of the Fishery Board for Scotland. 179 
VIIL—ON THE RATE OF GROWTH OF FISHES. By T. W. 
Wemyss Fuuron, M.D., F.R.S.E., Superintendent of Scientific 
Investigations. 
(Plates XII., XIII.) 
CONTENTS. 
INTRODUCTION. Page. 
Species Dealt With, bt Bee Ps by ee Wed UO 
Methods, =e as ee “te cise ak been USO 
Comparison Between Different Species, ... % ay S80 
Influence of External Conditions, * ane Eds Seuss oe 
A Law of Growth, ase ae as af nee sen) aS” 
Plaice (Plewronectes platessa), x Ade oe - od PRS 
Common Dab (P. limanda), ... ie a ee late 
Flounder (P. flesus) ... Beis ae ate Ly ee eee lOe 
Lemon Dab (P. microcephalus), ae ae rae a los 
Long Rough Dab (Drepanopsetta platessoides), ane “ee Se LOO: 
Turbot (Rhombus (Bothus) maximus), Bic iff Aes x0 2-199 
Brill (Rhombus levis), sae a es ae ae 6 208 
Cod (Gadus callarias), ae ae ee a2 a Soa AY 
Haddock (G. eglefinus) a a ee es Sinn ete 
Whiting (G. merlangus), ... Be See wil ue Bae ed 
Grey Gurnard (Tvrigla gurnardus), ... sine = ant Bree a4) 
Tables of Measurements, I.-XXYV., ... F4 zits sh Alt! 
INTRODUCTION. 
For a considerable number of years special attention has been devoted 
to the study of the growth of fishes by the scientific department of the 
Board. In 1889, I began observations on this subject by {wo methods, 
(1) by marking fishes (plaice, dabs, lemon dabs, brill, turbot, cod, &e.) by 
attaching to them brass labels bearing a number, the method which is 
now so largely used in connection with the international investigations, 
and then returning them alive to the sea; in the case of the herring, by 
removing a portion of the caudal fin; (2) by keeping the fishes in tanks, 
and noting the changes that occurred from time to time in their length 
and weight.* 
Since then very many fishes have been dealt with by another method— 
viz., by collating the measurements of large numbers of each species, by 
which the earlier series or generations can be separated from one another 
and the rate of growth ascertained, the measurements grouping themselves 
into curves or waves. This method was used to a limited extent by 
Miescher Ruesch in his classic studies on the salmon of the Rhine, and 
by other observers, as Ljungman, in studying the growth of the herring. 
These observers, however, did not classify the measurements in a scientific 
manner, which was first done by Dr. C. G. J. Petersen, who thus placed 
av important method at the service of investigators. 
Species Deatt WITH. 
In the course of my investigation on growth during recent years, a large 
number of fishes have been dealt with—viz., nearly 209,000, belonging to 
21 species. The results in regard to many of them have been given in a 
* “An Experimental Investigation on the Migrations and Rate of Growth of the Food- 
Fishes,” Eleventh Annual Report, Part III., p. 117. 
