THIS ARTICLE HAS BEEN RETRACTED: Effects of diet, stocking density and environmental factors on growth, survival and metamorphosis of clam, Paphia malabarica (Chemnitz) larvae

Abstract

R e t r a c t e dEffects of diet, stocking density and environmental factors on growth, survival and metamorphosis of clam, Abstract A series of experiments were conducted to evaluate the e¡ects of diet, stocking density and environmental factors on the growth, survival and metamorphosis of short neck clam Paphia malabarica larvae. These experiments examined the following factors: diet [Isochrysis galbana, Nannochloropsis salina and a mixture of I. galbana and N. salina (1:1 w/w)], stocking density (1, 3, 5 and 7 larvae mL À1 ), light intensity (unshaded, partially shaded and fully shaded) and water ¢ltration (un¢ltered and sand ¢ltered). Results indicated that N. salina could replace 50% of I. galbana as a food source for the clam larvae with an increase in growth, survival (47.2%), metamorphosis (33.5%) and early settlement. Larval growth decreased signi¢cantly with increasing stocking density. A density of 1^3 larvae mL À1 appeared to be optimal for normal growth of clam larvae. Neither diet nor stocking density used in the study had a signi¢cant e¡ect on larval survival. Under partially shaded (light intensity 51000^5000 lx) and fully shaded (light intensity o1000 lx) conditions, larval growth was signi¢cantly faster than under direct sunlight (unshaded). Larvae grew signi¢cantly faster in the un¢ltered water than in the ¢ltered water.

Effects of stocking density, temperature, and salinity on larval survival and growth of the red race of the sea cucumber Apostichopus japonicus (Selenka)

“…3 Percentages of deformed, early-, mid-, and late auricularia and dolilaria larvae of red A. japonicus on day 9 at different salinities fecal material and discarded food material with increasing stocking density may lead to microbiological problems and a buildup of ammonium, which is deleterious to larvae in culture (Sastry 1979). In addition, competition for space and food may be another reason why at high densities the larvae grew at a slower rate than at lower densities (Yan et al 2006;Raghavan and Gopinathan 2008). Therefore, for red A. japonicus, a culture density of 0.5-1 larvae/ml is recommended for larvae before feeding, and 0.1-0.2 larvae/ml is appropriate after feeding begins.…”

Effects of stocking density, ration and temperature on growth, survival and metamorphosis of auricularia larvae of the California sea cucumber, Parastichopus californicus

“…High stocking density has been reported to negatively affect larval growth, survival and metamorphosis in many marine invertebrate species (Aldana‐Aranda, Lucas, Brule, Salguero & Rendon, ; Daume, Huchette, Ryan & Day, ; Li & Li, ; Liu, Dong, Tang, Zhang & Xiang, ; Liu et al., ; Sprung, ). Rearing at high densities can result in mechanical/physical interference between larvae, accumulation of particulate waste and deterioration of water quality, which are all factors that may negatively influence larval survival and metamorphosis (Avila, Grenier, Tamse & Kuzirian, ; Basch, ; Liu et al., ; Raghavan & Gopinathan, ; Sprung, ). Cragg () found that the collision of individuals of scallop larvae caused abrupt cessation of the beating of the preoral cirri and closure of the valves, which can result in inhibition of feeding activity and increased energy expenditure for body homeostasis (Liu et al., ).…”

Combined effects of temperature, salinity and rearing density on growth and survival of juvenile ivory shell, Babylonia areolata (Link 1807) population in Thailand

“…However, Chaitanawisuti and Kritsanapuntu (1998) reported that growth, in both shell length and body weight, and survival of juvenile B. areolata were not affected by stocking rearing density using component experimental design (50, 100, 150 and 200 ind m À2 ). The negative effects of high rearing density on growth and survival of economic aquaculture animals suggests there is rearing density-dependent intraspecific competition for space and food (Parsons & Dadswell 1992;Foster & Stiven 1996;Huchette, Koh & Day 2003;Yan, Zhang & Yang 2006;Raghavan & Gopinathan 2008;Velasco & Barros 2008). First, there are differences between stocks and cultivation sites.…”

“…The differing results can be explained in two ways. Reduced growth and survival at higher rearing densities may be attributable to a deterioration of water quality (De Blok1972; Kinne1976; Raghavan & Gopinathan 2008). Next, the range of rearing densities was very narrow in the experiment of Kritsanapuntu (1998).…”

“…(1) Generally, B. areolata perch in the sand layer when feeding, however, if rearing density was too high, there would not be enough space in the crowded sand layer, which increases the probability of physical collision and associated damage, and the healing process would slow growth rate (Foster & Stiven 1996;Huchette et al 2003;Yan et al 2006;Raghavan & Gopinathan 2008;Kritsanapuntu, Chaitanawisuti, Santhaweesuk & Natsukari 2009). (2) If temperature and rearing densities were high, a change in the physicochemical properties of water, and an associated decline in water quality, in the breeding tank would occur.…”