PeerJ Author 270 Points Contributions by role Author 270 Contributions by subject area Animal Behavior Ecology Marine Biology Zoology Peter M Zhadan PeerJ Author Summary Animal Behavior Ecology Marine Biology PeerJ Contributions Articles 2 April 6, 2021 Quantitative study of the behavior of two broadcast spawners, the sea urchins Strongylocentrotus intermedius and Mesocentrotus nudus, during mass spawning events in situ Peter M. Zhadan, Marina A. Vaschenko, Peter A. Permyakov https://doi.org/10.7717/peerj.11058 PubMed 33868807 November 22, 2019 Long-term study of behaviors of two cohabiting sea urchin species, Mesocentrotus nudus and Strongylocentrotus intermedius, under conditions of high food quantity and predation risk in situ Peter M. Zhadan, Marina A. Vaschenko https://doi.org/10.7717/peerj.8087 PubMed 31772840