Sonoma County sheriff's Lt. Scott Dunn said the department's dive team searched the area Tuesday but the thick kelp made searching for Su unsafe even for divers wearing oxygen tanks.
"They dived as much as they could for several hours," Dunn said.
Authorities also scanned the water from the bluffs above to see if Su's body washed ashore, Dunn said.
Su, 29, of Sunnyvale disappeared around 3 p.m. Sunday while diving with his cousin. The U.S. Coast Guard searched the area until nearly midnight that day.
Dunn said it's likely Su's body will not be disentangled from the thick kelp until the wave action from the season's first good storm dislodges the kelp from the rocks where Su was diving. Su was wearing a weight belt, Dunn said.
Sunny warm weather that is predicted through the weekend could help the kelp grow even more, Dunn said.
The California State Parks Department is checking the area daily and the sheriff's department's helicopter cruises past the area whenever it is out on the Sonoma Coast, Dunn said.
This will be one of the last weekends for abalone diving because the season ends at the end of the month, Dunn said.