Wind-driven settlement patterns in the acorn barnacle Semibalanus balanoides

Abstract

We quantified daily larval settlement of the acorn barnacle Semibalan~is balanoides in a small embayment within Narragansett Bay, Rhode Island, USA, to examine the hypothesis that local wind patterns influence shoreline settlement. Daily larval settlement and the accumulation of barnacle recruits were both strongly correlated with local wind patterns within and among years. When prevailing winds were out of the south, larval settlement was enhanced on the northern side of the bay, whereas when winds were out of the north, larval settlement was enhanced on the southern side of the bay. These patterns were observed over 2 settlement seasons and led to daily as well as interannual spatial patterns in both larval settlement and the accumulation of barnacle recruits. The patterns of shoreline settlement appear to be caused by wind-induced changes in larval concentrations on different sides of the bay. Water column larval densities were strongly correlated with daily wind patterns. Larval densities were always highest on the down-wind side of the bay. Our data show that spatial and temporal patterns in the settlement of benthic invertebrates can be strongly linked to local weather conditions through the transport of larvae by wind-dr~ven currents.

Spatially heterogeneous, synchronous settlement of Chthamalus spp. larvae in northern Baja California

“…Studies of larval settlement and recruitment at larger scales (100s of meters to kilometers) have yielded mixed results (Ebert et al 1994, Jenkins et al 2000, Connolly et al 2001, O'Riordan et al 2004. Spatial coherence in settlement over larger scales has been interpreted in terms of mesoscale patterns of retention/advection associated with coastal upwelling (Ebert et al 1994), or spatially-consistent onshore winds across a large area (Bertness et al 1996, Jeffery & Underwood 2000. Spatial heterogeneity in settlement numbers, on the other hand, has been interpreted as a result of the interaction between small-scale variability of transport mechanisms and larval behavior.…”

“…These mechanisms include wind-induced upwelling and relaxation (Farrel et al 1991, Wing et al 1995a,b, Shanks et al 2000, surface winds and currents (Hawkins & Hartnoll 1982, Bertness et al 1996, linear internal waves (Norris 1963, Shanks 1983, 1987 and internal tidal bores (Pineda 1991, 1994a, 1999, Pineda & López 2002. Once larvae have been transported onshore, settlement patterns may be determined by smaller-scale factors such as nearshore hydrodynamics, larval behavior, and substrate availability (Pineda 2000).…”

Stage-specific distribution of barnacle larvae in nearshore waters: potential for limited dispersal and high mortality rates

“…Thus, local populations have been regarded as open subunits that contribute with their reproductive output to an offshore pool of larvae, and field-based research has focused on the physical processes that may transport competent larvae back to adult habitats. Timing and spatial distribution of larval settlement have been linked to the occurrence of phenomena such as linear internal waves (Norris 1963, Shanks 1983, internal tidal bores (Pineda 1991(Pineda , 1994a, persistent onshore winds (Bertness et al 1996), and the onshore displacement of surface waters during relaxation of wind-induced upwelling (e.g. Wing et al 1995).…”

Causes of decoupling between larval supply and settlement and consequences for understanding recruitment and population connectivity

“…The effects of coarse-to large-scale hydrodynamics 16 on larval supply have been inferred from measurements of larval concentrations and time series 17 of physical measurements that characterize the hydrodynamic processes (e.g., Garland et al, 18 2002;Shanks and Brink, 2005). In other studies, coarse-to large-scale hydrodynamic processes 19 are correlated to time series of larval settlement, but larval concentrations in the water are not 20 measured (e.g., Bertness et al, 1996;Jacinto and Cruz, 2008). Some studies have measured both 21 larval concentrations and settlement (e.g., Jeffery and Underwood, 2000;Ma, 2005;Porri et al, 22 2006;Dudas et al, 2009), and recruitment (e.g., Palma et al, 2006;Rilov et al, 2008), to 1 determine the relationship with hydrodynamics.…”