of the Fishery Board for Scotland. 



65 



Spawning Seasons. 



Ewart records that from the specimens of herring ova which he received 

 from week to week it was evident that spawning took place off the Aber- 

 deenshire coast from August 1883 to June 1884, a period of ten months. 

 Schneider says that at Karlshamn (Baltic) spawning and spent herrings 

 were captured throughout the year. 



The Table of Full herrings, page 60, gives an indication of the extent 

 to which spawning takes place in Scottish waters. Spawning, may be 

 regarded as starting in July and continuing to the following July. During 

 that interval spawning rises to the two maxima — (1) Summer, viz., August- 

 September, and (2) Winter, viz., February-March. There is evidently a 

 considerable amount of spawning taking place in autumn. Brook found 

 ripe herrings in September and October. Milroy records herrings practi- 

 cally ripe, with eggs 1*2 mm. in diameter, from Loch Fyne, Lochboisdale, 

 and the Moray Firth in December. 



Between April and July spawning is at a minimum. Brook said that a 

 race of herrings spawned in the Campbeltown district in May. During 

 this research some Clyde herrings, 27 in number, measuring from 17 to 

 23 cm. in length, showed in February a condition of the reproductive 

 organs that suggested the possibility of their spawning in the interval 

 between the winter and summer spawnings. Additional samples obtained 

 in December and January (vide p. 67), point to this condition occurring 

 regularly. 



The dominating factors of the spawning are the spring and summer 

 seasons. The liberal supplies of food then available determine the spawning 

 to follow the summer at a shorter or longer interval. 



Each locality has very definite spawning seasons. This fact points to 

 the fishes themselves being localised and dependent on the local conditions 

 of the food and the temperature and salinity of the water of the region. 



The autumn spawning season is made up of late summer-spawners and 

 early winter-spawners. 



Brook found ripe males in Loch Fyne in J uly, and both males and females 

 ripe in August. 



How long will it be after a fish has an ovary containing eggs 1*0 mm. in 

 diameter before it spawns ? That will, no doubt, depend directly on the 

 food supply, and while it may be soon in summer, may be lengthened out 

 considerably during the latter half of the year. 



Brook was of the opinion that some of the Clyde herrings might spawn 

 twice in a year. There does not, however, seem to be any proof of this 

 contention. 



Matthews pointed out that the reproductive organs of herrings obtained 

 from the Campbeltown district were larger than those of some East Coast 

 herrings. I believe that a herring that is spawning for the second time 

 may have a larger reproductive organ than a fish of the same size which is 

 spawning for the first time. 



Food. 



In nearly all the samples some of the herrings had food in the stomach, 

 or remains of food in the gut. The nature of the food that has been 

 found in the stomachs of the herrings has been treated by Dr. Scott. 



In the preceding part of the paper I have added, after the description of 

 each sample, a note as to the presence or absence of food. 



The stomach was found in several definite conditions — (1) It contained 

 food. The stomach was then a thin-walled bag. (2) It was empty. 

 Sometimes it was a big thin-walled bag. This condition indicated that 

 the fish had been feeding. The stomach may have been empty in conse- 

 quence of the fish having disgorged its food when captured. 



