MEPS 561:189-201 (2016)  -  DOI: https://doi.org/10.3354/meps11915

Environmental drivers of salp Thalia democratica population dynamics from in situ observations

Maria Pascual1,*, Michael G. Neubert2, José Luis Acuña3, Andrew R. Solow2, Carlos Dominguez-Carrió1, Joaquín Salvador1, Alejandro Olariaga1, Verónica Fuentes

1Institut de Ciències del Mar, 08003 Barcelona, Spain
2Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
3Universidad de Oviedo, 33003 Oviedo, Spain
*Corresponding author:

ABSTRACT: Thalia democratica blooms are a recurrent phenomenon in many coastal areas of the Mediterranean Sea and have significant ecological effects. To better understand the environmental drivers of salp blooms, we conducted 8 surveys to sample T. democratica in contrasting seasonal, temperature and chlorophyll conditions. In each survey, short-term variations in the abundances of different salp stages were assessed by sampling the same population at 30 min intervals. Using these data, we estimated the parameters in a set of stage-classified matrix population models representing different assumptions about the influence of temperature and chlorophyll on each stage. In the model that best explains our observations, only females are affected by changes in water temperature. Whether this is a direct influence of temperature or an indirect effect reflecting low food availability, female reproduction cessation seems to slow population growth under unfavourable conditions. When conditions become favourable again, females liberate the embryo and change sex to male, allowing for mating under extremely low salp densities and triggering the bloom. In contrast to previous findings, our results suggest that females, rather than oozooids, are responsible for the sustainability of salp populations during latency periods.


KEY WORDS: Matrix population models · Pelagic tunicate ecology · Population latency · Gelatinous zooplankton blooms


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Cite this article as: Pascual M, Neubert MG, Acuña JL, Solow AR and others (2016) Environmental drivers of salp Thalia democratica population dynamics from in situ observations. Mar Ecol Prog Ser 561:189-201. https://doi.org/10.3354/meps11915

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