Interactions between gnathiid isopods, cleaner fish and other fishes on Lizard Island, Great Barrier Reef

Grutter, A.S. (2008) Interactions between gnathiid isopods, cleaner fish and other fishes on Lizard Island, Great Barrier Reef. Journal of Fish Biology, 73 9: 2094-2109. doi:10.1111/j.1095-8649.2008.02073.x


Author Grutter, A.S.
Title Interactions between gnathiid isopods, cleaner fish and other fishes on Lizard Island, Great Barrier Reef
Journal name Journal of Fish Biology   Check publisher's open access policy
ISSN 0022-1112
Publication date 2008-12-01
Year available 2008
Sub-type Article (original research)
DOI 10.1111/j.1095-8649.2008.02073.x
Open Access Status DOI
Volume 73
Issue 9
Start page 2094
End page 2109
Total pages 16
Place of publication United Kingdom
Publisher Wiley-Blackwell Publishing Ltd
Language eng
Subject C1
9699 Other Environment
060205 Marine and Estuarine Ecology (incl. Marine Ichthyology)
Abstract The rate of emergence of micropredatory gnathiid isopods from the benthos, the proportion of emerging gnathiids potentially eaten by Labroides dimidiatus, and the volume of blood that gnathiids potentially remove from fishes (using gnathiid gut volume) were determined. The abundance (mean ±s.e.) of emerging gnathiids was 41·7 ± 6·9 m−2 day−1 and 4552 ± 2632 reef−1 day−1 (reefs 91–125 m2). The abundance of emerging gnathiids per fish on the reef was 4·9 ± 0·8 day−1; but excluding the rarely infested pomacentrid fishes, it was 20·9 ± 3·8 day−1. The abundance of emerging gnathiids per patch reef was 66 ± 17% of the number of gnathiids that all adult L. dimidiatus per reef eat daily while engaged in cleaning behaviour. If all infesting gnathiids subsequently fed on fish blood, their total gut volume per reef area would be 17·4 ± 5·6 mm3 m−2 day−1; and per fish on the reefs, it would be 2·3 ± 0·5 mm−3 fish−1 day−1 and 10·3 ± 3·1 mm3 fish−1 day−1 (excluding pomacentrids). The total gut volume of gnathiids infesting caged (137 mm standard length, LS) and removed from wild (100–150 mm LS) Hemigymnus melapterus by L. dimidiatus was 26·4 ± 24·6 mm3 day−1 and 53·0 ± 9·6 mm3 day−1, respectively. Using H. melapterus (137 mm LS, 83 g) as a model, gnathiids had the potential to remove, 0·07, 0·32, 0·82 and 1·63% of the total blood volume per day of each fish, excluding pomacentrids, caged H. melapterus and wild H. melapterus, respectively. In contrast, emerging gnathiids had the potential of removing 155% of the total blood volume of Acanthochromis polyacanthus (10·7 mm LS, 0·038 g) juveniles. That L. dimidiatus eat more gnathiids per reef daily than were sampled with emergence traps suggests that cleaner fishes are an important source of mortality for gnathiids. Although the proportion of the total blood volume of fishes potentially removed by blood-feeding gnathiids on a daily basis appeared to be low for fishes weighing 83 g, the cumulative effects of repeated infections on the health of such fish remains unknown; attacks on small juvenile fishes, may result in possibly lethal levels of blood loss.
Formatted abstract
The rate of emergence of micropredatory gnathiid isopods from the benthos, the proportion of emerging gnathiids potentially eaten by Labroides dimidiatus, and the volume of blood that gnathiids potentially remove from fishes (using gnathiid gut volume) were determined. The abundance (mean ±s.e.) of emerging gnathiids was 41·7 ± 6·9 m−2 day−1 and 4552 ± 2632 reef−1 day−1 (reefs 91–125 m2). The abundance of emerging gnathiids per fish on the reef was 4·9 ± 0·8 day1; but excluding the rarely infested pomacentrid fishes, it was 20·9 ± 3·8 day−1. The abundance of emerging gnathiids per patch reef was 66 ± 17% of the number of gnathiids that all adult L. dimidiatus per reef eat daily while engaged in cleaning behaviour. If all infesting gnathiids subsequently fed on fish blood, their total gut volume per reef area would be 17·4 ± 5·6 mm3 m−2 day−1; and per fish on the reefs, it would be 2·3 ± 0·5 mm−3 fish−1 day−1 and 10·3 ± 3·1 mm3 fish−1 day−1 (excluding pomacentrids). The total gut volume of gnathiids infesting caged (137 mm standard length, LS) and removed from wild (100–150 mm LS) Hemigymnus melapterus by L. dimidiatus was 26·4 ± 24·6 mm3 day−1 and 53·0 ± 9·6 mm3 day−1, respectively. Using H. melapterus (137 mm LS, 83 g) as a model, gnathiids had the potential to remove, 0·07, 0·32, 0·82 and 1·63% of the total blood volume per day of each fish, excluding pomacentrids, caged H. melapterus and wild H. melapterus, respectively. In contrast, emerging gnathiids had the potential of removing 155% of the total blood volume of Acanthochromis polyacanthus (10·7 mm LS, 0·038 g) juveniles. That L. dimidiatus eat more gnathiids per reef daily than were sampled with emergence traps suggests that cleaner fishes are an important source of mortality for gnathiids. Although the proportion of the total blood volume of fishes potentially removed by blood-feeding gnathiids on a daily basis appeared to be low for fishes weighing 83 g, the cumulative effects of repeated infections on the health of such fish remains unknown; attacks on small juvenile fishes, may result in possibly lethal levels of blood loss.
Keyword cleaning behaviour
coral reefs
Gnathiidae
Host–parasite interactions
larval fishes
marine parasites
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Created: Wed, 15 Apr 2009, 00:44:37 EST by Gail Walter on behalf of School of Biological Sciences