Adult demography and larval processes in coastal benthic populations intertidal barnacles in Southern California and Baja California

The geographic distribution and dynamics of coastal benthic populations are shaped by physical biological interactions affecting larval dispersal and the demography of juvenile and adult individuals. This thesis focused on nearshore patterns of larval distribution and regional patterns in demography of intertidal barnacles in Southern and Baja California. Horizontal and vertical distributions, and the mortality rates of larvae, were assessed from short tenn (i.e. days) smallscale observations (0.1-1 km) in nearshore waters. Observations on spatial variability of adult barnacle demography were gathered over 1.5 years at scales of hundreds of kilometers. Stage-specific horizontal distributions and nearshore current measurements suggested that larvae of Balanus glandula and Chthamalus spp. may experience limited dispersal. High mortality rates could further limit travel distances and the exchange of individuals among disjunct populations. Data on vertical distributions indicated that nauplii and cyprids of Balanus nubilus and Pollicipes polymerus occur at different depths. Nauplii remained near the surface at all times, whereas cyprids occurred in the bottom half of the water column. Such distributions, combined with vertical variability in horizontal flows, might cause the observed horizontal segregation ofnauplii and cyprids. Differences in survival, growth rate,· size structure, and per capita fertility of adult Balanus glandula were observed between Dana Point (Southern California) and Punta Baja (Baja California), a site located near the species' southern limit of distribution. Effects of spatial differences in demography on population persistence were assessed with a stage-structured matrix model. Model analyses indicated that the Punta Baja population is more susceptible to environmental stochasticity and more prone to local extinction than populations located further north. This thesis emphasizes the importance of characterizing factors that affect the dynamics of benthic populations at mUltiple spatial-temporal scales, and the usefulness of small· scale highfrequency observations of nearshore phenomena, especially in relation with the dispersal of larvae.

Grantor dc:publisher

Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

Year dc:date.issued

2005

Author dc:creator

• Tapia, Fabian J.

• Benthic animals
• Larvae
• Dispersal

Language dc:language.iso

en_US

DOI

10.1575/1912/1709

OAI identifier oai:identifier

oai:darchive.mblwhoilibrary.org:1912/1709