Growth and reproduction patterns of the winged pearl oyster, Pteria sterna, cultivated in tropical environments of Mexico: Implications for pearl farming

Abstract

The winged pearl oyster, Pteria sterna, sustains a growing pearl industry in northwestern Mexico, where a subtropical climate prevails. In tropical areas of Mexico, pearl cultivation may be profitable, but insufficient information on the biology and ecology of the species limits the definition of protocols for creating pearl farms. We measured absolute growth, growth rate, reproductive stages, changes in oocyte size, and size at first maturity of juvenile P. sterna cultivated in Bahía de Acapulco over one annual cycle (2009–2010), and compared their response in this tropical area with reports from subtropical areas of Mexico. We also compared the von Bertalanffy growth model with one proposed in this study for aquaculture purposes. The growth rate was higher during the first six months (5.3 mm month^–1) and then decreased to 3 mm month^–1 until juveniles reached a size of 60 mm in one year. Growth rates were higher in February and lower in July through September. Both models described well the growth of P. sterna, but the adjustment and the estimation of parameters was better with the proposed model. Gametogenesis started in December 2009 at 50.9 mm (males) and 59.5 mm (females); gonad development occurred continuously throughout the year with a peak in February–March (~25–26 ºC; 2.8 µg L^–1 chlorophyll a concentration), when the gonad index was highest and oocytes were larger. When compared to other studies conducted in subtropical areas, the species uses different strategies to channel available energy into growth and reproduction in tropical regions; P. sterna grows quickly in Bahía de Acapulco and may obtain the size necessary for grafting (70–80 mm shell height) in 15–17 months.