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Fatty Acid Composition of Adult and Larval Sunray Venus Clams Macrocallista nimbosa: Environmental and Gametogenic Impacts

Laramore, Susan, Sturmer, Leslie, Baptiste, Richard, Yang, Huiping, Sinacore, Carolyn, Urban-Gedamke, Elizabeth
Journal of shellfish research 2017 v.36 no.2 pp. 403-416
adults, algae, aquaculture, chlorophyll, clams, diet, females, gametogenesis, germ cells, hatcheries, larvae, males, markets, omega-3 fatty acids, polyunsaturated fatty acids, spawning, spring, temperature, turbidity, Florida
The sunray venus clam has been advanced as an alternative species to hard clams for aquaculture in Florida. Although interest and market potential are high, hatchery operators continue to experience problems with consistent year-round spawns. Gametogenesis in other species has been linked to changes in fatty acid (FA) profiles, which are in turn affected by temperature and diet. Knowledge of specific FAs that are important for the development of high-quality gametes has implications in determining optimal conditions for maturation systems. This study compared the FA profile of sunray venus clams (wild, cultured) collected from two locations during the natural fall spawning cycle to (1) determine which FAs are associated with gametogenesis and (2) assess the impact of exogenous influences. The FA profile of developing clam larvae was likewise examined to offer additional insight into endogenous and exogenous influences. Males and wild females exhibited fall spawning peaks, with the majority in gametogenesis in the spring. Males had a second spawning peak in February, and cultured females spawned continuously throughout the 6-mo study period. The FA profile appeared to be less associated with gametogenesis than with sex or exogenous influences. Decreases in n-6 PUFAs (inverse relationship) and increases in n-3 PUFAs (positive relationship) were associated with gametogenesis in males and wild females, but not cultured females, perhaps because of the protracted spawning period. Differences were noted between the sexes, regardless of month or location, with females having a higher amount of total FAs, MUFAs(16:1 n-7), and SFAs (16:0 and 14:0), but lower n-3 PUFAs (22:6 n-3). There was little difference in the FA profile of clams collected at the two locations, although the wild population tended towards higher total FAs and n-3 PUFAs. Diet (chlorophyll a concentration and turbidity) appeared to have a stronger link with changes in FA profile and gametogenesis than temperature. Discernable differences were observed in the FA composition (n-3 and n-6 PUFAs) of larvae and 5-day postset that reflected the impact of both endogenous and exogenous (diet) influences. These results indicate that algal species with select FA profiles may increase maturation, particularly in females, leading to more consistent spawns.