TABLE 1.

Definitions of eight functional traits derived from raw morphological length measurements of individual fishes (see Figure S1 for an illustration)

	Functional Trait	Calculation	Ecological relevance
Universal trait	Total body length	TL	Proxy for overall body size; indication of trophic level or relative food web position
Food acquisition	Eye size*	Ed/Hd	Prey detection
	Oral gape position*	Mo/Hd	Feeding method in the water column
	Jaw length	$\frac{1}{2}$(Uj +Lj)/Hl	Proxy for size of oral gape; indication of the size of potential prey
Locomotion	Elongation	TL/mBd	Indication of overall body shape; greater elongation indicates steady swimming ability (Claverie & Wainwright, 2014)
	Eye position*	Eh/Hd	Indication of vertical position in the water column
	Caudal peduncle throttling*	CFd/CPd	Indication of the efficiency of caudal propulsion; reduction of drag
	Pectoral fin position*	PFi/PFb	Indication of maneuverability using pectoral fins

Traits adapted from Villéger et al. (2010) are identified by an asterisk.

Abbreviations: CFd, caudal fin depth; CPd, caudal peduncle depth; Ed, maximum eye diameter; Eh, eye height; Hd, head depth; Hl, head length; Lj, lower jaw length; mBd, maximum body depth; Mo, mouth open; PFb, body depth at pectoral fin base; PFi, pectoral fin insertion; TL, total body length; Uj, upper jaw length.