Feeding habits of the speckled guitarfish Rhinobatos glaucostigma (Elasmobranchii: Rhinobatidae)

Abstract

The stomachs of 464 speckled guitarfish Rhinobatos glaucostigma were sampled from the south-eastern Gulf of California (GC) to determine diet composition. Numerical indices and prey-specific index of relative importance ((%I)PSIR ) were used to determine the feeding strategy of the species. An analysis of similarity (ANOSIM) was used to determine differences in diet with respect to sex, season (dry or rainy) and maturity stages (immature or mature). The diversity and niche breadth (by sex, season and maturity) and a general trophic level were determined. The overall diet was dominated by shrimps ((%I)PSIR = 43.47), amphipods ((%I)PSIR = 18.89) and crabs ((%I)PSIR = 18.07). ANOSIM demonstrated differences in the diet by maturity and season, but not by sex. Rainy and dry season diets were dominated by shrimps and amphipods, respectively. Immature specimens fed mainly on amphipods, whereas mature fish preferred shrimps and crabs. Rhinobatos glaucostigma showed a narrow niche breadth with an intermediary trophic level (TL = 3.72) and can be considered as a secondary consumer in the soft-bottom demersal community of the south-east GC. Understanding the feeding habits and trophic level of R. glaucostigma is vital to help identify the segments of the population vulnerable to overfishing by artisanal and industrial fisheries, and to aid in conservation and management of this elasmobranch.

Comparative diets of sympatric batoid elasmobranchs in the Gulf of Oman

“…On the other hand, the diet of Rhinobatos punctifer consisted mostly of crustaceans, especially shrimp species. Similar results have been reported in other guitarfish species (Harris et al 1988, Blanco-Parra et al 2012, Navarro-González et al 2012, Espinoza et al 2013, Lara-Mendoza et al 2015. Brevitrygon walga, Maculabatis randalli, and Pastinachus sephen preyed on epibenthic organisms like crustaceans, polychaetes, bivalves, and echinoderms, Table 2.…”

Feeding guilds among batoids in the northwest coast of the Baja California Sur, Mexico

“…As it grows, it tends to feed on other trophic groups, such as fish and cephalopods (Bizzarro, 2005; Curiel‐Godoy et al, 2016; Downton Hoffmann, 2007). Previous data on the feeding habits of the genus Pseudobatos confirm its high preference for different groups of crustaceans, as reported by Wilga and Motta (1998) for P. lentiginosus in Florida, USA; Payán et al (2011) for P. leucorhynchus in the Colombian Pacific; do Carmo et al (2015) for P. percellens in Brazil; Lara‐Mendoza et al (2015) for P. glaucostigma in the southeastern Gulf of California; and Silva‐Garay et al (2018) for P. planiceps in Peru. The similarity in the feeding habits of P. productus with other species of the genus Pseudobatos would be associated with coastal habitat with sandy or muddy bottoms where they burrow to ambush their prey instead of chasing them (Flowers et al, 2020; Talent, 1982; Valenzuela‐Quiñonez et al, 2017).…”

A new cuspidate ptychodontid shark (Chondrichthyes; Elasmobranchii), from the Upper Cretaceous of Morocco with comments on tooth functionalities and replacement patterns

“…21 ), † Ptychodus maghrebianus sp. nov., the platyrhinid † Tingitanius and guitarfishes most likely represented second-level consumers, whose diet largely was based on thin-shelled molluscs, crustaceans and small fishes (see also Basusta et al, 2007 ; Lara-Mendoza et al, 2015 ). Based on the feeding niches of aquilopelagic (e.g., Manta ) and macroceanic-tachypelagic (e.g., Megachasma and Rhincodon ) planktivorous elasmobranchs (see Cort’es, 1999; Couturier et al, 2013 ), a similar trophic level (3–3.5 = second-level consumer) would be hypothesizable for Cretomanta .…”