MEPS 337:187-196 (2007)  -  doi:10.3354/meps337187

Divergent origins of sympatric herring population components determined using genetic mixture analysis

Dorte Bekkevold1,*, Lotte A. W. Clausen2, Stefano Mariani3,5, Carl André4, Tina B. Christensen1, Henrik Mosegaard3

1Department of Inland Fisheries, Danish Institute for Fisheries Research, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
2Department of Marine Fisheries, Danish Institute for Fisheries Research, Technical University of Denmark, 2920 Charlottenlund, Denmark
3Molecular Ecology & Fisheries Genetics Laboratory, Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK
4Tjärnö Marine Biological Laboratory, Department of Marine Ecology, Göteborg University, 452 96 Strömstad, Sweden
5Present address: UCD School of Biological & Environmental Science, University College Dublin, Dublin 4, Republic of Ireland

ABSTRACT: The origin and reproductive interactions of sympatric, spatially separated spawning components of Atlantic herring Clupea harengus have received long-standing interest. In the western Baltic most herring spawn in spring, with smaller components spawning in winter. We used microsatellite DNA analysis and a novel Bayesian genetic mixture analysis approach to compare the genetic relationships of 2 western Baltic winter-spawning aggregations with those of their sympatric spring-spawning components, and combined information for genetic markers and morphological traits (otolith-determined hatching time and growth relationships) to test alternative hypotheses for the origin of winter spawners. We show that genetic relationships between sympatric components differ greatly between the 2 locations; the results indicate that winter spawning has arisen via 2 fundamentally different processes: (1) as a result of ‘spawning-time switching’ in a local spring-spawning component and (2) via 1 or more founder events from an extant winter-spawning population into an area otherwise dominated by spring spawners.

KEY WORDS: Sympatric spawning · Clupea harengus · Microsatellite DNA · Spawning-time switching · Life history · Founder event · Assignment analysis

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