CANADIAN BIOLOGY 11 



SESSIONAL PAPER No. 38a 



X. — GROWTH OF THE COD A SCALE STUDY (mR. R. P. WODEHOUSe). 



Mr. Wodehouse made a similar " Study of the Cod," which is embodied in report 

 No. X. He examined 376 cod from various parts of Passamaquoddy bay, during the 

 period from June 12 to August 12, and while he points out that the scales are a guide 

 to tlie rate of growth, a retardation in springtime introduces a confusing factor. 



It is almost impossible, he says, at times to decide with certainty the age of old 

 cod which have spawned repeatedly. Other factors add to the difficulty, such as the 

 scarcity of food, temporary inability of the fish t osecure ample food for itself, and 

 other conditions which affect the scale-growth, Mr. Wodehouse gives an interesting 

 comparison between some young cod, less than one year old (two batches of them), 

 taken five weeks apart, and showing in that time a growth of slightly less than IJ 

 inch. By summarizing the tables and striking an average for each year, the author 

 finds that the size of the Qod at the following ages may be taken to be: one year, 5-70 

 inches long; two years, 14-13 inches long; three years old, 19-6 inches; four years 

 old, 25 -'6 inches; five years old, 32-3 inches; six years old, 35-62 inches; seven years 

 old, 39-09 inches; and eight years old, 45-27 inches. 



There is, of course, individual variation. Indeed the author states that " scarcely 

 any two fish have the same life-history." 



XI. — DETERRENT EFFECTS OF LIGHT ON MIGRATING EELS (PROF. P. COx). 



Professor Cox has completed his third report, contributed to the present series, 

 upon an interesting subject, namely, " The Deterrent Effects of Light on Ascending 

 Eels in Rivers." The theory has been mooted that eels, which are a pest in some 

 rivers, might be excluded by the use of strings of lights suspended across the channels 

 up which they migrate. The experiments were conducted at the end of July, in the 

 tanl^s of the laboratory at St. Andrews, and later, at the exit of Bocabec lake, New 

 Brunswick. The details are interesting, and show that eels, afraid of the lights at 

 first, hasten back into the darkness but seem to become accustomed after three or four 

 nights' experience, and linger for a longer time in the luminous area. Moving lights 

 were effective for one or two nights, but later they paid little attention to them. Dr. 

 Cox calls attention to the abnormal conditions under which the experiments were 

 conducted. 



The usual time for migration of eels was passed, and the fish were transferred 

 from salt water to fresh and vice versa, and moreover the fish were penned, not free, 

 in order to facilitate the observations. The conclusion reached is that such lights do 

 not deter migrating eels. 



XII. POSSIBLE AREAS FOR LOBSTER BREEDING IN BRITISH COLUMBIA (dR. MCLEAN FRASER) . 



Dr. McLean Eraser gives an account of his " Examination of Possible Lobster- 

 Breeding Areas on the east coast of Vancouver Island, B.C.," and in a very full report 

 furnishes details on the nature of the bottom, depth, temperature, density, salinity, 

 etc., of the waters examined from Victoria on the south, to Texada and Lasqueti 

 islands on the north. After referring to the several shipments of lobsters and lobster 

 eggs, by the Dominion Government, from the Atlantic to the Pacific coast, the author 

 expresses the opinion that the temperature in the straits of Georgia is never too high 

 to incommode lobsters, and he found in July, 1914, that the temperatures were as 

 follows : — 



63-1° F. at the surface, 

 56.3° F. at 5 fathoms, 

 51-0° F. at 20 fathoms, 

 50. Y° F. at 25 fathoms, 



