Interactions between the introduced Pacific oyster Crassostrea gigas and the indigenous blue mussel Mytilus edulis. Local-scale food competition

• Main Author: Hans, I.W.
• Format: Report
• Language: English
• Published: RIVO 2004
• Subjects: crassostrea gigas; eastern scheldt; marine biology; mussels; oysters; mariene biologie; mossels; oesters; oosterschelde; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://research.wur.nl/en/publications/interactions-between-the-introduced-pacific-oyster-crassostrea-gi

The aim of this study was to determine if food competition between mussels and oysters occurs, and how mussel and oyster growth is affected by this interaction. This was done by relating mussel growth to oyster density relating oyster growth to oyster biomass and perform a field control, by inventory the natural situation of wild mussels living in an oyster bed on a tidal flat located in the Dutch Oosterschelde estuary. Mussel growth and condition were found to be negatively affected with increasing oyster biomass, while oyster growth was not affected. Growth was not affected by confounding factors in both bivalve species. Oysters appeared to form a suitable substratum for mussels to settle. Considering the rapid expansion of the Pacific oyster population, the observed overgrowth of wild mussel beds by Pacific oysters in the Wadden Sea, the relatively high filtration rate of Pacific oysters and the fact that Pacific oysters and mussels use the same food source, food competition between these species is likely to be the process underlying these findings.