Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish

Garden eels are elongated zooplanktivorous fish that live in colonies on sandy bottoms, often adjacent to coral reefs. Each eel digs its own burrow, from which it partially emerges to forage on drifting zooplankton while being “anchored” with its tail inside the burrow. Feeding rates and foraging mo...

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Main Authors: Alexandra Khrizman, Irena Kolesnikov, Dmitri Churilov, Amatzia Genin
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-03-01
Series:Frontiers in Marine Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2024.1330379/full
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author Alexandra Khrizman
Alexandra Khrizman
Irena Kolesnikov
Dmitri Churilov
Amatzia Genin
Amatzia Genin
author_facet Alexandra Khrizman
Alexandra Khrizman
Irena Kolesnikov
Dmitri Churilov
Amatzia Genin
Amatzia Genin
author_sort Alexandra Khrizman
collection DOAJ
description Garden eels are elongated zooplanktivorous fish that live in colonies on sandy bottoms, often adjacent to coral reefs. Each eel digs its own burrow, from which it partially emerges to forage on drifting zooplankton while being “anchored” with its tail inside the burrow. Feeding rates and foraging movements were examined in the garden eel Gorgasia sillneri and compared with corresponding measurements carried out as part of this study and by (Genin et al.)1 with 3 species of “free”, site-attached coral-reef fish. Feeding rates by the garden eels were substantially lower than those of the free fish. In the eels, those rates monotonically increased with increasing current speed up to ~20 cm/s, whereas in the free fish maximum rates were observed under moderate flows. A nearly linear increase in feeding rate as function of prey density was observed in both the garden eels and the free fish. However, the slope of that increase in the eels was over an order of magnitude more gradual than that reported for the free fish. The different functional responses of the two fish groups appear to be related to their morphology and maneuverability capabilities. Being elongated, anchored in a burrow and able to modulate body posture according to the flow speed allow the eels high feeding rates under strong currents. The tradeoff, compared with free fish, include limited maneuverability, slower swimming, and smaller foraging volume, rendering the eels’ functional response less efficient to increasing prey density. This cost appears to be compensated by the eels’ ability to occupy sandy, shelter-less bottoms, which in some locations are immensely more abundant than coral-covered rocks, where most planktivorous free fish live.
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spelling doaj.art-f38acbeefb2249aa98b73f766fbff43f2024-03-04T16:12:30ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-03-011110.3389/fmars.2024.13303791330379Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fishAlexandra Khrizman0Alexandra Khrizman1Irena Kolesnikov2Dmitri Churilov3Amatzia Genin4Amatzia Genin5The Interuniversity Institute for Marine Sciences in Eilat, Eilat, IsraelFredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, IsraelThe Interuniversity Institute for Marine Sciences in Eilat, Eilat, IsraelThe Interuniversity Institute for Marine Sciences in Eilat, Eilat, IsraelThe Interuniversity Institute for Marine Sciences in Eilat, Eilat, IsraelDepartment of Ecology, Evolution, and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, IsraelGarden eels are elongated zooplanktivorous fish that live in colonies on sandy bottoms, often adjacent to coral reefs. Each eel digs its own burrow, from which it partially emerges to forage on drifting zooplankton while being “anchored” with its tail inside the burrow. Feeding rates and foraging movements were examined in the garden eel Gorgasia sillneri and compared with corresponding measurements carried out as part of this study and by (Genin et al.)1 with 3 species of “free”, site-attached coral-reef fish. Feeding rates by the garden eels were substantially lower than those of the free fish. In the eels, those rates monotonically increased with increasing current speed up to ~20 cm/s, whereas in the free fish maximum rates were observed under moderate flows. A nearly linear increase in feeding rate as function of prey density was observed in both the garden eels and the free fish. However, the slope of that increase in the eels was over an order of magnitude more gradual than that reported for the free fish. The different functional responses of the two fish groups appear to be related to their morphology and maneuverability capabilities. Being elongated, anchored in a burrow and able to modulate body posture according to the flow speed allow the eels high feeding rates under strong currents. The tradeoff, compared with free fish, include limited maneuverability, slower swimming, and smaller foraging volume, rendering the eels’ functional response less efficient to increasing prey density. This cost appears to be compensated by the eels’ ability to occupy sandy, shelter-less bottoms, which in some locations are immensely more abundant than coral-covered rocks, where most planktivorous free fish live.https://www.frontiersin.org/articles/10.3389/fmars.2024.1330379/fullforagingmovementflowprey densityRed Seaniche
spellingShingle Alexandra Khrizman
Alexandra Khrizman
Irena Kolesnikov
Dmitri Churilov
Amatzia Genin
Amatzia Genin
Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
Frontiers in Marine Science
foraging
movement
flow
prey density
Red Sea
niche
title Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
title_full Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
title_fullStr Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
title_full_unstemmed Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
title_short Zooplanktivory in garden eels: benefits and shortcomings of being “anchored” compared with other coral-reef fish
title_sort zooplanktivory in garden eels benefits and shortcomings of being anchored compared with other coral reef fish
topic foraging
movement
flow
prey density
Red Sea
niche
url https://www.frontiersin.org/articles/10.3389/fmars.2024.1330379/full
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