Long‐term demographic and reproductive trends in Ciona intestinalis sp. A

Abstract

Ciona intestinalis sp. A (Tunicata, Ascidiacea) is a marine invertebrate with a widespread distribution and high invasive potential, yet little is known about its ecology. Here, the macrodynamics of demographic and reproductive trends were first determined using archive data covering 2002–2012. Species abundance in the central Tyrrhenian Sea (Campania, Italy ‐ NW Mediterranean) displayed Poisson distribution across 2002–2008, massive die‐off in 2009/2010 and population recovery in 2011/2012. We defined the seasonal ranges of sea surface temperature in which sampling size, animal size and reproductive status reached their highest values. In 2003/2004, self and non‐self fertilization appeared to follow reverse trends across the year. The long‐term recording run here on Ciona intestinalis sp. A provides novel insights into its population biology and ecology, and represents a valuable tool for sampling management and research planning.

Co-occurrence and reproductive synchrony do not ensure hybridization between an alien tunicate and its interfertile native congener

“…Seawater temperature greatly influences the development, growth and survival of C intestinalis spp. (Dybern 1965;Marin et al 1987), with species A and species B reported as warm-water and coldwater species, respectively (Procaccini et al 2011;Caputi et al 2014). We observed higher growth rates at 17°C, for species A than species B during laboratory experiments (data not shown), confirming previous findings (Petersen et al 1995) based on the growth rate of the nominal species C. intestinalis in localities where only species A or species B are now reported [e.g.…”

“…The six sampling dates correspond to at least six different adult generations in European waters (e.g. Dybern 1965;Caputi et al 2014). In each locality, ca.…”

Temporal correlation of population composition and environmental variables in the marine invader Ciona robusta

“…No C. robusta population inhabits close‐by surroundings of the Fusaro Lagoon, and the closest known population (Castel Volturno) is located ca. 20 km north along the Tyrrhenian Sea coast (Caputi et al, ). However, the lagoon is used for mussel cultivation, making services for mussel growing, transport, and harvesting possible recruiting sources.…”

“…Ascidians are benthic animals that populate coastal marine habitats with strong natural fluctuations of physico‐chemical parameters and high levels of pollution (Caputi, Crocetta, Toscano, Sordino, & Cirino, ; Carver, Chisholm, & Mallet, ; Dybern, ; Lambert, ; Simkanin, Davidson, Dower, Jamieson, & Therriault, ). These invertebrates are non‐selective filter feeders that uptake and bioaccumulate metals and other pollutants from the environment (Ignatiades & Becacos‐Kontos, ; Papadopoulou & Kanias, ; Radford, Hutchinson, Burandt, & Raftos, ).…”

“…Dystrophic crises (e.g., eutrophication, anoxia) in summer, during which several marine species disappear almost completely, including C. robusta , are counterbalanced by favorable environmental conditions (e.g., decreased levels of water temperature and salinity) in spring, autumn, and winter (Carrada, ). Of note, this ascidian species experienced total extinction along the southern Italian coasts during 2010, with recolonization of the Fusaro starting in 2011 (Caputi et al, ).…”