Surfacing frequency as an index of bioenergetics components of air breathing fishes

Abstract

Surfacing frequency (Sf) in obligatory air-breathing fishes is a behavioural index of O₂ uptake; as both are interrelated, there is a possibility of predicting one from the other. From the point of cause and effect relationship, feeding (C) is regarded as the cause and Sf and O₂ uptake as its effects. Hence, the last two are predictable from the cause. A pathway for predicting the bioenergetics components, feeding (C), metabolism (M) and growth (P) from a behavioural index of surfacing frequency has been proposed. In this model, C occupies the focal point connecting on the horizontal plane Sf on one side and P on the other side and M vertically. The developed multiple regression models predict the bioenergetics components of the fishes, Macropodus cupanus and Channa striatus of different weight classes ex-posed to different rations and temperatures; the percentage of variation accounted for by the equations is over 90. The pathway can also be followed for predicting bioenergetics components of gill-breathing fishes, if feeding rate alone is known. On application of the relevant part of the pathway toSalmo trutta, the percentage of variation accounted by the equations is 95.