Do ectoparasites determine cleaner fish abundance? Evidence on two spatial scales

Abstract

Cleaner fish on coral reefs can have a significant impact on the diversity and distribution of their fish clients. Understanding the factors affecting the distribution of cleaners themselves therefore becomes an important consideration for elucidating the mechanisms controlling coral reef fish community structure. We hypothesised that obligate cleaner fish, which rely almost exclusively on ectoparasites gleaned from clients, should be more abundant in areas rich in their preferred prey, namely parasitic gnathiid isopod larvae. We tested predictions from this hypothesis on 2 spatial scales in the Caribbean: among reefs within Barbados, and among 6 islands spanning the Greater and Lesser Antilles. As predicted, densities of coral-dwelling cleaning gobies Elacatinus spp., which are active cleaners, were higher in areas of high rates of emergence of gnathiid larvae from the benthos. This relationship was not observed in sponge-dwelling cleaning gobies, which rely mainly on nonclient-gleaned food sources. The density of coral-dwelling cleaners was also correlated with client density, but contrary to our prediction was not related to ectoparasite loads of a common reef fish client. Cleaning goby abundance is more likely to be a consequence than a cause of ectoparasite availability, since cleaning goby recruitment is usually linked to factors related to foraging, and territorial clients do not preferentially settle near cleaning gobies. Whether the link between cleaner abundance and ectoparasite availability is mediated through differential recruitment or differential survival of cleaners in parasite-rich and parasite-poor areas remains to be determined.KEY WORDS: Cleaning symbiosis · Reef fish community structure · Gobiosoma spp. 263: 189-196, 2003 Côté 2001), the distribution of reef fish clients should be affected by the presence of cleaning stations. However, there is mixed support for this prediction. Higher territorial densities of the Caribbean longfin damselfish Stegastes diencaeus were not observed around cleaning goby Elacatinus spp. stations , and experimentally vacated longfin damselfish territories near cleaning stations were not colonised faster than territories further away from cleaners, which would have been expected if proximity to cleaners was important to damselfish (Cheney & Côté 2003). Moreover, other species of damselfish that also visit cleaning gobies were distributed randomly with respect to cleaning stations . By contrast, at larger inter-reef scales, there are marked reductions in the diversity of non-territorial clients when cleaner wrasses are removed from reefs, and increases when cleaners are added (Bshary 2003, Grutter et al. 2003. Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerIf cleaning organisms have a significant impact on the diversity and distribution of their clients, then understanding the factors affecting the distribution of cleaning organisms themselves becomes an important consideration. The distribution of cleane...

Does Competition for Clients Increase Service Quality in Cleaning Gobies?

“…apparent high competition) by clients with more parasites. On Barbadian reefs, there is in fact a negative covariation between overall client density and individual ectoparasite load (Pearson’s correlation, r = −0.90, n = 5 reefs, p = 0.037; data from Cheney & Côté 2003). In addition, the differences in client species composition observed among reefs also support the notion that ectoparasite loads were spatially variable.…”

Comparison of sampling methodologies and estimation of population parameters for a temporary fish ectoparasite

“…Gnathiids on coral reefs appear to be host generalists ( Jones et al., 2007 , Nagel and Grutter, 2007 , Coile and Sikkel, 2013 ) and are therefore highly connected within their communities (for a discussion of measures of connectivity see Ings et al., 2008 ). These gnathiids participate in cleaning symbioses as the major food item of cleaners ( Losey, 1974 , Cheney and Côté, 2003 , Becker and Grutter, 2004 , Clague et al., 2011 , Waldie et al., 2011 ) and appear to influence the interaction between host and cleaners ( Grutter, 1999a , Sikkel et al., 2004 , Sikkel et al., 2005 ). In high numbers, gnathiids can reduce hematocrit and even kill adult fish ( Jones and Grutter, 2005 , Hayes et al., 2011 ).…”

“…Emergence traps are one of the most common trap designs used to study gnathiid ecology ( Chambers and Sikkel, 2002 , Cheney and Côté, 2003 , Jones and Grutter, 2007 ). They are used to quantify the density of gnathiids emerging from a fixed area of substrate and for a fixed time period.…”

Cleaner gobies evolve advertising stripes of higher contrast

“…The potential for cheating by clients includes attack and predation on these small, relatively immobile fishes, but they are rarely found in the guts of predatory species (K.L.C., personal observation). The types of clients visiting stations can vary considerably by depth, geography and habitat (Colin, 1975;Cheney and Côté, 2003;Arnal et al, 2001;Côté, 2000;Floeter et al, 2007), and stripes may communicate different information to different species and may initiate different responses. The average blue-toyellow contrast ratio among all piscivores that we included was 1.6 on average coral color and 2.0 on average sponge color.…”