Gill Dimensions for Three Species of Tunny

Abstract

Measurements of gill dimensions have been made for many species of fish (e.g. Byczskowska-Smyk, 1957, 1958, 1959; Gray, 1954; Hughes, 1966; Price, 1931; Saunders, 1962; Hughes & Morgan, 1969) with the purpose of estimating the total area of the respiratory surface. Of these, only Price (1931) and Hughes & Morgan (1969) have made a serious effort to determine the relation between size and area within single species. Price reported that for Micropterus dolomieu the total area was related to body weight by the power of 0·78. For the roach and several other species, Hughes and Morgan have found that the relationship is closer to the power of 0·9. For the large number of species ranging from ‘sluggish’ to ‘active’ that he examined, Gray (1954) reported about an order of magnitude of range in the total gill area per gram of fish, but specimen size varied considerably. I. E. Gray (personal communication to G.M.H., 1959) has pointed out that it is important to compare fish of approximately the same size. In his 1954 paper he included Scomber scombrus and Gymnosarda alleterata (= Euthynnus alletteratus) and has also reported (personal communication to G. M. H.) data on the blackfin tuna and the yellowfin tuna. Except for this preliminary work, few studies appear to have been reported on members of the genus Thunnus, which is of considerable interest as it includes some of the largest and most active teleosts.