Changes in shell dimensions of pearl oysters, Pinctada mazatlanica (Hanley 1856) and Pteria sterna (Gould 1851), during growth as criteria for Mabé pearl implants

Abstract

The relationship between the shell dimensions of pearl oysters. Pinctada nmzallaiiica (Hanley 1856) and Pteria sterna (Gould lHSl), was studied to determine the possible change of form of Ihc shell during growth. The intention was to delermine the number, size and location of nuclei that could be implanted in oysters used for Mabe pearl production. Using the database of our Pearl Culture Research Programme developed in Bahia de La Paz. Mexico, we obtained measurements of 500 shells of P. mazatlaniai and 500 shells of P. sterna, representing i years of continuous growth under extensive culture conditions. The heightlength, height-thickness and the height-weight relationships of both species were analysed, as was the height-wing length relationship for /'. sterna. There was isometric growth up to tOOmm shell height, and negative-allometric growth after 120-12 5 mm for P. mazatlanica. The heightthickness relationship followed a linear model. whereas the height-weight relationship was exponential. No clear allometric pattern was found in P. sterna and all relationships litted the power equation.

Reproduction, Development and Growth

“…For example, Alagarswami and Chellam (1977) found that young ( Ͻ 36 mm) Akoya pearl oysters changed from a sub-quadrate shape to an oblong shape. Similarly, P. mazatlanica was reported to undergo isometric growth up to a size of around 100 mm when shape began to change from being " symmetrical " to " oblong " ( Saucedo et al , 1998 ). Strong variation in shell morphology was reported for Pt.…”

“…Galtsoff, 1931 ;Alagarswami and Chellam, 1977 ;Yoo et al ., 1986 ;Gaytan-Mondragon et al ., 1993 ;Southgate and Beer, 1997 ;Saucedo et al , 1998 ). Such data can be used in assessing the effects of different growth conditions and to describe ontogenetic changes ( Gervis and Sims, 1992 ).…”

“…Strong variation in shell morphology was reported for Pt. sterna , even in oysters of the same size and age, with no clear pattern of isometric or allometric growth in young or adult oysters ( Saucedo et al , 1998 ). Morphometric relationships may also be infl uenced by culture conditions.…”

Effect of Stocking Density on Growth and Survival of the Rainbow Pearl Oyster Pteria sterna (Gould 1852) during Nursery and Late Culture in Bahía de La Paz, Baja California Sur, México

“…We used shell volume (cm 3 ) and mortality incidence (%) as indicators for treatment evaluation. Shell volume allowed more consistent interpretation of growth trends in P. mazatlanica (Saucedo et al 1998;Monteforte and Morales 2000).…”

Use of calcein to estimate and validate age in juveniles of the winged pearl oysterPteria sterna

“…In the Pteriidae family (pearl oysters), growth and age have been studied for the main pearl producing species, including Pinctada fucata (Pandya 1976;Chellam 1978;Velayudhan et al 1996), P. margaritifera (Southgate and Beer 2000;Pouvreau et al 2000), P. maxima (Gervis and Sims 1992;Lee et al 2008), P. mazatlanica (Gaytán-Mondragón et al 1993;Monteforte and Garcia-Gasca 1994;Saucedo and Monteforte 1997a;Saucedo et al 1998), and Pteria sterna (Araya-Núñez et al 1991;Bückle-Ramírez et al 1992;Del Rio-Portilla et al 1992;Monteforte et al 1995). In most of these studies, age estimations were made by assigning an average date at the moment when spat were separated from artificial collectors and tagged prior to starting the nursery period.…”