1884.] Artificial Fertilisation of Herring Ova., 



455 



is, therefore, as far as has been ascertained, little or no surface-food 

 for the millions of herring-fry which will undoubtedly be soon 

 hatched on the Ballantrae Bank. It may be possible to secure spe- 

 cimens of the larval herring, and thus ascertain what they are 

 feeding on. 



II. The Natural Spawning Process. 



The presence of a large school of porpoises and dolphins, and the 

 excitement and rocket-like movements of the gannets, taken together 

 with the calmness of the sea on the afternoon of Friday, the 

 7th March, led us to expect that there would be a good night's fish- 

 ing. We therefore arranged to be on the fishing- grounds early on 

 the Saturday morning, well provided with large tanks for receiving 

 live herring, and with hatching and carrying-boxes for their spawn. 

 Our expectations having been realised, we had at our disposal on 

 Saturday morning thousands of mature living herring. Selecting 

 about fifty of the largest and ripest, they were placed in tanks on 

 board the " Jackal," and conveyed as rapidly as possible to the 

 Rothesay Aquarium. On the way there was time to make a number 

 of experiments, and to cover several plates of glass with artificially 

 fertilised ova, but before referring to these experiments, and the 

 method adopted for artificially impregnating the eggs, I shall 

 describe how the eggs are deposited and fertilised by the herring 

 themselves. This, so far as I am aware, has not been previously 

 observed. In the best account we at present possess of the structure 

 and habits of the herring, Professor Huxley says, "When spawning 

 takes place naturally the eggs fall to the bottom and attach them- 

 selves." " But at this time the assembled fish dart wildly about, and 

 the water becomes cloudy with the shed fluid of the milt. The eggs 

 thus become fecundated as they fall, and the development of the 

 young within the ova sticking to the bottom commences at once."* 

 Mr. Mitchell, in his book on " The Herring," referring to the once 

 famous spawning-bed off Dunbar, states that, " About the 30th of 

 August the shoals began to deposit their spawn a short distance from 

 the harbour, and on the 3rd of September the fishermen found that a 

 very large body of herrings remained fixed to the ground in the 

 process of spawning, the ground being of a rocky or stony nature." 

 It is not added how the fishermen knew the herring remained fixed 

 to the ground. It is not likely that a diving-dress was used, but even 

 if it had been, nothing could have been made out, as it is extremely 

 difficult even in a good light to observe what takes place in an 

 aquarium. While many fishermen believe that herring spawn on 

 hard ground, some believe that they also spawn on a clayey bottom, 

 and while some think that they spawn near the bottom, others affirm 



* " Nature," April, 1881. See also " Jahresbericlit der Commission in Kiel." 



