Inter‐population ovarian fluid variation differentially modulates sperm motility in Atlantic cod Gadus morhua

• Published in: Journal of Fish Biology
• Main Authors: Beirão, J., Purchase, C. F., Wringe, B. F., Fleming, I. A.
• Other Authors: Natural Sciences and Engineering Research Council of Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: atlantic cod; Gadus morhua
• Online Access: http://dx.doi.org/10.1111/jfb.12685; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjfb.12685; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfb.12685

This study tested the hypothesis that the effects of Atlantic cod Gadus morhua ovarian fluid on sperm motility variables are population specific. Sperm from a northern G. morhua population were activated in the presence of ovarian fluid from either northern or southern G. morhua at different concentrations. Ovarian fluid acted as a filter, in some cases reducing sperm swimming performance compared with seawater. Fluid from females foreign in population (southern) to the males (northern) had a greater inhibiting effect than those from the native population. Follow‐up analysis indicated that the ovarian fluids had lower Ca 2+ concentration in northern than southern G. morhua , which could be the causative mechanism. If widespread, such cryptic female choice could reduce the incidence of intraspecific hybridization among diverged populations and contribute to reproductive isolation.