PARENT SESSION
OOS 1: Genetic Explorations of the Seascape: Using Molecules and Experiments to Understand Marine Biodiversity.
Organized by: E Sotka and R Thacker
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room E 141 .

Can gene flow tell us where the larvae go: Assessing population connectivity in kelp bass.

Selkoe, Kimberly^*,1, ¹ University of California Santa Barbara, Santa Barbara, CA

ABSTRACT- Many aspects of marine larval dispersal are poorly understood due to the challenges of tracking marine larvae in the plankton. I used microsatellite marker analysis to address the patterns of larval dispersal for kelp bass, Paralabrax clathratus, a common predator in kelp forests between southern Baja and Central California. Kelp bass have a 30-day pelagic larval phase during summer and fall. At the regional scale, I assessed spatial and temporal changes in the genetic makeup of pulses of recruits collected biweekly over 2 summers at 5 sites in the Santa Barbara Channel. Abrupt genetic differences occurred sporadically among sites and within sites over the 2 year period. These genetic shifts do not appear to be caused by high genetic drift, selection or localized reproduction. Rather, the timing and location of genetic shifts correspond to shifts in current boundaries, suggesting that changes in larval source were the cause of the genetic changes. Large pulses of larval input often coincided with southward flow despite the sharp decline in kelp bass abundance to the north of the Channel. These pulses were also often genetically distinct, suggesting that small, peripheral populations can be important larval sources for, and significant genetic contributors to, large central populations. At the range-wide scale, I investigated the spatial co-variation in gene flow, abundance, genetic diversity and regional summer circulation patterns to address long-term effects of connectivity on the species' population dynamics. Preliminary data suggest that abundance, gene flow and genetic diversity all peak in areas with summertime convergence zones which may serve as larval sinks, and dip in areas of primarily linear flow which may reduce the amount and frequency of larval recruitment and exchange. Future work will address whether this scenario is general to the many marine species that have similar ranges and larval durations to kelp bass.

Key words: genetics, connectivity, larvae