Get out! she signalized: sex segregation of freshwater fish

Project No. P505/12/P647

Applicant: RNDr. Marie Prchalová, PhD.

Financial support: Czech Science Foundation

Duration: 2012-2014

Sex segregation is widespread in animal kingdom. But it has not been investigated much in freshwater fishes. The guppy is the only aquatic vertebrate for which hypotheses of sex segregation were verified. In this project we will study sex segregation of the five most common fish species of lentic freshwaters of Europe. Using gillnet sampling and segregation coefficient we will be able to say whether fishes are sexually segregated and how (habitat vs. location segregation). Three potential reasons for segregation will be tested (predation pressure, water temperature, food availability). Sex dimorphism will be studied in detail as well. Parameters as life expectancy, growth, condition, length-weight relationship and morphology of branchial sieve will be compared between sexes. Females of the target species can be more active and have better condition, which could bias the representativeness of gillnet sampling. Thus we plan an easy experiment when we will perform gillnet sampling in a rented pond stocked with a completely known fish community in terms of sex ratio and condition.