Abstract Reviews can be useful to provide an overview of specific knowledge areas to facilitate research guidelines and the comparison of study results. Therefore, we aimed to detect regions, environments, and taxonomic groups of elasmobranch that lack information on their feeding ecology and consequently need further attention. Using specific keywords on diet and feeding studies, we searched for articles on the trophic and feeding ecology of elasmobranchs. We found an increase in studies over the last 24 years, with an emphasis on stomach contents and stable isotopes. The USA, Australia, Mexico, Argentina, and Brazil were the countries with the highest number of published articles. Australia, the USA, Argentina, Brazil, Mexico, South Africa, Spain, Uruguay and India were the countries with the highest number of species studied. Estuarine and freshwater environments seem to need more attention, since studies on species in these environments were scarce (~3%). The total number of shark and ray species studied showed no significant differences (164 and 186, respectively), but most of the articles reviewed concerned sharks (67.5%). The larger elasmobranch families also need more attention, especially demersal species such as Rajidae, Dasyatidae, Arhynchobatidae, and Sycliorhinidae. Feeding studies only analyze some of the data deficient (DD) species (~7%) included in the IUCN Red List, pointing to the need to obtain more information about them.

RESUMO Um estudo anterior sugeriu que a raia-prego (Hypanus americanus) apresenta uma marcante mudança ontogenética no seu uso de hábitat no Arquipélago de Fernando de Noronha (FNA), local turístico atraente no Brasil, que pode ser associado a mudanças em seus hábitos alimentares e estratégias de forrageamento. Aqui, nós conduzimos amostragens visuais subaquáticas (~100 h em 3 anos de estudo) nesse local para descrever o comportamento de forrageamento dessa mesma espécie em detalhes e acessar seu padrão de atividade diário. Nós observamos que H. americanus tem capacidade para comportamentos complexos e altamente plásticos (nós descrevemos mais de 21 deles) enquanto forrageia. O tempo dos eventos de forrageamento parece estar relacionado com o tamanho (e também sexo) das raias, ambiente e profundidade. Além disso, nossos resultados apoiam a ideia de uma segregação de hábitat mediada pelo tamanho e sexo das arraias, mas que ela é capaz de modular seu repertório de forrageio baseado principalmente em estímulos ambientais. Finalmente, nós descobrimos que H. americanus forrageia de forma intermitente ao longo do dia e ciclos de marés, mas é menos ativa durante os períodos não-crepusculares e nas enchentes e vazantes das marés. Esses resultados, somado ao fato que a espécie utiliza tanto ambientes recifais quanto praianos, devem ser considerados pelos tomadores de decisão em planos de manejo.

ABSTRACT Previous study suggested that the southern stingray (Hypanus americanus) displays a marked ontogenetic shift in its habitat use in the Fernando de Noronha Archipelago (FNA), an attractive touristic spot in Brazil, that could be associated with changes in its feeding habits and foraging strategies. Here, we conducted underwater visual surveys (~100 h a 3 years’ study) at this site to describe the foraging behavior of the same species in details and to assess diel patterns in activity. We observed that H. americanus is capable of several complex and highly plastic behaviors (we described more than 21 of them) while foraging. The foraging events’ timing appears to be related to the size (as well as sex) of the stingrays, environment and depth. In addition, our results support a segregation of habitat mediated by the size and sex of the stingrays, but it is able to modulate its foraging repertoire based mainly on environmental stimulus. Finally, we found that H. americanus forage intermittently throughout the day and tidal cycle, yet are less active during non-crepuscular periods and at flood and ebb tides. These results, coupled with the fact that the species uses both reef and beach environments, should be considered by decision makers in management plans.