Effect of stocking density on growth, settlement and survival of clam larvae, Meretrix meretrix

Effect of stocking density and food ration on growth and survival of veliger and pediveliger larvae of the taquilla clam Mulinia edulis reared in the laboratory

“…On the other hand, Yan et al (2006), working with the japanese clam Ruditapes philippinarum, found no difference in growth between densities of 10, 15 and 20 larvae ml -1 . Larval cultures of the clam Meretrix meretrix (Liu et al 2006) at densities of 5, 10, 20, 40 and 60 larvae ml -1 presented the same tendency, showing no difference for densities of 10, 20 and 40 larvae ml -1 , and a difference for 5 larvae ml -1 , which presented a greater growth. Liu et al (2006) recommend using moderate densities of 10 to 20 larvae ml -1 for massive hatchery production, because they allow rapid growth, short settling times and high survival rates.…”

“…The decrease in survival of cultures with an initial density of 20 larvae ml -1 may be explained according to the proposition of Liu et al (2006), which attributes high mortality in larviculture to poor water quality or diseases. As the stocking density increases, more metabolic waste matter is accumulated in the water, which produces a decrease in its quality and also if the ration is equal for different larval densities than the availability of food is inversely to the stocking density.…”

“…The most critical stage of the production of seeds is the settlement, between a pediveliger larvae that initiates metamorphosis and postmetamorphic growth, until postlarvae reach a size of 1 mm (Helm & Bourne 2004). Larvae are highly sensitive to environmental factors, which can affect their growth and therefore their artificial culture stages (Liu et al 2006). The effects of density on clam culture are well documented (Hadley & Manzi 1984, Beal & Kraus 2002, Royo et al 2002, Helm & Bourne 2004, Royo et al 2005; however many of these studies were mainly focused on juveniles (valvar lengths from 3.9 mm to 10-15 mm), with very little attention to the postlarval stage.…”

“…The effects of density on clam culture are well documented (Hadley & Manzi 1984, Beal & Kraus 2002, Royo et al 2002, Helm & Bourne 2004, Royo et al 2005; however many of these studies were mainly focused on juveniles (valvar lengths from 3.9 mm to 10-15 mm), with very little attention to the postlarval stage. Liu et al (2006) tested several stocking densities (5, 10, 20, 40 and 60 larvae ml -1 ) for the clam Meretrix meretrix to study their effect on larval settling, shell size, time and survival showing an inverse relationship between rearing density and larvae final size. Oliva et al (2013) determined the effect on stocking density and type of diet on the growth and survival of M. edulis postlarvae cultivated in sand at densities of 5, 10 and 20 postlarvae cm -2 .…”

Metabolic profiling of mussel larvae: effect of handling and culture conditions

“…After 10 days of rearing, mean levels of fumarate and succinate were both lower in the flow through system, which indicates subtle differences in central carbon metabolism, aerobic respiration, and energy production through variations in larval activity and/or nutrient assimilation and conversion. Stocking density is known to affect larval bioenergetics due to changes in animal behaviour (Liu et al 2006 ), and may partially explain the variation in TCA cycle intermediates between the different rearing conditions. Free amino acids (FAA's) and free fatty acids (FFA's) were responsible for the majority of other dissimilarities between the flow through and static systems.…”