t)54 NATURAL HISTORY OF AQtJATIC ANIMALS. 



a wind blowing on shote will favor their inward migration; at other times it appears to have a 

 directly opposite effect. Even when they reach the portion of the coast ior which they are bound, 

 the facilities of ttn-ir capture depend upon meteorological conditions; and the Scottish Meteoro- 

 logical Society has beeu engaged for several years in ascertaining what these are, and how they 

 may be best applied by the fishermen.^ 



' "Theiiuiuiry was restiietcd tit first to the east coast of Scotland, and to pond-fishing districts therein, viz, Wiclt, 

 Bncliie, Peterhead, and Eyemouth, the last including the fishing ports of Dunbar and Eyemouth, Berwick and North 

 Sunderland. Copies of the weekly returns sent to the fishery board from these districts during July to September 

 the seasim for the herring fishing for that part of Great Britain, for six years, beginning with 1867 and ending with 

 187^, giving the catch per week, the number of boats out in each district, were extracted from the reports, and an 

 average of ihese six years calculati-d at several of the stations. These were finally compared day by day with two 

 series of sea temperatures; one takim olf Harris, and the other near Edinburgh. 



"The temperature of the sea was found to rise very rapidly about the middle of July, and to keep oscillating 

 Slightly about a uniform temperature of 50° until the 13th of August, when it rapidly rose to the annual maximum, 

 namely, 5T^ri, aud ranged relatively high until the first of September. This period of highest annual temperature, 

 namely, fjoui the middle of July to the first of September, was found to be coincident with the fishing si-ason in the 

 northern districts of Scotland; aud the neriod when the temperature rises to the absolute maximum is farther coin- 

 cident with the date of the largest catches during the fishing season. The committee, however, consider it ijrema'ure 

 to lay great stress on the striking coexistence of these facts, since it is impossible, without further statistics, to say 

 whether these rela ions are of a permanent character. The fishing season did not begin until the sea temperature 

 had risen to about 55|° in July, nor did it continue after it had fallen below .55|° in September. 



"An important omission in these tables is, that they do not show whether they indicate the surface or bottom 

 temperature of the sea, the difference in this respect being very appreciable. Another omission is, as to the relation 

 betwern the spawning season of the Herring and their shoreward movement. Along the coast of the United States, 

 the great spawning ground of the sea Herring is off the southern end of Grand Manan, where the surface aud bottom 

 temperatures sometimes differ at the spawning season by as many as five or six degrees. 



"An importantr relation was also observed by the committee between the exceptional atmospheric temperatures 

 and the migrations of the Herring, the fishing season beginning much later in the year, when the summer temper- 

 atures are losv, than when they are high. As regards the relation between barometric observations and the fisheri<'s, 

 it api)ears that during the periods when good or heavy catches were taken, in a great majority of cases the barometer 

 was high and steady, the winds light or moder.ate, and electrical phenomena wanting; when the captures were light, 

 the observations often indicated a low barometer, strong winds, unsettled weather, and thunder and lightning. 



"In conclusion, the committee recommend that, in further elucidation of the subject, steps should be taken to 

 obtain information which may lead to the solution of the following queries: 

 " 1. What determines the time of the commencement of the fishing? 



"2. What determines the fluctuations in the catches of Herring in-different districts, or in the same district on 

 dilferent days ? 



"3. What causes the absence of Herring during some seasons from certain districts of the coast? 

 "4. What determines the ending of the fishing season ? 

 "The information required demands — 



"1. An extension of the area examined, so as to include the Moray Firth, the Shetland, Orkney, and Hebrides 

 Islands, and the west coast of Scotland. 



"2. Daily returns of the number of boats fishing and the catch. 



"3. The erection of self-registering sea thermometers at different points on the coast, similar to those now in 

 operation at Peterhead Harbor. 



"4. Thermometric observations taken by the fishermen themselves over the grounds fished ; ns it is only by the 

 observations of numerous thermometers in continuous immersion that we can hope to obtain accurate information 

 regarding those currents of cold and warm water round our coasts which are often found to interpenetrate each 

 other, and which are supposed, with apparently good reason, to influence greatly the migration of the Herring. It 

 is said that the Dutch fishermen derive valuable practical advantages from a system of this kind, aud there can be no 

 doubt that favorable results might confidently be looked for if a similar system were generally adopted by our 

 fishermen. 



"It is an interesting fact in the natural history of the Herring that, while the season for their capture is quite 

 definite and generally uniform at any one point, it varies on different parts of the coast; thus, on the east of Great 

 Britain, froiri Shetland in the north to Flamborough Head in the south, it occurs in July, August, and September, 

 and a little earlier in the north than in the south. At Yarmouth the Herring season is in October and November ; off 

 the Kentish coast, in November aud December; along the south coast of England, from October to December ; off 

 Cornwall, in August and September ; in the North Channel, in June and July ; and in the Hebrides, May and June. 



"It is suggested by the Scottish committee in their report that when the periods of migration on all parts of the 

 British sea-coast will have been calculated as closely as in Scotland, these will be found to bear a critical relation to 

 the annual epochs of the temperature of the sea. This gives a renewed imporfance to the inquiries undertaken by 



