Ecology of swarming in the planktonic copepod Dioithona sp. (Crustacea: Copepoda)

Abstract

Swarming behaviour of copepods was studied at a coral reef in Lungdong Bay, northeastern Taiwan. Copepod distribution was documented by underwater photography and samples were obtained by SCUBA diving, deploying plankton nets, and suction devices. Copepod assemblages found at Lungdong Bay comprised four copepod orders (Calanoida, Cyclopoida, Harpacticoida and Poecilostomatoida). A new representative of Dioithona sp swarmed predominantly in summer (April to September 2008). The average density of the swarms was positively affected by temperature. Both the position and the average density were negatively affected by typhoons. Abundances were highest at the reef bottom, followed by the sea bottom outside the reef, in March and April 2008. In May, the highest densities were found at the water surface outside the reef. Adult females dominated the stage composition only at the reef surface during April, whereas early copepodids were most abundant at all other sampling dates and sites.

Keywords:

• swarming
• social aggregations
• behaviour
• plankton ecology

Acknowledgements

We appreciate financial support from the Centre of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University to J.S.H. We are grateful to the National Science Council of Taiwan, ROC, grant Nos. NSC 96-2611-M-019-006, NSC 97-2611-M-019-004, NSC 99-2611-M-019-009 and NSC 100-2611-M-019-010 for financial support to J.-S. Hwang. The authors acknowledge all the samplings from the laboratory members of J.S. Hwang's technicians, graduate students and Mr Yu-Cheng Wu.

Notes

†Both authors contributed equally to this work.