Data from: Dietary partitioning among three cryptobentic reef fish mesopredators revealed by visual analysis, metabarcoding of gut content, and stable isotope analysis

Understanding how mesopredators partition their diet and the identity of
consumed prey can assist in understanding the ecological role predators
and prey play in ecosystem trophodynamics. Here, we assessed the diet of
three common coral reef mesopredators; Pseudochromis flavivertex,
Pseudochromis fridmani, and Pseudochromis olivaceus from the family
Pseudochromidae, commonly known as dottybacks, using a combination of i)
visual stomach content analysis, ii) stomach content DNA metabarcoding
(18S, COI), and iii) stable isotope analysis (δ15N, δ13C). In addition, P.
flavivertex is found in two distinct color morphs in the Red Sea,
providing an opportunity to analyze intra-morph differences. These
techniques revealed partitioning in the dietary composition and resource
use among species. Arthropods comprised the main dietary component of P.
flavivertex (18S > 60%; COI > 10%), and P. olivaceus (18S =
57.2%) while P. fridmani ingested predominantly mollusks (18S = 51.3%, COI
= 24.6%). Despite being small predators, microplastics were found in the
gut content of some of these fishes. Stable isotope analysis showed
differences in species' isotopic niche breadth and trophic position.
Pseudochromis olivaceus presented the largest isotopic niche (SEAC =
1.61‰2), while P. fridmani showed the smallest isotopic niche (SEAC =
0.45‰2) among species. Although the two techniques used for stomach
content analysis did not show differences in the diet within color morphs
of P. flavivertex, they differed in the isotopic niche and resource use.
Despite our limited sampling, our findings provide evidence of
species-specific differences in the trophic ecology of dottybacks and
demonstrate their important role as predators of cryptic invertebrates and
small fishes. This study highlights the importance of combining several
approaches (short-term: visual analysis and DNA metabarcoding; and
long-term: isotope analysis) when assessing the feeding habits of coral
reef fish, as they provide complementary information necessary to delimit
their niches and understand the role that small mesopredators play in
coral reef ecosystems.