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Abstract Introduction: The sea urchin Diadema mexicanum, due to its bioerosion activity, is considered of ecological importance. This phenomenon could negatively or positively affect coral reef ecosystems. The bioerosion process varies according to the abundance and size of the sea urchin. Objective: Juvenile organisms possess different metabolic needs compared to adults, so knowing their stomach content according to size allows us to quantify the selection of substrate bioeroded. Methods: To determine this, D. mexicanum individuals were collected in 12 sites from January 2009 to September 2010 along the Eastern Tropical Pacific coast. The stomach content was categorized in Carbonated Fraction (CF), Non-Carbonated Fraction (NCF), and Organic Matter (OM). Stomach content was analyzed according to a) juvenile (< 2.5 cm) or adult (> 2.5 cm) stage and b) locality. Results: Juveniles presented the following stomach content average percentages: 20.7 % OM, 12 % NCF and 67.9 % CF; and adults: 11.4 % OM, 14.8 % NCF and 73.8 % CF. Based on a Wilcoxon test and a Kendall linear regression, the following results were obtained. The carbonated fraction in the stomach increased by 0.47 units on average for every cm of growth (p < 0.05). OM consumed by D. mexicanum increases only 0.05 units for every cm of growth (p < 0.05). We found a difference of stomach content depending on the site (p < 0.05) and life stage (p < 0.05). Localities like Huatulco and Coco presented significant differences that could be related to local oceanographic conditions. Conclusions: We relate these changes of the stomach fractions to the necessity of the juvenile sea urchins for nutrients to maintain their growth. The amount of OM is crucial for the development of early stages, meaning that there is a difference in substrate selection associated with growth.

Resumen Introducción: El erizo de mar Diadema mexicanum, por su actividad de bioerosión, es considerado de importancia ecológica. Este fenómeno podría afectar negativa o positivamente a los ecosistemas de arrecifes de coral. El proceso de bioerosión varía según la abundancia y el tamaño del erizo de mar. Objetivo: Los organismos juveniles poseen diferentes necesidades metabólicas en comparación con los adultos, por lo que conocer el contenido estomacal según el tamaño, nos permite cuantificar la selección de sustrato bioerosionado. Métodos: Para determinar esto, se recolectaron individuos de D. mexicanum en 12 sitios desde enero de 2009 hasta septiembre de 2010 a lo largo de la costa del Pacífico Tropical Oriental. El contenido estomacal se clasificó en Fracción Carbonatada (FC), Fracción No Carbonatada (NCF) y Materia Orgánica (MO). El contenido estomacal se analizó según a) estadio juvenil (< 3 cm) o adulto (> 3 cm) y b) localidad. Resultados: Los juveniles presentaron los siguientes porcentajes promedio del contenido estomacal: 20.7 % OM, 12 % NCF y 67.9 % CF; y adultos: 11.4 % OM, 14.8 % NCF y 73.8 % CF. Con base en una prueba de Wilcoxon y una regresión lineal de Kendall, se obtuvieron los siguientes resultados. La fracción carbonatada en el estómago aumentó en promedio 0.47 unidades por cada cm de crecimiento (p < 0.05). La MO consumida por D. mexicanum aumenta solo 0.05 unidades por cada cm de crecimiento (p < 0.05). Encontramos una diferencia en el contenido estomacal según el sitio (p < 0.05) y el estadio de vida (P < 0.05). Localidades como Huatulco y Coco presentaron diferencias significativas que podrían estar relacionadas con las condiciones oceanográficas locales. Conclusiones: Relacionamos estos cambios de la composición porcentual del contenido estomacal con la necesidad de los erizos de mar juveniles de nutrientes para mantener su crecimiento. La cantidad de MO es crucial para el desarrollo de las primeras etapas, lo que significa que existe una diferencia en la selección de sustrato asociada con el crecimiento.

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The trophic relationships of pelagic fishes with migratory traits such as the South Pacific Bonito, Sarda chiliensis chiliensis (Cuvier, 1832), have not been studied in depth in the past. The objective of the present research was to analyze the feeding habits of South Pacific Bonito by sex and to analyze a comparison between summer and autumn months in three different areas of the eastern South Pacific by applying different techniques used in trophic biology. Between December 2013 and June 2014, specimens were captured in the areas of Pozo de Lisas (Ilo, Peru), La Capilla (Arica, Chile) and Chanavayita (Iquique, Chile). The feeding dynamics and trophic composition of the diet were analyzed, as well as the feeding strategy and trophic relationships. A total of 1404 specimens were analyzed, of which 654 had stomach contents. Seven prey items were identified: (a) fish remains; (b) squid jaw remains; (c) squid gladius remains; (d) caudal fin remains; (e) Engraulis rigens; (f) Pleuroncodes monodon and (g) N/A (not determined). The Pozo de Lisas and La Capilla areas showed homogeneity in their prey items, while the Chanavayita area showed more diversity. Regarding the importance of prey items in the diet of S. chiliensis in the three localities, it would be correct to state that it is a generalist species.

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The objective of this study was to analyse the feeding habits and trophic interactions between four oceanic predatory fish around the Fernando de Noronha Archipelago (FNA), Brazil, in the western equatorial Atlantic (3.86°S/32.42°W), internationally recognized as an environment of high economic and ecological value. For this purpose, biological samples of yellowfin tuna (Thunnus albacares), wahoo (Acanthocybium solandri), barracuda (Sphyraena barracuda) and dolphinfish (Coryphaena hippurus) were collected for stomach content and stable isotope analysis. Values of the index of relative importance revealed varied diets, with a strong presence of teleost fishes (Diodontidae and Exocoetidae) for all species, with yellowfin tuna having a greater diversity of food items. Despite being generalists/opportunists, the feeding strategy of these predators showed a tendency towards a specialized diet in the use of the available resources around the FNA. They presented a narrow trophic niche width (Levin's index, Bi < 0.6) and low overlap between species, except between barracuda and wahoo (MacArthur and Levin's, R0  = 0.72). Isotopic compositions had broad values of δ13 C and δ15 N, and were significantly different between species. Our results provide information about the four species' trophic organization and suggest that the predators avoid competition by preying on different prey, thus allowing their coexistence.

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Abstract: The length-weight relationship (LWR) and diet of a small trichomycterid catfish, Cambeva guareiensis, was studied based on 58 specimens captured in Corrente stream, Guareí River basin, São Paulo, Brazil. LWR analyses showed values of a ranged from 0.0097 to 0.0149 and b from 2.858 to 3.250. The analysis of the diet showed that high amounts of aquatic insects (93.75% of total items) were consumed by the species. In addition, we found no statistically significant differences when comparing the diet between the dry and rainy periods. Our study contributes to the knowledge on populational biology and feeding ecology of trichomycterid fishes in Brazilian streams.

Resumo: A relação peso-comprimento (RPC) e dieta de um pequeno bagre trichomycterídeo, Cambeva guareiensis, foi estudada com base em 58 espécimes capturados no riacho Corrente, bacia do rio Guareí, São Paulo, Brasil. As análises de RPC mostraram valores de a variando entre 0,0097-0,0149 e de b entre 2,858-3,250. A análise da dieta mostrou que altas quantidades de insetos aquáticos (93,75% do total de itens) foram consumidas pela espécie. Além disso, não encontramos diferenças estatisticamente significativas quando comparamos a dieta entre os períodos seco e chuvoso. Nosso estudo contribui para o conhecimento da biologia populacional e ecologia alimentar de peixes trichomicterídeos em riachos brasileiros.

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The impact of microplastics on wildlife is a recent problem for which methods to evaluate exposure still need development. Being able to identify and quantify microplastics (particles < 5 mm) in the gastric contents of live crocodiles allows us to evaluate exposure, at both individual and population level, and also its contribution as transporter of other contaminants. The method was validated to determine and quantify microplastics in crocodile stomach contents recovered during an experiment where a known amount of this contaminant was given to crocodiles via oral administration. Through stomach flushing we were able to recover more than 80 % of the total volume of microplastic administrated to each crocodile. In summary, the method used during the experiment consists of 1) immobilization of the crocodile; 2) extraction of microplastics from stomach contents obtained through stomach flushing; 3) separation, identification and quantification of recovered microplastic fragments using microscopy and FTIR. •Low cost method that uses a small number of materials, does not take long to produce results and can easily be performed in the field or the laboratory.•Effective in extracting stomach contents (95 %).•High (>80 %) and good (>60 %) recovery efficiencies within two and four days after ingestion of microplastics by crocodiles.

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The relationships between fish size and sagitta otolith measurements were calculated for the first time for 15 species belonging to six families from the northern Brazilian coast. A total of 220 fish were sampled from the bycatch landed by the bottom-trawl industrial shrimp-fishing fleet between August and September 2016. All species had strong relationships between otolith measurements and fish total length with the coefficient of determination (r 2) ranging between 0.71 and 0.99. The variable most strongly related to fish total length was found to be the sagittal otolith length (OL) with 98% of the variability. These relationships are a useful tool to estimate length and mass of preyed fish from otoliths found in stomach contents of marine predators.(AU)

As relações entre o tamanho corporal do peixe e as medidas do otólito sagitta foram calculadas pela primeira vez para 15 espécies pertencentes a seis famílias de peixes demersais da costa norte do Brasil. Um total de 220 peixes foi amostrado da captura acidental realizada pelo arrasto de fundo da frota pesqueira industrial de camarão entre agosto e setembro de 2016. Todas as espécies apresentaram fortes relações entre as medidas do otólito e o comprimento total do peixe, com o coeficiente de determinação (r 2) variando entre 0,71 e 0,99. A variável mais fortemente relacionada ao comprimento total dos peixes foi o comprimento do otólito sagital (OL) com 98% da variabilidade. Essas relações representam uma ferramenta útil para estimar o comprimento e a massa de peixes predados a partir dos otólitos encontrados no conteúdo estomacal de predadores marinhos.(AU)

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The relationships between fish size and sagitta otolith measurements were calculated for the first time for 15 species belonging to six families from the northern Brazilian coast. A total of 220 fish were sampled from the bycatch landed by the bottom-trawl industrial shrimp-fishing fleet between August and September 2016. All species had strong relationships between otolith measurements and fish total length with the coefficient of determination (r 2) ranging between 0.71 and 0.99. The variable most strongly related to fish total length was found to be the sagittal otolith length (OL) with 98% of the variability. These relationships are a useful tool to estimate length and mass of preyed fish from otoliths found in stomach contents of marine predators. (AU)

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In this study, an analytical strategy to identify brucine, strychnine, methomyl, carbofuran (alkaline compounds), phenobarbital, and warfarin (acid compounds) using thin-layer chromatography (TLC) screening with ultraviolet (UV) detection at 254 nm in stomach content is shown. The optimum mobile phase was found to be a chloroform: ethyl acetate: diethylamine (0.5:8.5:1) mixture for alkaline substances while a mixture of chloroform: acetone (9:1) has given better results for acidic substances. As for extraction, an equal proportion between distillated water and crude material (1:1) is required. For alkaline compounds, a filtration system was created in order to avoid any interferences from the biological matrix while for acidic compounds only centrifugation (4000 rpm/10 minutes) was required to obtain an appropriate sample. After the respective pretreatments, a one-step liquid-liquid extraction (LLE) has been employed for alkaline substances using a 3 mL of chloroform: ethyl ether (2:1) mixture for 2 min while acidic analytes used 3 mL of chloroform only during 5 min. For both methodologies described, the respective organic layers were dried down and re-suspended with 50 µL of methanol for further TLC plate application. The methodologies have been developed, successfully validated and applied to gastric contents from real case samples of suspected animal poisoning. Positive results from TLC/UV screening were confronted with HPLC-UV and confirmed by GC-MS.

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The gastric armature of decapod foregut is a feeding structure that sparks controversial debates about the role dietary and historical components have in shaping its morphological traits. Having previous information about the natural diet is an interesting way to gather evidence on this issue. For the present study, we analyzed the morphological traits of gastric ossicles involved directly in the maceration of food in nine species of freshwater crabs of the family Trichodactylidae (Brachyura: Decapoda) representing five genera, three tribes and two subfamilies. The analyzed gastric ossicles were quite consistent among closely related species, suggesting that the observed traits had a clear phylogenetic component. However, it was also noted that the morphological traits of the gastric teeth of trichodactylid crabs match well with the natural diet and presented likeness with general features of other species with a similar trophic habit. We discuss the influence of phylogeny and function on the design of morphological traits and propose to quantify the role of phylogeny and function in shaping morphological traits through the analysis of phylogenetic signals.

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This study analyzed the diet during early developmental stages of Astyanax lacustris (AA),Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) and Prochilodus lineatus (PL), under experimentalconditions. Fish larvae, 350 of each species, were stocked separately in 16 fiber-cement tanks (500 L), fromwhich, three larvae of each species were collected every three days, for 36 days. Tanks were fertilized (1.5 gNPK-7: 14: 8) and had 50% of the surface with macrophytes. Larvae were grouped in age classes = I: 5 to11, II: 14 to 20, III: 23 to 29 and IV: 32 to 38 days and, dissected for analysis of the digestive tract.Methodologies of dominance, frequency of occurrence and points of food items were used. For AA andPM larvae, measurements were taken for the number and size of organisms to determine the percentparticipation in biovolume. Changes in diets of larvae in different age classes were found as well as betweendifferent species, with the same age. Rotifers were dominant in the content of digestive tracts of all speciesat Class I, and the larvae diets became more distinct with increasing age, in which AA consumed mainlyrotifers, PM, larger organisms (mainly cladocerans), PL, algae (diatoms as the main item) and PP with amore diversified diet (rotifers, ostracodes and algae). In conclusion, early stages of these species presenteddistinct diets, undergoing remarkable changes in the first 38 days of life.(AU)

Estudou-se a alimentação dos estágios iniciais de desenvolvimento de Astyanax lacustris (AA),Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) e Prochilodus lineatus (PL) em condiçõesexperimentais. As larvas, 350 cada espécie, foram estocadas separadamente, em 16 tanques de fibrocimento(500 L) dos quais foram coletados três indivíduos de cada um, a cada três dias, por 36 dias. Os tanquesforam fertilizados (1,5 g de NPK-7:14:8) e tinham 50% da superfície com macrófitas. As larvas foramagrupadas em classes de idade = I: 5 a 11, II: 14 a 20, III: 23 a 29 e IV: 32 a 38 dias e, dissecadas para aabertura do trato digestório. Foram empregadas as metodologias de dominância, frequência de ocorrência epontos dos itens alimentares. Para as larvas de AA e PM, foram contados e tomadas medidas das dimensõesdos organismos para determinar a participação percentual do biovolume. Observaram-se mudanças nasdietas das larvas em diferentes classes de idade e também entre larvas de espécies diferentes, com mesmaidade. Houve predomínio de rotíferos nos conteúdos dos tratos digestórios de todas as espécies na classe I,as dietas das larvas passaram a ser mais distintas com o incremento da idade, com AA consumindoprincipalmente rotíferos, PM organismos maiores (principalmente cladóceros), PL tendo algas(diatomáceas como item principal) e PP com uma dieta mais variada (rotíferos, ostracodes e algas).Conclui-se que as formas jovens destas espécies apresentaram dietas distintas, passando por nítidasalterações nos primeiros 38 dias de vida.(AU)

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This study analyzed the diet during early developmental stages of Astyanax lacustris (AA), Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) and Prochilodus lineatus (PL), under experimental conditions. Fish larvae, 350 of each species, were stocked separately in 16 fiber-cement tanks (500 L), from which, three larvae of each species were collected every three days, for 36 days. Tanks were fertilized (1.5 g NPK-7: 14: 8) and had 50% of the surface with macrophytes. Larvae were grouped in age classes = I: 5 to 11, II: 14 to 20, III: 23 to 29 and IV: 32 to 38 days and, dissected for analysis of the digestive tract. Methodologies of dominance, frequency of occurrence and points of food items were used. For AA and PM larvae, measurements were taken for the number and size of organisms to determine the percent participation in biovolume. Changes in diets of larvae in different age classes were found as well as between different species, with the same age. Rotifers were dominant in the content of digestive tracts of all species at Class I, and the larvae diets became more distinct with increasing age, in which AA consumed mainly rotifers, PM, larger organisms (mainly cladocerans), PL, algae (diatoms as the main item) and PP with a more diversified diet (rotifers, ostracodes and algae) . In conclusion, early stages of these species presented distinct diets, undergoing remarkable changes in the first 38 days of life.

Estudou-se a alimentação dos estágios iniciais de desenvolvimento de Astyanax lacustris (AA), Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) e Prochilodus lineatus (PL) em condições experimentais. As larvas, 350 cada espécie, foram estocadas separadamente, em 16 tanques de fibrocimento (500 L) dos quais foram coletados três indivíduos de cada um, a cada três dias, por 36 dias. Os tanques foram fertilizados (1,5 g de NPK-7:14:8) e tinham 50% da superfície com macrófitas. As larvas foram agrupadas em classes de idade = I: 5 a 11, II: 14 a 20, III: 23 a 29 e IV: 32 a 38 dias e, dissecadas para a abertura do trato digestório. Foram empregadas as metodologias de dominância, frequência de ocorrência e pontos dos itens alimentares. Para as larvas de AA e PM, foram contados e tomadas medidas das dimensões dos organismos para determinar a participação percentual do biovolume. Observaram-se mudanças nas dietas das larvas em diferentes classes de idade e também entre larvas de espécies diferentes, com mesma idade. Houve predomínio de rotíferos nos conteúdos dos tratos digestórios de todas as espécies na classe I, as dietas das larvas passaram a ser mais distintas com o incremento da idade, com AA consumindo principalmente rotíferos, PM organismos maiores (principalmente cladóceros), PL tendo algas (diatomáceas como item principal) e PP com uma dieta mais variada (rotíferos, ostracodes e algas). Conclui-se que as formas jovens destas espécies apresentaram dietas distintas, passando por nítidas alterações nos primeiros 38 dias de vida.

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Abstract Catches and exports of skate Rioraja agassizii place this species as vulnerable to extinction on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.(AU)

Resumo A raia-santa, Rioraja agassizii é uma espécie endêmica da qual pouco se conhece sobre sua biologia e ecologia, o que a leva a ser classificada como vulnerável a extinção. O objetivo foi identificar e quantificar a composição da dieta alimentar da R. agassizii através da análise do conteúdo estomacal de exemplares capturados nos períodos de 2005-2006 e 2012-2013. Foram analisados os conteúdos alimentares e quantificados em abundância (N%), peso (M%), frequência de ocorrência (FO%) e índice de importância relativa (IRI) de cada item. Os resultados mostraram que em 2012-13 a dieta foi composta por peixes, seguido de decápodes, especialmente camarões, entretanto em 2005-06 foi composta basicamente por camarões. A diferença nas dietas não quer dizer que os hábitos alimentares mudaram, pois em 2012-13 além dos peixes, os camarões também foram classificados como maior importância alimentar. Considerando que a quantidade e variedade dos itens ingeridos está relacionada, principalmente, a fatores ambientais são necessários mais estudos que relacionem áreas de captura, sazonalidade e profundidade.(AU)

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Abstract Catches and exports of skate Rioraja agassizii place this species as “vulnerable to extinction” on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

Resumo A raia-santa, Rioraja agassizii é uma espécie endêmica da qual pouco se conhece sobre sua biologia e ecologia, o que a leva a ser classificada como “vulnerável a extinção”. O objetivo foi identificar e quantificar a composição da dieta alimentar da R. agassizii através da análise do conteúdo estomacal de exemplares capturados nos períodos de 2005-2006 e 2012-2013. Foram analisados os conteúdos alimentares e quantificados em abundância (N%), peso (M%), frequência de ocorrência (FO%) e índice de importância relativa (IRI) de cada item. Os resultados mostraram que em 2012-13 a dieta foi composta por peixes, seguido de decápodes, especialmente camarões, entretanto em 2005-06 foi composta basicamente por camarões. A diferença nas dietas não quer dizer que os hábitos alimentares mudaram, pois em 2012-13 além dos peixes, os camarões também foram classificados como maior importância alimentar. Considerando que a quantidade e variedade dos itens ingeridos está relacionada, principalmente, a fatores ambientais são necessários mais estudos que relacionem áreas de captura, sazonalidade e profundidade.

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Abstract Catches and exports of skate Rioraja agassizii place this species as vulnerable to extinction on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

Resumo A raia-santa, Rioraja agassizii é uma espécie endêmica da qual pouco se conhece sobre sua biologia e ecologia, o que a leva a ser classificada como vulnerável a extinção. O objetivo foi identificar e quantificar a composição da dieta alimentar da R. agassizii através da análise do conteúdo estomacal de exemplares capturados nos períodos de 2005-2006 e 2012-2013. Foram analisados os conteúdos alimentares e quantificados em abundância (N%), peso (M%), frequência de ocorrência (FO%) e índice de importância relativa (IRI) de cada item. Os resultados mostraram que em 2012-13 a dieta foi composta por peixes, seguido de decápodes, especialmente camarões, entretanto em 2005-06 foi composta basicamente por camarões. A diferença nas dietas não quer dizer que os hábitos alimentares mudaram, pois em 2012-13 além dos peixes, os camarões também foram classificados como maior importância alimentar. Considerando que a quantidade e variedade dos itens ingeridos está relacionada, principalmente, a fatores ambientais são necessários mais estudos que relacionem áreas de captura, sazonalidade e profundidade.

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Instead of teeth, modern mysticetes bear hair-fringed keratinous baleen plates that permit various bulk-filtering predation techniques (from subsurface skimming to lateral benthic suction and engulfment) devoted to various target prey (from small invertebrates to schooling fish). Current knowledge about the feeding ecology of extant cetaceans is revealed by stomach content analyses and observations of behavior. Unfortunately, no fossil stomach contents of ancient mysticetes have been described so far; the investigation of the diet of fossil baleen whales, including the Neogene family Cetotheriidae, remains thus largely speculative. We report on an aggregate of fossil fish remains found within a mysticete skeleton belonging to an undescribed late Miocene (Tortonian) cetotheriid from the Pisco Formation (Peru). Micro-computed tomography allowed us to interpret it as the fossilized content of the forestomach of the host whale and to identify the prey as belonging to the extant clupeiform genus Sardinops. Our discovery represents the first direct evidence of piscivory in an ancient edentulous mysticete. Since among modern mysticetes only Balaenopteridae are known to ordinarily consume fish, this fossil record may indicate that part of the cetotheriids experimented some degree of balaenopterid-like engulfment feeding. Moreover, this report corresponds to one of the geologically oldest records of Sardinops worldwide, occurring near the Tortonian peak of oceanic primary productivity and cooling phase. Therefore, our discovery evokes a link between the rise of Cetotheriidae; the setup of modern coastal upwelling systems; and the radiation of epipelagic, small-sized, schooling clupeiform fish in such highly productive environments.

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Resumen Mensualmente entre junio 2010 y agosto 2011 en la ensenada de Turpialito, Golfo de Cariaco, Venezuela, se recolectaron macroalgas e identificaron, y ejemplares de Echinometra lucunter con diámetro de testa 41.04 ± 6.60 mm para examinar el contenido estomacal y el índice de llenado. Se identificaron 65 especies de macroalgas, pertenecientes a los Phylla Rhodophyta, Heterokontophyta y Chlorophyta. La mayor biomasa anual la presentaron Halimeda opuntia (56.5 g.m-2), Acanthophora spicifera (15.94 g.m-2), Sargassum vulgare (15.28 g.m-2) y Centroceras clavulatum (12.26 g.m-2). Los ítems alimenticios más frecuentes fueron las macroalgas filamentosas: Sphacelaria sp. (546) y Herposiphonia sp. (441) y la foliácea Dictyota sp. (410), y entre los invertebrados esponjas (155), moluscos bivalvos (70) y crustáceos cirrípedos (65). El ID osciló entre 0.8 y 6.0% (2.6 ± 1.21 %), con máximos en diciembre 2010 (6.0 ± 2.21 %), abril (4.3 ± 0.34 %) y junio 2011 (4.0 ± 1.79 %), con oscilaciones mensuales asociadas a los períodos de surgencia y estratificación. El conocimiento de las características principales de la dieta, es necesaria para proponer planes de cultivo y de conservación de la especie.

Abstract Echinometra lucunter is relatively abundant in the Venezuela coast, however no details are known about its diet. We compare the stomach contents and repletion index of E. lucunter with macroalgae available in their environment (June 2010-August) and the nutrient cycle at the Golfo de Cariaco. Seventy-one species of macroalgae were identified: Rhodophyta (45), Heterokontophyta (11) and Chlorophyta (15). The mean testa diameter was 41.04 ± 6.60 mm. The food preferences included filamentous, siphonal and calcaeous macroalgae; main food items were the filamentous macroalgae Sphacelaria sp. and Herposiphonia sp., and foliose Dictyota sp., including invertebrates such as sponges, bivalves and barnacle crustaceans. The repletion index was 0.8 - 6.0 % (2.6 ± 1.21 %), maximum values were associated to primary productivity cycle, i.e. December 2010 (6.0 ± 2.21 %), April (4.3 ± 0.34 %), June 2011 (4.0 ± 1.79 %). Food preferences could be associated to the upwelling season and productivity cycle. Rev. Biol. Trop. 63 (Suppl. 2): 233-242. Epub 2015 June 01.

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This study reveals the food composition of pelagic fishes living in the southwestern Atlantic Ocean. As such more common pelagic species are considered to be top predators, the study proposes to know what constitutes their main food. Fish are not commonly found within their stomach contents, but instead, cephalopods are their most common food. As can be observed, Teuthida cephalopods compose their principal diet. The stomach contents of specimens of Xiphias gladius, Thunnus albacares, T. obesus, T. alalunga, Isurus oxyrinchus and Alopias superciliosus caught during July 2007 to June 2009 by using tuna longliners were studied. Teuthida cephalopods constitute the main food item for the three tuna species, while X. gladius feeds mainly on Ommastrephidae cephalopods. Though the differences among the kinds of cephalopods exist, they constitute the principal resource these fish use to live at least in the southern Atlantic Ocean.

Este estudo descreve a composição da dieta de peixes pelágicos que vivem no Oceano Atlântico Sudoeste. Como tais espécies pelágicas são consideradas predadoras de topo, o estudo propõe conhecer o que constitui sua principal fonte de alimento. Peixes não são comumente encontrados em seus conteúdos estomacais, em vez disso, os cefalópodes são os alimentos mais comuns. Como pode ser observado, cefalópodes Teuthida compreendem sua dieta principal. O conteúdo estomacal de espécimes de Xiphias gladius, Thunnus albacares, T. obesus, T. alalunga, Isurus oxyrinchus e Alopias superciliosus, capturados durante julho de 2007 a junho de 2009 prela frota atuneira, foram estudados. Cefalópodes Teuthida constituem o principal item alimentar das três espécies de atum, enquanto X. gladius alimenta-se principalmente de cefalópodes Ommastrephidae. Embora as diferenças entre os tipos de cafalópodes existam, eles constituem o principal recurso que estes peixes usam para viver, pelo menos no Oceano Atlântico Sudoeste.

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A garoupa-verdadeira (Mycteroperca marginata) é uma espécie marinha geralmente associada a fundos rochosos e recifes. O presente trabalho investiga a dieta e estratégia alimentar de uma população da garoupa-verdadeira que habita um longo (4,5 km) par de molhes de pedra na desembocadura do estuário da laguna dos Patos, sul do Brasil. Não há trabalhos anteriores realizados nesse tipo de habitat construído pelo homem e este trabalho fornece uma base de comparação com estudos de dieta de outras populações da garoupa-verdadeira ocorrendo em habitats naturais. De modo similar ao encontrado em estudos prévios realizados em substratos naturais, caranguejos e peixes foram as principais categorias de alimento consumidas (%IRI = 85,1 e %IRI = 12,6, respectivamente), enquanto camarões e moluscos tiveram menor importância na dieta (%IRI = 1,9 e %IRI = 0,4, respectivamente). Como reportado anteriormente para populações de garoupa-verdadeira que habitam recifes e fundos rochosos, o presente trabalho revelou marcadas mudanças na dieta em função do tamanho da espécie. Siri-azul e peixes tornam-se gradativamente mais importantes na dieta de indivíduos maiores (> 500 mm de comprimento total, CT). Finalmente, foi observado que a população de garoupa-verdadeira teve uma estratégia alimentar generalista com uma elevada variação entre indivíduos no consumo de presas. Essa estratégia permaneceu similar ao longo do aumento em tamanho da espécie. Os resultados do presente trabalho sugerem que substratos rochosos estabelecidos pelo homem propiciam locais de alimentação adequados para a garoupa-verdadeira no sul do Brasil e que poderiam ser usados como ferramentas adicionais nos esforços de conservação dessa espécie ameaçada.

The dusky grouper (Mycteroperca marginata) is a marine species usually associated with rocky bottoms and reefs. The present work investigated the diet and feeding strategy of a dusky grouper population inhabiting a 4.5 km long pair of rocky jetties located in the mouth of Patos Lagoon estuary. No prior research has been conducted in such man-made habitat and the current study provides a basis for comparative studies on the diet of the dusky grouper populations inhabiting natural vs. manmade rocky habitats. Similarly with previous studies on natural substrates, crabs and fishes were the main food categories consumed (%IRI = 85.1 and %IRI = 12.6, respectively), whereas shrimps and mollusks had lower importance in the diet (%IRI = 1.9 and 0.4, respectively). As previously reported for dusky grouper populations inhabiting reefs and rocky bottoms, the present work revealed conspicuous size related dietary shifts. Blue crabs and fishes become increasingly important food itemsin the diet of larger individuals (> 500 mm, TL). Finally, it was found that the studied dusky population has a generalist feeding strategy with a high between-individual variation in prey consumption. Such strategy remained similar across the size increment of the species. Our findings suggest that man-made rocky substrates provide suitable feeding grounds for the dusky grouper in southern Brazil and could be used as an additional tool in the conservation efforts of this endangered species.

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A garoupa-verdadeira (Mycteroperca marginata) é uma espécie marinha geralmente associada a fundos rochosos e recifes. O presente trabalho investiga a dieta e estratégia alimentar de uma população da garoupa-verdadeira que habita um longo (4,5 km) par de molhes de pedra na desembocadura do estuário da laguna dos Patos, sul do Brasil. Não há trabalhos anteriores realizados nesse tipo de habitat construído pelo homem e este trabalho fornece uma base de comparação com estudos de dieta de outras populações da garoupa-verdadeira ocorrendo em habitats naturais. De modo similar ao encontrado em estudos prévios realizados em substratos naturais, caranguejos e peixes foram as principais categorias de alimento consumidas (%IRI = 85,1 e %IRI = 12,6, respectivamente), enquanto camarões e moluscos tiveram menor importância na dieta (%IRI = 1,9 e %IRI = 0,4, respectivamente). Como reportado anteriormente para populações de garoupa-verdadeira que habitam recifes e fundos rochosos, o presente trabalho revelou marcadas mudanças na dieta em função do tamanho da espécie. Siri-azul e peixes tornam-se gradativamente mais importantes na dieta de indivíduos maiores (> 500 mm de comprimento total, CT). Finalmente, foi observado que a população de garoupa-verdadeira teve uma estratégia alimentar generalista com uma elevada variação entre indivíduos no consumo de presas. Essa estratégia permaneceu similar ao longo do aumento em tamanho da espécie. Os resultados do presente trabalho sugerem que substratos rochosos estabelecidos pelo homem propiciam locais de alimentação adequados para a garoupa-verdadeira no sul do Brasil e que poderiam ser usados como ferramentas adicionais nos esforços de conservação dessa espécie ameaçada.(AU)

The dusky grouper (Mycteroperca marginata) is a marine species usually associated with rocky bottoms and reefs. The present work investigated the diet and feeding strategy of a dusky grouper population inhabiting a 4.5 km long pair of rocky jetties located in the mouth of Patos Lagoon estuary. No prior research has been conducted in such man-made habitat and the current study provides a basis for comparative studies on the diet of the dusky grouper populations inhabiting natural vs. manmade rocky habitats. Similarly with previous studies on natural substrates, crabs and fishes were the main food categories consumed (%IRI = 85.1 and %IRI = 12.6, respectively), whereas shrimps and mollusks had lower importance in the diet (%IRI = 1.9 and 0.4, respectively). As previously reported for dusky grouper populations inhabiting reefs and rocky bottoms, the present work revealed conspicuous size related dietary shifts. Blue crabs and fishes become increasingly important food itemsin the diet of larger individuals (> 500 mm, TL). Finally, it was found that the studied dusky population has a generalist feeding strategy with a high between-individual variation in prey consumption. Such strategy remained similar across the size increment of the species. Our findings suggest that man-made rocky substrates provide suitable feeding grounds for the dusky grouper in southern Brazil and could be used as an additional tool in the conservation efforts of this endangered species.(AU)

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Feeding habits of the fish Lagodon rhomboides (Perciformes: Sparidae) at the coastal lagoon of Chelem, Yucatán, México. Stomach contents of Lagodon rhomboides, the most abundant fish species from seagrass beds in Chelem Lagoon, Yucatan, Mexico, were analyzed. The specimens were collected using a beach seine at eight stations distributed randomly in the lagoon during July, September and November 2002. The trophic components were analyzed by means of the relative abundance (%A) and frequency of occurrence (FO) indices. The trophic similarity between different ontogenetic stages was determined using the Bray-Curtis Index. A total of 90 stomach contents were analyzed. This species is omnivorous, including vegetal and animal material and has a wide trophic spectrum with 58 alimentary items. Trophic ontogenetic variation was significant with a transition from one feeding stage to the next. Small individuals (4.0 -8.0 cm LE) preferentially consume plankton preys and microcrustaceans, while in bigger sizes, the macrocrustaceans, annelids and macrophytes were the main food. Rev. Biol. Trop. 56 (4): 1837-1846. Epub 2008 December 12.

Se analizó el contenido estomacal de Lagodon rhomboides (Sparidae), la especie más abundante de pez en la zona de pastos marinos en la laguna de Chelem, Yucatán, México. Los especímenes se recolectaron utilizando un chinchorro playero en ocho estaciones distribuidas aleatoriamente durante julio, septiembre y noviembre del 2002. Los componentes tróficos fueron analizados por medio del porcentaje de la abundancia relativa (%A) y la frecuencia de presencia (FO). La similitud trófica entre las diferentes etapas ontogénicas fue determinada usando el índice de Bray-Curtis. Se analizaron un total de 90 contenidos estomacales. Esta especie es omnívora e incluye en su alimentación componentes tanto de origen vegetal como animal; muestra una amplia generalización trófica con 58 componentes alimenticios. La variación trófica ontogénica fue significativa con una progresión alimenticia de una etapa alimenticia a la siguiente. Los individuos de menos talla, consumen preferentemente presas planctónicas y microcrustáceos s (4.0 - 8.0 cm de LE), mientras que en los de mayor talla, los macrocrustáceos (carideos), poliquetos y macrófitas constituyen el alimento principal.

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