66 



Appendices to Second Annual Report 



loss of herring nets during storms, or when over-fished. In this way the 

 disappearance of herring from the once much-frequented spawning bank 

 off Dunbar, and from the equally famous Guillam Bank in the Moray 

 Firth, has been accounted for by many intimately acquainted with fishery 

 questions. The reason given for the disappearance of the herring is that 

 the nets loaded with putrefying fish, which are left on the spawning ground, 

 cause the surviving herring to select more agreeable banks elsewhere. 



It is further stated that the presence of the bones of herring previously 

 destroyed are sufficient to drive away any shoals that may reach the 

 bank during one or more spawning seasons, after the destruction of the 

 herring occurred. 



Having again and again brought up trammel nets when on the 

 Ballantrae Bank loaded with fish in all stages of putrefaction — nets which 

 when nearing the ship gave abundant evidence of their approach — I was led 

 to consider what influence the loss of nets might have in causing herring 

 to forsake their usual spawning beds. At first I was inclined to accept 

 the theory that the presence of the nets, or the remains of dead fish, led to 

 the desertion of the bank, but after further inquiry and consideration I 

 believe that the lost nets (if they have any influence in destroying the 

 fishing at any station), do not so much frighten away the herring as lead 

 to the destruction of the greater portion of the spawn deposited on the 

 bank. This will be best understood by an example. Let us suppose the 

 spawning ground is limited, and that some hundreds of nets are lost 

 either owing to a storm or because of their giving way through the 

 excessive number of fish taken. Let us suppose further, that these nets 

 are lost over, or are carried by the waves into the basin-shaped areas, 

 where, as the observations made seem to show, the greater portion of 

 the spawn is deposited, we can easily understand how the meshed fish, 

 as they begin to putrefy, will taint the water in their vicinity, and gradually 

 lead to the destruction of the developing embryos, which are so sensi- 

 tive to impurities of all kinds. 



This pollution would be continued and extended by portions of the 

 nets continuing to fish throughout the whole season, so that not only 

 might the eggs first deposited be destroyed, but fish which might have 

 spawned at some other part of the bank would be taken, and their eggs 

 though shed rendered useless, for although portions of the lost nets 

 secured were thickly coated with eggs (PI. IX. fig. 8), the eggs were never 

 developing, they had probably never been fertilised. In this way the 

 greater part of a shoal might be destroyed, and what is of even greater 

 importance, nearly all the eggs deposited during the spawning period 

 might also be destroyed, so that only a comparatively small brood would 

 be hatched, the survivors of which, instead of returning when ready to 

 spawn to their birth-place, might in answer to their strong gregarious 

 instinct, cast their lot with the first large shoal they met in with. 



IV. 



THE SPAWNING OF THE HERRING. 



At the beginning of the century it was known that herring spawned 

 over ground ' neither rocky nor sandy,' but consisting ' of gravel more or 

 ' less coarse ; ' * but how the spawn was deposited, whether at the bottom 

 or near the surface, seems not to have been observed. Widegren,f in an 

 essay 'On the Herring,' mentions that the whole process of spawning 

 occupies not more than five or six hours, and that the males pour milt 

 over the eggs after they have been deposited by the females. 



* Prof. Walker, Trans, of High. Soc, 1803. 

 t United States Com. Rep., part iii. 



