58 
looks as if it were alive. In the spring we must search keenly to find any Proto 
at the same places. Boats placed clean in the water in the spring are in a short 
time covered with Balanmi and Mytilus, and all wood-work which is not very thick, 
is pierced in the course of a summer by Teredo and Limnoria. Clavellina lepadi- 
formis literally »flowers« in enormous masses in the summer and disappears again 
im the autumn, to hibernate as small, grayish crusts. Something similar happens 
to Aurelia and Cyanea. 
The whole of the animal life on the Zostera is essentially a summer 
phenomenon. Bissoa, Cerithium, Trochus, Lacuna etc., certainly hibernate among 
its roots; it is only late in the year that they crawl up to feed and spawn, and 
the water is then full of their young. Certain Actwmiae, the Nudibranchs and 
hydroids first appear late in the summer; briefly, wherever our eyes can see it, there 
is an enormous annual production in our fjords from spring to autumn. 
We could also say the same of the vegetation here (Rosenvinge). It has taken 
me a long time, to get my eyes opened to this great production in our fjords 
from spring to autumn; most of it is indeed hidden under water. Our fjord 
fisheries follow this pulsation of the year, in the case of the eel, plaice and other 
flat-fishes; in the main they yield only what is gained in growth from 
spring to autumn; thus the fisheries in the fjords are of little account in the 
spring but rich in the autumn, until all that can be used is fished up or 
emigrate; the fishermen must then wait, until a new growth has taken place 
in the course of the next summer. 
Briefly then there is a large annual production in the fjords, and our 
Tables also show high values for several species in the autumn. On the other 
hand, what the increment may be in deep and large waters such as for example 
in the Kattegat and Belt Sea, we do not know; only exact, quantitative deter- 
minations will be able to show this; what I have seen hitherto with regard to the 
deeper waters, has given me the impression, that the fauna here does not change 
with the seasons to any obvious extent, — nor is it reasonable to assume before- 
hand, that such does happen.”) 

X. Producers and consumers in the Limfjord in 1909—1910. 
The animals best represented in Table V are those which live on 
detritus and plants, thus the producers; but a large and specially important 
group of consumers, namely the fishes, are quite wanting, partly owing to 
£) I may refer here to a recently published work by V. Franz: Ueber die Ernåhrungs- 
weise einiger Nordseefishe, besonders der Scholle. (Wiss. Meeresunt., IX Bd., Hefte 2, Helgoland 
1910). F. is of the opinion, that we cannot possibly assume, that more plaice food is found in the 
North Sea at certain, definite seasons than at others, and bases his views on the fact, that most 
of the animals the plaice feeds on, live for several years. 
