A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Growth and reproduction of an estuarine population of the colonial hydroidCordylophora caspia (Pallas) in the northern Baltic Sea
Tekijät: JORMALAINEN V, HONKANEN T, VUORISALO T, LAIHONEN P
Kustantaja: BIOLOGISCHE ANSTALT HELGOLAND
Julkaisuvuosi: 1994
Journal: Helgoländer Meeresuntersuchungen
Tietokannassa oleva lehden nimi: HELGOLANDER MEERESUNTERSUCHUNGEN
Lehden akronyymi: HELGOLANDER MEERESUN
Vuosikerta: 48
Numero: 4
Aloitussivu: 407
Lopetussivu: 418
Sivujen määrä: 12
ISSN: 0174-3597
DOI: https://doi.org/10.1007/BF02366254
Verkko-osoite: https://hmr.biomedcentral.com/articles/10.1007/BF02366254
Tiivistelmä
Growth and reproduction of the colonial hydroid Cordylophora caspia were monitored during the breeding season in natural conditions. In 1987, a life history study was carried out on the upright stems of the main stolen. Mean size of uprights varied cyclically. The first peak coincided with the peak number of sexual hydranths, after which the mean upright length decreased, possibly indicating somatic costs of sexual reproduction. Extrinsic factors like flooding may also have contributed to cyclical changes in upright size. In 1988 and 1989, colonies were reared on experimental plates in the estuary. In 1988, colonies grew until mid July, after which they regressed to a dormant condition and then started growing again in mid August. Predation and space competition are discussed as possible causes for this dormancy in the middle of the growing season. In 1989, colonies grew continually, with the exception of a decline in colony biomass and number of feeding hydranths at tile end of July, just following the peak of sexual reproduction. Sexual reproduction started in the early stages of colonial development for all years. During early summer, C. caspia allocated resources simultaneously in colonial growth and sexual reproduction. However, sexual reproduction had a clear peak in mid summer, and thereafter sexual reproduction ceased while colonial growth continued.
Growth and reproduction of the colonial hydroid Cordylophora caspia were monitored during the breeding season in natural conditions. In 1987, a life history study was carried out on the upright stems of the main stolen. Mean size of uprights varied cyclically. The first peak coincided with the peak number of sexual hydranths, after which the mean upright length decreased, possibly indicating somatic costs of sexual reproduction. Extrinsic factors like flooding may also have contributed to cyclical changes in upright size. In 1988 and 1989, colonies were reared on experimental plates in the estuary. In 1988, colonies grew until mid July, after which they regressed to a dormant condition and then started growing again in mid August. Predation and space competition are discussed as possible causes for this dormancy in the middle of the growing season. In 1989, colonies grew continually, with the exception of a decline in colony biomass and number of feeding hydranths at tile end of July, just following the peak of sexual reproduction. Sexual reproduction started in the early stages of colonial development for all years. During early summer, C. caspia allocated resources simultaneously in colonial growth and sexual reproduction. However, sexual reproduction had a clear peak in mid summer, and thereafter sexual reproduction ceased while colonial growth continued.
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