RATE OF GROWTH OF SOME SEA FISHES. 



223 



to mine, namely, that he hatched his specimens as well as reared 

 them, while mine were obtained at an early stage of life from the 

 sea. I believe that this is the only case in which larvee artificially 

 hatched from marine pelagic fish eggs have been successfully 

 reared in captivity. This success can only be attributed to the fact 

 that the young fry were turned into a large reservoir of clean sea 

 water. The reservoir was made by building, two dams across a 

 narrow rocky gully, opening on to the shores of the inlet on which 

 Flodevig stands. Flodevig is about 6 miles from the town of 

 Arendal on the south coast of Norway. The reservoir was about 

 43 yards long, 20 yards broad, and 5 yards in greatest depth, and 

 sea water could be constantly pumped into it by means of a steam- 

 engine. The reservoir was like an enclosed portion of the sea- 

 shore, and seaweeds grew in it as on the shore. 



Into this large reservoir Daunevig put, on the 3rd May, 1886, 

 about 500,000 cod larvae hatched on the 27th April. The larvse 

 when put in were 5 mm. or ^ of an inch in length. Up to the 

 6th of June their growth was slow, they measured then only 15 mm., 

 and up to this time they refused the artificial food, namely, finely 

 chopped mussels and fish, which was offered to them. After this 

 they began to eat the food thrown into the pond, and their rate of 

 growth rapidly increased. On July 12th, when two and a half 

 months old, they measured 5'5 cm. or nearly 2*2 inches. The sub- 

 sequent growth will be seen from the following table : 



1886 



1888 



Bate. 

 May 3 

 June 6 

 July 12 

 Aug. 12 

 Sept. 12 

 Oct. 12 

 Feb. 

 Autumn 



Age. 

 6 days 



1 month 9 days 



2 months 15 days 



3 months 15 days 



4 months 15 days 



5 months 15 days 

 1 year 10 months 



2^ years 



Length. 



5 mm. 



1*5 cm. 



5'5 cm. 



7"0 cm. 



8*5 cm. 

 11-5 to 15-7 cm. 



35-6 to 40-7 cm., 14 to 16 inches. 

 9 to 18 inches. 



is taken from a separate report 



The last entry in the above list 

 by Dannevig on the work done at Flodevig between 1883 and 1888. 

 This report is dated February, 1889, but the paragraph concerning 

 the cod was apparently written in the autumn of 1888. It is 

 there stated that the total number of fish surviving was from 200 to 

 400, and that they seemed likely to spawn in the following spring. 

 I have not been able to find anything further about these fish in 

 later reports. 



Fulton finds the smallest ripe cod to be 20 inches long, and Holt 

 thinks that the smallest ripe female is considei-ably larger. 

 Dannevig's specimens had not reached 20 inches in two and a half 



