Feeding ecology and ontogenetic dietary shift of yellowstripe goatfish Mulloidichthys flavolineatus (Mullidae) at Reunion Island, SW Indian Ocean

Abstract

We analyzed stomach contents and muscle isotopic composition (δ 13 C, δ 15 N) of yellowstripe goatfish Mulloidichthys flavolineatus from a coral reef to investigate size-related dietary changes and resource or habitat partitioning. Juveniles (<12 cm total length [TL]), young adults (12 ≤ TL < 17 cm) and adults (≥17 cm TL) showed a high diet overlap, especially between juveniles and young adults. According to stomach contents analysis, M. flavolineatus widens its prey spectrum with increasing size from a common prey pool that includes polychaetes, tanaids and harpacticoid copepods. We observed a significant increase in δ 13 C values (from -17.1 ± 0.5 ‰ for juveniles to -10.7 ± 0.8 ‰ for adults), which were correlated to fish size. Adults (δ 15 N mean of 11.1 ± 1.8 ‰) were one trophic level above juveniles and young adults (7.7 ± 0.5 and 7.4 ± 0.5 ‰, respectively). These patterns of isotopic changes confirmed ontogenetic dietary shifts. However, trophodynamics can be influenced by physiological factors such as growth and sexual maturity. M. flavolineatus shift from a pelagic to a macrobenthic diet, which is equilibrated at the adult stage. Results from combined stomach contents (prey volume) and stable isotope analyses suggested a dominant contribution of polychaetes (macrofauna), possibly through selective feeding. Conversely, on the basis of prey volume and stable isotope data, meiofauna did not feature significantly in the diet despite their high abundance in stomachs. Two adult groups were distinguished based on their δ 15 N values (11.9 ± 0.8 and 7.8 ± 0.6 ‰), indicating possible stage-specific partitioning in habitat use inside the reef. KEY WORDS: Yellowstripe goatfish · Ontogenetic diet shift · Stomach contents · Stable isotopes · Mixing model · Southwestern Indian Ocean Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 386: [181][182][183][184][185][186][187][188][189][190][191][192][193][194][195] 2009 Knowledge of the trophic interactions between fish and their food resources is of immediate significance to understanding processes that structure shallow-water tropical communities. A number of studies on goatfish diets are reported from the Pacific (Sorden 1982, Lukoschek & McCormick 2001, Sampey et al. 2007), the tropical West Atlantic (Munro 1976, Humann & DeLoach 2002, the Mediterranean and the Red Sea (Ben-Eliahu & Golani 1990, Golani & Galil 1991, Wahbeh 1992. Published data from the Indian Ocean are scarce and concern only the genus Upeneichthys (Platell et al. 1998). Sympatric mullid species can greatly differ in their depth distribution, foraging substratum selection and feeding modes (Gosline 1984, McCormick 1995, Platell et al. 1998. While main food items vary widely among species, all Mullidae are benthic carnivores, using their sensory hyoid barbels to drive out prey. Mulloidichthys flavolineatus is considered to be a specialist benthic predator, foraging mainly on sediments around reefs (McCormick 1995). Past studies from the Hawaiia...

Trophic specializations of damselfishes are tightly associated with reef habitats and social behaviours

“…Research devoted to the study of variations in trophodynamics remain scarce, especially for coral reef ecosystems (see exceptions in Kolasinski et al 2009;Greenwood et al 2010;Wyatt et al 2012;Davis et al 2014;Hanson et al 2016). The coral reef ecosystem of Moorea presents a complex topography, including a protected lagoon with many coral patches, a fringing reef shaped as a wall, and a barrier reef with a crest bounding the open ocean (Fig.…”

Contrasting Responses in the Niches of Two Coral Reef Herbivores Along a Gradient of Habitat Disturbance in the Spermonde Archipelago, Indonesia

“…The analysis of stable isotopes in coral reef food webs offers a powerful tool in elucidating trophic variation among consumers (Cocheret de la Moriniere et al, 2003;Carassou et al, 2008;Kolasinski et al, 2009;Greenwood et al, 2010;Dromard et al, 2013Dromard et al, , 2014Plass-Johnson et al, 2013, 2015b, however further clarification of sources of variability is needed to successfully apply this method within highly diverse systems. In our study, turf algae was more abundant at the degraded sites, however, the parrotfish C. bleekeri may have altered its feeding behavior because of specific structural (rubble) preferences for finding foods with 13 C values closer to Padina sp.…”

Ontogenetic diet shifts in the reef fish Pseudanthias rubrizonatus from isolated populations on the North-West Shelf of Australia

“…data). In contrast, yellowstripe goatfish Mulloidichthys flavolineatus (Mullidae) displayed shifts in δ 13 C signatures between the juvenile and young adult stage, while trophic position (δ 15 N) did not change greatly until the adult stage (Kolasinski et al 2009). The pattern of the small fish in our study displaying lower stable isotope values for both δ 13 C and δ 15 N was evident at all locations with the exception of Yodel.…”

“…Direct gut analysis can, in many cases, be logistically difficult (Vander Zanden et al 1998) and lead to uncertainty when prey items are partially digested and difficult to identify (Kolasinski et al 2009). In addition to contents, changes in the morphology of the alimentary canal, such as the ratio of gut length to size, can provide an indication of trophic position in fishes (Kapoor et al 1976, Clements & Choat 1993, German & Horn 2006, Wagner et al 2009).…”

“…Gut analysis provides information about the most recent prey consumed (Kolasinski et al 2009), but does not reflect diet in the longer term.…”