Efforts to enhance the food supply for the protected delta smelt are showing initial success, according to wildlife and water resources experts. They gathered at the Yolo Bypass to the Sacramento River last week to discuss their work to increase the number of plankton available to the fish. Cooperative efforts by state and federal agencies, Sacramento Valley farmers and water providers have resulted in the creation of a phytoplankton bloom, the experts said. Phytoplankton are microscopic creatures and the major food source for zooplankton, another minuscule creature that represents the main food source for delta smelt.