Experiments to examine transplant procedures on the seagrass Halodule beaudettei

During the growing seasons of 1999 and 2000 five experiments were performed to test growth of the seagrass Halodule beaudettei (shoal-grass) in nursery pond conditions. Sediment oxidation state, sediment source, container type, flow regime, and light transmittance were tested to improve nursery pond cultivation techniques and to test assumptions about the decline of seagrasses in Galveston Bay, Texas. Oxidized and reduced sediments exhibited no statistical difference as mean percent change in the number of stems of shoal-grass, after 47 days. Sediment from three source locations, West Bay, East Beach Lagoons, and the experimental pond bottoms, showed no significant difference in the mean percent change in the number of stems of shoal-grass at 48 and 95 days. A statistical difference was seen in the container type experiment, trays versus pots, at 48 days where shoal-grass had double the number of stems produced in trays; however no significant difference was found at 93 days. A significant difference was found in the flow regime experiment, no-flow versus flow, at 47 days in the mean percent change of shoal-grass with double the number of stems produced in the flow regime. Significant differences were observed between the low light and high light treatments with shoal-grass, widgeongrass (Ruppia maritima), star grass (Halophila engelmannii), and turtlegrass (Thalassia testudinum), with survival and growth occurring in the high light treatment and decline and death occurring in the low light treatment. The importance of reduced sediment may have been overstated in the past as sediment reduction occurs rapidly with submersion. It appears that while West Bay sediment did not have a deleterious effect on shoal-grass, West Bay simulated light conditions did. Container type seems to be important at first but not so much in the long term. Some flow, water movement, or current appears to be important.