Population structure and swarm formation of the cyclopoid copepod Dioithona oculata near mangrove cays

Ambler, J. and Ferrari, F.D. and Fornshell, J.A. (1991) Population structure and swarm formation of the cyclopoid copepod Dioithona oculata near mangrove cays. Journal of Plankton Research, 13 (6). pp. 1257-1272.

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    Abstract

    The cyc1opoid copepod Dioithona om/ata forms swarms in water <311 cm deep among prop mots of red mangroves (Rhizop/lOra mangle) which fringe protected areas of two lagoonal cays, Twin Cays. Belize. During 7 of 8 months surveyed by in .fitu obser...ation, swarms were present but differed in size from small cylindrical swarms (5-10 cm diameter) to bands extending up to 12011 m. Swarms were never observed at night. Swarms formed at dawn when light intensities reached an average ...alue of 13.82 (log... quanta cm-~ S-I) and dispersed at dusk at similar intensities. Swarms observed in June formed earlier and dispersed later in the day than swarms observed in January; their swarming behavior followed seasonal changes in light intensity. Mean dioithonan density in swarms (10 ml- I ) was much higher than the mean density (0.15 ml- ' ) of non-swarming dioithonans around mangrove pro)' roots. In open water 3-5 m aw:ty from the mangroves. mean dioithonan density was 7.9 x 10-' 011- 1 during the day. and 2.68 x 10-3 011- 1 at night. Swarms were composed predomimmtly of :tdults and copepodid stages IV :md V. :Ilthough younger eopepodid stages could be present. Nauplii were never present. The 'a\'erage copepodid stagc' for all 95 swarms sampled was 5.3, where 6.0 represents a swarm with only adults. In open water 3-5 m away from the m:mgroves, the youngest copepodids (stage onc) dominated the dioithonan population during the day. At night when swarms dispersed to open waters. average copepodid stage was higher (3.5) compared with the day value (1.2) in open waters. Although densities in swarms were higher in June than January, average copcpodid stage in June was higher (5.6) than that in January (4.9). A higher percentage of adults were females during June than January. Therefore higher densities did not result from increases of smaller stages in swarms. but perhaps changes in behavior or population structure.

    Item Type: Peer-reviewed Journal Article
    Related URLs:
    Publisher: Oxford University Press
    Keywords: population structure, swarm formation, cyclopoid copepod,Dioithona oculata
    Subjects: (A) Biodiversity > (AF) Invertebrates > (AFB) Marine
    (Z) Other or Unspecified
    Publication Sources: (3) Other Source > (3C) Other Universities
    Date Deposited: 13 Jan 2011 13:58
    Last Modified: 20 Jan 2011 14:24
    URI: http://eprints.uberibz.org/id/eprint/1212

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