650 REPORT OF commissionp:r of fish and fisheries. [16] 



season, and the very large species of Salpa, so abundant bitlierto, was 

 only once met with this year, but the small species {S. Cahoti) occurred 

 iu large numbers, and with it several very brilliant species of SajyMrina 

 were taken. 



EVIDENCE OF GREAT DESTRUCTION OF LIFE LAST WINTER. 



One of the most peculiar facts connected with our dredging this sea- 

 son (1882) was the scannty or absence of many of the species, especially 

 of Crustacea, that were taken in the two previous years, in essentially 

 the same localities and depths in vast numbers — several thousands at a 

 time. Among such species were Euprognatha rastellifera, Catapagurus 

 socialis, Pontophilus brevirostriSj and a species of Mnnida. The latter, 

 which was one of the most abundant of all the Crustacea last year, was 

 not seen at all this season. An attempt to catch the "Tile-fish" {Loph- 

 olatilus) by means of a long trawl-line, on essentially the same ground 

 where eighty were caught on one occasion last year, resulted in a total 

 failure this year. It is probable, therefore, that the finding of vast num- 

 bers of dead tile-fishes floating at the surface in this region last winter, 

 as was reported by many vessels, was connected with a wholesale de- 

 struction of the life at the bottom, along the shallower part of this belt 

 (in 70 to 150 fathoms), where the southern forms of life and higher tem- 

 peratures (48° to 52°) are found. This great destruction of life was prob- 

 ably caused by a very severe storm that occurred in this region at that 

 time, which, by agitating the bottom-water, forced outward the very 

 cold water that, even in summer, occupies the great area of shallower 

 sea, in less than 60 fathoms, along the coast, and thus caused a sudden 

 lowering of the temperature along this narrow, comparatively warm zone, 

 where the tile-fish and the Crustacea referred to were formerly found. 



As the warm belt is here narrow, even in summer, and is not only 

 bordered on its inner edge, but is also underlaid by much colder water, 

 it is evident that even a moderate agitation and mixing up of the warm 

 and cold water might, in winter, reduce the temperature so much as to 

 practically obliterate the warm belt at the bottom. But a severe storm, 

 such as the one referred to, might even cause such a variation in the 

 position and flow of the tidal and other currents as to cause a direct flow 

 of the cold inshore waters to temporarily occupy this area, pushing out- 

 ward the Gulf Stream water. The result would be the same in either 

 case, and could not fail to be destructive to such species as find here 

 nearlj'^ their extreine northern limits. 



In order to test this (piestion more fully, Professor Baird also em- 

 ployed a fishing vessel, the Josie Reeves, to go to the grounds and fish 

 systematically and extensively for the tile-fish. On her first trip, end- 

 ing September 25, she did not find any Tile-fish, but took another 

 food fish [Scorpcena dactylopiera\ known on the European coast, and 

 first taken by us in 1880. 



