214 



NA rURE 



[December 29, 1904 



1898, has steadily decreased from 1,050,000 cwt. to 

 602,600 cwt., and the value per cwt. has slightly decreased. 

 The reason given for the reduction in value of line-caught 

 fish is that the trawlers have been landing large quantities 

 of cod. Thus, in spite of the large increase in the number 

 of steam liners, which are, of course, independent of wind 

 in getting to the fishing grounds, the catch per boat fell 

 from about 182 cwt. to about 121 cw^t. 



It is interesting to note that for the herring fishing in 

 the Buckie and Peterhead districts experiments have been 

 made with sailing boats fitted with auxiliary steam power. 

 The value of steam power is shown in another part of the 

 report, where the catch of the Scotch boats (sailing craft) 

 working from English ports during October and November 

 is compared with that of the English boats, a large number 

 of which are steamers. The Scotch boats caught more than 

 655 per cent, of the total catch, but only got 4fc| per cent. 

 of the total value, the steamers always being able to make 

 the market first. 



The west coast mackerel fishing has shown great improve- 

 ment, the catch in 1903 being 57 per cent, better than in 

 igo2. The trade apparently only requires development, as 

 " shoals of mackerel almost every year visit the coast." 



In the report- on salmon fisheries we learn that during the 

 vear Mr. Calderwood, Inspector of Salmon Fisheries for 

 Scotland, made inquiries as to the views of the various 

 fisherv boards with regard to the limitation of netting in 

 narrow w-aters, this move being an outcome of the report 

 of the Royal Commission on Salmon Fisheries. 



Some of Jhe boards have already taken steps to reduce 

 the netting in their rivers. In the .\nnan all nets have been 

 removed, while in the Spey only about three miles of water 

 is now- netted. In the Aberdeenshire Dee an association 

 has, for about thirty years, annually bought off the nets 

 on some sixteen miles of water, and now both upper and 

 lower proprietors are seeking to secure the permanent re- 

 moval of these nets. 



While eleven of the boards consulted passed resolutions 

 in favour of reducing the netting, six were unable to express 

 an opinion, and only one, the North Esk Board, passed a 

 resolution against any such reduction. In Mr. Calderwood's 

 words : — " The resolution was prepared and agreed to by 

 the lower proprietors — who are in the majority — before the 

 meeting took place, and was based upon the argument, 

 supported by good evidence, that the present amount of 

 netting in the district — which netting has been constant for 

 a great number of years — has not produced a decline in the 

 stock of fish. The question of improving the general 

 interest of their -whole district is complicated by other con- 

 siderations which need not be referred to here." 



One of the most important papers in this report is Mr. 

 Calderwood's contribution to the life-history of the salmon 

 as observed by means of marking adult fish, the first part 

 of which appeared in the report for 1901. Since then 62 

 additional re-captures of marked fish have been made, which, 

 with those previously caught, gives a total of 252 re-captured 

 fish. From this material, and also from other results 

 obtained in Scotland, Ireland, and Norway, Mr. Calderwood 

 has been able to draw some important conclusions. We now 

 have evidence bearing out the commonly accepted view that 

 the great majority of salmon after visiting the sea return 

 to the river they left. 



The marking experiments seem to show that grilse spend 

 less time in fresh water than salmon, running up and down 

 from the redds more quickly than the latter. 



Another very interesting fact brought out is that a grilse 

 kelt after ruiining down to the sea may return within a 

 few i-nonths as a summer salmon of about 10 lb., or may 

 remain in the sea until the following year, returning to the 

 river as a spring salmon. This partly upsets the belief that 

 spring salmon are old fish, for, although there is no doubt 

 that old fish do run up in the spring, we now know that 

 a fish of 18 or 20 lb. may only be five years old, according 

 to Mr. Calderwood, and on its second return from the sea. 



There is evidence showing that some fish spawn in two 

 successive seasons, and one case. No. 7298, seems to suggest 

 that the fish was spawning for the third year in succession. 



There is a diagram, in which fish of various weights are 

 considered as being of various ages, which shows the 

 interesting facts observed as to the " dual migration " which 

 e.xists, perhaps, in all stages of the salmon's life-history. 



NO, 1835, VOL. 71] 



We know that all the fish of one hatching do not migrate 

 to the sea at the same time. Some migrate at one year old, 

 the great majority at two years, and some again at three 

 years. 



For the smolt to grilse stage Mr. Calderwood mentions 

 three cases in which the smolts returned after a year and 

 some months as grilse of 32, 35, and 62 lb. respectively, 

 and says " we have no data to show any other seasonal 

 migrations which may occur at this stage." We do not 

 know whether the authority for the cases is untrustworthy, 

 but we recollect records of smolts marked and released being 

 re-caught after a few months as grilse up to 8 lb. weight. 

 Such cases are mentioned by Fraser (" On the Salmon, &c.," 

 1833, pp. 15, 16) and by Brown (" Stormontfield Experi- 

 ments," p. 92), who savs " the e.xperiments here have shown. 

 . . . that ail the smolts of one year do not return the same 

 vear as grilse, the one half returning next spring and 

 summer as small salmon." 



Mr. Calderwood shows that what he considers five-year-old 

 fish do not increase in weight in the w-ay that four-year-olds 

 and six-year-olds do, and he suggests that this may represent 

 the period in the life of the adult salmon when the repro- 

 ductive function is at its best, and thus asserts itself at the 

 expense of the body-growth. 



Surely this classing of fish into ages by size can only 

 be roughly correct at best. We do not yet know to what 

 extent fish spawn annually or biennially, or whether a fish 

 may rest several seasons after spawning. Vet if Mr. 

 Calderwood's suggestion that the activity of the reproductive 

 organs checks growth is sound, surely a fish spawning three 

 years in succession — as No. 7298 suggests may happen — 

 would be considerably smaller than a fish of the same age 

 which spawned in alternate years or less often. 



There are several other interesting papers in this part, 

 but space precludes us from referring to them. 



Part iii., scientific investigations, contains eight papers 

 on various subjects connected with rnarine fisheries. Dr. 

 T. Wemyss Fulton, the superintendent, gives an account of 

 the trawling investigations, and in another paper continues 

 the report of his investigations on the rate of growth of 

 fishes. He also reports upon the operations of the Nigg 

 Marine Hatchery, and has another paper entitled " Ichthyo- 

 logical Notes " on the various interesting species taken 

 during the year. 



.An important paper is that by Dr. Williamson on the life- 

 histories of the edible crab and other decapod Crustacea. 

 Dr. Williamson has discovered that the ova of the crab are 

 not attached by mucilage to the long hairs of the spinnerets 

 as was supposed, but that the eggs are actually pierced by 

 the hairs, and are thus spitted in rows, the eggs not being 

 attached to one another. 



Dr. Thomas Scott contributes a paper on some rare and 

 interesting marine Crustacea, and another upon some fish 

 parasites new to the Scottish marine fauna. 



The report is published at His Majesty's Stationery Office, 

 and can be obtained through any bookseller. 



Fr.^nk B.\LFOt.iR Browne. 



PRIZE A]VJRDS OF THE PARIS ACADEMY 



OF SCIENCES. 

 A T the annual meeting of the .Academy of Sciences the 

 ■^ list of prizes awarded for the year 1904 was announced 

 as follows : — 



Geometry. — The Bordin prize to M. Servant, for his 

 memoir on the determination of surfaces applicable to the 

 paraboloid of revolution which pass through a given con- 

 tour ; the Vaillanf prize, divided between M. Emile Borel 

 (3000 francs), and M. Bricard (looo francs); the Franctvur 

 prize to M. Emile Lemoine ; and the Poncelet prize to M. 

 DisWi Andrd. 



Meclianics. — A Montyon prize to M. Gustave Richard. 



Xa-L'igaiioii. — The extraordinary prize, of 6000 francs, 

 divided in equal parts between M. Jacob (for his theoretical 

 researches on the transmission of submarine explosions), 

 M. Gavde (for a study of the resistance of hulls to sub- 

 n-iarine explosion), and M. La Porte (for hydrographic work 

 on the coast of Brittany) ; the Pluitiey prize to .M. Lucien 

 .Mottez, for iinportant services to submarine navigation. 



Astronomy. — The Pierre Guzman prize is not awarded: 



