The biometry of gills of 0-group European flounder

The gill surface area of 0-group, post-metamorphic Pleuronectes flesus L. w as examined using digital image analysis software and expressed in relation to body mass according to the equation logY = loga + c logW (a = 239.02; c = 0.723). The components that constitute gill area, total filament length, interlamellar space and unilateral lamellar area were measured. The measur ement of the length of every filament on all eight arches showed that commo nly used methods of calculation can lead to an under-estimation of up to 24 % of total filament length. Direct measurements of unilateral lamellar area with digital image analysis showed that previously reported gill area data for the same species was over-estimated by as much as 58%. In addition, in this species the neglect of gill pouch asymmetry after metamorphosis, can bring about a 14% over-estimation of total gill area. (C) 2000 The Fisherie s Society of the British Isles.