According to sperm competition models, a male spawning in a disfavoured role should have spermatozoa with higher velocity but shorter longevity compared with a male spawning in a favoured role. Moreover, immunosuppressive androgens are needed to produce both secondary sexual characters and sperm cells. The ‘sperm protection’ hypothesis suggests that the immunosuppressive action of androgens has...

A model that assesses risks posed by feminization to wild populations of roach was developed. A population life table matrix model that considered both sexes and a newly developed fertility kinetic function was applied to calculate the intrinsic population growth rate (lambda) of roach populations where males had been feminized. The maximum sustainable yield (MSY) was used to quantify the effec...

Diplostomum is a taxonomically problematic genus of trematodes, with many members harmful at the metacercarial stage to fish in aquaculture. We found metacercariae eye vitreous humor rudd, Scardinius erythrophthalmus; bleak, Alburnus alburnus; and roach, Rutilus rutilus, Karelia (Russia) identified them as numericum based on combination morphological ecological data. Previously, D. was thought ...

We compared the repeatability, reproducibility (intra- and inter-measurer similarity), separative power and subjectivity (measurer effect on results) of four morphometric methods frequently used in ichthyological research, the "traditional" caliper-based (TRA) and truss-network (TRU) distance methods and two geometric methods that compare landmark coordinates on the body (GMB) and scales (GMS)....