Growth and survival of the Calafia mother-of-pearl oyster Pinctada mazatlanica (Hanley 1856) under different sequences of nursery culture-late culture at Bahía de La Paz, Baja California Sur, México

Abstract

The Calafia mother‐of‐pearl oyster, Pinctada mazatlanica (Hanley), and the Rainbow nacre shell, Pteria sterna (Gould), represent an important resource for México because of their potential in pearl production. The present work deals with the effect of different sequences of nursery culture‐late culture on growth and survival of P. mazatlanica, from September 1993 to October 1994. The collected spat presented two main size groups: small (mean shell height of 7 mm), and large (13 mm). They were arranged into four experimental batches for each size group at a constant stocking density of 40–45 juvenile pearl oysters per Nestier cage. Three batches remained in nursery culture for 2, 4 and 6 months respectively, after which they were transferred to late culture in rail cages. A control group remained in nursery culture for 12 months. Growth was evaluated monthly and compared through anova and HSD Tukey tests. In addition to the shell height, width, depth (mm) and weight (g), data of shell volume (height × width × depth, in mm3) was also introduced to estimate and compare growth among the experimental groups. Mortality was estimated by counting the dead specimens every month and obtaining the percentage from a 100% initial survival at the start of the experiment. The juveniles showed different responses to the change from nursery culture to late culture; the level of each response varied significantly among the experimental groups at the end of the study. It seemed that a 6‐month period for nursery culture was propitious for P. mazatlanica.

Growth and survival of the pearl oyster Pteria hirundo (L.,1758) in an intermediate stage of culture in Santa Catarina, Brazil

“…The small seeds of pearl oysters are more vulnerable, as shown by Monteforte and Morales-Mulia (2000), whom also recommend a careful handling, with a frequency of 2 months, in order to avoid damage to the byssus. They also pointed out the necessity to further study the stock density and cleaning effects on P. mazatlantica.…”

“…They also pointed out the necessity to further study the stock density and cleaning effects on P. mazatlantica. However, for Pinctada mazatlantica, as well as for Pteria sterna, preliminary studies indicated that the collectors should be recovered not later than 3 months after immersion, otherwise high seed mortality can occur as a result of predation and competition among associated species (Monteforte and Garcia-Gasca, 1994;Monteforte and Wright, 1994;Monteforte et al, 1995;Wright, 1997).…”

“…In Mexico, there are several studies with Pteria sterna (Gould, 1851) and Pinctada mazatlantica (Hanley, 1846) (Monteforte and Cariño, 1992;Monteforte and Garcýa-Gasca, 1994;Monteforte and Wright, 1994;Monteforte, et al, 1995;Monteforte et al, 1996;Monteforte and Morales-Mulia, 2000). Pinctada imbricata (Roding, 1758) is studied in Venezuela, Colombia (Borrero, 1994;Pico et al, 1999), andAustralia (O'Connor andLawler, 2004), showing good culture potential.…”

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

“…Culture artifacts and pearl oysters were surveyed monthly (cleaning, counting, measuring, repartition), and salinity (ppm) and water temperature (°C) were recorded. At the end of nursery culture, half of the surviving individuals of each D group were transferred into sandwich nets (S) which were vertically suspended at a depth of 10-11 m. The other half were transferred to rail cages (C) which were placed horizontally over iron rod structures on the sea bottom at a depth of 12 m. Details of manufacture and management can be seen in Monteforte and Morales (2000). Individuals were arranged in rows along the shelves of these artifacts.…”

“…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).…”