Choquet, M., G. Burckard, S. Skreslet, G. Hoarau & J.E. Soreide. (2021). No evidence for hybridization between Calanus finmarchicus and Calanus glacialis in a subarctic area of sympatry. Limnology and Oceanography. 66:314-325. JAN 2021.
Choquet, M., G. Burckard, S. Skreslet, G. Hoarau & J.E. Soreide
2021
No evidence for hybridization between Calanus finmarchicus and Calanus glacialis in a subarctic area of sympatry.
Limnology and Oceanography
66:314-325. JAN 2021
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In the North Atlantic and the Arctic Ocean, four species of the copepod genusCalanusdominate the zooplankton biomass. Because of their morphological resemblance, knowledge of their respective distribution range has long been biased by misidentification, until the recent use of molecular tools uncovered numerous areas of sympatry. As hybridization betweenCalanus finmarchicusandCalanus glacialishas been claimed in the East-Canadian Arctic based on microsatellites, we investigated further the potential for interbreeding in newly uncovered areas of sympatry.Calanusspecies and stage composition were analyzed during winter in two Norwegian subarctic fjords, using molecular markers developed specifically for species identification and hybrid detection betweenC. finmarchicusandC. glacialis. Overall,C. glacialiswere the most abundant throughout the winter, followed byC. finmarchicusandCalanus hyperboreuswith only a few records ofCalanus helgolandicus. The presence ofC. glacialis,C. hyperboreus, andC. finmarchicus'nauplii was recorded, indicating that these species reproduce locally. In January and February, the simultaneous occurrence of males and females of bothC. finmarchicusandC. glacialissuggested a potential for interspecies mating. However, genetic admixture tests performed on all 1126 individuals revealed no signal of hybridization, implying a strong reproductive isolation mechanism. We conclude that no evidence supports a potential for hybridization betweenC. finmarchicusandC. glacialis.
