Longer development provides first‐feeding fish time to escape hydrodynamic constraints

Abstract

What is the functional effect of prolonged development? By controlling for size, we quantify first-feeding performance and hydrodynamics of zebrafish and guppy offspring (5 ± 0.5 mm in length), which differ fivefold in developmental time and twofold in ontogenetic state. By manipulating water viscosity, we control the hydrodynamic regime, measured as Reynolds number. We predicted that if feeding performance were strictly the result of hydrodynamics, and not development, feeding performance would scale with Reynolds number. We find that guppy offspring successfully feed at much greater distances to prey (1.0 vs. 0.2 mm) and with higher capture success (90 vs. 20%) compared with zebrafish larvae, and that feeding performance was not a result of Reynolds number alone. Flow visualization shows that zebrafish larvae produce a bow wave 0.2 mm in length, and that the flow field produced during suction does not extend beyond this bow wave. Due to well-developed oral jaw protrusion, the similar-sized suction field generated by guppy offspring extends beyond the horizon of their bow wave, leading to successful prey capture from greater distances. These findings suggest that prolonged development and increased ontogenetic state provides first-feeding fish time to escape the pervasive hydrodynamic constraints (bow wave) of being small.

The remarkable dynamics in the establishment, rearrangement, and loss of dentition during the ontogeny of the sterlet sturgeon

“…Thus, the small sturgeon larvae feed on proportionally largest food items. Moreover, it is also interesting to note that the first‐feeding larvae are most susceptible to starvation due to inefficacy of the suction feeding caused by hydrodynamic constraints of the water environment 39,40 . In the Adriatic sturgeon, Boglione et al 41 hypothesized that the youngest larvae do not use suction feeding for prey capture.…”

“…Moreover, it is also interesting to note that the first-feeding larvae are most susceptible to starvation due to inefficacy of the suction feeding caused by hydrodynamic constraints of the water environment. 39,40 In the Adriatic sturgeon, Boglione et al 41 hypothesized that the youngest larvae do not use suction feeding for prey capture. Instead, the early presence of oral teeth would be used for predacious seizing and firmly gripping the prey before establishment of the fully functional suction feeding.…”

Origin, form and function of extraembryonic structures in teleost fishes

“…These yolk reserves are transferred to embryonic and larval tissues by a process of resorption and represent the sole source of nutrients during the endotrophic phase, which extends from fertilization to the onset of feeding, and can last several days depending on the species (e.g. about 5, 8, 20 and 47 days in zebrafish, turbot, Atlantic cod and Atlantic halibut, respectively [219,220]). When the larva begins to feed, exogenous nutrients from the diet are added to endogenous yolk reserves in the endo-exotrophic phase until the yolk is completely resorbed and the larva is nourished exclusively by exogenous nutrients in the exotrophic phase [219,221,222].…”