The effect of Manila clam cultivation on an intertidal benthic community: the early cultivation phase

Influence of intertidal Manila clam Venerupis philippinarum aquaculture on biogeochemical fluxes

“…In contrast, sediment structure did not differ between netted and non-netted treatments in the present study, as also reported by Munroe & McKinley (2007) for Baynes Sound. This is in contrast to studies by Spencer et al (1996Spencer et al ( , 1997 who observed a 4-fold increase in sedimentation, but less silt, on netted plots compared to non-netted plots. This latter research was done over a complete 2 to 3 yr Manila clam cultivation cycle, unlike the present study.…”

“…Previous research has shown that anti-predator nets and fouling may obstruct or reduce water flow, increasing siltation (Kaiser et al 1996, Spencer et al 1996, Goulletquer et al 1999, Munroe & McKinley 2007, Nizzoli et al 2007). In the present study grain size varied with net status, although this pattern differed between plots with and without clams.…”

“…Toupoint et al (2008) also found a limited increase of organic content due to Manila clam culture, suggesting this may have been due to tidal currents or the short period that nets were used. Sediment organic content may be increased through clam biodeposition (Jie et al 2001) or entrapment by anti-predator nets (Kaiser et al 1996, Spencer et al 1996, Bendell-Young 2006. Organic matter in biodeposits is easily degraded by microbial metabolism (Nizzoli et al 2007), however, and thus may be rapidly assimilated.…”

“…Nevertheless, suspension-feeding bivalves play important functional roles in aquatic ecosystems, since they may affect various physical and biological processes in both the water column and the benthic environment (Newell 2004, Nizzoli et al 2006a). Numerous studies have described the influence of bivalve culture on various components of the environment, including nutrient cycling (Doering et al 1987, Baudinet et al 1990, Nizzoli et al 2006a,b, Richard et al 2006, 2007b, Thouzeau et al 2007), localized organic loading (Mattsson & Lindén 1983, Weise et al 2009), benthic macrofaunal communities (Kaiser et al 1996, Spencer et al 1996, Jie et al 2001, Callier et al 2008, and seston (Newell 2004, Guyondet et al 2013. High densities of infaunal filter-feeding bivalves may influence benthic environments either directly, through their metabolic activity (e.g.…”

“…Netting is thus considered an important tool to reduce the predation impacting Manila clam production. Anti-predator nets, however, may increase the concentration of organic matter on the sea floor by creating a barrier to water movement (Spencer et al 1996, Bendell-Young 2006. They may also influence benthic macrofaunal communities.…”