The Effects of Stocking Density, Bag Mesh Size, and Bottom Sediment on the Growth and Survival of the Eastern Oyster, Crassostrea virginica, with Emphasis on Controlling Oyster Spat Fouling

Abstract

This study was designed to determine if oyster spat fouling upon adult oysters, Crassostrea virginica, cultured in coastal Georgia could be controlled by stocking density, bag mesh size, substrate type, and tidal level (intertidally or subtidally). Oyster gowth and survival was also monitored for each treatment. Sediment type had no effect on the number of spat per oyster either in intertidal or subtidal areas. Greater growth occurred in subtidal bags placed on sandmud and sandclay substrates. Intertidal mud and sandhnud bottom treatments showed the least growth. Survival of oysters grown intertidally (64%) was better the those cultured subtidally (27%). Mesh size of the oyster growing bags -had no effect upon oysler fouling or growth (shell length) and survival of the oysters they contained. Stocking density did affect oyster fouling, with lower fouling per oyster in higher density treatments. Density had no effect on oyster growth (shell length) or survival at the levels tested. Heavy fouling occurred on all oysters in the mesh and stocking density experiments while they were suspended off-bottom, but an I l -fold decrease in fouling occurred after bags were placed on the sublidal river bottom.