Delayed consequences of the influence of simulated geomagnetic storms on roach Rutilus rutilus embryos

This study presents data collected over a 3 year period on the effects of simulated geomagnetic storms (SGMS) on Eurasian roach Rutilus rutilus embryos. Effects were studied during different stages of early development. Rutilis rutilus were raised in ponds for 4 months after exposure to SGMS. The mass, standard length and morphological characteristics of under-yearlings exposed as embryos were recorded. A decrease in length-mass indices in under-yearlings was noted after they had been exposed to SGMS during the first 2 days or during the third and fourth days of early development. Near the time point of 48 h post fertilisation, either no effect or an increased size was observed. In addition, exposure to SGMS led to a redistribution of the vertebral number between the sections of the vertebral column as well as changes in the number of seismosensory system openings in the mandibular and praeoperculum bones of under-yearlings. Observed effects are similar to previously published data on the influence of anthropogenic magnetic fields on roach, namely changes in linear-mass indices, number of vertebrae and number of seismosensory system openings in the mandibular bones of under-yearlings exposed as embryos. Possible mechanisms of magnetic influence on early development of fish are discussed.