Dispersal vs. retention: correspondence of species-specific reproductive cycles and settlement periods in a blue mussel hybrid zone

MR Gilg, SE Kirby, R Sullivan, LW Knapp, TJ Hilbish
2007 Marine Ecology Progress Series  
While long distance dispersal of planktotrophic larvae in marine organisms has traditionally been considered the norm, several recent studies have shown that local retention of larvae and hydrodynamic barriers to dispersal often exist. This study focuses on the question of whether genetically distinct populations within a blue mussel hybrid zone typically exchange larvae or if larvae are often retained within the population of origin. Larvae were tracked to their point of settlement using a
more » ... tic marker and analyzed for correlations with differential timing of reproduction and settlement among 3 genetically distinct populations (Mytilus edulis, M. galloprovincialis and hybrid). Correspondence of allele frequencies to local reproduction and settlement suggest that larvae settling within the M. edulis and the hybrid zone populations originated from those locations. On the other hand, larvae settling within the M. galloprovincialis populations often contain significant proportions of immigrants from the hybrid zone. The observed patterns are consistent with previous studies of the local hydrodynamics, suggesting that physical barriers to dispersal often exist and result in retention of larvae. KEY WORDS: Larval dispersal · Retention · Mytilus · Hybrid zone Resale or republication not permitted without written consent of the publisher 157 Editorial responsibility: Lisa Levin (Contributing Editor),
doi:10.3354/meps07145 fatcat:oiajnycamjfotgx3i2uuaz7itq