Essays about: "northern pike"

Showing result 16 - 18 of 18 essays containing the words northern pike.

  1. 16. Size selective predation of pike on whitefish : The effects on resource polymorphism in Scandinavian whitefish populations

    University essay from Institutionen för ekologi, miljö och geovetenskap

    Author : Johan Fahlman; [2014]
    Keywords : pike; whitefish; predation; resource polymorphism; divergence;

    Abstract : The mechanisms behind speciation have been subject of debate for centuries. The presence of resource polymorphism has been discovered to play a significant part in this process, and has been proven to induce phenotypic and genetic divergence. READ MORE

  3. 17. Growth of whitefish ecotypes : A comparison of individual growth rates in monomorphic and polymorphic populations

    University essay from Institutionen för ekologi, miljö och geovetenskap

    Author : Fredrik Olajos; [2013]
    Keywords : whitefish; growth rate; scales; pike; polymorphism;

    Abstract : In resource polymorphism, ecological opportunity and selective predatory pressure can be considered key factors in phenotypic divergence. In post-glacial lakes of Scandinavia, the European whitefish (Coregonus lavaretus L.) is a common species and has repeatedly diverged along the benthic - pelagic resource axis. READ MORE

  4. 18. The effects of water chemistry on fish species distribution : a comparison between isolated and connected lakes in northern Sweden

    University essay from SLU/Dept. of Forest Ecology and Management

    Author : Johanna Öhman; [2004]
    Keywords : fish; water chemistry; isolation; anoxia; dissolved oxygen; DO; acidity; pH; pike; perch; roach; crucian carp; stickleback; bream; bleak; ide; ruffe; Västerbotten; northern Sweden; ice; winter; lake;

    Abstract : The correlation between water chemistry and fish species distribution was examined in forty small, coastal lakes in northern Sweden. Lakes were fished in summer and water chemistry sampled mainly in late winter. Twenty out of the forty lakes were isolated from other water bodies and twenty had a direct connection to the sea. READ MORE