Population Demographics ofTridacna noae(Röding, 1798) in New Ireland, Papua New Guinea

Abstract

ABSTRACT The recent resurrection of a Tridacna maxima sensu Rosewater (1965) ecotype as a distinct species, Tridacna noae (Roding, 1798), has raised concerns that inadvertent confusion of the two species in the past may have led to overestimates of T.maxima densities and errors in determining demographic parameters. To assess the potential impacts of such a scenario, this study examined the population demographics of T. noae within the center of its geographic distribution in the Kavieng lagoonal system of New Ireland Province, Papua New Guinea. The study found that 42% of the T. maxima sensu Rosewater population could be delineated as T. noae, with T. noae being the most abundant giant clam species at 7 of the 20 study sites. Past confusion of the two species is likely to be of the greatest concern on reef sites with high or medium levels of exposure to oceanic influences where T. maxima (2.08 ± 0.41 per 400 m2, 1.86 ± 0.59 per 400 m2, respectively) and T. noae (2.06 ± 0.36 per 400 m2, 1.25 ± 0.28 per 40...