B. Hyclrograpliical Investigations. 



7 HE importance of physical observations during the fisheries in 

 Lofoten was argued by professor Sabs already in his first 

 report to the government in 1864, but not till 1878 temperature 

 measurements VN'ere undertaken during the fishing season, l)y the 

 then supervising chief, Mr. Juel. The observations were made in 

 the harbour of Svolvaer and at a distance of 1 — 3 geogr. miles 

 SSE of Svolvajr lighthouse. (See official report of 1878 p. 54 — 66). 

 On February 25th, at the latter place, exceptionally high tempera- 

 tures were measured, even up to 11".5 C. at a depth of 60 fathoms; 

 at the same time the bottom temperature (6 fathoms) in Svolvair 

 harbour was above 4° C. Setting apart the ] 1".5 C, it appears 

 from the tables that the temperature at 60 fathoms has varied 

 between 3".75 and 7" C. During the two winters that I have 

 undertaken measurements in Lofoten, i have nowhere found such 

 a high temperature as 7" at a depth of 60 fathoms, so the tem- 

 perature of the water strata in 1878 must have been higher than 

 usually. Whether, however, this circumstance has influenced tlie 

 fishing of that year, which by-the-bye was very rich, is hkely to 

 be doubtful. 



Temperature measurements were continued in the following 

 year 1879 at Svolv^r (report 1879 p. 86—112). At the end of 

 January and beginning of 5'ebruary the temperature of the air was 

 on the average below zero (lowest temp. — 9". 4 C. on Feb. 4th). 

 The measurements close outside Svolva^r harbour also show very 

 low temperatures in the upper layers of tlie sea, from 7th to 19th 

 Feb. 0° to — 0*'.75 C. being noted for the surface. The low tem- 

 perature of the air, however, does not appear to liave influenced 

 Very much the surface temijerature of the fishing-sea close to Svol- 

 "Vfflr. Otherwise in the upper water strata, indeed even at the usual 

 fishing depths of 40, 50, 60 fathoms, there have been great changes 

 of temperature. Only at a depth of 70 fathoms it remains, nearly 

 ^vithout exception, between 6" and 7" C. (31st Jan. to lOth April). 

 The observations were continued at Lijdingen in May and June by 

 the direction of telegraph inspector Lie. Whereas the previous 

 observations had throughout given the surface water as the coldest, 

 the measurements of Mr. Lie show a displacement of the minimum 

 to a few fathoms below the surface. The surface temperature in 

 the month of May remains between 3" and 6''.2 C. and thus does 

 Hot reach that of the bottom water. At a depth of 70 — 100 fathoms 

 file temperature for May and June is between 6° and 7", and at 



the bottom (100 f.) the variations do not exceed 0".3 C. (6.02— 

 6°.5). Thus, while the temperature minimum, earlier in the year 

 lay in the surface, it is towards the middle of May displaced to a 

 few^ fathoms below the same. Gradually the minimum sinks lower, 

 so about June 26th it is at about 30 fathoms, when the surface 

 temperature has risen above the comparatively constant bottom tem- 

 perature by more than 2" C. 



The measurement on June 26th 1879 gave the following results: 

 fathoms 9" C. 



10 



70,2 



20 - 



6».0 



30 - 



50.4 



40 - 



5°.6 



50 - 



6<'.0 



70 - 



60.4 



300 - 



60.5 



In the same year 1879 at the fishing station Skraaven some 

 series of observations were taken, which I here print complete as 

 they appear to me to be characteristic. 



Skraaven in Lofoten : 



Depth 



^72 



Va 



^4 



1 'A 



fathoms 



10.75 C. 



30.00 c. 



10.75 C 



10.75 c. 



10 — 



10.75 - 



30.00 - 



10.75 - 



10.75 - 



20 — 











25 — 



10.75 - 



30.00 - 



20.15 - 



10.75 - 



30 — 



10.75 - 



30.00 - 



20.15 - 





35 — 



50.00 - 



30.00 - 



20.15 - 





40 — 



50.50 - 



50.00 - 



40.00 - 



20.50 - 



45 — 





60.00 - 



40.00 - 





50 — 



60,00 - 



60.00 - 



40.00 - 



30.50 - 



55 — 







50.00 - 



40.00 - 



60 — 



70.00 - 



60.25 - 



60.00 - 



60.00 - 



70 — 



60.75 - 



60.75 - 



60.50 - 



60.50 - 



80 — 











90 — 



60.50 - 



60.75 - 



60.75 - 



60.75 - 



100 — 











120 — 



70.00 - 



70.00 - 



70.00 - 



70.00 - 



160 — 



70.00 - 



70.00 - 



70.00 - 



70.00 - 



180 — 



60.75 - 



70.00 - 



70.00 - 



70.00 - 



190 — 



60.75 - 



70.00 - 



70.00 - 



70.00 - 



