88 BRITISH FISHERIES 



eggs of the herring were heavier than sea-water, 

 and sank to the bottom on being emitted by the 

 parent fish, and this fact was confirmed in these 

 later investigations, and it was also determined that 

 the food of the fish consisted of small pelagic 

 crustaceans. No further work was done till 1856, 

 when Dr Buys Ballot suggested an inquiry into the 

 course of the great herring fishery, and the Board 

 of Trade issued instructions for the collection of 

 samples from all parts of the coast of Scotland, 

 observations being made at the same time and 

 recorded on a form revised by Professor Huxley. 

 Much material was thus collected, but there is no 

 record of its examination. 



Several investigations were then made into the 

 effects of trawling. Complaints were common 

 that the trawl destroyed the spawn and fry of 

 fishes, and Professor Allman made a number of 

 dredgings between 1860 and 1863, with the 

 object of determining whether or not this was 

 the case. The demersal nature of herring ova 

 was again confirmed in the course of these 

 investigations, and the incubation period of the 

 egg was found to be from twenty-five to thirty 

 days. Two principal spawning periods were 

 found to exist, one in the spring and the other 

 in the autumn. These researches ceased with 

 the agitation which originated the inquiry of 

 the Royal Commission which reported in 1863, 

 and no further biological work was carried out. 



