Thieltges et al., 2006; Decottignies et al., 2007; Thomsen
et al., 2007; Brandt et al., 2008; Molnar et al., 2008;
Kochmann et al., 2008; Wrange et al., 2010; Padilla et al.,
2011). In Europe, the native flat oyster, Ostrea edulis has
been replaced by the introduced Japanese oyster,
Crassostrea gigas (see Figures 13, 14a, b). The same situation has occurred in many other estuaries throughout the
world (Ruesink et al., 2005; Molnar et al., 2008; Kimbro
et al., 2009) where native species have declined (Beck
et al., 2009) and nonnatives have been introduced to
support a commercial fishery (NRC, 2004).
In many nearshore and estuarine areas, introduced oysters
are transforming the landscape in manifest ways (reviewed
in Ruesink et al., 2005; Smaal et al., 2005; Molnar et al.,
2008; Padilla et al., 2011). In the Wadden Sea, for example
(Nehls and Büttger, 2007), the invasion of the Pacific oyster
Crassostrea gigas is causing major habitat shifts from
the formerly dominant native bivalve, the blue mussel,
Mytilus edulis which formed beds to intertidal oyster reefs
(Figures 14a, b). The consequences for native benthic communities, mussel-eating birds and other higher food web
consumers, the mussel fisheries, etc. have yet to be resolved.
In some cases diseases (MSX) or hitchhikers (slipper shells,
Crepidula spp.) have had significant impacts (Elton, 1958;
Burreson and Ford, 2004; Decottignies et al., 2007).
Restoration
As mentioned already, past oyster restoration efforts have
focused on recovering lost or impaired oyster fisheries
(MacKenzie, 1996; MacKenzie, 1997a, MacKenzie,
1997b, MacKenzie, 1997c, Beck et al., 2009, 2011).
Because of the significant decline of oyster reefs worldwide
(e.g., Beck et al., 2009, 2011) and related efforts to reconstitute these species’ habitats, numerous attempts (from small
to large scale) have been initiated, especially in North
America for non-resource-related ecosystem functions
(Coen and Luckenbach, 2000; Gutiérrez et al., 2003; Coen
et al., 2007; Brumbaugh and Coen, 2009; La Peyre
et al. 2014; Powers and Boyer, 2014). As mentioned above,
the focus of recent (since 1990s) enhancement and restoration efforts has been for the other “ecosystem services”
(Luckenbach et al., 1999; Coen and Luckenbach, 2000;
Grabowski and Peterson, 2007; Baggett et al., 2014;
Bivalve Molluscs, Figure 12 Ostrea lurida from above beds
(see Figure 11) in Vancouver Island, Canada (Source: B. Kingslett,
Deep Bay Field Station, Vancouver Island University, BC, Canada).
Bivalve Molluscs, Figure 13 Relatively recent distribution of the Pacific oyster, Crassostrea gigas. Orange is its “invasive” (nonnative)
range, blue is its “native” range (prior to reanalysis by molecular approaches), and white is unknown (potential) occurrence from
Molnar et al. (2008, see Figure 4).
96
BIVALVE MOLLUSCS
et al., 2007; Brandt et al., 2008; Molnar et al., 2008;
Kochmann et al., 2008; Wrange et al., 2010; Padilla et al.,
2011). In Europe, the native flat oyster, Ostrea edulis has
been replaced by the introduced Japanese oyster,
Crassostrea gigas (see Figures 13, 14a, b). The same situation has occurred in many other estuaries throughout the
world (Ruesink et al., 2005; Molnar et al., 2008; Kimbro
et al., 2009) where native species have declined (Beck
et al., 2009) and nonnatives have been introduced to
support a commercial fishery (NRC, 2004).
In many nearshore and estuarine areas, introduced oysters
are transforming the landscape in manifest ways (reviewed
in Ruesink et al., 2005; Smaal et al., 2005; Molnar et al.,
2008; Padilla et al., 2011). In the Wadden Sea, for example
(Nehls and Büttger, 2007), the invasion of the Pacific oyster
Crassostrea gigas is causing major habitat shifts from
the formerly dominant native bivalve, the blue mussel,
Mytilus edulis which formed beds to intertidal oyster reefs
(Figures 14a, b). The consequences for native benthic communities, mussel-eating birds and other higher food web
consumers, the mussel fisheries, etc. have yet to be resolved.
In some cases diseases (MSX) or hitchhikers (slipper shells,
Crepidula spp.) have had significant impacts (Elton, 1958;
Burreson and Ford, 2004; Decottignies et al., 2007).
Restoration
As mentioned already, past oyster restoration efforts have
focused on recovering lost or impaired oyster fisheries
(MacKenzie, 1996; MacKenzie, 1997a, MacKenzie,
1997b, MacKenzie, 1997c, Beck et al., 2009, 2011).
Because of the significant decline of oyster reefs worldwide
(e.g., Beck et al., 2009, 2011) and related efforts to reconstitute these species’ habitats, numerous attempts (from small
to large scale) have been initiated, especially in North
America for non-resource-related ecosystem functions
(Coen and Luckenbach, 2000; Gutiérrez et al., 2003; Coen
et al., 2007; Brumbaugh and Coen, 2009; La Peyre
et al. 2014; Powers and Boyer, 2014). As mentioned above,
the focus of recent (since 1990s) enhancement and restoration efforts has been for the other “ecosystem services”
(Luckenbach et al., 1999; Coen and Luckenbach, 2000;
Grabowski and Peterson, 2007; Baggett et al., 2014;
Bivalve Molluscs, Figure 12 Ostrea lurida from above beds
(see Figure 11) in Vancouver Island, Canada (Source: B. Kingslett,
Deep Bay Field Station, Vancouver Island University, BC, Canada).
Bivalve Molluscs, Figure 13 Relatively recent distribution of the Pacific oyster, Crassostrea gigas. Orange is its “invasive” (nonnative)
range, blue is its “native” range (prior to reanalysis by molecular approaches), and white is unknown (potential) occurrence from
Molnar et al. (2008, see Figure 4).
96
BIVALVE MOLLUSCS