Extreme spatial variation in the growth and reproductive output of the acorn barnacle Semibalanus balanoides

Abstract

Geographic vanahon in secondary production can profoundly influence populahon and community processes yet is rarely studied in benthic manne organisms In this paper w e document stnlung vanahon withln and among locations in the growth and reproducbve output of the acorn barnacle Sernlbalanus balanoides and discuss the potential consequences of our results on understanding recruitment and other population processes Within Narragansett Bay (Rhode Island, USA) barnacle growth and reproduction is far greater than at nearby open coast locations At comparable tidal heights recruits in the Bay grew to nearly twice the basal diameter and had almost 10 times the reproductive output compared to recruits on the open coast Transplant experiments suggest that the high secondary production of Bay barnacles is largely a phenotypic response to high primary production Within-and among-site patterns in barnacle secondary production associated with enhanced flow velocities were also conspicuous Barnacles at low tidal heights, in habitats exposed to large tidal currents and in waveexposed habitats had higher growth and reproduction than barnacles at hlgher tidal heights or habltats with lower velocities Water column food concentrations and fluid velocities both strongly influence barnacle growth and reproduction through their combined effects on the flux of food to indi\~lduals Our results imply that predictable variation in food supply rates may lead to important and equally predictable consequences on regional larval production and the density-dependent dynamics of adult benthic populations

Strong influences of larval diet history on subsequent post–settlement growth in the freshwater molluscDreissena polymorpha

“…Although the observed significant differences in postmetamorphic growth capacity among cohorts recruiting on different days could have a genetic basis (Bertness & Gaines 1993;Hilbish et al 1999), these differences in growth capacity may ultimately result in considerable variation among daily cohorts in survival and recruitment success. This is because individual size can influence vulnerability to predation (Kornobis 1977), as well as the outcome of competitive interactions (Connell 1961;Bertness 1989).…”

Barnacle reproductive hotspots linked to nearshore ocean conditions

“…Nonetheless, empirical examples of bottom-up effects on marine populations and communities are relatively rare, in part because of the difficulty of manipulating potential factors on the appropriate spatial and temporal scales (3,20). Here we test whether bottom-up ecological processes, specifically variation in nearshore primary productivity on the scale of 10s of kilometers, influences reproductive output in an ecologically and scientifically important primary consumer, the intertidal barnacle Balanus glandula.…”

“…First principles suggest why organisms in some places should produce more offspring than those in other places, e.g., due to genetic or environmental variation. Yet few empirical examples (3)(4)(5)(6)(7)(8) exist from marine populations of spatial variation in reproductive output at scales relevant to management (10s to 100s of kilometers). Moreover, marine population models for reserve design often include the assumption that the coastal ocean is a wellmixed and fairly uniform environment, where potential recruits to the adult populations are part of a global ''pool'' (9).…”

Recruitment, abundance, and predation on the blue mussel (Mytilus edulis) on northeastern estuarine rocky shores

“…In initiating this study, we specifically selected sites within each estuary so as to examine the possible influence of location (inner vs. outer bay) on mussel population dynamics. We hypothesized that adult abundances, recruitment rates, and consumer pressure would be elevated at inner bay sites, in keeping with previous investigations where enhanced nutrients and primary productivity have been shown to fuel increased biomass and reproduction of primary consumers like mussels and barnacles, and to contribute to more rapid succession and intensified species interactions (e.g., Bertness et al 1991, Menge et al 2003, Leslie et al 2005.…”

“…Half of the sites in each estuary were within each of the location categories (i.e., n ¼ 2 inner bay and n ¼ 2 outer bay sites per estuary for the recruitment monitoring and consumer exclusion experiment; n ¼ 3 inner bay and n ¼ 3 outer bay sites per estuary for intertidal surveys). Inner bay sites tend to be exposed to higher inputs of land-based nutrient pollution and more variable salinity (Valiela et al 1992, National Research Council 2000, Boesch et al 2001, Nixon et al 2008, whereas outer bay sites tend to have greater oceanic influence, and consequently lower primary productivity and more stable salinity (e.g., as reported in Bertness et al 1991). All sites were characterized by minimal tidal currents and wave action (i.e., they were wave-protected), and dominated by continuous rocky benches.…”