Allometry of gill dimensions in some British and American decapod crustacea

The gill areas and their component measurements of 16 species of North American crab and seven species of British decapod crustaceans have been analysed in relation to body mass using the method of logarithmic transformation.
A wide range of relationships was found, each of which is typical for a given species. The slope, b , of the log/log regression lines varied from 0·5 to 1·0, the lower values being most commonly found in the Macrura. For the North American species the average slope is about 0·8 whereas for British brachyurans the relationship was close to linear (b=0·97).
The analysis shows that the increase in gill surface body size is mainly due to the increasing area for individual platelets or gill lamellae.
Comparison of weight-specific gill areas for animals of the same body weight suggests that the most active species have larger gill areas. For some of these species the values (900mm²/g) approximate to those of active fish.
As plots for interspecific relationships derived from average values for many individual species have slopes which are not typical for any of the component species, it is concluded that caution must be exercized when interpreting such interspecific plots in Allometric studies.