Reproductive biology of the rayed pearl oyster (Pinctada imbricata radiata, Leach 1814) in Izmir Bay

Abstract

The present study was carried out to determine gonadal stages and quality of pearl oyster meat (Pinctada imbricata radiata, Leach, 1814) in Izmir Bay (Turkey). Pearl oyster samples were collected from the study area at a depth of ~5 m between February 2013 and January 2014. The highest and lowest temperature was measured in July and January as 27°C and 14.2°C, respectively. The maximum chlorophyll a value of 4.640 μg l−1 was calculated in May and the lowest value of 1.009 μg l−1 was recorded in April. Individuals reached their first maturity in April. Spawning activity was observed from June to September and the gonad index (GI) was at the highest level during those months. The development was observed from April to February. The overall female to male ratio was 1.32:1 (p < 0.05) and it did not affect the GI (p > 0.05). There is a strong positive correlation between the GI and temperature (p < 0.05). The highest condition index (CI) was recorded in May as 12.31 ± 0.51, whereas the lowest one in January as 7.37 ± 0.22. As a result, this study revealed that the pearl oyster population in the region is characterized by high reproductive activity, especially during the summer months.

Growth and Survival Performance of Smooth Scallop (Flexopecten glaber Linnaeus, 1758) at Different Depths in the Aegean Sea

“…The food sources of the scallops are phytoplankton, detritus, bacteria, and other organic substances that it filters from the water (Bricelj & Shumway, 1991, Beninger & Decottignies 2005. While high nutrient availability is assumed to increase both tissue and gonad growth, nutrient deficiency basically directs metabolic energy to maintain reproductive activity (Delgado & Perez-Camacho, 2005;Yigitkurt, 2021). In this study, seasonal chlorophyll-a peaked throughout the water column in July and August.…”

Rayed pearl oyster Pinctada radiata (Leach, 1814) (Bivalvia: Pteriidae) in the eastern Adriatic Sea – recent observations

“…During the study around the island of Linosa in the Sicilian Channel (Italy), both adult and juvenile specimens were observed and a maximum size of 78.7 mm was recorded [15]. The average value of shell height (64.78 mm) corresponds to the average shell height of samples collected in 2017 [14] and those from the Aegean Sea [19], as well as samples from Turkey [20,21] and Tunisia [22]. The biometric parameters measured in the samples collected in Montenegro, the nearest observed established population, were lower, the shell height ranged from 32 mm to 52 mm with an average shell height value of 38.3±6.1 mm [12].…”

Spat efficiency of the smooth scallop Flexopecten glaber in the Aegean Sea, Türkiye

“…The high variability in the natural collection of scallops is a common feature of many pelagic bivalve species in the larval stage; therefore, detailed knowledge of settlement patterns and spat availability is needed to reduce costs and labor (Cry et al 2007;Papa et al 2021). The abundance of spat on collectors can be influenced by several factors: spawning season, time of collector deployment, suitability of the substrate, fouling and/ or predation, food availability, and water conditions (Avendano et al 2007;Acarli et al 2011;Yiğitkurt et al 2020;Yigitkurt 2021). After spawning, scallop larvae swim for 3-4 weeks until metamorphosis; it is very important to deploy the collectors two weeks before this period (to ensure that a microfilm layer forms on the collectors).…”