Consequences of maternal isolation from salinity stress for brooded embryos and future juveniles in the estuarine direct‐developing gastropod Crepipatella dilatata

Sedentary, shallow-water marine invertebrates have many ways to cope with environmental stress. In responding to salinity changes, for example, marine bivalves and gastropods typically use their shells as barriers: bivalves simply close their valves (Shumway 1977; Djangmah et al. 1979), while some gastropods can adhere tightly to a hard substrate (Fretter 1984; Chaparro et al. 2011), thereby isolating the mantle cavity from the external environment. Although such behaviors can maintain high salinities in the mantle cavity for long periods of time, despite greatly reduced external salinities (Chaparro et al. 2009a), they can create other problems, particularly for brooded embryos, as water quality within the mantle cavity gradually deteriorates (Chaparro et al. 2009a). Such deterioration can include severe reductions in pH (Montory et al. 2009), accumulation of ammonia and other toxic excretion products (Chaparro et al. 2009a, 2011), and greatly decreased concentrations of dissolved oxygen (Chaparro et al. 2009a; Segura et al. 2010). Such conditions can have an immediate impact on incubated embryos, such as dissolution of the embryonic shell and cessation of further embryonic shell growth (Chaparro et al. 2009b; Montory et al. 2009), delayed hatching (Pechenik 2006), and increased energy costs through the activation of anaerobic pathways (Segura et al. unpubl). Sublethal stresses experienced during brooding may also affect the offspring well after the stress has ended, although Abstract At reduced salinities, brooding females of some gastropods and bivalves may isolate their mantle cavities from the environment for several days, maintaining internal osmotic concentration but causing severe declines in dissolved oxygen and pH, and increases in ammonia and other toxic substances in the mantle fluid. This study in November–December examined the immediate consequences of such stresses for brooded embryos of Quempillén estuary gastropod Crepipatella dilatata, in terms of time to juvenile emergence and rates of embryonic growth [measured as shell length (SL)]. Juveniles were also monitored for latent effects on feeding rates, oxygen consumption, and growth for the first 4 weeks after emergence into normal salinity seawater. An acute salinity stress lasting 3 days applied to females that were brooding pre-shelled or intermediateshelled stages increased embryonic incubation periods, but without affecting SL at emergence. Growth rates were reduced for encapsulated embryos regardless of the stage at which the salinity stress was applied. Latent effects on juvenile development included slower shell growth and reduced rates of oxygen consumption and feeding. These effects were sustained for the first month after release from the female. The results suggest that marked reductions in salinity lasting for several days indirectly but negatively