Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 588:101-119 (2018) - DOI: https://doi.org/10.3354/meps12436 Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations Peter M. Zhadan1,*, Marina A. Vaschenko2, Sergey D. Ryazanov1 1V. I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, 43 Baltiyskaya Street, 690041 Vladivostok, Russia 2National Scientific Center of Marine Biology, A. V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevsky Street, 690041 Vladivostok, Russia *Corresponding author: pzhadan@poi.dvo.ru ABSTRACT: We used video recordings of spawning behaviour of the sea urchin Strongylocentrotus intermedius conducted in parallel with an analysis of gonadal state and measurement of environmental variables (tidal level, phytoplankton, temperature, salinity and oxygen concentration) in situ to study the role of environmental factors in triggering sea urchin spawning. The observations were performed during 3 reproductive seasons, each of 2 mo duration, in 2 bays with different levels of phytoplankton (measured as chlorophyll a [chl a]). The only significant positive correlation found was between sea urchin spawning frequency and chl a concentration. Despite a high level of gonad maturity, sea urchin spawning was rarely recorded in the bay with low levels of chl a whereas mass spawning occurred in the bay with higher chl a concentration, with the peak of spawning activity centred around the full moon. Spawning was predominantly nocturnal. Immediately before and during spawning, males actively moved. Females began to spawn only when there were several spawning males nearby. In both sexes, each spawning event included several episodes of gamete release of different duration and with different intervals between them. The same male likely can participate in several spawning events. The following hierarchy of drivers of S. intermedius spawning activity was revealed: (1) increasing the phytoplankton concentration induced active motion and spawning in males, (2) both an elevated phytoplankton level and the presence of sperm stimulated spawning in females and (3) the night time and the new and full lunar phases increased the probability of spawning. KEY WORDS: Broadcast spawning · Echinoderms · Reproductive synchrony · Phytoplankton · Temperature · Circadian rhythm · Lunar cycle Full text in pdf format Supplementary material PreviousNextCite this article as: Zhadan PM, Vaschenko MA, Ryazanov SD (2018) Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations. Mar Ecol Prog Ser 588:101-119. https://doi.org/10.3354/meps12436 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 588. Online publication date: February 08, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.