Marenzelleria viridis (Polychaeta: Spionidae): a review of its reproduction
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, meer
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| Trefwoord |
Marenzelleria viridis (Verrill, 1873) [WoRMS]
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| Author keywords |
reproductive biology; Baltic Sea; North Sea; review |
| Abstract |
The features of the reproductive biology such as morphology of gametes, larval morphology, larval development and development of gametes of Marenzelleria viridis Type II from the Baltic were summarized. Further reproductive features of Baltic Sea populations are given and the purpose of the review is to account for the successful immigration of M. viridisinto the oligohaline areas of the Baltic considered against a background of such variables as population density and structure, salinity, temperature, food availability, oxygen and sulphide levels. Gametogenesis started in spring. Fecundity of animals depended on salinity, temperature, age and size of worms. Mature oocytes contained large cortical alveoli not yet known for polychaetes. Animals spawned in autumn in all years of investigation. The pelagic larvae of M. viridisType II were found mainly from September to November. Larval development depended on water temperature and lasted about 4 to 12 weeks. Successful larval development from egg to juvenile was not possible below salinities of 5‰, but colonization of oligohaline regions took place by larvae with more than 4 setigers or by swimming juveniles. Reproductive features of M. viridisType II from the Baltic were compared and discussed with the results of M. viridisType I populations from the North Sea and North America. The two M. viridistypes reproduced at different time, M. viridisType I reproduced in spring and M. viridisType II in autumn. Both types showed also differences in larval development, gametal development and sex ratio of mature worms. |
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