SEA-FISHERIES LABORATORY. 325 



HERRING INVESTIGATIONS 

 (WITH DESCRIPTION OF A NEW FISH-MEASURING 



BOARD.) 



By W. Riddell, M.A. 



The present paper is a preliminary contribution to the 

 biometric study of Irish Sea herring, with a view to discovering 

 whether these show any sub-division into local " races," such 

 as have been described by Heincke. So far a complete 

 examination along the lines indicated by Heincke has not 

 been made, only a few characters having been examined, 

 but it is hoped in future work to carry out a more extended 

 series of measurements, including the vertebral characters, 

 on larger numbers of fish. 



The characters so far examined have been as follows : — 



1. Total length from extremity of snout to the vertical 

 line joining the tips of the lobes of the caudal fin when in its 

 natural position. [T]. 



2. Total length to base of tail. [T. cd.]. 



3. Length from tip of snout to beginning of dorsal 

 fin. [D]. 



4. Length from tip of snout to beginning of pelvic 

 fin. [7]. 



5. Length from tip of snout to anus. [A.]. 



6. Lateral length of head. [I. cp. I.]. 



7. Number of keeled scales between anus and pelvic 

 fins. [ffj. 



In addition, the sex has been noted, and the condition 

 of the gonads according to Hjort's scale. As regards the 

 latter, I have included under V all cases where, even if the 

 roe and milt were not actually flowing, the condition of the 

 gonads showed that they were to all intents ripe, and the 

 products would shortly be fit for extrusion. 



