Fishes of the IVestern North Atlantic 



43 



kilo).^* Data for the smallest 1 1 specimens from the St. Lawrence River, taken from 

 August to November in peches located near Quebec City, are tabulated in Table i. 

 Judging by their long snouts, dorsal scutes in a continuous row without separation, 

 general coloration, and small size, we consider all of these specimens to be less than 

 one year old. During the first year, juveniles of A.fulvescens (Table i) and of A. oxy- 

 rhynchus grow at about the same rate. 



Date 



Sept. 19, 

 Oct. 19, 

 Aug. 8, 

 Nov. ig, 

 Oct. 31, 

 Sept. 12, 

 Aug. 20, 

 Sept. 30, 

 Aug. 29, 

 Aug. 25, 

 Sept. 30, 



Average . 



Table I. Growth Rate of A.fulvescens. 

 Total Length 



1952 

 1953 

 1947 



1947 

 1952 



1944 

 1952 



1947 

 1947 

 1952 



1947 



(mm) 

 63 

 84 

 87 



99 

 106 

 109 

 117 

 121 

 121 

 123 

 123 

 104.8 



(inches) 

 2.48 

 3-31 

 3-43 

 3-9° 

 4-17 

 4.29 

 4.61 

 4.76 

 4.76 

 4.84 

 4.84 



4-13 



Fork Length 



(inches) 



2.24 



3-23 

 3. II 



3-54 

 3.86 



Weight 



(mm) 



57 

 82 



79 

 90 

 98 



96 

 107 

 109 

 III 

 1 12 

 1 12 



95.8 



3.78 

 4.21 

 4.29 



4-37 

 4.41 

 4.41 



3-77 



(g) 

 0.9 

 2.0 



2-5 



3.2 



4-4 



4-3 

 4.8 



4-7 

 7-7 

 6.5 

 6.2 



4.29 



(oz.) 



0.032 



0.071 



0.088 



0.113 



0.155 



0.152 



0.169 



0.166 



0.271 



0.229 



0.219 



0.151 



Place 



St. Nicolas 



St. Nicolas 



Neuville 



Neuville 



Neuville 



Neuville 



Neuville 



Neuville 



St. Vallier 



Neuville 



Neuville 



Although the ages of Lake Sturgeon in our material from the St. Lawrence River 

 have not as yet been determined, probably their range is up to 30 years, or even more. 

 According to Cuerrier and Roussow, who studied the growth of fulvescens from the 

 upper St. Lawrence River (Lake St. Francis), fish 3-22 years old averaged 16.5-37.5 

 inches FL {24: 8-14). The oldest fish in their material, a female 23 years of age, 

 was 50.5 inches FL and weighed 42 pounds. 



Spawning and Reproduction.'^^ The principal spawning season for A. fulvescens in 

 Quebec extends from about the beginning of May to the end of June. The smallest 

 male ready to breed, taken at St. Vallier on May 5, 1944, was 38 inches TL {j^t^ in. FL) 

 and weighed 1 1 pounds 4 ounces. The smallest mature female, taken at the same place 

 on June 13, 1949, was 45 inches TL (41 in. FL) and weighed 17 pounds. The Lake 

 Sturgeon from Lake Nipigon, Ontario, does not become sexually mature until it is 

 about 22 years of age, when it is approximately three feet TL (j5: 15-25). 



Roussow, in studying cross sections of the first pectoral ray of A. fulvescens., 

 found variations in the broad and narrow zones on this bone (6^: 553—572). He con- 

 cluded that "the growth retardations caused by the ripening of the gonads and the 



28. For the length-weight relationship of St. Lawrence specimens from Quebec, see Vladykov (7S: 57). Roussow 

 has given some information on the rate of growth and movements of A . ftd'vescens from the St. Lawrence 

 and Ottawa rivers (6j: 1-124). Resuhs of extensive tagging at Quebec of 1,507 A.fulvescens and 2,995 A.oxy- 

 rhynchus have been summarized by Magnin and Beauheu {^0: 237-252). 



29. Additional information on spawning habits and experimental hatching of Lake Sturgeon has been given by 

 Stone (69: 118-123) and Carter [16: 60-63). 



