916 resultados para shark feeds
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
The reproductive biology of the Brazilian sharpnose shark, Rhizoprionodon lalandii, off southeastern Brazil was investigated using data from gillnet landings. The size-at-maturity for males and females was estimated to be 59 and 62 cm total length (LT), respectively. Ovarian fecundity ranged from 3 to 7 follicles (mean = 4.S4), and uterine fecundity from 1 to S embryos (mean = 3.3). There was a slight positive relationship between female LT and the number of ovarian follicles, but uterine fecundity was not related to female LT. Embryonic growth is fast following fertilization during summer and autumn. Gestation requires 11 - 12 months, and peak parturition is between August and September. A comparison of size-at-maturity between animals from northeastern and southeastern Brazil suggests the existence of at least two stocks of R. lalandii along the Brazilian coast.
Resumo:
Although the Brazilian sharpnose shark, Rhizoprionodon lalandii (Muller and Henle, 1839), is an inshore species widely distributed in the Western Atlantic from Panama to Uruguay, there is little available information on its biology. During a long-term study of small coastal sharks caught by gill net fisheries in southeastern Brazil (PROJETO CACAO), 3643 specimens of R. lalandii were examined, comprising 61.3% of the total sharks,and including all sizes classes, from 30 to 78,5 cm TL., and weights from 100 to 2950 g. The length-weight relationships were not significantly different between sexes, Overall sex ratio favoured the males slightly at the rate of 1.3: 1. Sex ratios, however, did differ significantly between season and size classes. This species occurred in this area all year long. Three seasonal size-class Occurrence patterns were recognized: (1) between October and March, the juveniles were more frequents (2) from April to July, adults were most common, and (3) from August to September, neonates were most numerically abundant. Such patterns we to associated with reproductive tactics that may reduce intra-specific and inter-specific competition with hammerhead shark neonates (Sphyrna lewini). probably result in reduced natural mortality of the offspring during their first few months. (C) 2005 Elsevier B.V. All rights reserved.
Resumo:
Eight embryonic thresher sharks Alopias vulpinus (53.9-124 cm total length) were collected from two females caught by commercial longline off southern Brazil in September and November 2004. Morphometric measurements are provided. (c) 2006 the Authors.
Resumo:
This study records the occurrence of a blue shark Prionace glauca foetus, with morphological abnormalities in the trunk and cephalic region, from a female caught by a pelagic longline in October 2003, in southern Brazil. (c) 2006 the Authors.
Resumo:
This experiment was undertaken to determine the possible presence of Salmonella in poultry diets. A total of two hundred samples of ration from 4 commercial poultry feed industries were examined. The results revealed the presence of salmonellae in 10% of the samples studied and 14 serotypes were identified. The procedure for Salmonella isolation included the pre-enrichment step and the strains were submitted to antimicrobial tests. The 29 strains were resistant to the followings antimicrobial agents (% of resistance in parenthesis): Erythromycin (100%), sulphonamides (100%), colistin (100%), streptomycin (100%), bacitracin (100%), penicillin (100%), tetracycline (92,9%), cephalothin (75%), carbenicillin (62,5%), ampicillin (46,5%), kanamycin (46,5%), nitrofurantoin (39,3%), neomycin (25%), amikacin (21,4%), sulphazotrin (21,4%), nalidix acid (18,8%), chloramphenycol (17,9%), linco-spectin (17,9%), gentamicin (17,9%), and cefoxitin (6,3%).
Resumo:
Similar to many small, range-restricted elasmobranchs, the Brazilian sharpnose shark (Rhizoprionodon lalandii) is listed as 'data deficient' by the International Union for the Conservation of Nature (IUCN). Data on stock assessment and sustainability are scarce, and there is no information on population structure. This constitutes a management problem because this shark comprises approximately 50% of the catch of small coastal sharks in Brazil. In this study, populations of R. lalandii distributed from the Caribbean to southern Brazil were investigated using sequences from the mitochondrial DNA control region. Analysis of molecular variance revealed strong structuring between population samples from the Caribbean and those from the Brazilian coast (F{cyrillic}ST=0.254, P<0.0001). Significant differences in the rates of genetic diversity between these major areas were also detected. The observed levels of population structuring are likely to be driven by female phylopatry. Therefore, the identification of both mating and nursery areas with parallel ban/restriction of fishing in these areas may be critical for the long-term sustainability of these populations. © 2013 John Wiley & Sons, Ltd.
Resumo:
ABSTRACT: Carcharhinus limbatus has a cosmopolitan distribution and marked genetic structuring, mainly because of its philopatric behavior. However, analysis of this structuring has not previously included South American populations. In the present study, we analyzed a sample of adult individuals collected on the northern coast of Brazil and compared the sequences of the mitochondrial control region with those of populations already genotyped. Relatively high haplotype diversity (12 haplotypes, genetic diversity of 0.796) was observed, similar to that in other populations but with a much larger number of private alleles. In contrast to populations studied previously, which were represented by neonates, the pronounced allelic variability found in the South American individuals may have resulted from migrations from other populations in the region that have yet to be genotyped. This population was also genetically distinct from the other Atlantic populations (Fst > 0.8), probably because of female philopatry, and apparently separated from the northwestern Atlantic group 1.39 million years ago. These findings indicate that the C. limbatus population from northern Brazil is genetically distinct from all other populations and should be considered as a different management unit for the protection of stocks.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
It is with great astonishment and concern that I read the letter to the editor by Barreiros et al1 in which the authors report an attack by a blue shark on a spear fisherman in the Azores. Whereas the first part of the article accurately details the circumstances of the accident, Barreiros et al, in the second part, devise a far-fetched and illegitimate connection with shark diving, in particular with shark feeding.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Cathetocephalus thatcheri gen. et sp. n. is described from the spiral valve of the bull shark, Carcharhinus leucas (Valenciennes), taken in the Gulf of Mexico and the Atlantic coast of Florida. A new family is erected for the new genus. The species most closely resembles Pillersium owenium Southwell, 1927, in that both possess a scolex which is perpendicular to the long axis of the strobila. It differs, however, in having a single neck and holdfast organ rather than a bifurcate neck with two bothridia. Also, the surfaces of the scolex differ from those of P. owenium by possessing fleshy papilliform structures on the leading and trailing edges rather than leaflike folds. Specimens with several strobilae are figured and discussed.