Micropredation by gnathiid isopods on settlement-stage reef fish in the eastern Caribbean Sea

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Date
2015Author
Artim, John M.
Sikkel, Paul C.
Sellers, Joseph C.
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The transition from a planktonic larval
stage to a benthic or demersal juvenile stage is a crucial event
in the life history of coral reef fishes, and recruitment success
has a strong influence on reef-fish population size. Post-settlement
predation is thought to limit recruitment success.
Most studies on post-settlement predation have focused on
piscivorous reef fishes. However, recent studies in the tropical
Pacific Ocean suggest that blood-feeding ectoparasites may
also be an important source of predation. Here we provide
further evidence that a gnathiid ectoparasite is capable of
such “micropredation” on settlement-stage fish in the eastern
Caribbean Sea. On 12 occasions in May–August, 2014 and
2015, during plankton light-trap recovery, we observed postsettlement
fishes from the families Apogonidae, Bothidae,
Gobiidae, Labrisomidae, and Tripterygiidae with attached
ectoparasitic juvenile gnathiid isopods. In one laboratory
experiment in which 10 settlement-stage French grunt,
Haemulon flavolineatum (Desmarest, 1823), were fed upon
by an average of one gnathiid per fish, all fish died compared
to none in the control group. In a subsequent experiment in
which individual settlement-stage French grunt were exposed
to 0–3 gnathiids each, all 50 fish that were fed upon by at least
one gnathiid died, compared with only one of 78 that were
not fed on by any gnathiids. Combined with observations on
damselfishes from the Pacific Ocean, these findings suggest
that gnathiids are capable of micropredation on larval fish at
time of reef settlement and that micropredation should be
further evaluated as a factor affecting success of settlement
and thus recruitment success of coral reef fishes.
URI
http://hdl.handle.net/10394/18631http://dx.doi.org/10.5343/bms.2015.1023
http://www.rsmas.miami.edu/bms/