Growth of winged pearl oyster (Pteria penguin) juveniles: a comparison of wire collector culture and circle net culture.

摘要

The aim of this study was to identify effective techniques for the culture of the winged oyster (Pteria penguin) by comparing the growth and mortality of juveniles cultured on a self-designed wire collector and in traditional circle nets. The juveniles were hatchery reared, nearly 5 mo old, and were cultured in Li'an Lagoon, Hainan Island, China. The mean shell height (SH) and total weight (TW) of the juveniles was 26.06+or-3.43 mm and 5.85.88+or-2.258 g, respectively. They were held for 7 mo in suspended culture either on self-designed wire collectors or in circle nets. The collector was made of galvanized seizing wire, consisting of a top circle, a bottom circle, and 3 pillars between the 2 circles. Every collector was settled with approximately 150 spat and hung naturally in the sea. The oysters cultured in circle nets had three stocking densities: 10 juveniles (D10), 20 juveniles (D20), and 30 juveniles (D30) per net. Juveniles held on wire collectors and in D10 circle nets showed the greatest growth during the experiment, and had significantly greater shell height (SH), maximum diagonal length, hinge length, and TW than oysters in other densities. Oysters in D30 showed the lowest mean SH and maximum diagonal length, hinge length, and TW. Mortality ranged from 3.33% in D10 to approximately 17% for oysters in D30 and on wire collectors. When other factors such as cost of equipment, labor, and ease of construction were considered along with growth and survival, the method of natural hanging on a wire collector is highly advisable in Li'an Lagoon because this method takes advantage of the strong byssi of winged oysters, substantially reduces cost, is easy to construct, and promotes increased growth. Although the loss of oysters was relatively high, it was balanced positively by growth rate and cost reduction, because the spat are hatchery produced and easily available.