SALMON— SPAWNING, SIZE OF KGGS. ^^ 



Marcli, 1881, and most of the male pars had milt in November, 1883, or when 

 2 years and 8 months okl ; also two or three smolts of the samo afo had ova 

 which probably would have matui-ed but they jumped out of the pond and so mot 

 with their deaths. In Novannbcr or Deeombe;', 188 1, or at 3 years and 8 months 

 age, all these Hshcs seemed ready to breed, and young were bred from their 

 spawn.* Consequently, descending to the sea prior to depositing ova is not a 

 physiological necessity for young salmon. f 



Whether simply the heat of the water, unless excessive, exercises any delete- 

 rious effect upon the breeding fish we have but little evidence on which to rely, 

 but in the United States Fishery lieports for 187G Mr. Atkins remarked of the 

 Atlantic salmon, Salmo salar, in the Penobscot in 1873, that the temperature in the 

 ponds in which those for spawning were confined, " between June 28th and 

 August 13th there were only tiv^e days when the water at the bottom of the pond 

 stood below 70° Fahr., and on one occasion, July 31st, it rose as high as 7(i^ Fahr. 

 Not only did no salmon die during this lieated term, but at the succeeding 

 spawning season they came out in perfect condition and yielded eg-gs of the 

 highest degree of health and vigour." 



At the spawning time+ these fish are in a poor condition, covered with slime 

 and often nearly as slippery as eels, for at this period they almost cease feedino-, 

 living upon the fat which has accumulated in their system during their residence in 

 the salt water, where the supply of food was abundant. Possibly the fat in the 

 salmon's system may be more rapidly used up in cold rivers than it is in warm 

 ones. 



The eggs of the salmon are small, nearly round, elastic bodies, of a clear white, 

 pink, or even coral colour. § Due to their tough outer coat they are very elastic 

 as may be seen by throwing one on the ground, from whence it will rebound like 

 an india-rubber ball. This strength and elasticity we know must be an exceedingly 

 important property if Ave i^emember where these eggs are deposited and what an 

 amount of pi*essure they have to undei'go. The following are the sizes observed in 

 some salmon eggs (see page 25 ante) : of Howietoun grilse up to 1\ lb. weio-ht 

 0-20 to 0'22 of an inch in diameter ; while of these fishes from the Teith, taken 

 Nov. 26th, 1885, a 10 lb. grilse had them 0-20 ; a 16 lb. salmon, Nov! 1881, 

 0"21< of an inch; a 15 lb. salmon, Nov. 26th, 1885, 27 of an inch, and the eo-o-s 

 of one large salmon in 1884, weight not noted, were up to 0'30 of an inch. 

 Here we observe a considerable variation in size from 0'20 of an inch in the 

 diameter of the eggs of a grilse, to 0*30 of an inch in that of a salmon, while these 

 eggs have been obtained of a still larger size.|| 



* Grilse, it has been asserted, in some rivers breed earlier in the cold season of the year than 

 do salmon, which it has been surmised is due to their being fish in which the time of reproduction 

 has been deferred from February or March until October or November. As at the i^eriod "rilse 

 spawn fertile male pars would be present in the rivers, it would aj^pear not improbable that they 

 might i^erform the necessary marital otiice. 



t Many have held the opinions which Rasch so fully detailed in 1860 when he commenced 

 by the inquiry why it is that all the male fish, including those that have gone to the sea and those 

 that remain behind in fresh water, have their reproductive organs fully developed, while the 

 female is under the necessity of making the journey to the sea before being able to spawn 

 (see page C9 ante). He considered that if smolts were prevented going to the sea they would 

 readily accustom themselves to a fresh- water home, if the piece of water were sufficiently extensive • 

 and " should the water be a very large lake, such as Ladoga, Wener, Peipus, and as rich in 

 nourishing food, the fresh-water salmon will then attain about tbe same size as the salmon of the 

 sea." He also observed that Hetting hatched out numbers of salmon ova, which he subsequently 

 turned loose into the Tyri-fiord : and during the last two years fish had been caught in that lake 

 resembling in every respect salmon proi^er. 



I It has been suggested that a sojourn in fresh water, even if such be merely temporary, may 

 give the first impulse towards bringing the sexual organs to maturity, but there does not ai)pcar 

 to be any evidence on which to base such a theory, and the breeding of the land-locked races and 

 the Howietoun experiments clearly demonstrate that the maturity of the breeding organs may 

 occur without any migration from the fresh waters in which the fish were originally hatclied. 



§ The micropyle in the salmon's eggs from the Teith had nine pits or depressions around the 

 opening in such as were examined. 



\\ Stoddart, Anfflefs Companion, 1847, held that the eggs were fertilized before tliey were 

 extruded, and that it was a " false but popular notion that the ova of the salmon, previous to its 

 being emitted, is in an unimpregnated state" (page 188). 



