204 



Fishery Bulletin 90(1), 1992 



to measure accurately, so an ad- 

 ditional 50 herring were taken 

 from the remaining TL 1983 

 sample for the morphometric 

 analysis. 



Morphometries 



Measurements Initially, 25 mor- 

 phometric characters described 

 by Meng and Stocker (1984) in 

 their analysis of Pacific herring 

 were measured on 100 Atlantic 

 herring, 50 from each location, 

 from the 1983 sample. The mea- 

 surements followed Hubbs and 

 Lagler (1958). Standard length 

 (SL) was measured to the near- 

 est 0.5mm on a measuring board. 

 The other measurements were 

 taken with vernier calipers to the 

 nearest thousandth of an inch 

 and converted to millimeters. 

 Multivariate analyses were used 

 to determine if the groups were 

 different from one another and 

 which characters contributed to 

 these differences. To address 

 length bias, multiple analysis of 

 covariance, performed under the 

 MANOVA subroutine in the sta- 

 tistical package for the social 

 sciences, was used to remove the 

 effect of SL on the other vari- 

 ables (Sokal and Rohlf 1969, 

 Steel and Torrie 1980). The re- 

 sults of multiple analysis of vari- 

 ance of the adjusted measure- 

 ments versus spawning group, 

 performed under the same sub- 

 routine, showed that the two 

 groups were significantly differ- 

 ent from each other and iden- 

 tified eight characters whose 

 means were significantly dif- 

 ferent (Snedecor and Cochran 

 1967, Safford 1985) (Fig. 2). The 

 binomial distribution predicted 

 the probability of eight signifi- 

 cant characters out of 25 as 1.77 

 xlO"^, given a probability of 

 0.05 that a single character 

 would be significantly different 

 due to chance alone. 



44' 



42' 



40' 



44°N 



66°E, 



Figure 1 



Atlantic herring spawning grounds in the Gulf of Maine region. 



PVI 



Figure 2 



Eight morphometric measurements used to derive the discriminant function: MXL = 

 maxillary length; PCD = pectoral to dorsal fin; PVD = pelvic to dorsal fin; AD = anal 

 to dorsal fin; AH = anal fin height; INL = interorbital distance; PCI = distance be- 

 tween insertions of pelvic fins; PVI = distance between insertions of pectoral fins. 



