Alternate Title

Relative Abundance of Postlarval and Juvenile Penaeid Shrimps in Submerged Aquatic Vegetation and Emergent Marsh Habitats


Postlarval and juvenile densities of Farfantepenaeus aztecus, Farfantepenaeus duorarum, and Litopenaeus setiferus were compared among emergent marsh (Spartina alterniflora), submerged aquatic vegetation (Ruppia maritima), and adjacent unvegetated areas at the east end of Fowl River along Mobile Bay, AL. A total of 108 samples were collected between July 1994 and Nov. 1995, of which 76 samples contained at least one of the three penaeid species. Of the 507 penaeid shrimp collected, 303 (60%) were collected in the R. maritima beds, 152 (30%) in the S. alterniflora, and 52 (10%) in the sand/mud habitat. The mean densities of F. aztecus, F. duorarum, and all three penaeid species combined were significantly greater in the R. maritima beds compared with those in both the S. alterniflora and sand/mud habitats. Presence of vegetation appeared to have little effect on shrimp size because no significant difference in size of shrimp between habitats was recorded. Generally, there was little correlation between shrimp density and abiotic factors within the three habitats, but a significant negative correlation was found between F. aztecus density and S. alterniflora density. Results suggest that habitats with submerged aquatic vegetation, R. maritima, are utilized more by both F. aztecus and F. duorarum over those characterized by the emergent vegetation, S. alterniflora. Because shrimp densities did not exhibit any patterns in relation to a variety of hydrographic factors, additional field studies should focus on biotic parameters (i.e., predation, competition, food availability, habitat structure) to better determine the factors that affect penaeid shrimp abundance within estuarine habitats.