The fitness of the Brazilian damsel Stegastes fuscus is increased by sharing the territory with the dusky grouper Epinephelus marginatus

Abstract

Stegastes fuscus and Epinephelus marginatus are known for co-habiting shelters. The damselfish S. fuscus uses the territory for nesting and must protect its eggs from grazers; the grouper E. marginatus is an omnivorous sitand-wait predator. This study aims to evaluate the effect of juvenile groupers on the reproductive success of the Brazilian damsel. Twenty-five hours of underwater observations were done in São Sebastião and Ilhabela, Northern shore of São Paulo, Brazil. Fitness increase was measured by the egg-clutch area and number of contributing females in 130 nests shared by groupers and another 130 where damselfishes stood alone. An egg predator crab was placed into the damselfish territory, and behavioural responses during 2 min were recorded for nests with or without E. marginatus, 80 replicates each. Nests shared by the dusky groupers had more eggs and received eggs from more females too. While fathers who were alone in the territory had to deal with the egg predator crab, in shared nests, the grouper would take care of the intruder, sometimes feeding on it. Therefore, the Brazilian damsel may benefit from the presence of the dusky grouper by increasing the fitness and diminishing the costs of parental care.

Integrative approach on the diversity of nesting behaviour in fishes

“…This cladogram was organized using the previously published work of Rabosky et al (2018) and Betancur-R. et al (2013) major Abudefduf saxatilis are easily found by predators, hence nesting males spend more time averting egg predators than Chromis multilineata (Pomacentridae), another pomacentrid that conceals eggs amid algae (Bessa & Sabino, 2012). A cooperative interaction between Stegastes fuscus damsels and the dusky grouper (Epinephelus marginatus, Serranidae) was reported, in which the damsel benefits from sharing its territory with a grouper because this serranid feeds on egg predators attracted by the nest (Bessa, 2011). Finally, predatory fishing also benefits from knowing nesting habits.…”

Habitat use of five sympatric predatory reef fishes at a remote island in the south‐western Atlantic

“…Serranidae ( i.e ., groupers and sea basses) are considered key marine teleost fishes, playing a crucial role as predators and mesopredators, and maintaining ecosystem structure, functioning and resilience (Baum & Worm, 2009; Bessa, 2011; Burkholder et al ., 2013). Groupers and sea basses inhabit diverse habitats of the reef ecosystems ( e.g ., unconsolidated substrates, coral and rocky reefs), most commonly in depths <200 m (Anderson et al ., 2014, 2019).…”