Follower fish of the goldspotted eel Myrichthys ocellatus with a review on anguilliform fish as nuclear species

Abstract

In a nuclear-follower fish foraging association, the follower benefits from food uncovered or flushed out when the nuclear fish disturbs the bottom, while nuclear species generally do not seem to be benefiting. Among nuclear species, eels (anguilliform fish) are known to be one of the most represented groups. Here we investigated the frequency and time duration of foraging associations among the goldspotted eel Myrichthys ocellatus and reef fish in a subtropical marginal reef. In addition, we reviewed nuclear eel species and their followers described in the literature. From a total of 211 goldspotted eels observed, seven follower species were recorded in 19% of the samples. The average time of the following associations per species ranged from 40 to 190 s. Four species were reported for the first time as M. ocellatus followers (Bodianus rufus, B. pulchellus, Stephanolepis hispidus, and Serranus baldwini) and three of them have never been reported in the literature as eel followers (B. pulchellus, S. hispidus, and S. baldwini). The literature describes 13 eel species acting as nuclear for 66 fish species, represented mainly by groupers and sea basses. The size of the eel was not correlated with the size of its follower and neither with the number of described follower species. The nuclear role of eels is likely to be an important component of the trophic ecology of small and medium-sized macrocarnivore fish.

A fish can change its stripes: investigating the role of body colour and pattern in the bluelined goatfish

“…Their capacity to form feeding aggregations through nuclear-follower foraging associations is well reported ( Hanaway-Moore & Keeler, 2012 ; Lukoschek & Mccormick, 2002 ; Sazima et al, 2007 ). Group foraging increases the feeding success of follower fish by providing access to otherwise unobtainable prey ( Ternes et al, 2018 ) while the nuclear fish (goatfish) may benefit through anti-predator mechanisms such as increased vigilance and dilution effects by the followers ( Cresswell et al, 2003 ). Many studies, particularly in the case of goatfish, suggest that nuclear fish are identified by followers via bottom disturbance and the resulting sediment plume ( Krajewski, 2009 ; Sazima et al, 2007 ).…”

Predation on the invasive swimming crab Charybdis hellerii (Crustacea, Decapoda) by Myrichthys ocellatus (Actinopterygii, Ophichthidae): the first record of consumption by a native fish

“…In this site, M. ocellatus was captured at the macroalgal beds adjacent to shallow reefs (also see study location in [26]). The goldspotted eel is very common in the study area [27,28], but there are no records of C. hellerii presence on both sites sampled prior to this study.…”

“…Myrichthys ocellatus preys mainly on mobile invertebrates, especially crabs of the families Portunidae, Xanthidae and Majidae [27][28][29]. During our stomach contents analysis, we found that the bulk of M. ocellatus diet is composed by these native crab species (e.g., Callinectes spp., Pitho sp., Epialtus sp.…”

“…The goldspotted eel is a crab predator found in various habitats, such as seagrass meadows, macroalgal beds, rocky shores and coral reefs [26][27][28]. It is also a conspicuous member of the ichthyofauna along a large extent of the area colonized by C. hellerii in the western Atlantic [43].…”