28 



BULLETIN OF THE BUREAU OF FISHERIES 



comers dig up many of the nests of those that came earlier, and destroy a regrettably 

 large number of eggs; but they replace those they destroy with fresh lots of their 

 own eggs, and many of the earlier eggs must escape destruction. Even in years of 

 very heavy runs, when waste of eggs is excessive, the net result is probably a more 

 complete seeding of all available gravels than occurs during runs of more moderate 

 dimensions. It may well be that a spawning escapement beyond a certain size 

 entails an economic loss. The increase in numbers of progeny produced by such 

 overplus of spawners may not compensate for surrendering the economic value of 

 the parents; but we have no evidence that " overseeding " of the beds ever occurs, 

 with a diminished run in consequence. That the reverse is the case, we have a 

 certain amount of evidence, and need only refer to the quadrennial run on the Fraser 

 River, which persisted throughout historic times despite almost incredible crowding 

 of the spawning grounds during the "big years." The more moderate spawning 

 of the intermediate years produced only the limited runs of those years; and when 

 finally the spawning escapement of a big year, because of a catastrophe, was during 

 one season reduced to a fraction of its usual size, the big run disappeared completely 

 and has never been restored. 



As bearing on this point, we have in evidence also the large and small runs of 

 pink salmon (Oncorhynchus gorhuscha), which occur in alternate years in virtually 

 every portion of its range. The pink salmon matures invariably in the second 

 year of its age. All the members of any run have developed from eggs laid down 

 during the second year previous. Every big year, then, produces a big year, although 

 with this species especially, the streams are crowded to capacity and beyond during 

 years of heavy run. The waste here again is enormous, and the economic phases of 

 the question may well be taken into consideration ; but it is well to keep in mind that 

 the net results of such excessive crowding of the streams are in the way of increased 

 runs. To those, therefore, whose duties lie in the examination of spawning grounds, 

 we recommended a certain hesitancy in certifying that the beds are "fully occupied" 

 by spawners or are "overseeded." 



During the summer of 1926 the ovaries from a number of females were preserved 

 and the eggs counted to determine the number produced by each female, and from 

 this the number that may be deposited on the spawning beds. The ovaries from 40 

 females were thus studied, the work being done by S. P. Smith, temporary scientific 

 assistant. From each of the two ovaries found in each female a portion weighing 5 

 grams was taken and the eggs counted. Then the entire ovary was weighed and the 

 number of eggs calculated. The results are given in Table 3 and are shown graphi- 

 cally in Figure 20. 



Table 3.— Number of eggs in Karluk River red salmon taken September 15, 1926 



Average length, centi- 

 meters 



Number 

 of indi- 

 viduals 



Left 

 ovary 



Right 

 ovary 



Total 



Average length, centi- 

 meters 



Number 

 of indi- 

 divuals 



Left 

 ovary 



Right 

 ovary 



Total 



53 



1 



1, 320 



1,510 



2, 830 



61 



10 

 8 

 4 

 1 

 2 

 1 



1, 884 

 2,039 

 1,828 

 2,085 

 1,975 

 i, 735 



1,917 

 2,018 

 1,915 

 2,750 

 2, 019 

 2,509 



3,801 

 4,058 

 3, 744 

 4, 835 

 3,994 

 4,244 



54 



62 _ 



55____ 



1 



1, 645 



1, 310 



2, 955 



63 



56 



64 



57 



2 

 1 

 3 

 6 



1,600 

 1,328 

 1,818 

 1,748 



1, 682 

 1,030 

 1,837 

 1,739 



3,282 

 2.358 

 3, 655 

 3, 487 



65 



58 



66 _ 



59 



Average 



60.. - .".„ 









3,728 













