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Stomach content analyses were performed in 28 dolphins stranded between 1994 and 2007 on the beaches of Rio de Janeiro State (23°06′S 44°18′W/22°14′S 41°54′W), Brazil, comprising six delphinid species: Stenella frontalis (N = 10), Steno bredanensis (N = 7), Tursiops truncatus (N = 4), Delphinus delphis (N = 5), Lagenodelphis hosei (N = 1) and Stenella coeruleoalba (N = 1). Fish otoliths and cephalopod beaks were used to identify the prey species and to estimate the original length and weight. Seven different cephalopod species from six families and 15 fish species belonging to 10 families were identified. Although the fish contribution could be underestimated, cephalopods constituted the group of higher importance, revealing that these invertebrates may represent an important source of energy for delphinids in the region. In this context, the squid Loligo plei should be highlighted due to its important contribution. Most preys were coastal and demersal, and such consumption could indicate coastal foraging habits of the quoted dolphin species. Although dolphins consumed many species of prey in common, they fed on different size-classes of prey. The foraging area of the dolphins could be the same region used by fishing operations, which would represent a risk for incidental capture.

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This study presents new information on feeding habits of Guiana dolphins, Sotalia guianensis, in south-eastern Brazil, together with new regression equations to evaluate the weight and length of fish from otoliths, showing an overview on the knowledge about this species' diet in this area. Eighteen stomach contents had been analysed and compared to 180 samples collected in another eight feeding studies. The analysed specimens were either incidentally caught in gillnets used in coastal waters by the fleet based in the Cananéia main harbour (25800 ′ S 47855 ′ W), south of São Paulo State, or found dead in inner waters of the Cananéia estuary between 2003 and 2009. Based on the index of relative importance analysis, the most important fish species were the banded croaker, Paralonchurus brasiliensis. Doryteuthis plei was the most representative cephalopod species. Stellifer rastrifer was the most important fish species observed in dolphins in inner estuarine waters and P. brasiliensis in recovered dolphins from coastal waters. Loliguncula brevis is the only cephalopod species reported from dolphins found in inner estuarine waters up to date. Doryteuthis plei was the most important cephalopod species observed in coastal dolphins. When considering other feeding studies, the most representative fish family in the diet of S. guianensis was Sciaenidae, which is mainly represented by demersal fishes. The main preys of S. guianensis are abundant in the studied areas, which may indicate an opportunistic feeding habit. The majority of them are not the most important target species by the commercial fishery in south-eastern Brazil.

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The list of Crustacean species from the state of Santa Catarina, southern Brazil, comprises 518 valid species, distributed in 17 orders and 152 families. This amount corresponds to 0.75% of the Crustacea worldwide and about 20% of Brazilian species. The order Decapoda is the most represented, with 280 species. The families of Decapoda with the greatest number of species recorded were: Aeglidae (19), Palaemonidae (13) and Portunidae (13). In addition, the occurrence of 19 species distributed in the orders Cyclopoida (1), Podocopida (2) and Decapoda (16) is reported for the first time. Exotic species (9) are distributed in four different orders - Isopoda (6), Calanoida (1), Thoracica (1) and Decapoda (1).

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Seabirds breeding in tropical environments experience high energetic 21 demands, when foraging in an oligotrophic environment. The globally threatened 22 Trindade petrel Pterodroma arminjoniana has its largest colony in Trindade Island 23 (20°30'S-29°19'W) inside the oligotrophic South Atlantic Subtropical Gyre. Diet 24 sampling methods, geolocator tracking and stable isotope analysis were used to describe 25 its diet, compare foraging trips and distributions, and assess temporal variations in the 26 trophic niche throughout the breeding period. Diet consisted mainly of squid and fish. 27 The high species diversity and wide range of prey sizes consumed suggests the use of 28 multiple foraging techniques. Stable isotope mixing models confirm that Trindade 29 petrels rely mainly on squid throughout the breeding period. Its broad isotopic niche 30 seems to reflect both a diverse diet and foraging range, since birds can reach up to 3335 31 km from the colony. Isotopic niche showed limited variation even in an eight-year 32 interval, apparently due to oceanographic stability, although changes in the isotopic 33 niche have demonstrated an adjustment to different conditions in different seasons. 34 Petrels change foraging areas and prey during the breeding period: pre-incubating birds 35 use more productive areas west of Trindade Island and obtain low-trophic-position prey; 36 incubating petrels perform longer trips southward to consume prey of high trophic 37 position; and chick-rearing petrels use areas around the island. These results 38 demonstrate that to deal with high demand breeding in a colony surrounded by 39 oligotrophic waters, Trindade petrels need to explore wide foraging areas and utilize a 40 diverse diet, besides adjusting trophic niche according to breeding stage. 41 42 43 44 90 tool to assess trophic ecology of organisms (Newsome et al. 2007, Mancini et al. 2014). 91Combining these two methods in dietary studies gives the advantages of both 92 approaches, thus allowing more robust inferences on trophic ecology of consumers. 93 The Trindade petrel, Pterodroma arminjoniana, breeds in Trindade Island in the 94 South Atlantic Ocean, and at least since 1950s in Round Island, Indian Ocean (Brown et 95 al. 2010). The species is listed as 'vulnerable' by IUCN (2016), and 'critically 96 endangered' by the Brazilian Red List (MMA 2014) because of its susceptibility to 97 human impacts and stochastic events, due to very small breeding range and population 98 size, besides hybridizing with Kermadec petrel P. negleca in Round Island (Brown et al. 99 2010). In Trindade Island ca. 1130 pairs breed all year round, with laying peaks in Luigi et al. 2009). The 101 period from laying to fledging is about 150 days-long; petrels incubate the single egg 102 for ~52 days and feed the chick for ~97 days (Luigi et al. 2009). Thus, a portion of the 103 population breeds during the austral spring-summer and another during the austral fall-104 winter seasons. 105 The gadfly petrels, genus Pterodroma, contain the largest number o...