Publication Date:
2020-04-17
Description:
The determination of the age of individual sea stars (Asterias rubens) by means of length measurements or identification of growth rings in the calcareous skeleton presents great difficulties. Age-determinations are, however, the prior condition to growth calculations. For the determination of growth parameters L00, K and t0 of the VON BERTALANFFY growth equation by means of the modal class progression analysis monthly dredging samples were taken in 12 profiles across the mouth of the Eckernförde Bay. Sea stars, which were exposed to lower temperatures during the first months after onset of growth, reach a larger asymptotic length than those exposed to higher temperatures. - By means of parallel diving observations to the dredging the mean biomass of Asterias in Kiel Bay was estimated to be about 32000 tons. Assuming a daily food uptake of 1 % of its own weight the sea star stock consumes about 120000 tons of food organisms per year. These data are discussed in context with biomass values of macrobenthos and cod in Kiel Bay. - The most striking finding, however, is the assumption of an intermediate phase, the "waiting stage", between the larval phase, serving propagation, and the growing stage, serving reproduction, in which tiny sea stars can remain for months waiting for a "free seat" in the ecological niche
Type:
Article
,
NonPeerReviewed
Format:
text
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