Life history traits of the sand stargazerDactyloscopus tridigitatus(Teleostei: Blennioidei) from south-eastern Brazilian coast

Author(s):  
Rogério Luiz Teixeira ◽  
Eduardo Hoffman de Barros ◽  
Rodrigo Barbosa Ferreira ◽  
Rafael Magno Costa Melo ◽  
Luiz Fernando Salvador-Jr

Individuals of the sand stargazerDactyloscopus tridigitatuswere collected monthly over a period of one year in an urban-sandy beach in south-eastern Brazil. We sampled 57 males, 64 females, and 6 juveniles, indicating a sex-ratio of approximately 1:1. Total length and weight did not differ significantly between sexes, showing no sexual dimorphism in size. The growth ofD. tridigitatuswas highly positive allometric and the correlation coefficient was significant for both sexes. Males were observed carrying two egg clumps under each enlarged pectoral fin during most of the year. In contrast, females showed a more restricted reproductive period, concentrated during the austral rainy season. The number of eggs in each clump carried by males did not differ significantly from the number of vitellogenic oocytes of mature females. The number of eggs carried by males was weakly correlated to male total length; however, female fecundity was strongly correlated to female total length.Dactyloscopus tridigitatusconsumed a high variety of prey items, including crustaceans, annelids, molluscs, teleosts, insects and eggs. Isopods were the most important component of the diet followed by polychaetes and amphipods. We concluded that promiscuous breeding, paternal care behaviour and invertivorous feeding habits seem to be important traits for the species' success in the studied habitat.

2001 ◽  
Vol 61 (2) ◽  
pp. 217-238 ◽  
Author(s):  
E. Y. MUTO ◽  
L. S. H. SOARES ◽  
R. GOITEIN

The feeding habits of Rioraja agassizii (syn. Raja agassizii) and Psammobatis extenta (syn. Psammobatis glansdissimilis) of the South-eastern Brazilian coast were studied by means of stomach content analysis. The samples were obtained on eight seasonal oceanographic cruises, carried out between October 1985 and July 1987. The importance of each food item was evaluated on the basis of the Index of Relative Importance and the feeding similarity by Percentage of Similarity. The results indicated that both species are benthic feeders, preying mainly on Crustacea, especially Amphipoda, Caridea and Brachyura. Teleostei were also important for R. agassizii. Seasonal variation of the diet seems to be associated with the availability of the prey, whose distribution and abundance are related to the dynamics of the water masses of the region. Juveniles and adults of P. extenta exploited the same resources while juveniles and adults of R. agassizii presented low diet similarity during most of the year. Caridea were an important food for all length classes of R. agassizii, while Amphipoda were for smaller specimens, and Teleostei for larger ones. The feeding overlap between the two species was higher during autumn 1986, winter 1986 and winter 1987.


Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Salvatore Siciliano

Along the central coast of Rio de Janeiro State (22°25′S–23°00′S), south-eastern Brazil, the marine tucuxi dolphin (Sotalia guianensis) feeds on neritic prey that are distributed through the water column and are abundant all year round. The most frequently found species were the teleost fish Trichiurus lepturus, Cynoscion guatucupa, Isopisthus parvipinnis and Porichthys porossisimus. Fish species were more important than cephalopod species in the diet of the marine tucuxi. Back calculations of prey sizes indicated that they feed mainly on young specimens. The present study provided additional information on the feeding habits of the marine tucuxi dolphin.


1996 ◽  
Vol 30 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Daniel Marucci

An. (Ker.) cruzii and An. (Ker.) bellator were monitored by the use of human bait and Shannon trap collections during a one-year period in 1994. Indoor and outdoor collections were made on human bait and inside the forest environment a Shannon trap was used. Both were undertaken in the evening crepuscular period. Results showed a greater abundance of An. cruzii in the forest, where as An. bellator was more abundant in the domiciliary environment. Through the application of the Polovodova method an age grading was established. Computing the parous and nulliparous females with Christopher's Stage III and above, more than 30.0% of blood-seeking specimens of both anophelines had had a previous blood meal. The higher abundance of An. bellator as compared with that of An. cruzii in the domiciliary environment may be explained by the influence of the neighboring low-lying coastal islands of the estuary system.


Author(s):  
Paulo A.S. Costa ◽  
Adriana C. Braga ◽  
Juan P. Rubinich ◽  
Antônio Olinto Ávila-da-Silva ◽  
Cassiano M. Neto

The age and growth of the snowy grouper, Epinephelus niveatus, from central and south-eastern Brazil were studied by otolith analysis from a sample of 341 specimens, ranging from 325 to 1216 mm in total length (TL) caught with bottom longlines between 1996 and 1998. Otolith length grew proportionally with the increasing TL of the fish. Marginal increment analysis indicated that a single opaque band forms each year during autumn–winter. The maximum estimated age was 54 years, which significantly extends the previously estimated life-span of 21–29 years for this species. The von Bertalanffy growth parameters for both sexes were estimated as L∞ = 1098.4 mm TL, K = 0.062 year −1 and t0 = –2.68. The study revealed differences in mean length-at-age and size at recruitment, as well as in growth parameters between the central and the south-eastern Brazilian coast, which can be attributed mainly to different fishing pressures. The snowy grouper was found at depths of 82–492 m, and showed a positive relationship between age and depth, suggesting differential movements of older fish to deeper waters.


Author(s):  
Laura Busin Campos ◽  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Marcos César de Oliveira Santos

AbstractThis study evaluated the feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil. Stomach contents were collected from a total of 145 dead specimens found incidentally caught by fishing vessels or stranded between 2005 and 2015. Fish otoliths, cephalopod beaks and whole non-digested prey were used for prey species identification. A total of 9337 prey items were identified, including 26 species of teleost fishes and three species of cephalopods. The most important prey families were Sciaenidae among fish and Loliginidae among cephalopods. Franciscana dolphins tended to feed on small fish (mean = 5.25 cm) and cephalopods (mean = 8.57 cm). The index of relative importance (IRI) showed that Pellona harroweri and Doryteuthis plei were the most important prey for both males and females. The PERMANOVA test confirmed that there is no significant difference between the feeding habits of different sexes, but detected a significant difference among seasons. Overall, our results show that franciscana dolphins are predominantly ichthyophagous and non-selective in relation to the type of prey, feeding on pelagic, demersal and pelagic-demersal prey.


2008 ◽  
Vol 42 (19-20) ◽  
pp. 1421-1434 ◽  
Author(s):  
Milena Wachlevski ◽  
Paulo H. C. De Souza ◽  
Katia Kopp ◽  
Paula C. Eterovick

Author(s):  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Manuela Bassoi ◽  
Roberta Aguiar dos Santos ◽  
Marcos César de Oliveira Santos

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 (25°00′S 47°55′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.


2016 ◽  
Vol 97 (6) ◽  
pp. 1259-1266
Author(s):  
Renato Junqueira De Souza Dantas ◽  
Lazaro Luiz Mattos Laut ◽  
Carlos Henrique Soares Caetano

Specimens of Fissidentalium candidum collected at Campos Basin, south-eastern Brazil, had their diet investigated in order to assess its feeding habits. Benthic prey exceeded the planktonic ones as expected and Foraminifera constituted the most frequent prey taxa, comprising about 99.5% of the scaphopod diet; the remaining components included a few molluscs (gastropods, bivalves and scaphopods), a nematode, an ostracod crustacean, fish otoliths, unknown partial organisms and inorganic material (e.g. sediment grains and polymetallic nodules). Amongst the species previously studied, F. candidum stood out by presenting the highest dietary diversity (H = 3.35) and species richness (N = 118). Predator and prey dimensions were not correlated and no spatial variation was observed in the diet amongst the three collection sites in the mid-slope of Campos Basin. Generalism, high rate of rare or unimportant species and high contribution of within-phenotype component to the niche width were important features of the trophic ecology of F. candidum. Inhabiting the deep water of Campos Basin, this dentaliid obtained most of its energy from the benthic microfauna, being a specialized foram predator with moderate preference for, and moderate selection against, several species.


Author(s):  
Magda F. Andrade-Tubino ◽  
Fernando Luiz K. Salgado ◽  
Wagner Uehara ◽  
Ricardo Utsunomia ◽  
Francisco Gerson Araújo

Abstract The introduction of non-native predator fish is thought to have important negative effects on native prey populations. Opsanus beta is a non-native toadfish that was originally described in the Gulf of Mexico, between the west coast of Florida and Belize. In the present study, we describe, for the first time, the occurrence of O. beta in Sepetiba Bay (22°55′S), south-eastern Brazil, probably brought into the bay through ships' ballast water. Thirteen specimens were recorded in this area near to Sepetiba Port. Similarly, three other records of this species in the Brazilian coast were also reported near to port areas at Rio de Janeiro (22°49′S), Santos (23°59′S) and Paranaguá (25°33′S) ports. To confirm the species identity, we employed DNA barcoding and compared our samples with sequences deposited on public databases, which indicated that our samples are highly similar (>99.9% of genetic similarity) to O. beta samples collected near its type locality. Several individuals were found in the capable spawning phase, according to histological analysis of the reproductive cell stages. The environmental plasticity of this species and the favourable local environmental conditions probably enabled the establishment of O. beta in this region. This raises concerns of potential high invasion impact due to this species' diet and reproductive capacity.


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