Meeting Abstract
Suction feeding is the most common feeding strategy across teleosts. It is expected that the morphological and functional diversity between fish species are driven by the need for unique suction feeding strategies that arise from trophic disparity. However, very few studies empirically measured the suction induced flow field, in only 3 species. Here, we used particle image velocimetry to examine temporal and spatial patterns of suction-induced flows in 16 teleost species, expanding across the teleost tree of life, representing species with diverse morphologies, mouth sizes (ranging 1.3-21 mm), dentition, and kinematics. We asked if suction flows scale with mouth, whether species that produce faster flows have slower ram speed, and whether the decay of suction flow is consistent across species. A significant relationship was found between maximum gape size and maximum flow speed both within and between species. However, while a positive inter-species relationship between gape size and flow speed was observed, intra-species relationships included positive, neutral and negative correlations among these factors. Norton and Brainerd (1993) famously suggested a tradeoff between ram speed and suction flows. However, we found a non-significant relationship between ram speed and maximal flow speed for any species or the collective and thus refute this hypothesis. Lastly, our results show a conserved spatial flow pattern across species. Flow speeds decayed exponentially as a function of distance from the mouth, with flow decaying to 5% at a distance of one mouth diameter for all species, indeterminate of gape size or flow speed. Our findings demonstrate immense diversity in flow speeds and influencing factors, despite a conserved spatial pattern in suction flows.
