256 



NA TURE 



[January i i, 1906 



sources. We have to deal first of all with the " Gull 

 Stream," or, as it is now termed, the " Norwegian branch 

 of the European stream," which, originating in the 

 Atlantic Ocean, flows north and east through the Scotland- 

 Shetland and the Faerie-Shetland channels, sometimes 

 reaching as far north as the Murman coast. A second 

 component is water of Arctic origin which enters the 

 Shetland-Faeroe channel as an offshoot from the east 

 Icelandic polar stream. Further, the hydrography of these 

 regions is complicated by the occasional presence of water 

 from the Norwegian Sea, from the coasts of Britain, or 

 from the North Sea itself. These various components are 

 traced by observations of their salinity, temperature, and 

 plankton contents. The Norwegian branch of the Euro- 

 pean stream is shown to exhibit a well marked periodicity. 

 In 1903 the inflow of Atlantic water through the Shet- 

 land-Faroe channel decreased from May on, and practicall} 

 ■ eased in November, resuming in February of 1904. The 

 southerly polar stream attained its greatest volume in 

 spring; it is apparently able to make its way southwards 



11 all seasons of the year, either as an undercurrent or at 

 the surface. When it is strong it may obstruct the 

 Norwegian stream in the Faaroe-Iceland channel, and cause 

 the latter to pass to a greater extent between Scotland 

 and Shetland. These are the principal results attained so 

 far, and they do not add much to our knowledge of the 

 hydrography of these regions; but it must be remembered 

 that they are founded on the results of one year's complete 

 investigations only, and are best to be appreciated at the 

 end of the five years' investigations and when they are 

 considered along with the results attained by the other 

 investigations now in progress. 



A must important part of the original scheme ot investi- 

 gations was the discussion of the statistics obtained by 

 the participating Stales. These matters receive proper 

 attention in the present volume, and Prof. Thompson dis- 

 cusses in a very attractive manner tin interesting series 

 of statistics furnished by the Granton Steam Fishing 

 Company, tend a similar series of statistics given by the 

 st.aui trawlers owned by .Messrs. Johnston, of Montrose 

 In each case the average catch per vessel has been calcu- 

 lated, and tables and curves are given showing, in an 

 interesting fashion, the seasonal fluctuations of the fishes 

 under review, which are haddock, whiting, cod, plaice, 

 turbot, and lemon sole. In the case of each fish there are 

 generally two maxima of abundance, one of which is 

 always well marked and the other not so well shown. In 

 the case of the haddock there is, however, a very close 

 correspondence between the catch of this fish and the 

 surface temperature of the sea, a correspondence which 

 Prof. Thompson points out is mosl probably due to the 

 fact that the great summer fishery for herring takes place 

 at the time when the surface waters of the sea have their 

 greatest temperature, and when the haddock is shoaling to 

 feed on the herring spawn. It is notable that in neither 

 oi these cases is then- any certain indication of a pro- 

 gressive de, lease or increase in the volume of the catches 

 oi any of the fishes in question. 



Perhaps the most valuable paper in the volume is that 

 contributed by Or. Fulton in which he elaborates the 

 method of studying the distribution and seasonal flue Ill- 

 ations of fishes first suggested by him in the reports ol 

 the Fishery Board for Scotland "some years ago. Mils 

 consists in obtaining accurate records of the catches made 

 In .1 large number of trawlers, and also information of 

 1 he places where these catches were made. This plan of 

 obtaining commercial fishery statistics (apart, of course, 

 from the ordinary official figures) was first practised bv 

 the Fishery Board, and a considerable number of Aberdeen 

 steam trawlers now regularly provide these figures. The 

 first results uf these investigations were published in the 

 annual reports of the Fisherj Board, bul line are now 

 utilised in connection with the other investigations .-I the 

 international organisation. The figures are collected by 

 the statistical staff ot the Fishery Board at the market in 



\berdeen, and are expressed as the quantities oi fish caught 

 per vessel per too hours' fishing. The North Sea' is 

 divided into a number of squares, each of which is hounded 

 bv one degree of latitude and two degrees of longitude. 

 All the cliches ,,f fish made on each of these squares 

 during each month of the year are then brought together 

 XO. 1889, VOL. J$~) 



and expressed as the cwts. of fish caught per 100 hours' 

 fishing on each area, and curves are constructed 

 which are superposed, and so show in a very in- 

 structive manner the variation in the abundance of each 

 kind of fish from month to month during the year. It 

 is thus shown that there are two maxima of abundance 

 for each fish during the year, one of which corresponds 

 with the spawning time of the species. It is further shown 

 that there is a " complementary or compensating fluctu- 

 ation " among different species on the same ground, one 

 species becoming abundant as another becomes scarce, so 

 that the sum total of the species on the same ground 

 remains reach constant during the year. 



Other reports in the same volume are those by Dr. T. 

 Scott on the Crustacea collected during the seasonal 

 cruises of the Goldseeker, and similar papers by Mr. Clark 

 on the other plankton collections. Prof. Thompson also 

 contributes a translation of a paper by Sandstrom and 

 Helland-Hansen on the mathematical investigation of 

 ocean currents. It is regrettable that the fishery experi- 

 ments of the Goldseeker have not been described and 

 summarised in this volume, but these will no doubt be the 

 subject of a future report. One must not omit to mention 

 the beautifully engraved charts of the North Sea which 

 illustrate the paper on the trawling statistics of Aberdeen. 



Jhe second of the reports under notice deals with the 

 part ot the international investigations which was entrusted 

 to the Marine Biological Association, and gives an account 

 of the researches carried out in the southern part of the 

 North Sea and in the English Channel. In some respects 

 this nport is complementary to that issued ley the Scottish 

 Fishery Board ; in the latter special attention is directed 

 to the results of the hydrographical work and to statistical 

 studies, while fishery investigations are not reported upon. 

 In the English Blue-book, on the other hand, the bulk of 

 He -pee is devoted to an account of the fishery investi- 

 gations. The hydrographical researches, which are re- 

 ported only by Mr. 1). Matthew's, were carried out in 

 a somewhat limited area, but are of very great interest. 

 It is shown that the water in the English Channel is 

 derived from two main sources : — (1) high salinity water 

 (.556 parts per thousand and upwards), which enters the 

 Channel as a current flowing in a northerly direction from 

 the Bay of Biscay ; and (2) low salinity water, entering 

 ih. Channel as a southerly current from the Irish Sea 

 and the Bristol Channel. The limits of these contributing 

 currents are well shown on the hydrographical charts, 

 where the lighter water is seen to be present mainly to 

 the west of a line running roughly south from the Scilly 

 Isles; while the denser water forms a tongue of variable 

 magnitude, according to the season, entering the Channel 

 in a north-easterly direction near Ushant. Within the 

 Channel itself the hydrographical conditions are very 

 complex ; a general drift of surface water from west to 

 east has been observed, but the distribution of the high 

 and low salinity waters in the Channel is far from simple. 

 Generally speaking, the main source of the water entering 

 the Channel during the summer and early autumn is the 

 Irish Sea, while during the rest of the year the denser 

 water of the Bay predominates. The observations have 

 been made for a year only, so that the very important 

 question whether or not these changes in the origin of 

 the contributing , waters are periodic remains still to be 

 investigated. 



Perhaps the most interesting part of the report is that 

 by Mr. Garstang dealing with the results of experiments 

 on the marking and liberation of living plaice and other 

 fishes. These experiments have now been carried out by 

 most of the national research staffs, and are yielding 

 results which are very instructive from the point of view 

 of the growth and migrations of the plaice especially. The 

 mark used is a brass label bearing a number, and fastened 

 to the body of the 1 fish by means of a silver wire passing 

 through the body and attached to the other side by a 

 hone button. litis mark can be attached to the fish 

 without permanent injury to the latter, and apparently 

 without any retardation of growth or other disturbance 

 of the normal habits of the fish. The results are recorded 

 in Mr. Garstang's report, and are illustrated by means of 

 synoptical charts which show the principal migrations made 

 by the fishes which have been recovered. I'p to the end 



