Study

Floating oyster, Crassostrea virginica Gmelin 1791, aquaculture as habitat for fishes and macroinvertebrates in Delaware Inland Bays: the comparative value of oyster clusters and lose shell

  • Published source details Marenghi F.P. & Ozbay G. (2010) Floating oyster, Crassostrea virginica Gmelin 1791, aquaculture as habitat for fishes and macroinvertebrates in Delaware Inland Bays: the comparative value of oyster clusters and lose shell. Journal of Shellfish Research, 29, 889-904.

Actions

This study is summarised as evidence for the following.

Action Category

Cease or alter maintenance activities on subtidal artificial structures

Action Link
Biodiversity of Marine Artificial Structures

Transplant or seed organisms onto subtidal artificial structures

Action Link
Biodiversity of Marine Artificial Structures
  1. Cease or alter maintenance activities on subtidal artificial structures

    A replicated, paired sites, controlled study in 2008 on eight subtidal pontoons in the Delaware Inland Bays, USA (Marenghi et al. 2010) found that reducing the frequency of cleaning activity did not increase the survival or growth of transplanted oysters Crassostrea virginica on floats attached to the pontoons, nor did it alter the non-mobile invertebrate, mobile invertebrate and fish community composition or increase their species diversity, richness or abundance on and around floats, but it did increase the macroalgal abundance. Data for all comparisons were reported as statistical model results. Over four months, transplanted oyster survival and growth was similar on floats cleaned every four or two weeks. The same was true for the overall community composition, and the species diversity, richness and abundance of non-mobile invertebrates and of mobile invertebrates and fishes on and around oyster floats. The abundance of macroalgae was higher on floats cleaned every four than every two weeks. Maintenance activities were altered on floats holding transplanted oysters attached to pontoons during June–September 2008. Hatchery-reared oysters (61 mm average length) were transplanted into wire baskets (25 mm mesh size) submerged 0.2 m beneath plastic floats (1.0 × 0.7 × 0.3 m) and attached to pontoons. One float with oysters (6 l) and one without were attached to each of eight pontoons in June 2008. Floats were cleaned with a freshwater hose every four weeks on four pontoons and every two weeks on four. Oyster survival and growth was monitored, non-mobile invertebrates on oyster shells were counted, and mobile invertebrates and fishes on and around floats were netted (3 mm mesh size) and counted over four months.

    (Summarised by: Ally Evans)

  2. Transplant or seed organisms onto subtidal artificial structures

     A replicated, paired sites, controlled study in 2008 on eight subtidal pontoons in the Delaware Inland Bays, USA (Marenghi & Ozbay 2010) found that 29–89% of oysters Crassostrea virginica transplanted onto floats attached to the pontoons survived and grew, regardless of cleaning frequency, and that transplanting oysters increased the invertebrate and fish species richness and diversity on and around floats, but had mixed effects on abundances, depending on the species. Over four months, transplanted oyster survival (29–89%) and growth (5–25 mm) was similar on floats cleaned every two or four weeks. In total, 23 mobile invertebrate and fish species were recorded on and around floats with transplanted oysters and 17 on and around floats without, while 11 non-mobile invertebrate species were recorded on transplanted oyster shells. Average mobile invertebrate and fish species diversity (reported as Simpson’s and Evenness indices) and richness was higher on and around floats with transplanted oysters (8–10 species/float) than without (4–7/float), and their combined abundance was similar (data not reported), although abundances varied by species (see paper for results). Oysters supported on average seven non-mobile invertebrate species/float. Mobile invertebrate and fish community composition differed on and around floats with and without oysters (data reported as statistical model results). Oyster recruits were seen on transplanted oysters. Hatchery-reared oysters (61 mm average length) were transplanted into wire baskets (25 mm mesh size) submerged 0.2 m beneath plastic floats (1.0 × 0.7 × 0.3 m) and attached to pontoons. One float with oysters (6 l) and one without were attached to each of eight pontoons in June 2008. Floats were cleaned every two weeks on four pontoons and every four weeks on four. Oyster survival and growth was monitored, non-mobile invertebrates on oyster shells were counted, and mobile invertebrates and fishes on and around floats were netted (3 mm mesh size) and counted over four months.

    (Summarised by: Ally Evans)

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