Section IV., 1913. [331 Trans. R.S.C 



Notes on the Scale-markings of the Halibut and their Bearing on Questions 

 Connected with the Conservation of the Fishery. 



By J. Playfair McMurrich, M.A., Ph.D., LL.D. 



(Read May 28, 1913) 



The importance of the Halibut fishery on our West Coast, 

 surpassed only by that of the Salmon, makes a knowledge of the life- 

 history of the fish a matter of some importance, especially in view of 

 the probability that regulation of the fishery is necessary if the supply 

 is to be maintained. And yet at present our knowledge of the essential 

 facts regarding the life-history of the Halibut is almost a blank. Thus, 

 to quote only one of the authorities on our marine fishes, Professor 

 Goode, after pointing out the great uncertainty as to its spawning 

 season, says* " It is not known whether the eggs float or rest upon the 

 bottom, nor is it known how long is the period of incubation, nor what 

 the rate of growth of the fish." 



The remarkable definiteness of the story that may be deciphered 

 from the markings of the scales upon the Salmon led me to undertake 

 an examination of the scales of the Halibut, in the expectation that 

 these also would reveal in their markings a more or less clear account 

 of the life-history of the fish. And they undoubtedly do so, but my 

 hopes of working the story out in detail were disappointed by the fact 

 that of scales collected from thirteen fish only those from three were 

 perfect, the rest showing more or less extensive injuries which ab- 

 solutely obliterated portions of the record. This condition is probably 

 correlated with the fact that the Halibut, like other flat-fishes, is a 

 bottom fish and the scales thereby liable to injury, but the frequency of 

 its occurrence necessitates the collection of material from a large 

 number of fish, if a series of perfect scales, sufficient for the determina- 

 tion of the details of the life-history, is to be obtained. But even from 

 the small amount of satisfactory material that I was able to collect, 

 certain facts concerning the life-history of the fish are clearly revealed, 

 and the imperfect scales, so far as they give information, confirm the 

 story told by the perfect ones. These facts are of such importance 

 that it has seemed advisable to place them on record, leaving the filling 

 in of the details of the story for future and more complete observations. 



The scales of the Halibut are elongated structures and are more 

 deeply imbedded in the skin than usual. In addition to the concentric 



*G. B. Goode.— American Fishes. 2nd Edn. 1903. 



