(3] THE SPRING HERRING FISHERIES OF NORWAY. 129 
The dependence of the herring on the temperature of the sea, which is a 
most important item in the daily life of the herring, has already formed 
the subject of investigations by Boeck, and it was my intention to con- 
tinue these investigations begun by him. With a Negretti & Zambra’s 
«deep-water thermometer, which, through Professor Mohn’s kindness, was 
loaned me by the Meteorological Institute, I took a number of observa- 
tions of the temperature, but unfortunately these were made too late 
in the season to throw much.light on the course of the herring during 
the present fishing period. These observations, however, furnish results 
relative to the temperature of the sea at different depths, which are 
important for us to know in connection with this whole herring question, 
and which became specially interesting when compared with Boeck’s 
earlier observations. 
The observations of the temperature, and other meteorological inves: 
tigations, made near the coast and with reference to the more or less 
mature spring herring, are of course as yet an incomplete work, and 
the most important question connected with the herring problem, the 
cause of the disappearance of the herring from our coast for years 
at a time, is probably still far from a satisfactory solution. In order to 
ascertain whether the temperatures and currents of the sea are really 
the principal causes of this phenomenon, these meteorological conditions, 
and their influence on the course of the herring, should be observed 
outsideo 98 s-awning ©2a:c> or during summer, when the herring 
are out 1 ©» Upen sea. | vestigation still belongs to the future. 
We do not ven know foi . ¢tain where the herring have their summer 
stations, but only suppose that we know the places where in all proba- 
bility they must be looked for (see Sars’s reports, especially the one for 
1873). The first and most important thing to do would beto go through 
these places with seines, which perhaps would not be very difficult. If 
such an expedition were made whenever a change should take place in 
_ the spring herring fisheries, we would get a good deal nearer to a solu- 
tion of the above-mentioned most important question—the periodical 
disappearance of the herring from our coast. \ 
I shall now proceed to give a brief review of the observations made 
this year, and in doing so I shall have to speak first of the history of 
the spring herring fisheries in recent times, and in connection therewith 
of the present condition of the spring herring; and secondly I shall 
have to add some remarks on the temperature of the sea during the 
fishing season. 
By unceasing and most meritorious labor Boeck has succeeded in 
showing a certain regularity in those changes to which the fisheries 
are subject during a so-called “herring period.”* According to Boeck’s 
investigations, this irregularity principally consists in the circumstance 
that during the first part of a “herring period” the fisheries gradually 
*Although this term is not entirely justified, I will nevertheless employ it in this 
report, as from very good causes it has became quite generally adopted. 
S. Mis. 29 9 
