquatic vegetation|
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