Influence of plankton concentration on gametogenesis and spawning of the black lip pearl oyster Pinctada margaritifera in Ahe atoll lagoon (Tuamotu archipelago, French polynesia)

Abstract

Pearl culture industry represents one of the dominant business sector of French Polynesia. However, it still entirely relies on unpredictable spat collection success. Our aim was to assess the influence of natural plankton concentration fluctuations on maturation and spawning of the black lip pearl oyster Pinctada margaritifera, during a 4 months survey conducted in Ahe atoll lagoon. Plankton concentration was assessed by chlorophyll a extraction and by microscope counts while gonadic index, gonado-visceral dry weights and histology were used to measure pearl oysters reproduction activity. We found that (i) plankton concentration fluctuations were mainly related to wind regime, (ii) gametogenesis rate was mainly related to plankton concentration, (iii) spawning occurred when maximal gonad storage was reached, (iv) plankton concentration was the main spawning synchronizing factor. These results contribute explaining P. margaritifera spat collection variability in French Polynesian atoll lagoon.

Seasonal variation in reproductive activity and biochemical composition of flat oyster (<em>Ostrea edulis</em>) in the Homa Lagoon, Izmir Bay, Turkey

“…Besides temperature, food availability is also affecting broodstock energy reserves and gametogenesis in bivalves (Baghurst and Mitchell 2002, Frias and Segovia 2009, Fourniera et al 2012. In this investigation, chlorophyll a and organic matter amounts were recorded as very high in the Homa Lagoon and levels are probably sufficient for the onset of gametogenesis and gonad development throughout the year.…”

Bivalve larvae transport and connectivity within the Ahe atoll lagoon (Tuamotu Archipelago), with application to pearl oyster aquaculture management

“…Better knowledge of factors controlling recruitment variability will also enable to better understand the wild populations structure and to rationalise a collecting strategy for aquaculture. In particular, gametogenesis, spawning and larval growth potential also determine spat collection variability (Fournier et al, 2012;Thomas et al, 2012). Coupling biology and physic-based approaches is now needed to perpetuate the pearl oyster aquaculture.…”

Multi-scale distribution and dynamics of bivalve larvae in a deep atoll lagoon (Ahe, French Polynesia)

“…food concentration and/or availability). Indeed, Fournier et al (2012) showed recently that P. margaritifera developed a clear opportunistic strategy of reproduction in which gametogenesis rate and spawning are directly related to plankton concentration, itself correlated to the wind speed.…”

“…In addition, abundances were negatively correlated with the distance from the eastern reef, which could partly be related to hydrodynamic effects on retention or through the effect of the compensatory current in deep layers . At last, the large scale heterogeneity in larval concentration may be related to the trophic resource heterogeneity described by Thomas et al (2010) and the opportunistic strategy of reproduction of P. margaritifera described by Fournier et al (2012), with higher plankton concentration close to the east and west reefs, corresponding to the sectors most concentrated in larvae. On the smallest scales, larval abundances were significantly correlated with temperature, salinity and food concentration, and exhibited vertical swimming behaviour leading to vertical structuring of abundances.…”