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

Abstract

This study was carried out to determine the spat efficiency of the smooth scallop Flexopecten glaber (Linnaeus) in surface and bottom water at the Ozbek coast (Türkiye) of the Aegean Sea from September 2017 to August 2018. The environmental parameters (temperature, salinity, chlorophyll-a, and total particulate matter) were also monitored at two depths. The average water temperature at the surface and bottom were 19.79 ± 5.62°C and 19.73 ± 5.24°C, respectively. The lowest chlorophyll-a values were recorded in February (1.12 g l-1) and June (1.23 µg l-1) at the surface and bottom, respectively. The highest chlorophyll-a value was recorded in August at both depths. Throughout the study, the number of F. glaber on the collectors was 270.33 ± 43.54 spat m-2 and 145.66 ± 18.03 spat m-2 were detected on the bottom collectors. A statistically significant difference was found between the growth of the spat attached to the surface and bottom collectors (p < 0.05).

From Isolated Valves to a Potential Marine Living Resource: History, Documented Distribution and Sustainable Population Enhancement Possibilities of the Smooth Scallop (Flexopecten glaber) on the Romanian Coast

“…In the Ionian Sea, spawning is reported between February and early August; the larvae swim for three to four weeks before settling, at water temperatures ranging from 15 • C to 18 • C [34]. In the Turkish Aegean (Izmir Bay), two spawning peaks were determined, in November/December and July/August, respectively, at water temperatures ranging from 12 • C to 28 • C [45]. In the Black Sea, the spawning period of the smooth scallop peaks in June and July [29], when seawater temperature is usually around 25 • C [46].…”

“…There are several collector types that can be used for smooth scallop spat settlement. The Turkish model [45] consists of individual collector systems made from 50 cm x 20 cm polyethylene mesh bags set on polyvinyl chloride (PVC) pipes, with a mesh size of the polyethylene bag of 5 × 4 mm. The collector system is designed as a surface and bottom collector.…”

“…The upper end of each rope is then tied to a longline submerged at 4 m depth so that collectors remain submerged from 5 to 14 m [41]. Using any of the collectors described, the highest number of spat settled closer to the seabed and density decreased towards the surface [34,41,45]. This tendency of spat to settle in deeper substrates may be explained by the need to avoid strong wave action, water turbulence and excessive fouling [48,49].…”

“…It is essential to deploy the collectors two weeks before the larvae settle to ensure that a microfilm coating forms [45]. Whereas peak spawning of Black Sea F. glaber is expected in July, the collectors should be deployed at sea in mid-June, aiming to maximize spat recruitment.…”