Dentition damage in parrotfishes feeding on hard surfaces at Fernando de Noronha Archipelago, southwest Atlantic Ocean

Abstract

Parrotfishes (Scaridae) are renowned for their beak-like dentition, which enables them to bite on coralline and rocky surfaces to feed on algae and detritus. These fishes dwell in a wide range of habitats, but most studies on parrotfish feeding behavior and ecology have been made on coral reef sites. We report on parrotfishes with damaged dentition at Fernando de Noronha, a volcanic archipelago off the coast of northeast Brazil, in the tropical southwest Atlantic Ocean. We recorded tooth damage only in adult individuals (> 40 cm total length [TL]) of 3 common species (Sparisoma amplum, S. axillare and S. frondosum) in the study area. The frequency of tooth damage varied among the species: 0.85% in S. amplum, 2.34% in S. axillare and 0.76% in S. frondosum. Two types of tooth damage were recorded: broken teeth and the whole dental plate protruding from the mouth. Individuals with damaged dentition were recorded at 6 out of 10 study sites. The abundance of parrotfishes with tooth damage and their presence at several sites within the archipelago indicate that this is a common and predictable event in the area. The reefs of Fernando de Noronha Archipelago comprise mostly basaltic rocks, which are much harder than the calcium carbonate matrix that generally composes coral reefs where most studies on parrotfish behavior and ecology have been conducted. This may explain the absence of reports of parrotfishes with damaged teeth in the scientific literature to date.

Diel vertical movements and feeding behaviour of blue humphead parrotfish Scarus ovifrons in a temperate reef of Japan

“…Bonaldo et al . (2007) studied three species of Sparisoma that regularly fed on algae turf on the volcanic (basaltic) rocks and found that only adult individuals (>40 cm TL) showed dental damage. As small individuals (≤35 cm TL) of S. ovifrons rarely left clear scars, they might be able to ingest EAM on rocks without severe dentition damage.…”

“…Considering scraping feeding mode in the genus Scarus, the authors expected S. ovifrons to feed more on calcareous (coral) substrata than on hard rocks, but they took bites primarily on rock substrata. Bonaldo et al (2007) studied three species of Sparisoma that regularly fed on algae turf on the volcanic (basaltic) rocks and found that only adult individuals (>40 cm TL) showed dental damage. As The combination of this study's focal follow survey and genetic analysis revealed that S. ovifrons mainly ingests epilithic red algae, whereas coralline algae were less targeted; similar findings have been reported by past Scarus studies on tropical coral reefs (Bruggemann et al, 1994;Hamilton et al, 2014; but see Mendes et al, 2018).…”

“…In marginal environments with limited coral reef development, the reefs are composed mostly of harder granitic or basaltic rocky substrata. The feeding apparatus of scraping and excavating parrotfishes is effective at gouging into calcareous substrata on coral reefs; nonetheless, it is inefficient in penetrating these rocky substrata, and attempts to do so often damage their teeth (Bonaldo et al ., 2007; Hoey et al ., 2018).…”

Validated cleaner: the cuculid bird Crotophaga ani picks ticks and pecks at sores of capybaras in southeastern Brazil

“…The Australian crow Corvus orru displays cleaning behaviour in presence of the introduced Asian bovid Bos javanicus, and this symbiotic relationship could have evolved in a very short time -about 150 years (Bradshaw & White 2006). Situations perhaps unique are reported for animals other than birds (e.g., Greene 1986, Sazima et al 2003, Bonaldo et al 2007, Wetherbee et al 2007, and thus a field researcher should pay attention to apparently rare behaviours and/or particular ecological situations. The results of such open-minded approach usually bring new insights, ideas, or concepts into the natural history and evolutionary biology research areas (Greene 1986).…”

Limited flexibility in resource use in a coral reef grazer foraging on seasonally changing algal communities

“…Other characteristics of these commonly targeted coral genera that may be selected for are their massive growth form and their relatively smooth surface (due to their small calyx sizes). Besides permitting relatively high yields, preference for these genera may be linked to the ease at which medium-sized parrotfishes can take bites without damaging their dentition (Bonaldo et al 2007). Parrotfish grazing efficiency may thus be limited by the surface characteristics of the substrate.…”