Mucus function and crossflow filtration in a fish with gill rakers removed versus intact
- 1 August 2007
- journal article
- research article
- Published by The Company of Biologists in Journal Of Experimental Biology
- Vol. 210 (15), 2706-2713
- https://doi.org/10.1242/jeb.000703
Abstract
SUMMARY: Filtration mechanisms are known for only two species of suspension-feeding tilapia, each of which relies on a different method of particle retention. We used high-speed video endoscopy to assess whether a third species of tilapia, Oreochromis aureus, with gill rakers intact as well as surgically removed, uses mucus in the oropharyngeal cavity for hydrosol filtration or uses crossflow filtration to retain particles during suspension feeding. Although a large amount of mucus was visible during feeding with rakers intact, particles were rarely retained in the mucus. The hypothesis that the presence of mucus results in particle entrapment by hydrosol filtration is rejected for O. aureus. Rather than functioning as a sticky filter,mucus is proposed to function in this species to regulate the loss of water between the rakers and between the anterior branchial arches, increasing crossflow speed and thereby increasing the inertial lift force that transports particles radially away from the arches. Gill raker removal resulted in an almost complete lack of observable mucus in the oropharyngeal cavity, probably due to the removal of mucus-secreting cells attached to the gill rakers. However, endoscopic videotapes showed that crossflow filtration continued to operate in the absence of gill rakers and mucus, indicating that the surfaces of the branchial arches play an important role in crossflow filtration.Keywords
This publication has 24 references indexed in Scilit:
- Experimental evaluation of the migration of spherical particles in three-dimensional Poiseuille flowPhysics of Fluids, 2004
- Feeding mechanisms in carp: crossflow filtration, palatal protrusions and flow reversalsJournal Of Experimental Biology, 2003
- Caught in the crossflowNature, 2001
- Computational Fluid Dynamics in the Oral Cavity of Ram Suspension-Feeding FishesJournal of Theoretical Biology, 2001
- Comparative feeding efficiency on indigenous and introduced phytoplanktivores from Lake Victoria: Experimental studies on Oreochromis esculentus and Oreochromis niloticusHydrobiologia, 1997
- Particle transport in clean membrane filters in laminar flowEnvironmental Science & Technology, 1992
- The occurrence, structure, and development of microbranchiospines among the tilapias (Cichlidae: Tilapiini)Canadian Journal of Zoology, 1988
- Particle Ingestion by Tilapia galilaea is Not Affected by Removal of Gill Rakers and MicrobranchiospinesTransactions of the American Fisheries Society, 1987
- Effects of unstirred layers on membrane phenomena.Physiological Reviews, 1984
- Particle-Grazing and Plankton Community Impact of an Omnivorous CichlidTransactions of the American Fisheries Society, 1984