November 25, 1922] 



NA TURE 



705 



protons are dislodged from the atoms of the element 

 struck and that therefore transmutation has been 

 actually carried out. 



The quantity of matter so transmitted is indeed 

 almost inconceivably small, but it is the first step 

 towards what may well be the greatest achievement 

 of the human race, the release and control of the so- 

 called " atomic energy." We now know with certainty 

 that four neutral hydrogen atoms weigh appreciably 

 more than one neutral helium atom, though they contain 

 identically the same units, 4 protons and 4 electrons. 

 The change of weight is probably due to the closer 

 " packing " in the helium nucleus, but whatever the 

 explanation may be transmutation of hydrogen into 

 helium must inevitably destroy matter and therefore 

 liberate energy. The quantity of energy can be 

 calculated and is prodigious beyond the dreams of 

 scientific fiction. If we could transmute the hydrogen 

 contained in one pint of water the energy so liberated 

 would be sufficient to propel the Mauretania across 



the Atlantic and back at full speed. With such vast 

 stores of energy at our disposal there would be literally 

 no limit to the material achievements of the human 

 race. 



The possibility that the process of transmutation 

 might be beyond control and result in the detonation 

 of all the water on the earth at once is an interesting 

 one, since, in that case, the earth and its inhabitants 

 would be dissipated into space as a new star, but 

 the probability of such a catastrophe is too remote 

 to be considered seriouslv. A recent newspaper article 

 pointed out the danger of scientific discovery, and 

 actually suggested that any results of research which 

 might lead to the liberation of atomic energy should 

 be suppressed. So, doubtless, the more elderly and 

 apelike of our prehistoric ancestors grumbled at the 

 innovation of cooked food, and gravely pointed out 

 the terrible dangers of the newly-invented agency, fire, 

 but it can scarcely be maintained to-day that subse- 

 quent history has justified their caution. 



The Herring Fishery and its Fluctuations. 



By B. Storrow, Dove Marine Laboratory, Cullercoats, Northumberland. 



HERRINGS are fished in every month of the year, 

 and the catches show considerable variation in 

 the size of the fish, the state of the reproductive organs, 

 and the age composition of the shoals. It is necessary, 

 therefore, before arriving at any conclusion with regard 

 to the fishery, to take into consideration the kinds of 

 herrings which are caught on the different grounds 

 throughout the year. 



In the beginning of the year, January, February, and 

 March, shoals are fished about the north-west of Ireland, 

 off the north of Scotland, including the Shetlands and 

 Orkneys, and in the Firth of Forth. These herrings are 

 all fish with the gonads well developed, and they spawn 

 towards the end of February or in March. They are 

 known as spring spawners and, except for the shoals of 

 the Firth of Forth, they, so far as the western part of the 

 North Sea is concerned, are caught in northern waters. 

 In April the spent fish from the spring spawning shoals 

 are caught all over the North Sea, from the Shetlands to 

 Bergen Bank, from North Shields to the Naze, and off 

 Yarmouth and Lowestoft. The catches are used chiefly 

 for bait by the drift-net fishermen, who at this time are 

 fishing with lines for cod, ling, halibut, etc. Among 

 some of the bait catches are found numbers of small fish 

 with the gonads not developed, and without doubt 

 these can be classified as virgin fish. 



During May the number of drifter-liners decreases 

 and catches of herrings are made from ten to thirty 

 miles off our coast. These catches consist of young fish 

 with the gonads at practically the same stage of develop- 

 ment as those found in catches made in April, 100 miles 

 from the nearest port, and when, for the offshore and 

 inshore fish, the growth as calculated from the scales is 

 compared, the agreement warrants the conclusion that 

 the young fish have moved shoreward from the deeper 

 waters. In good seasons this movement towards the 

 shore coincides with increased landings of herrings. 



Throughout June waves of migrating herrings come 

 on to the grounds, and in the beginning of July the 

 migrations are large enough to bring about a consider- 

 able increase in the fisher}-. These June and early July 



NO. 2769, VOL. I 10] 



migrants have been found, off the Northumberland 

 coast, to be marked with a comparatively small first- 

 year growth, as determined from the scales, which, for 

 the most part, show three winter rings. Recovering 

 spents from spring spawning shoals are found among 

 catches of young developing herrings, but after the 

 beginning of July they disappear, or the numbers found 

 are insignificant. 



Herrings with three winter rings and with a com- 

 paratively larger first-year growth than the June fish 

 invade the grounds during July and August and give 

 the high catches which are taken in these months in a 

 successful fishery. Towards the end of August and the 

 beginning of September shoals of larger and older herrings 

 appear. They are full fish with their reproductive 

 organs developed, and they, together with the young 

 herrings sufficiently developed, form autumn spawning 

 shoals. After spawning they disappear quickly and 

 only young fish are to be caught. 



The summer fishery of the east coast, the Shetlands 

 excluded, is one which depends chiefly on young fish, 

 and samples examined from Wick to Scarborough have 

 been found to contain from 50 to 70 per cent, of fish 

 with three winter rings on their scales. Fish of this 

 age, therefore, determine the productivity of the fishery. 



In September herrings are caught in the vicinity of 

 the Dogger Bank by Dutch luggers and by trawlers, off 

 Scarborough and Grimsby by drift-nets. Some of these 

 fish are autumn spawners, but some, especially those 

 caught by trawlers, are spring spawners, which now 

 make their reappearance in great numbers. An 

 examination of catches made on these grounds points 

 to the herrings coming from the north-east to the south- 

 western end of the Dogger Bank and then moving in a 

 south-westerly direction to the Grimsby grounds. 



The East Anglian harvest begins in September and 

 continues to the beginning of December. In the early 

 part of the fisher}- many of the catches are landed from 

 the grounds off Grimsby and it is not until October 

 that the large fleets concentrate off Yarmouth and 

 Lowestoft. This fishery is essentially one for full 



