Effect of epinephrine and seawater turbulence on the metamorphosis of the great scallop

Abstract

Bivalve metamorphosis is defined by anatomical, morphological and physiological transformation. Despite its importance, few studies have been devoted to this critical phase of Pectinidae (Cragg and Crisp, 1991). The development of reliable hatchery technology (Loosanoff and Davis, 1963) allowed a better knowledge of this phase, with the first research focusing mainly on describing organogenesis (Sastry, 1965). Since 1985, the role of chemical cues has been investigated. Its influence on metamorphosis has been studied in detail in Pacific oysters, Crassostrea gigas (Coon et al., 1985) and C. virginica (Coon et al., 1986) and in the European oyster Ostrea edulis (Shpigel et al., 1989). However, for Pectinidae these kinds of data are sparse (Kingzett et al., 1990;Chevolot et al., 1991). Nevertheless, during metamorphosis, the process of fixation differs greatly between Pectinidae and Ostreidae, the latter being characterized by cementation during settlement. Consequently, the chemical cues involved and the control pathway could be different.Some experiments have suggested enhancement of bivalve setting by physical factors; the role of these sensory inputs in oyster metamorphosis has been schematized by Bonar et al. (1990). Shpigel et al. (1989) have shown that exposure of O. edulis larvae to either epinephrine or shell chips alone resulted in similar rates of metamorphosis. Consequently, the relative importance of the two types of cues, chemical and physical, needs to be clarified. Such a study has been carried out at the experimental mollusc hatchery of Argenton (Britanny, France), C. gigas and the great scallop (Pecten maximus) being the two biological models used. The purpose of this research was to develop a reliable method to enhance the rate of metamorphosis of the great scallop.The effect of epinephrine, abundantly described in the oyster, and the influence of seawater flow rate, which seems to be of great importance for the Pectinidae

Influence of exogenous chemicals on larval development and survival of the king scallop Pecten maximus (L.)

“…A C C E P T E D M A N U S C R I P T 13 growth, is similar to that witnessed in previous studies (Nicolas et al, 1996;Nicolas et al, 1998;Robert and Nicholas, 2000).…”

“…P. maximus is known to exhibit protracted metamorphosis over a 2 to 3 week period, during which 35 to 70% of larvae metamorphose, with metamorphosis in the first week often not exceeding 5% (Nicolas et al, 1996;Nicolas et al, 1998;Robert and Nicholas, 2000).…”

“…Epinephrine 1 -10 X X Chevolot et al, 1991;Nicolas et al, 1996;Nicolas et al, 1998 Homogentisic acid 1 X Chevolot et al, 1991 Jacaranone 0.5 X Chevolot et al, 1991 L-DOPA 1 -5 X Chevolot et al, 1991;Nicolas et al, 1998 A C C E P T E D M A N U S C R I P T 8 equivalent to 30 cells μl -1 day -1 , consisting of Pavlova lutheri (PLY75), Isochrysis sp. (clone T-ISO) (PLY506A) and Chaetoceros calcitrans (PLY537) at a ratio of 1:1:1.…”

“…The influence of chemical cues cannot be considered in isolation to other factors. Several studies have demonstrated that bivalves settle or metamorphose more readily in the presence of seawater turbulence (Eyster and Pechenik, 1987;Nicolas et al, 1996;Nicolas et al, 1998). In P. maximus cultures in still water conditions and without chemical induction, the metamorphosis rate after 1 week rarely exceeds 5%, however turbulence alone has increased metamorphosis of this species by as much as 16% (Chevolot et al, 1991;Nicolas et al, 1996;Nicolas et al, 1998).…”

“…Several studies have demonstrated that bivalves settle or metamorphose more readily in the presence of seawater turbulence (Eyster and Pechenik, 1987;Nicolas et al, 1996;Nicolas et al, 1998). In P. maximus cultures in still water conditions and without chemical induction, the metamorphosis rate after 1 week rarely exceeds 5%, however turbulence alone has increased metamorphosis of this species by as much as 16% (Chevolot et al, 1991;Nicolas et al, 1996;Nicolas et al, 1998). Additionally the provision of adequate nutrition, both in terms of quantity and quality, is also critical to larval development in P. maximus (Nicolas and Robert, 2001;Tremblay et al, 2007).…”