Indirect effects of an ectoparasite reduce successful establishment of a damselfish at settlement

Grutter, Alexandra S., Crean, Angela J., Curtis, Lynda M., Kuris, Armand M., Warner, Robert R. and McCormick, Mark I. (2011) Indirect effects of an ectoparasite reduce successful establishment of a damselfish at settlement. Functional Ecology, 25 3: 586-594. doi:10.1111/j.1365-2435.2010.01798.x


Author Grutter, Alexandra S.
Crean, Angela J.
Curtis, Lynda M.
Kuris, Armand M.
Warner, Robert R.
McCormick, Mark I.
Title Indirect effects of an ectoparasite reduce successful establishment of a damselfish at settlement
Journal name Functional Ecology   Check publisher's open access policy
ISSN 0269-8463
1365-2435
Publication date 2011-06-01
Year available 2010
Sub-type Article (original research)
DOI 10.1111/j.1365-2435.2010.01798.x
Open Access Status Not yet assessed
Volume 25
Issue 3
Start page 586
End page 594
Total pages 9
Place of publication Oxford, U.K.
Publisher Wiley-Blackwell Publishing
Language eng
Abstract P>1. The sublethal impact of parasites on host behaviour and the mechanism linking them to population level effects remain largely unquantified. On the Great Barrier Reef, juvenile gnathiid isopods (mobile ectoparasites) are one of the most common ectoparasites of fishes. Previous laboratory studies on damselfishes suggest that a single gnathiid can kill settlement-stage larvae and very young juveniles, while repeated attacks affect the growth of a juvenile damselfish. Nothing, however, is known of how gnathiids affect the performance, and the survival of settlement stage fishes in the wild.
Formatted abstract
1. The sublethal impact of parasites on host behaviour and the mechanism linking them to population level effects remain largely unquantified. On the Great Barrier Reef, juvenile gnathiid isopods (mobile ectoparasites) are one of the most common ectoparasites of fishes. Previous laboratory studies on damselfishes suggest that a single gnathiid can kill settlement-stage larvae and very young juveniles, while repeated attacks affect the growth of a juvenile damselfish. Nothing, however, is known of how gnathiids affect the performance, and the survival of settlement stage fishes in the wild.

2. We sampled juveniles of the damselfish Pomacentrus amboinensis for gnathiids and tested the effect of a single gnathiid (Gnathia auresmaculosa) on juvenile survival in the laboratory. We also tested the effect of this gnathiid on the swimming performance, oxygen consumption, and successful establishment in the wild of settlement-stage larvae.

3. Of the juvenile fish sampled at dawn, 3·5% had a gnathiid attached; at other times of the day, fish had no gnathiids. In the laboratory, most gnathiids (79%) remained attached to juvenile fish for up to 6 h and all fish survived exposure to one gnathiid.

4. When tested in pairs in a double-lane swim chamber, fish that had previously been fed on by one gnathiid ceased swimming first in 77% of the trials and had a lower critical swimming speed compared to fish not exposed to a gnathiid. Previously parasitized fish had a 35% higher oxygen consumption rate than did unexposed fish. When tagged fish were placed in pairs on dead coral patches in the wild and monitored, the previously parasitized fish disappeared from the reef first in 67% of the trials.

5. Our analysis indicates that a single ectoparasitic gnathiid isopod significantly decreases the performance of young P. amboinensis and their persistence on the reef. Gnathiids, by affecting fish performance, may therefore indirectly affect the successful establishment of fishes on the reef at settlement, a critical transitional stage for most coral reef fishes. Unsuccessful establishment on the reef most likely increases the interactions of settling fish with predators and thus gnathiids may contribute to the high mortality observed at this time.
Keyword Coral reefs
Fish behaviour
Gnathiidae
Parasites
Pomacentridae
Recruitment
Settlement
Trait-mediated indirect effects
Coral-reef fishes
Great-barrier-reef
Larval-juvenile transition
Gnathiid isopods
Lizard Island
Marine fish
Parasite manipulation
Selective predation
Swimming abilities
Host behavior
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article first published online: 29 OCT 2010.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biological Sciences Publications
 
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Created: Sat, 03 Sep 2011, 01:47:30 EST by Gail Walter on behalf of School of Biological Sciences