Are cleaner fish clean?

Full description

Abstract [Related Publication]:

Cleaner fish remove parasites from other organisms, called clients. While there is an extensive body of work on the positive role of cleaners for their clients and reef communities, remarkably, potential parasites hosted by specialised cleaner fishes themselves have not been explored. In this study, we surveyed the parasite community of the Indo-Pacific cleaner wrasse Labroides dimidiatus, and compared it to other wrasses from the same region. Labroides dimidiatus was found to be infected by eight parasite groups including ectoparasites (copepods, isopods, trichodinids, monogeneans and turbellarians) and endoparasites (myxozoans, trematodes and cestodes) representing at least 12 species. The abundance and prevalence of most parasite groups was comparable to other wrasses, with the exception of bucephalid trematodes, which are not known to infect any other tropical wrasses except for Labroides species. This adds to mounting evidence that some parasite species exhibit atypical life cycles that exploit cleaning symbiosis. Particularly noteworthy was the discovery of gnathiid isopods on L. dimidiatus, which are generally considered the cleaner’s primary food item. Our findings provide new evidence for a potential role of wild cleaner fish as vectors of parasites to new clients, which highlights potential costs associated with cleaning symbiosis.

Data Methods:

Bluestreak cleaner wrasse, Labroides dimidiatus, were collected in two locations in north-eastern Australia. A total of 10 L. dimidiatus were collected from Welsby Light beacon in Rainbow Channel, Moreton Bay, southeast Queensland (26° 56’S, 153° 09’E) and a total of 30 L. dimidiatus were caught from various sites off Lizard Island (14° 40’S, 154° 24’E) on the Great Barrier Reef. Fish were dissected under a low-power dissection microscope for external parasites. For internal parasites, the entire alimentary tract was removed from the body and placed in vertebrate saline. Helminth parasites were heat-fixed in near-boiling saline solution and preserved in 70% ethanol. Other parasites were directly preserved in 70% ethanol. To compare the parasite community of Labroides dimidiatus with other wrasses from the Great Barrier Reef, we compiled data from Muñoz and Cribb (2005; 2006) and Muñoz et al. (2007). We first compared the parasite abundance and composition between L. dimidiatus and two common and extensively-sampled labrid species, Hemigymnus melapterus  and Coris batuensis collected at Lizard Island. We then compared parasite prevalence in 14 species of wrasses, also collected at Lizard Island, with that of L. dimidiatus collected in this study.  All data analyses were performed in R version 4.0.2 (R Core Team 2020).

The full methodology is available in the publication shown in the Related Publications link below.

Software/equipment used to create/collect the data: Excel

Software/equipment used to manipulate/analyse the data: R studio

Notes