Patterns of settlement, survival and growth of oysters across the Great Barrier Reef

Abstract

Settlement plates of coral rock were moored on the Central Great Barrier Reef in order to evaluate the distribution of competent bivalve larvae and post-settlement growth and survivorship of oysters in different regions. Oysters were chosen because they dominate plates. The regions and sites were outer reef (Myrmidon), central reef (John Brewer), inner reef (Pandora) and an inshore non-reef habitat (Bowling Green Bay). Cross-shelf differences were studied by transferring plates from John Brewer Reef to the other sites with the return of some plates to John Brewer to control transfer effects. Cross-reef and fish predation effects were studied by transferring caged and uncaged plates to the fore reef, reef flat and back reef at John Brewer. Transfer to the back reef also evaluated the effect of Acropora colonies as relative refugia from fish predation and sand flats as an area relatively free of the invertebrate predators associated with coral rubble. There were clear regional settlement differences. Myrmidon Reef had lowest densities (6 2 ind 500cn1-'), high species richness ( l ? of 24 species identified in the project), and low equitabllity dominated by Ostrea foliurn. John Brewer ( l 6 species) had high densities (> 100 ind. 5 0 0 c m -~) and hlgh specles equitability. Pandora Reef had the most species (20) and the highest densities because of a massive settlement of Pinctada maxima, most of which fell off the plates after recovery. Bowling Green Bay had low density (-16 ind. 500cn1-~) and only 13 species, Ostrea angasi being a strong dominant. Average bivalve sizes increased from the outer to the inner reef. The cross-shelf transplant experiments showed strong trends in the growth rate with Myrmidon having the slowest and John Brewer and Pandora having the fastest growth. Growth rates of Plnctada and Ostrea spp. and Crassostrea commercialis differed significantly across the shelf. Ostrea spp. were largest at John Brewer, while Pinctada spp. and most Crassostrea spp. were largest at Pandora. At Bowling Green Bay oysters were smaller than at Pandora. Survivorship of Crassostrea spp. was about the same in all areas, but Pinctada and Ostrea spp. had significantly higher mortality at Bowling Green Bay and Pandora. In the cross-reef experiment immediate fish predation was highest on plates set in sand and lowest on plates under an Acropora thicket and there was much less fish predation at the reef flat and back reef sites. Oysters suffered very large mortalities from predation by invertebrates, especially gastropods, at all sites, but this was reduced for plates over sand substrata.

The Trans‐atlantic History of Diversity and Body Size in Ecological Guilds

“…Such evidence connecting planktic productivity and maximum size exists for oysters (Brown 1988, Dayton et al 1989, Kirby 2001, Lescinsky et al 2002), scallops (MacDonald and Thompson 1985, mussels (Page andHubbard 1987, Blanchette et al 2007), the New Zealand hard clam Austrovenus stutchburyi (Marsden 2004, Beu 2006, reef-associated bivalves (Highsmith 1980, Birkeland 1989, Vermeij 1990, and turritellid gastropods (Allmon 1992, Teusch et al 2002, Teusch and Guralnick 2003. A connection between high benthic productivity and size of large herbivores has been established for abalones (Haliotidae) by Estes et al (2005) and limpets by Bustamante et al (1995a, b).…”

Physical factors of differentiation in macrobenthic communities between atoll lagoons in the Central Tuamotu Archipelago (French Polynesia)

“…Studies on spatio-temporal patterns of recruitment are available particularly for fish (Dufour & Galzin 1993, Leis et al 1998) and coral communities (Connell et al 1997. Conversely, few studies address issues on recruitment of molluscs (Dayton et al 1989), echinoderms (Fisk 1992, Keesing et al 1993) and algae (Santelices 1990, Stiger & Payri 1999. Our observations are an invitation for experimental research to be conducted on these forgotten taxa and to compare the results for the Tuamotu Archipelago with other regions worldwide.…”

Comparative effects of microalgal species and food concentration on suspension feeding and energy budgets of the pearl oysters Pinctada margaritifera and P. maxima (Bivalvia:Pteriidae)

“…Both pearl oyster species occur in the Great Barrier Reef region (GBR), northeast coast of Australia (Hynd 1955, Dayton et al 1989), but they occur in different habitats, as outlined in the 'Introduction'. Pinctada margantifera tends to occur on coral reefs offshore from the mainland, whereas P. maxima occurs on substrates ranging from mud to sand and gravel, but not on coral reefs.…”