w"t ig-lit ill grams — k X 



86 TRAXSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



and for each centimetre group have also been found, but 

 tlie tables are not published, since they can be 

 summarised in a future report. In this connection I add 

 a short note relative to the length-weight function in 

 the plaice. 



The Length and Weight Relation in Plaice. 



In l!)()o* Professor A. Meek showed that the weight in 

 ounces of a plaice is given by the relation w = aP, 

 I beinsT the length in inches and a a coefficient, which 

 was found in the series of figures considered to be about 

 OOOGT. Subsequently Professor D'Arcy Thompson 



suiTirested that the formula 



(length in centimetres)* 

 100 

 sliould be used in fishery investigations. It was adopted 



by Henking and Heincke in 1907, t and has since been 

 generally employed. 



The coefficient Ic ranges in value from about O'T to 

 about T2 according to the fishing ground, the season, 

 and the length of tlie fisli. It is a reliable index of the 

 vague attribute known as the " condition " of the fish. 

 When a plaice is plump and well nourished, and full of 

 roe, k is big; when it is thin, " watery," or spent, k is 

 small. 



Genei'ally speaking it is greatest in the early 

 summer months, and least in the late winter, since at the 

 latter season plaice usually cease to feed. In the case 

 of a siiMinii'i- fishery, such as that cari'ied on during the 

 months, .lune to August, near Nelson Buoy and its 

 vicinity, this is the way in which k varies; but in tlie 

 case of a winter fishery, such as that carried on off the 

 coast ot North Wales duiiiig the months of Octobei- to 



*Xorthiiml)ir]an(l Sua-Fish. ConiniiKcc. Kept, on Sci. Invests, fnr 

 19P3. Ncwfastle, 1903, p. 40. 



t " SchoUen u. SchoUenfischcrci." Bolcili^;, Dcul.scblandR a.d. Int. 

 ^lecrceforsch., IV, V, Berlin 1907. 



