Channeling vorticity: Modeling the filter-feeding mechanism in silver carp using μcT and 3D PIV

Document Type

Article

Publication Date

10-1-2018

Abstract

Invasive silver carp are thriving within eutrophic environments in the United States, in part because of their highly efficient filter-feeding mechanism. Silver carp utilize modified gill rakers to capture a specific range of food; however, their greatly modified filtering morphology allows them to feed on phytoplankton and zooplankton ranging in size from 4 to 85 μm. The filtering apparatus of silver carp comprises rigid filtering plates where the outer anatomyof these plates is characterized by long parallel channels that change in orientation along the length of the plate. Here, we investigate the underlying morphology and concomitant hydrodynamics that support the filtration mechanisms of silver and bighead carp. Bighead carp are also invasive filter feeders, but their filtering apparatus is morphologically distinct from that of silver carp. Using 3D particle image velocimetry, we determined how particles and fluid interact with the surface of the gill rakers/plates. Filtering plates in silver carp induce strong directed vortical flow, whereas the filtering apparatus of bighead carp resulted in a type of haphazard cross-flow filtration. The organized vortical flow established by silver carp likely increased the number of interactions that the particle-filled water had with the filtering membrane. This strong vortical organization is maintained only at 0.75 body lengths s-1, and vortical flow is poorly developed and maintained at slower and faster speeds. Moreover, we found that absolute vorticitymagnitude in silver carp is an order of magnitude greater than in bighead carp.

Identifier

85054441563 (Scopus)

Publication Title

Journal of Experimental Biology

External Full Text Location

https://doi.org/10.1242/jeb.183350

ISSN

00220949

PubMed ID

30111555

Issue

19

Volume

221

Grant

IOS 1025845

Fund Ref

National Science Foundation

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