212 PHYSOSTOMI. 



extensive herring fishery existed at Cromarty ; about the latter year an immense 

 shoal was driven ashore near the town : they left the vicinity in a single night 

 and for upwards of half a century no shoals re-appeared. Still this may have 

 been simply a coincidence. 



Many reasons have been adduced in order to account for these fishes deserting 

 certain localities. In Long Island, one of the Hebrides, it was asserted they were 

 driven away by the manufacture of kelp, although kelp fires did not drive them 

 away from other places. The firing of guns, or an old Highland idea the shedding 

 of blood. Steam-boats have been supposed to disturb the shoals. 



The two main objects of migration would appear to be seeking some locality 

 where eggs may be safely deposited for the species to be continued : or else a search 

 for food in order to maintain the growth and existence of the individual. But it 

 would seem that fish may seek new ground, due to that they usually reside in 

 becoming unsuited from any cause (see page 218), as absence of food, or constant 

 attempts at their capture by incessant netting. If, having selected waters further 

 from the shore than formerly, the ova were deposited and hatched, it does not 

 seem unreasonable to suppose that the progeny would locate themselves where 

 they were reared. In time, perhaps, this new location might be found unsuited, 

 and the shoal return to the spot they first inhabited, and where possibly a more 

 abundant supply of surface-food exists. 



Respecting the effect of temperature and various meteorological conditions of 

 the atmosphere as affecting migrations and captures, so little has yet been ascer- 

 tained on theSe points that I think it better to refrain from speculating upon 

 them. Fishermen assert that prevalent winds are a cause of migrations, and if 

 so this is probably effected through acting on their food. Also that unusually 

 severe and long-continued xrost during winter and spring induce movements 

 among large shoals, and bring them nearer in shore. Seasonal changes, however, 

 doubtless have an effect in hastening or retarding the advent of herrings ; while 

 diurnal variations may likewise be coincident with the bathymetrical depths at 

 which they are found ; storms may drive them from shallow to deeper water ; 

 while the herring season commences and also terminates earlier in the north than 

 it does in the south ; but much more than this facts scarcely warrant us to assume. 



The Scotch Meteorological Society observe that the results of examining the 

 daily register of thermometers used in twenty fishery districts on the east coast, go 

 to show a close relation between the fluctuations of the catches and changes 

 of temperature, wind, sunshine, cloud, thunder, and other weather phenomena. 

 Maximum catches having been recorded when the temperature of the sea was 

 about 55'5 degrees, while thunderstorms if widespread were followed for days 

 with small catches over the area which had been covered by them. 



Mr. Cleghorn concluded an interesting report upon these fisheries with a 

 comprehensive summary. Some of his conclusions were as follows : — That there 

 were fishing stations some years ago on the Scotch coast which are now 

 exhausted, a steady increase having taken place in their produce up to a certain 

 point, then violent fluctuations and finally extinction. The races of herrings near 

 our large cities have disappeared first, and in districts where the tides are rapid, 

 as among islands and in lochs. Where the fishing grounds are circumscribed the 

 fishings are precarious and brief ; while on the other hand extensive sea-boards 

 having slack tides, with little accommodation for boats, are surer and of longer 

 continuance as fishing stations. 



I will now refer to the herring fisheries along the north-east and east coast'of 

 Scotland respecting which we are told that, " at the beginning of the present 

 century herrings were so abundant along the north-east coast of Scotland, and 

 came so close in shore that numbers of them were caught by people standing upon 

 the rocks having no other instrument of capture than baskets tied on long poles," 

 a condition of affairs which hardly applies to the present time. 



At Wick, the largest race usually arrives with the new year, remaining until 

 about March and then disappears. Mr. Reid found in January, 1882, that some 

 were a foot in length and thick in proportion, but all were full of milt or roe. The 

 next herrings come in May or June in the shape of a few small ones of little value as 



