64 



Appendices to Second Annual Report 



to a diminution of herring in future years. How long the herring frequent 

 the banks before they spawn is not known — some say two months. 

 In all probability they all begin to seek the spawning grounds about the 

 same time, but the length of stay will depend partly on their condition on 

 arrival, and partly on the temperature of the water, for the rate at which 

 the roe and milt ripen is greatly influenced by the amount of food stored 

 up, and by the surrounding temperature. This being the case, the fishing 

 of any season is likely to depend to a certain extent on the temperature, 

 for when high the herring will soon mature, spawn, and leave the coast; 

 while when low the roe and milt will ripen more slowly, and this will lead 

 not only to the individual herring remaining longer, but also to a greater 

 crowding on or near the spawning ground at the same time. This may 

 account for the takes being greater during a season with a prevailing low 

 temperature than when there is an average high temperature. 



Widegren mentions that the spawning process only occupies about six 

 hours, but although I have spawned hundreds of herrings, some of them 

 half spent before taken, I have never succeeded in expressing either all the 

 eggs or all the milt, so that it may be inferred that herring remain several 

 days on the bank after spawning actually begins. The time occupied in 

 spawning is referred to in a paper * which, with the permission of the 

 Scottish Fishery Board, was communicated to the Royal Society in March 

 last. In this paper the spawning is referred to as follows : — 



'■ When at Ballantrae I noticed that the trammel-nets secured often more 

 ■ males than females. Is this partly owing to the males swimming some- 

 ' what higher than the females, and partly owing to the males taking 

 ' longer to shed their milt, and hence remaining longer on the spawning- 

 ' ground 1 It may be found that while the females discharge all their 

 ' spawn in three or four days, the males require nearly double that time to 

 1 get rid of their milt. Mr Wilson, fishery officer at Girvan, at my request, 

 ' made a number of experiments with ripe herring. He found that on 



* opening a female herring, after as much spawn as possible had been ex- 

 ' pressed by the hand, about a fourth of the roe remained, while on press- 

 ' ing a ripe male in the same way about a third of the milt remained, and 



* he observed that it was more difficult to express the milt than the roe. 

 ' Mr Wilson states, in answer to other queries — (1) that the ripest fish are 

 1 caught in the trammel-nets, while most of the unripe fish are obtained 

 4 in the drift-nets ; (2) that at the end of the fishing season there are 

 1 about three males taken for every two females, indicating not necessarily 

 ' that the males are more abundant than the females, but rather that the 

 ' males remain longer on the spawning ground ; and Mr Wilson believes 

 ' that herring prefer quiet water free from strong currents when spawning, 

 ' and that when the weather is fine the herring remain long upon the 

 { bank and deposit their spawn leisurely, but when there are strong cur- 

 ' rents, they either hurry the spawning process or disappear into deeper 



water.' 



III. 



THE SPAWNING GROUND. 



It has long been known that herring were wont to spawn on hard 

 ground, and this was placed beyond doubt by the investigation instituted 

 by the Fishery Board in 1862-63. From a very complete survey of the 

 Ballantrae Bank it is now evident, not only that herring select hard 

 ground, but also that they prefer to deposit their spawn in the hollow 

 somewhat basin-shaped gravel-coated areas, where presumably the water is 



* 'On the Natural and Artificial Fertilisation of Herring Ova,' Proceedings Royal 

 Society, London, 1884. 



