MEPS 524:1-9 (2015)  -  DOI: https://doi.org/10.3354/meps11240

ABSTRACT: Hybrids between 2 abundant copepod species, Calanus glacialis and C. finmarchicus, were recently detected along the Atlantic and Arctic Canadian coast. Hybridization may affect population dynamics and, thus, impact local productivity. Our study aims to characterize the effect of hybridization on Calanus demography by comparing the in situ reproductive phenology and fitness of parental species and their hybrids. Environmental conditions were monitored and adult Calanus females were sampled in the upper layer in the St. Lawrence Estuary every second week from the pre-bloom (March to May) to bloom period (June to July) in 2010. Maximal abundance of hybrids (17%) occurred in April between the maxima of C. glacialis (March) and C. finmarchicus (June). The different reproductive phenology of hybrids and parental species likely reduces interspecific gene flow. Contrastingly, fitness components such as the egg production rate of hybrids matched those of their maternal ancestor over the sampling interval. Still, hybrids represented only 10% of total abundance, and their population-based egg production rate was always smaller than that of one parental species. The pre-bloom conditions during the peak abundance of hybrids may partially explain their small reproductive output in that area. Consequently, the impact of hybridization on the parental species’ population size seems small in 2010 in the St. Lawrence Estuary. However, long-term and spatial surveys are required to conclude on the general effect of hybridization on the population size of parental species over the vast area where they co-occur.

KEY WORDS: Life history traits · Reproductive output · Egg production rate · Females · Copepod · Hybridization

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Cite this article as: Parent GJ, Plourde S, Joly P, Turgeon J (2015) Phenology and fitness of Calanus glacialis, C. finmarchicus (Copepoda), and their hybrids in the St. Lawrence Estuary. Mar Ecol Prog Ser 524:1-9. https://doi.org/10.3354/meps11240 Export citation Share:    Facebook - - linkedIn