vi PREFACE 



obtaining in successive seasons of the year, the physical, chemical, biological, and 

 other conditions, which so profoundly affect animal and plant life in the sea. 



Dr. Hjort has succinctly summarized in his Introductory Keport his own main 

 results, and the results obtained by the scientific staff working under him, in connec- 

 ■ tion with the expedition. 



The herring resources of the Atlantic coastal waters of Canada and of the gulf 

 of St. Lawrence offer a field for enormous commercial development, and Dr. Hjort 

 gave primary attention to the study of the Canadian herring. 



As the Preliminary Report on the various types of Canadian herring described 

 by Dr. Hjort was published three years ago, it is not necessary to repeat its main 

 points here, and Mr. Einar Lea's further and more elaborate detailed results must be 

 studied in his report now presented; but it may be pointed out that, on the whole, 

 four very different groups of herring may be distinguished, viz. : — 



(1) The Newfoundland type (with the remarkable exception of the St. George 

 Bay herring), which grows slowly during the first summer, but from the third summer 

 on grows at a rapid rate. The samples studied ranged from four to twenty years in 

 age, and the age-group of 1904 was dominant, recalling Dr. Hjort's discovery of a 

 dominant age-group in JSTorway — a single year-class maintaining a dominant position 

 in successive season's catches for several years. The typical Newfoundland herring 

 in growth and age composition of the schools form a group distinct and apart, as 

 demonstrated by all the samples studied. 



(2) The second type are formed by the herring off cape Gaspe, Magdalen islands, 

 and Northumberland straits, roughly embracing the west and northwest waters of the 

 gulf of St. Lawrence, which grow rapidly during the first summer, and slowly in later 

 years, and are thus smaller later on than Newfoundland herring of the same age. 

 The 1903 and 1907 year-classes dominated. 



(3) A third type from the Cape Breton (Atlantic) coast, from North Sydney 

 south, which have a moderate first-summer's growth, but a more rapid growth from 

 the third summer on. The divergent type from bay St. George, Newfoundland, belongs 

 to this group. The dominant age-group is that of 1903. 



(4) A fourth type from Chedabucto bay and southwest along the Nova Scotia 

 shore, which grows well during the whole of its first five or six years, and outdistances 

 all the other types of herring. The 1911 year-class was found to prevail, while in the 

 large, older herring from Nova Scotia, the 1908 year-class dominated, and in the 

 Halifax and Lockport samples the 1908, 1910, and 1911 year-classes were best repre- 

 sented. 



Mr. Einar Lea makes the important observation in his report that the samples of 

 herring which resembled each other in age-composition, also exhibited great resem- 

 blance as regards growth, hence the types signalized would appear to be valid and 

 unquestionable, though more extended researches are urgent to fvilly confirm these 

 results. 



The special investigations upon the herring yielded conclusions so interesting 

 that it seemed necessary to extend the studies in hand to other species, and to eluci- 

 date faunistic conditions generally in all the Gulf and Atlantic waters embraced in 

 the scheme. 



Problems as to the influence of the earth's rotation, the effects of the annual 

 melting of the great fields of ice, the features of temperature, salinity, specific gravity, 

 etc., of the sea water, and other matters vital to the vertebrate and invertebrate life, 

 and especially fish-life, off our Atlantic coast, were included. 



Professor Gran's masterly plankton studies show that in the gulf of St. Lawrence 

 there is a plentitude of minute floating plants of northern types, whose development 

 each season appears to be annually much later than in the northern European waters. 

 The prevalence of an Arctic temperature for so large a part of the jeav is the explana- 

 tion. 



