Distribution, burrowing, and growth rates of the clam Tridacna crocea on interior reef flats

摘要: Larvae of the burrowing clam Tridacna crocea (Tridacnidae) settle preferentially on top detached coral heads lying surface interior reef flat in Great Barrier Reef province. This species burrows as it grows, eroding central surfaces boulders, producing structures that superficially resemble micro-atolls. Storm surges roll these onto now flattened surface, killing live population clams, and exposing fresh underside for unimpeded larval settlement. As clams grow burrow into substratum, head becomes progressively finally breaks apart. Field observations growthring data documented growth rate; rates plus volumes were converted to annual sediment production. At average densities approximately 140 gm/m2/yr are eroded. Concomitant with erosion is a calcium carbonate increase shell amounting 60gm/m2/yr. Assuming stable structure, mortality equal estimated growth, total production 200 gm/m2/yr. Clams usually aggregated at higher densities, however, numbers regularly exceeding 100 clams/m2. Consequently maximum rate locally often 4,500