Recruitment pattern of commercially harvested clam, venerupis aurea (bivalvia: veneridae) at the southern region of Lake Timsah, Suez Canal, Egypt

摘要

The recruitment pattern of the venerid Venerupis aurea was monitored from August 2004 to September 2005 to investigate the feasibility of collecting natural spat for management or maricultural purposes. Three sites of varying adult densities were chosen in the southern region of Lake Timsah, Suez Canal, Egypt. Recruitment is used, herein, to refer to juveniles of generally less than 9 mm shell length. The separation between juveniles and adults was based on the size at onset of maturity. Recruitment of V. aurea was continuous throughout most of the year and varied significantly among the three sites. Monthly collections yielded an average of 687.1, 239.5, and 115.3 spat m-2 at sites I, II, and III, respectively. Higher abundance of recruits occurred during the period from November 2004 to March 2005. The average density of juveniles for this period (n = 5) was 1508.0, 293.6, and 262.4 ind. m-2 at the three sites, respectively. The data suggest that the survival of recruits is probably influenced by abiotic factors, particularly sediment composition, rather than by biotic factors such as adult-juvenile interactions. The growth in length for juveniles from site I is accompanied by growth in weight (isometric growth). At site II and III, weight increased relatively slower than length indicating negative allometric growth.