On the Hatching of Herring Ova in Deep Water 



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But although it has been proved that herring ova are 

 capable of hatching in deep water, it may be said that the 

 fry would never succeed in finding their way to the surface ; 

 and further, that having reached the surface, the food so 

 necessary for the early stages of their existence may not be 

 found forty to sixty miles from shore. First, as to their 

 power of reaching the surface. 



In a paper published in the Fishery Board Eeport for 

 1883, I mentioned that, " as soon as the fry escaped, they 

 began to ascend by a wriggling motion towards the surface 

 of the water, rising at first only a few inches at a time, to 

 turn and slowly sink head downwards towards the bottom. 

 During the first day they seldom succeeded in rising more 

 than two or three feet from the bottom, and this they only 

 succeeded in accompKshing after many attempts ; but on the 

 second day they readily, almost without a single rest, rose 

 three feet at a time ; and on the fourth day they succeeded 

 in swimming freely on the surface of the water." 



There can be little doubt as to the purpose of this strong 

 instinct to reach the surface ; it is to bring them to the 

 strata of water in which there is the largest supply of food. 

 When hatched, the fry have in their yolk-sac sufficient 

 nourishment for several days — the number of days depending 

 on the time required for hatching. Those who have seen 

 the small, almost invisible, newly-hatched herring fry will 

 naturally think 100 fathoms is a long way for them to travel 

 before they reach their food supplies. If, however, the fry 

 are kept under observation, it is found that, after the first 

 day, they can ascend at the rate of a fathom per minute. At 

 this rate they could ascend 100 fathoms in 1 hour 40 min. 

 If we allow for a rest of 30 sec. every three feet for the 

 ascent, we have another hour and 40 sec. to add. Again, if 

 we suppose they sink 30 inches during each rest, we increase 

 the distance to be covered to 150 fathoms ; in other words, 

 we add 50 min. to the time required, which gives a total of 

 4 hours 10 min. for the 100 fathoms. This being the case, 

 we cannot suppose that the fry would have any difficulty in 

 ascending 200 fathoms before the nourishment in the yolk- 

 sac was exhausted. 



