HISTORY OF THE AMERICAN MENHADEN. 73 



cal Society, is regarded to liave been from 58° to 59° during- the week end- 

 ing August 19, but on the 21st, when tbe nets were sbot, tbe temperature 

 bad iallen to 05°, and tbis was tbe first uigbt tbe berring were caugbt. 

 Tbey were found low in tbe nets during tbe prevalence of warm weatber 

 between Nortbumberland and Peterbead. 



" Tbe Meteorological Society of Scotland bave for two or tbree years 

 bad tbis capriciousness in tbe movements of tbe berring under special 

 investigation, and in the past year tbe deep-sea tbermometers provided 

 to tbe society by tbe Marquis of Tweeddale, its president, for test- 

 ing tbe temperature of tbe sea, were again sent out by the Fisbery 

 Board to tbeir officers, and tbe temperature obtained at different periods 

 of tbe berring fisbery. Daily registers of tbe weatber were kept and . 

 otber particulars furnisbed to tbe society, botb by tbe district fisbery 

 ofilcers and by Samuel McDonald, esq., commander of tbe " Vigilant," 

 fisbery-cruiser. From tbe registers and tbe information tbus supplied, 

 tbe following conclusions bave in tbe mean time been drawn by tbe 

 committee of tbe society : 



"From tbe observations of tbe catcb of berrings and tbe tempera- 

 ture of tbe sea off tbe east coast of Scotland, during tbe two seasons of 

 1874 and 1875, it is seen (1) tbat tbe temperature of tbe sea from tbe 

 middle of August to tbe close of the fisbiug season was continuously and 

 considerably bigber in 1875 tban 1874 ; and (2) tbat tbe catch of her 

 rings was continuously and considerably lower during 1875 than during 

 tbe same period of 1874. 



"Another result is tbis : If there be a district where, from any cause, 

 tbe temperature of tbe sea is lower tban in surrounding districts, in 

 tbat district tbe catcb of berrings is heavier ; and converselj^, if there 

 be a district where, from any cause, tbe temperature of tbe sea is bigber 

 tban in surrounding districts, in tbat district tbe catcb of berrings is 

 less. Among tbe causes which bring about a local increase or decrease 

 of sea-temperature, tbe chief are clouded or clear skies in respective dis- 

 tricts, according as these occur during tbe day or during the uigbt. 

 These local variations in tbe temperature of tbe sea in their bearings on 

 the catcb of herrings have been shown by tbe observations both of 1874 

 and 1875. 



"Another important point is the relations of surface temperature to 

 bottom temperature, and the relations of the deepest parts of tbe sea to 

 the positions of the fishing grounds. It is found, for instance, tbat when 

 the surface temperature is high — higher than lower down — ^tbe fish, if 

 any be caught, strike the nets far down, in such a way as to lead to the 

 supposition that a good deal of failure may often arise from the nets not 

 going deep enough. Tbe fish prefer, apparently, so far as the inquiry 

 has gone, tbe lower to tbe higher temperature. Tbe herring committee 

 are most desirous of carrying out tbis line of inquiry into greater detail, 

 if some of the fishermen could be induced to take tbe trouble of observ- 

 ing tbe temperature of tbe sea at tbe surface and also at the depth at 

 which the fish strike tbe nets. 



