Date of Award

Fall 2010

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies


Coastal and Marine Systems Science


College of Science

First Advisor

James O. Luken

Second Advisor

Keith R. Walters

Third Advisor

Doug Van Hoewyk


Water hyacinth is considered to be a problematic invasive species worldwide. The plant currently is managed as a nuisance to navigation in the Waccamaw River, SC. Although actively managed, the natural survival and growth of water hyacinths under conditions experienced within the Waccamaw, a tidal blackwater river, have not been examined. Water hyacinth biomass was determined by sequential harvest within three river locations. In addition a field experiment was conducted in which plants were placed within cages made out of nylon netting and PVC and anchored within three river zones. Cages were deployed for one month after which plants were removed and growth measured. Salinity tolerance of individual plants also was investigated in a controlled mesocosm experiments. Mid- and lower-river sites had greater growth and extension in root length, longest leaf length, widest leaf width, and stem base diameter. Most biomass was in the leaves. Biomass was greater in the back of the water hyacinth mat during the fall season, than in the spring. Salt levels ≥ 4.5 ppt resulted in no plant production. Results suggest the plant responds to an increase in nutrients with greater growth. However, results also suggest standing crop and growth are reduced in this aquatic system when compared to other studies and plant growth will be reduced as individuals are transported naturally down the river towards estuarine regions of increased salinity.