162 S
.K. Meidel et al. J. Exp. Mar. Biol. Ecol. 240 1999 161 –178
1. Introduction
Larval survival and development can have a pronounced effect on the rates of settlement and recruitment, and hence on the distribution, demography, and dynamics of
adult populations of benthic marine invertebrates Scheltema, 1986; Grosberg and Levitan, 1992; Balch and Scheibling, 1999. To a great extent, rates of survival and
development of larvae are determined, either directly or indirectly, by larval nutritional condition. For planktotrophic larvae, it is well established that food quality and quantity
have a direct positive effect on larval condition, manifested by increased survival and growth, and by accelerated development and metamorphosis e.g. Gastropoda: Aldana
Aranda et al., 1989; Bivalvia: Strathmann et al., 1993; Decapoda: Anger, 1984; Asteroidea: Lucas, 1982; Echinoidea: Hart and Strathmann, 1994; Holothuroidea:
Martinez and Richmond, 1998. Maternal reproductive characteristics such as fecundity, egg size, and egg quality also can be affected by food quality and quantity e.g. Bayne et
al., 1978; Thompson, 1982; George et al., 1990, 1991; Qian, 1994; Lucas and Lawes, 1998. However, because planktotrophic larvae obtain nearly all of their energy from
sources other than the egg, possible effects of maternal condition as manifested by egg size or quality on larval development have been largely ignored in this group. In the
few studies which have addressed this issue, maternal condition was shown to influence characteristics of planktotrophic larvae such as size, chemical composition and survival
rate; however, when present, these effects were small or did not persist throughout the developmental period e.g. George, 1990; George et al., 1990; de Jong-Westman et al.,
1995b; Guisande and Harris, 1995; Bertram and Strathmann, 1998; Lucas and Lawes, 1998. The relative importance of parental condition and larval feeding on larval
survival and development remains largely unknown but see Bertram and Strathmann, 1998.
¨ Strongylocentrotus droebachiensis Muller is the dominant herbivore in the shallow
rocky subtidal zone in the northwest Atlantic, where it undergoes periodic population outbreaks leading to the destruction of kelp beds and formation of sea urchin-dominated
barren grounds Mann, 1977; Wharton and Mann, 1981. Following this transition, gonadal production of sea urchins decreases in barrens with the reduction in macroalgal
food availability Lang and Mann, 1976; Johnson and Mann, 1982; Meidel and Scheibling, 1998. Differences in adult nutrition which affect fecundity also may
influence egg quality in sea urchins from kelp beds and barrens. Recent studies of S
. droebachiensis have shown that larvae from parents raised on different artificial diets in
the laboratory de Jong-Westman et al., 1995b, or collected from different natural habitats Bertram and Strathmann, 1998, differ in their rates of development, growth
and survival.
In this study, we investigate the relative importance of parental nutritional con- ditioning and larval food ration on the size and morphology of larvae of S
. droebach- iensis, and their rates of development, survival and metamorphosis, in a laboratory
experiment. We also measure the size of juveniles shortly after settlement to determine whether differences in larval quality persist beyond metamorphosis. To circumvent the
confounding of geographic genetic variability and adult nutritional condition e.g. George, 1990; George et al., 1990; Bertram and Strathmann, 1998, we use juveniles
S .K. Meidel et al. J. Exp. Mar. Biol. Ecol. 240 1999 161 –178
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from a single locality and rear them to reproductive maturity under tightly controlled conditions. Because food quality and quantity varies widely between adult populations in
kelp beds and barrens Meidel and Scheibling, 1998, any effect of parental nutrition on larval survival and metamorphosis may influence the overall reproductive success of this
species. Understanding the potential importance of parental condition in determining larval quality may shed light on the population dynamics of sea urchins in shallow water
communities.
2. Materials and methods
