Evol Ecol Res 13: 45-54 (2011) Full PDF if your library subscribes.
Contemporary divergence in migratory timing of naturalized populations of chinook salmon, Oncorhynchus tshawytscha, in New Zealand
Thomas P. Quinn1, Martin J. Unwin2 and Michael T. Kinnison3
1School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA, 2National Institute of Water & Atmospheric Research Ltd., Christchurch, New Zealand and 3School of Biology and Ecology, University of Maine, Orono, Maine, USA
Correspondence: T.P. Quinn, School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195, USA.
Hypotheses: Recently established populations, sharing common ancestry but facing different reproductive habitat seasonality, will genetically diverge in the timing of their reproductive migrations.
Organism: Exotic populations of chinook salmon (Oncorhynchus tshawytscha) established from common ancestors introduced to South Island of New Zealand between 1901 and 1907.
Site of experiments: Early rearing at Silverstream Hatchery, Waimakariri River, New Zealand, followed by release to sea, growth in coastal ocean, and return to freshwater.
Methods: We reared early- and late-spawned juveniles from two populations that differ in spawning time in the wild, and released those fish to mature at sea. We obtained dates of migratory return to freshwater, fish age, and experimental group identity from angler captures at river mouths. Analyses involved assessment of population, spawning date, and age at return effects for the current experiment, plus an expanded analysis of data from previous release experiments.
Results: After ∼26 generations, the population that reproduces later in the wild now returns to freshwater an average of 18 days later than the early spawning population. This divergence is likely genetic, given the common-garden nature of our experimental design, and was apparent even after accounting for significant effects of age at return and marginal effects of initial spawning date.
Keywords: evolution, migration, phenology reproduction, salmon, timing.
DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.
© 2011 Thomas P. Quinn. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.
Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.
All copies of abstracts and articles must preserve their copyright notice without modification.