Trophic Niche Breadth Research Articles

Dietary changes and histophysiological responses of a wild fish (Geophagus cf. proximus) under the influence of tilapia cage farm

The influence of cage fish farm on the trophic, histopathological and metabolic aspects of a wild fish species (Geophagus cf. proximus) was evaluated considering diet, liver histopathology and the concentration of total proteins in the liver, gonads and muscles in fish from two sampling areas (cage farm and control). Diet composition and trophic niche breadth differed significantly between the sampling areas. Detritus, aquatic plants and Cladocera composed the diet in the control area, while mollusks and pelleted feed, followed by detritus, were highly representative of the diet of fish in the cage farm area. More severe histopathological alterations were found in the specimens collected in the cage farm area. These alterations include severe pancreatic hyperplasia and hepatic steatosis. Total protein concentrations in muscles showed no significant difference between the areas. For the liver, the highest concentration was found in fish from the cage farm area, whereas for gonads, higher values were detected in the fish from the control area. These results show that there were hepatic and gonadal metabolic changes in farm-associated specimens compared to specimens from the control area. The high protein and lipid contents of the diet promoted severe histopathological alterations in the liver, impairing hepatic function and possibly interfering in the mobilization of proteins to the gonads. Thus, the relationship between dietary changes and histophysiological alterations suggests an influence of cage fish farm on the ecology of farm-aggregated fish species.

Temporal variation in trophic relationships among three congeneric penguin species breeding in sympatry.

Penguins are a monophyletic group in which many species are found breeding sympatrically, raising questions regarding how these species coexist successfully. Here, the isotopic niche of three sympatric pygoscelid penguin species was investigated at Powell Island, South Orkney Islands, during two breeding seasons (austral summers 2013–2014 and 2015–2016). Measurements of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios were obtained from blood (adults) or feather (chicks) samples collected from Adélie Pygoscelis adeliae, chinstrap P. antarctica, and gentoo P. papua penguins. Isotopic niche regions (a proxy for the realized trophic niches) were computed to provide estimates of the trophic niche width of the studied species during the breeding season. The isotopic niche regions of adults of all three species were similar, but gentoo chicks had noticeably wider isotopic niches than the chicks of the other two species. Moderate to strong overlap in isotopic niche among species was found during each breeding season and for both age groups, suggesting that the potential for competition for shared food sources was similar during the two study years, although the actual level of competition could not be determined owing to the lack of data on resource abundance. Clear interannual shifts in isotopic niche were seen in all three species, though of lower amplitude for adult chinstrap penguins. These shifts were due to variation in carbon, but not nitrogen, isotopic ratios, which could indicate either a change in isotopic signature of their prey or a switch to an alternative food web. The main conclusions of this study are that (1) there is a partial overlap in the isotopic niches of these three congeneric species and that (2) they responded similarly to changes that likely occurred at the base of their food chain between the 2 years of the study.

Food habits of three carnivores in a mosaic landscape of São Paulo state, Brazil

Sao Paulo is the most developed state in Brazil, but despite intense land use changes, some mammal species still inhabit remnant fragments of native vegetation of the state. We used fecal analyses to investigate prey diversity, trophic niche breadth, and trophic niche overlap of pumas, ocelots, and maned wolves in protected and non-protected areas in Sao Paulo state. During 18 months, we inspected more than 10,000 km of roads and trails and collected 233 fecal samples. Maned wolves showed generalist food habit, ocelots were predominantly carnivores, and pumas were strict carnivores. The European hare, an exotic species which had not yet been reported in the study area, was identified in the feces of a puma. Trophic niche breadth was the lowest for maned wolves (BA = 0.339) and the highest for pumas (BA = 0.723). Trophic niche overlap was high between maned wolves and ocelots (Ojk = 0.765) and between pumas and ocelots (Ojk = 0.639). Significantly different diets of maned wolves and ocelots were observed between dry and rainy seasons. Our findings indicate that these three species may adapt their diets to the disturbed landscapes. This is the second study characterizing food habits of ocelots in Cerrado areas but the first considering a large number of samples.

Trophic niche dynamics of three nearshore benthic predators in The Bahamas

Carbon and nitrogen stable isotopes (δ13C and δ15N) were used to examine trophic niche dynamics of three co-occurring predators in The Bahamas. Variable estimates of core trophic niche width and total trophic niche overlap were observed between nurse sharks (Ginglymostoma cirratum), southern stingrays (Hypanus americanus), and Atlantic chupare stingrays (Styracura schmardae). Nurse sharks exhibited little trophic overlap with either species of stingray and exhibited higher δ15N values, suggesting limited potential resource competition. Southern and Atlantic chupare stingrays exhibited higher total trophic niche overlap, highlighting higher levels of resource competition. Nurse sharks exhibited the broadest δ13C range, implying utilization of multiple resource pools to facilitate energetic requirements, compared with southern stingrays and Atlantic chupare stingrays. Southern stingrays exhibited the smallest core trophic niche width, highlighting reliance upon a narrower range of resource pools, likely supported by a single habitat type. We postulate that the persistence of the three sub-sampled predator populations is supported by potential resource partitioning and utilization of multiple trophic resource pools. Further information regarding trophic niche dynamics and patterns of resource use is required for data-poor species to identify how populations and communities may respond to the adverse effects of exploitation, such as fisheries impacts, habitat alteration, and pollution.

Feeding habits of the Cichlid Chromidotilapia guntheri (Sauvage, 1882) in some hydrosystems of Ivory Coast

The feeding habit of Chromidotilapia guntheri was investigated in seven hydrosystems of Ivory Coast. The contents of 156 non-empty stomachs were examined from specimens caught in the rivers Soumié, Eholié, Noé, Ehania and Banco, the Bea rill and the Kpoda lake. Diets composition, feeding strategy and trophic niche width were analyzed among hydrosystems. Stomach content analysis indicated that C. guntheri feeds preferentially on plants and insects debris and secondarily, it consumed insects’ larvae, nymphs and adults in all habitats. This species would be an omnivorous with a detritivorous tendency. As feeding strategy, it practices a generalist strategy even if some individuals displayed specialization intentions on insects at different stages of metamorphosis. Investigations on ontogenetic shift revealed that juveniles and adults of C. guntheri consume substantially the same types of prey with varying amounts depending on the size of the fish. However there is a significant decrease in the proportions of gastropods and oligochaetes ingested when growing.

The effects of spatial scale and isoscape on consumer isotopic niche width

Abstract The mean and variance of ecological variables are dependent on sampling attributes such as the coverage of environmental heterogeneity (sampling extent) and spatial scale. Trophic niche width is often approximated by bulk tissue stable isotopes of C and N, that is, the population isotopic niche. However, recent studies suggest that environmental heterogeneity (experienced by individuals) may be more important in defining the isotopic niche width than trophic variability. We hypothesised that isotopic niche width will increase monotonically with spatial scale, largely produced by environmental variation, for example, nutrient source. To refine this hypothesis, by describing the shapes of isotope scaling curves, we explored a previously published dataset describing three Chilean intertidal species representing different feeding guilds (grazing snails, suspension‐feeding mussel). We tested these hypotheses on a new, larger dataset describing three functionally analogous intertidal species from Northern Ireland. We generated isotopic variance–area curves from a spatially explicit bootstrap and investigated the scale dependency of environment–isotope relationships, including wave exposure and sub‐habitat heterogeneity. Spatial scale explained 50% of the variance in population isotopic niche widths (bivariate C‐N ellipse area) by simple, nonlinear relationships. Finer scales (<1–10 km lag) accounted for most variance. Scale dependence was strong for δ15N variance, of which >40% was explained by modelling linear coefficients. A δ15N baseline gradient, or isoscape, dominated δ15N variance scaling patterns, from sheltered, terrestrially influenced embayments to exposed, pelagic‐dominated coastline. Consumer δ13C variance had a weaker scale dependence, plateauing at mesoscales (>20 km lag). We show that isotopic niche width is strongly dependent on sampling spatial extent, which controls the environmental heterogeneity experienced by individual consumers. Environmental heterogeneity must be accounted for before isotopic niche width can be considered to accurately represent trophic niche width. Studies conducted at different spatial scales are likely to identify different environment–isotope relationships. We recommend that spatial scale should be incorporated into sampling designs explicitly, easiest by maintaining a consistent lag distance or area within which populations are sampled. Identified isoscapes can be de‐trended, where necessary. A plain language summary is available for this article.

Evaluating potential competitive interactions following stocking through trophic niche breadth

Responsible fisheries enhancement should include comprehensive monitoring programs to detect ecological effects of fish releases and support adaptive management. Competition for food and shelter is one such impact, and density-dependent effects may occur if release numbers are above levels that the ecosystem can support. Herein we present a novel application of trophic niche breadth estimated from stable isotope data to examine potential competitive interactions arising from eastern king prawn (Melicertus plebejus) stocking. Eastern king prawn and potential competitors (Macrobrachium intermedium, Atherinosoma microstoma, Leptatherina presbyteroides, Ambassis jacksoniensis and Gobiopterus semivestitus) were sampled from two stocked and two reference estuaries, before and after stocking. Stable isotope ratios were measured and used to model trophic overlap and trophic niche breadth. A statistically significant increase in niche breadth was evident for two competing species in one stocked estuary, and one competing species in another. M. intermedium, the species that had the greatest trophic overlap with eastern king prawn, did not show any change in niche breadth. The potential for competition and the role of environmental variability (including rainfall and run-off, mouth opening regime and seasonal changes) in driving the patterns observed are discussed. This approach shows promise for monitoring competitive effects arising from aquaculture-based fisheries enhancements in the future.

Diet, dietary selectivity and density of South American grey fox, Lycalopex griseus, in Central Chile.

The South American grey fox Lycalopex griseus is a canid widely distributed in southern South America; however, some aspects of its biology are still poorly known. We studied the diet and density of L. griseus in the Lago Peñuelas Biosphere Reserve, in Central Chile. The trophic niche breadth was B = 6.16 (Bsta = 0.47) and prey diversity was H' = 2.46 (Hmax ' = 3.17, J' = 0.78). The highest proportions of prey consumed in the diet were Oryctolagus cuniculus (52.21%) and other mammals (32.78%). We compared these results with a latitudinal gradient of diet results for this species in Chile. L. griseus eats mostly mammals (>90% of total prey), consuming the rodent Phyllotis darwini and reptiles in the northern zone; Oryctolagus cuniculus, Octodon degus and Abrocoma bennetti in the central zone; Abrothrix spp. and lagomorphs in the southern zone; and Lepus capensis and Ovis aries in the austral zone. The estimated density of L. griseus in Lago Peñuelas NR was 1.3 foxes/km2 .

Historical niche partitioning and long‐term trophic shifts in Laurentian Great Lakes deepwater coregonines

AbstractOver the last 100 yr, anthropogenic stressors have decimated the assemblage of deepwater coregonines that once underpinned the food webs of the Laurentian Great Lakes. As a part of ongoing restoration efforts, fisheries managers are interested in reintroducing deepwater coregonines from remnant populations to reestablish historical food web connections. However, little is known about historical trophic position and niche partitioning among deepwater coregonines in the Great Lakes. We used nitrogen stable isotope analysis of amino acids to compare trophic position of museum‐preserved (1920s) and present‐day forage fishes in Lakes Michigan and Superior. In the 1920s, deepwater coregonines exhibited clear trophic niche partitioning, with trophic positions spanning a full trophic level. Additionally, species trophic positions were tightly conserved between lakes. In Lake Superior, trophic niche partitioning has been maintained over the last 100 yr, but trophic position has shifted downward by ~0.5 trophic level. The more dramatic species loss in Lake Michigan corresponds with a sharp reduction in trophic niche breadth over time. Our study reveals remarkable trophic niche breadth among deepwater coregonines prior to the major anthropogenic impacts on the Laurentian Great Lakes and provides a food web benchmark for restoring the historical trophic diversity of this iconic species flock.

Seasonal changes at population and individual levels in the diet of juvenile catfish in a Neotropical floodplain

ABSTRACTIntra-population variation in niches is a widespread phenomenon in animal populations, but, in fish, this knowledge is still scarce. Here, we investigated the population and between-individuals variations in the diet of juvenile Pimelodus maculatus, in dry and wet seasons, in a floodplain from Pantanal, Brazil. A significant difference was verified, being that during the dry season, the diet was mainly composed of fish remains and detritus, while in the wet season, the main food item was fruit/seed. Values of trophic niche breadth were low and seasonally similar. High values of diet variation between individuals and low values of clustering degree, as well as the nestedness metric based on overlap and decreasing fill (NODF), were found. This combination showed that there are generalist and specialist individuals within the population, in which the diet of the last is composed of a subset of food items consumed by generalists. In addition, the median individual specialization index was statistically lower in the wet season, suggesting that individuals could be more diet specialists during this period. Thus, the seasonality in the food resources supply seems to be the main mechanism driving diet variations of juvenile P. maculatus at both population and individual level.

Prey availability, prey selection, and trophic niche width in the lizard Psammodromus algirus along an elevational gradient.

Mountains imply enormous environmental variation, with alpine habitats entailing harsh environments, especially for ectotherms such as lizards. This environmental variability also may imply variation in prey availability. However, little is known about how lizard trophic ecology varies with elevation. In this study, we analyze diet, prey availability, prey selection, and trophic niche width in the lacertid lizard Psammodromus algirus along a 2,200-m elevational gradient in the Sierra Nevada (SE Spain). The analysis of fecal samples has shown that Orthoptera, Formicidae, Hemiptera, Coleoptera, and Araneae are the main prey, although, according to their abundance in pitfall traps, Formicidae and Coleoptera are rejected by the lizard whereas Orthoptera, Hemiptera, and Araneae are preferred. Prey abundance and diversity increase with elevation and diet subtly varies along with the elevational gradient. The consumption of Coleoptera increases with elevation probably as a consequence of the lizard foraging more in open areas while basking. The electivity for Araneae increases with elevation. Araneae are rejected in the lowlands—where they are relatively abundant—whereas, at high elevation, this lizard positively selects them, despite they being less abundant. The lizard trophic niche width expands with elevation due to concomitant greater prey diversity and hence this lizard feeds on more prey types in highlands. Although no sex difference in diet has been found, the trophic niche is broader in females than males. As a whole, alpine lizards show a trophic niche similar to that found at lower elevations, suggesting that P. algirus is well adapted to the harsh environment found in alpine areas.

Relaciones tróficas entre mamíferos herbívoros nativos y exóticos del Parque Provincial Ischigualasto (San Juan, Argentina)

The communities of herbivores are more frequently composed of native and exotic species. Exotic species, with a recent history of co-occurrence among them and with native species, would exhibit less resource distribution strategies than native species, which co-evolved together establishing relationships between them and their environment. Aiming to assess trophic relationships in a community of herbivores that co-occur in Ischigualasto Provincial Park, we analyzed seasonal diet compositions, trophic niche breadth and diet overlap, and made associations based on condition (native or exotic) and body size (large or small). In the hyper-arid Monte region, where the study was conducted, shrub cover was the most representative cover throughout the year. The diets of native and exotic herbivores were based on this functional group of plants. Particularly native species made intensive and sustained use of shrubs during both the wet and dry seasons. Exotic species showed higher similarity in their diets and a constant trophic niche breadth all over the year (broader than that of native species). There was less similarity among the diets of native species, and their trophic niche was narrower, particularly in the dry season. Diet overlap between natives and exotics showed no variations between seasons, not even considering species of similar body size. Probably, no important overlaps are detected in food resource use because of the low densities of exotic species currently present in Ischigualasto Provincial Park. In any event, we recommend permanent monitoring that allows assessing potential competition between native and exotic species. DOI: https://doi.org/10.25260/EA.17.27.3.0.545

Comparative analysis of the diet of feral and house cats and wildcat in Europe

Differences in availability of food resources are often manifested in the differentiation of feeding habits of closely related mammal species. Therefore, we assumed that the diet composition and trophic niche of house (i.e., highly dependent on human households), feral (i.e. independent on human households) domestic cats (Felis silvestris catus) and wildcats (Felis s. silvestris) differs. Based on the literature data from Europe (53 study sites), we compared the diet of these three felids analyzed with use of indirect methods (stomach and scat analyses). In the case of the house cat, we additionally compared consumption data obtained directly from prey brought home. Data were expressed as the relative frequency of occurrence to compare dietary patterns. The main prey of the three cat types were small mammals in different ratios. According to the stomach and scat samples, the diet composition of the cat types showed differences in the consumption of rodents, insectivores, wild ungulates, and household food, supporting the “dietary differences originate from varying resources” hypothesis. More opportunistic house cats had a broader trophic niche than feeding specialist wildcats, while feral cats had an intermediate position. The trophic niche breadth of all three cat types increased along a latitudinal gradient from northern to southern areas of Europe. The predation of the house cat which was examined from prey brought home differed from the data obtained by indirect diet analysis; however, it yielded similar results to the diet of the feral cat and the wildcat. Due to their high numbers and similarity of its diet to the wildcat, house cats are a threat to wild animals; therefore, their predation pressure needs to be further investigated.

Floral Resource Partitioning between Centris (Heterocentris) analis (Fabricius, 1804) and Centris (Heterocentris) terminata Smith, 1874 (Hymenoptera, Apidae, Centridini), in an Urban Fragment of the Atlantic Forest

The knowledge on plant species used for the collection of floral resources is crucial to understanding interactions between plants and bees. The aim of the present study was to identify floral resources used by Centris analis and Centris terminata to provision brood cells and determine the niche breadth and overlap of these two species in a fragment of the Atlantic Forest in Brazil. This study was conducted at the Universidade Federal da Bahia and Parque Zoobotânico Getúlio Vargas, both of which are located in urban areas of the city of Salvador in the state of Bahia. Twelve and eight pollen types were identified in C. analis and C. terminata nests, respectively. The most frequent pollen types were from species of Malpighiaceae and Fabaceae. A larger trophic niche breadth was found in the Parque Zoobotânico Getúlio Vargas for C. analis and in the Universidade Federal da Bahia for C. terminata. Pianka’s index demonstrated trophic niche overlap between C. analis and C. terminata, which was greater in the Parque Zoobotânico Getúlio Vargas. This study is the first to provide data on plants used as food sources by species of the genus Centris in a fragment of the Atlantic Forest situated within urban areas.

Diet of the Wavy Turban Snail,Megastraea undosa(Gastropoda: Turbinidae), in Subtropical Rocky Reefs

The wavy turban snail, Megastraea undosa (W. Wood), is an important fishery resource along the Mexican Pacific coast and a keystone species in subtropical rocky reefs. Its diet was determined from stomach contents of 125 specimens collected in three rocky reefs of the western coast of the Baja California Peninsula in July and November 2006 and March 2007. The snail consumed 20 taxa of seaweeds, 1 seagrass, and 11 taxa of invertebrates. The diet had significant variation depending on site and date. Main food items were Macrocystis pyrifera, Ecklonia arborea, and Corallina spp. Of secondary importance were red algae of the family Delesseriaceae and the genera Plocamium and Gelidium, the brown alga Stephanocystis osmundacea, the seagrasses Phyllospadix spp., the hydrozoan Dynamena, and the isopod Idotea. Analysis showed that the snail was a grazer with a mixed feeding strategy, feeding abundantly on kelp or coralline algae and also consuming many other resources, which was reflected in its variable trophic niche width with a Levins index ranging from 0.21 to 0.79.

Diet and body shape changes of pāroko Kelloggella disalvoi (Gobiidae) from intertidal pools of Easter Island.

This study assesses seasonal variation in the morphology and diet of juveniles and adults of the Easter Island endemic goby Kelloggella disalvoi from intertidal pools during September-October 2015 (spring) and June-July 2016 (winter), utilizing geometric morphometric and gut-content analyses. A set of 16 landmarks was digitized in 128 individuals. Shape changes related to size changes (i.e. allometry) were low (18·6%) and were seasonally similar. Body shape changes were mainly dorsoventral (44·2% of variance) and comprised posteroventral displacement of the premaxilla and bending of the body. The latter included vertical displacement of the anterior portion of the first and second dorsal fins and the entire base of the caudal fin. Diets mainly comprised developmental stages of harpacticoid copepods (from eggs to adults), ostracods, isopods, gastropods and bivalves. Also, trophic niche breadth remained constant throughout development and did not vary between seasons. Nonetheless, significant dietary differences were detected in specimens collected during spring (main prey items: harpacticoid copepods and copepod eggs) and winter (harpacticoid copepods and copepod nauplii). Finally, there was weak but significant covariation between diet and morphology: molluscivores were characterized by having an inferior mouth gape, whereas planktivores had an anteriorly directed premaxilla.

Diet of Aplastodiscus perviridis Lutz 1950 (Anura, Hylidae) in subtemperate forests of southern Brazil

Diet studies allow us to understand important questions about a species behavior in relation to resource use. Aplastodiscus perviridis Lutz 1950 is an arboreal anuran that occurs in southern and southeastern Brazil and western Argentina. In this study, we described and analyzed the diet composition of a population of A. perviridis in southern Brazil. We evaluated the diet by examining the gastrointestinal contents of 42 specimens, 12% of which had no gastrointestinal content, while 12 prey categories were registered. Acarina, Araneae, Coleoptera-adults and Lepidoptera-larvae were the prey categories with the largest relative importance values. The trophic niche breadth was lower than those recorded for other hylids, suggesting a more specialized character. Keywords: prey, niche, behavior, Araucaria forest, predation.

Invasive cane toads are unique in shape but overlap in ecological niche compared to Australian native frogs.

SummaryInvasive species are an important issue worldwide but predicting invasiveness, and the underlying mechanisms that cause it, is difficult. There are several primary hypotheses to explain invasion success. Two main hypothesis based on niche spaces stand out as alternative, although not exclusive. The empty niche hypothesis states that invaders occupy a vacant niche space in the recipient community, and the niche competition hypothesis states that invaders overlap with native species in niche space. Studies on trait similarity/dissimilarity between the invader and native species can provide information on their niche overlap. Here, we use the highly invasive and well‐studied cane toad (Rhinella marina) to test these two hypotheses in Australia, and assess its degree of overlap with native species in several niche dimensions. We compare extensive morphological and environmental data of this successful invader to 235 species (97%) of native Australian frogs. Our study is the first to document the significant morphological differences between the invasive cane toad and a continent‐wide frog radiation: despite significant environmental overlap, cane toads were distinct in body size and shape from most Australian frog species, suggesting that in addition to their previously documented phenotypic plasticity and wide environmental and trophic niche breadth, their unique shape also may have contributed to their success as an invasive species in Australia. Thus, the invasive success of cane toads in Australia may be explained through them successfully colonizing an empty niche among Australian anurans. Our results support that the cane toad's distinct morphology may have played a unique role in the invasiveness of this species in Australia, which coupled with a broad environmental niche breadth, would have boosted their ability to expand their distribution across Australia. We also propose RLLR (Relative limb length ratio) as a potentially useful measure of identifying morphological niche uniqueness and a potential measure of invasiveness potential in anuran amphibians.

Diet of an invading clupeid along an urban neotropical reservoir: responses to different environmental conditions

The river plate sprat Platanichthys platana (Regan, 1917) is a small clupeid fish of South American fresh and brackish waters which was introduced outside of its native range, becoming widespread in the Billings Complex, a highly eutrophic urban reservoir located in the metropolitan area of Sao Paulo city, Upper Tiete River Basin (Sao Paulo State, Brazil). To better understand some aspects related to the invasion of this species in the reservoir, we assessed its diet through the analysis of stomach contents, niche breadth and feeding selectivity. Simultaneously to fish catches, zooplankton samples were collected at three reservoir arms with different anthropic influences during the dry and rainy seasons of 2014. Zooplankton diversity and dominance varied between sites, while composition at the genus level was similar. Sprat fed predominantly on zooplankton (68.3%), consuming a broad diversity of prey (Bosmina, Lecane , Chydoridae, Cyclopoida and Harpacticoida copepods), which were selectively predated. Consumed species varied according to site, season and fish size, with Cladocera being dominant at the most eutrophic site (Borore). Considering spatial differences in the consumed zooplankton, the analysis of percentage similarity (SIMPER) indicated the highest dissimilarity (95.3%) between the Borore (hypereutrophic) and Grande River Reservoir (supereutrophic) sites, while trophic niche width increased from the most impacted (Borore) to the most preserved site (Capivari). The high captures of the sprat in the Billings Complex reported by local fishermen, indicated the adaptability of this invasive fish to the new habitat, suggesting that it may possess a central role as the dominant zooplankton predator in the system.

Trophic ecology of the blotched stingray, Urotrygon chilensis (Elasmobranchii: Myliobatiformes: Urotrygonidae), in three areas of the Mexican Pacific

Background. There is a current global consensus that to achieve a sustainable use of fisheries resources, management of every organism subject to exploitation is required rather than only those targeted directly by the fisheries. Further understanding the feeding habits of the species in the ecosystem as well as the predator–prey relationships and their trophic levels is crucial. Batoids occupy an important ecological niche as benthic predators in estuaries and bays. There is no directed fishery for the blotched stingray, Urotrygon chilensis (Günther, 1872), but it is commonly caught incidentally by trawl and bottom gillnets fisheries subsequently diminishing its population. Recently, artisanal fisheries in Mexico have become focused on batoid species due to the depletion of shark catches, although there are few studies on its biology and ecology. Materials and methods. We analysed the trophic ecology of the blotched stingray in two main areas from the Mexican Central Pacific to understand the species’ diet and detect possible differences throughout fishing areas using stomach content analysis. We analysed the overlap in diets between areas and the trophic level at each area. Results. We analysed 423 specimens and found 15 prey groups. Representatives of the two crustacean higher taxa—Cladocera and Peracarida were the most important food items in the north area, while the crustacean family Penaeidae was the most important in the south area, having no significant overlap between areas (Cλ = 0.33). The estimated trophic position for the blotched stingray was 3.51–3.56 in both areas, and according to the Levin’s index, the range of the trophic niche breadth for the blotched stingray was 0.059 and 0.039, which indicates that it is a specialist predator. Conclusion. The blotched stingray is a specialist predator that can adapt to different prey depending on which organisms are present in the ecosystem. It is necessary to continue with these types of studies for the other species inhabiting the area, in addition to monitoring fisheries landings, fishing effort, and variations in biotic and abiotic factors in the area over a long period. However, this study outlines an approach for reaching the ultimate goal of sustainable exploitation of marine resources on an ecosystem level.