Marine Biology

, Volume 161, Issue 1, pp 149–163 | Cite as

Demography and interannual variability of salp swarms (Thalia democratica)

  • Natasha HenschkeEmail author
  • Jason D. Everett
  • Martina A. Doblin
  • Kylie A. Pitt
  • Anthony J. Richardson
  • Iain M. Suthers
Original Paper


Swarms of the pelagic tunicate, Thalia democratica, form during spring, but the causes of the large interannual variability in the magnitude of salp swarms are unclear. Changes in asexual reproduction (buds per chain) of T. democratica populations in the coastal waters of south-east Australia (32–35°S) were observed in three austral springs (October 2008–2010). T. democratica abundance was significantly higher in 2008 (1,312 individuals m−3) than 2009 and 2010 (210 and 92 individuals m−3, respectively). There was a significant negative relationship (linear regression, r 2 = 0.61, F 1,22 = 33.83, P < 0.001) between abundance and asexual reproduction. Similarly, relative growth rates declined with decreasing abundance. Generalised additive mixed modelling showed that T. democratica abundance was significantly positively related to preferred food >2 μm in size (P < 0.05) and negatively related to the proportion of non-salp zooplankton (P < 0.001). Salp swarm magnitude, growth, and asexual reproduction may depend on the abundance of larger phytoplankton (prymnesiophytes and diatoms) and competition with other zooplankton.


Phytoplankton Phytoplankton Community Asexual Reproduction Advance Very High Resolution Radiometer Growth Index 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research was funded by ARC Discovery Grant DP0880078 held by I.M.S. and Mark E. Baird. The authors thank the captain and crew of the RV Southern Surveyor 10/2008, 05/2009, 08/2010, and 09/2010. We especially thank the 08/2010 chief scientist Dr. Matthew Taylor, CSIRO scientists, and our colleagues for their assistance during the voyages. We also thank the Plankton Ecology Laboratory, CSIRO, for Port Hacking zooplankton identifications and Dr. James Smith (UNSW) for help with statistical analyses. We would like to acknowledge the valuable reviews provided by the three anonymous reviewers that have helped to improve the clarity and focus of this manuscript. This is contribution 108 from the Sydney Institute of Marine Science.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Natasha Henschke
    • 1
    • 2
    Email author
  • Jason D. Everett
    • 1
    • 2
    • 3
  • Martina A. Doblin
    • 2
    • 3
  • Kylie A. Pitt
    • 4
  • Anthony J. Richardson
    • 5
    • 6
  • Iain M. Suthers
    • 1
    • 2
  1. 1.Evolution and Ecology Research CentreUniversity of New South WalesSydneyAustralia
  2. 2.Sydney Institute of Marine ScienceMosmanAustralia
  3. 3.Plant Functional Biology and Climate Change Cluster, Faculty of ScienceUniversity of Technology SydneyBroadwayAustralia
  4. 4.Australian Rivers Institute, Coast and EstuariesGriffith UniversityGold CoastAustralia
  5. 5.Climate Adaptation Flagship, CSIRO Marine and Atmospheric ResearchEcosciences PrecinctBrisbaneAustralia
  6. 6.Centre for Applications in Natural Resource Mathematics (CARM), School of Mathematics and PhysicsThe University of QueenslandSt. LuciaAustralia

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