Parasitology of juvenile mullet (Mugil liza) and effect of formaldehyde on parasites and host

Few studies have been performed with parasites of marine and estuarine fish in southern Brazil. In the present study, unpublished results show the ways of parasitism of juvenile mullet by parasites. The toxicity of formaldehyde and the effectiveness of this chemotherapy in controlling parasites in reared juvenile mullet Mugil liza were also studied. Juvenile mullets (1 +/- 0.26 g; 4.1 +/- 0.4 cm) were exposed to different concentrations of 37% formaldehyde: control group and five formaldehyde concentrations which were tested: T1 (13.5), T2 (21.6), T3 (40.5), T4 (81) and T5 (135) mg L-1 with 8 fish per repetition in triplicate. To verify the drug effectiveness in parasitic control, juvenile mullets were exposed to 1 h prophylactic bath of 37% formaldehyde with a control group and five formaldehyde concentrations: T1 (67.5), T2 (135), T3 (270), T4 (405) and T5 (540) mg L-1, 8 fish per repetition in triplicate. Ligophorus cf. uruguayensis (Monogenoidea: Ancyrocephalidae) and Solostamenides cf. platyorchis (Monogenoidea: Microcotylidae) were identified in the gills. Digenea and Nematoda were observed in the intestines. This is the first occurrence of S. cf. platyorchis in Brazil. During the toxicity test, the LC50-96 h was estimated at 20.77 mg L-1 of formaldehyde. During the 1 h formaldehyde prophylactic bath, all parasites were eliminated in formaldehyde concentrations between 135 and 540 mg L-1. High survival rate was observed in all treatments. Values of prevalence and intensity of infestation observed in this study showed the potential damage caused by Monogenoidea to mullet. Formaldehyde baths with 135 mg L-1 are recommended to control Monogenoidea in mullet and the safe limits for formaldehyde use were presented. Besides, the endoparasites were tolerant to formaldehyde exposure. (C) 2012 Elsevier B.V. All rights reserved.

A new species of mullet (Teleostei : Mugilidae) from Venezuela, with a discussion on the taxonomy of Mugil gaimardianus

The original description of Mugil gaimardianus has created various taxonomic problems in the past since the description is ambiguous and the type specimen is apparently lost. The name M. gaimardianus could not be reliably applied to any known species and was suppressed by the International Commission on Zoological Nomenclature (ICZN) (Bulletin of Zoological Nomenclature, 51: 286-287, 1994). Nevertheless, karyological evidence has shown that there is a species of mullet in Venezuelan coastal waters that does not conform to the description of any other mullet from the Western Central Atlantic and has the feature of a red eye that was often used by earlier authors to define nominal M. gaimardianus. The purpose of this study was to make a morphological description of these unusual specimens, provide a morphological diagnosis from other species of Mugil present in the Caribbean and Western Central Atlantic and establish a valid name for the species. (c) 2007 the Authors Journal complication (c) 2007 the Fisheries Society of the British Isles.

An old taxonomic dilemma: the identity of the western south Atlantic lebranche mullet (Teleostei: Perciformes: Mugilidae)

The identification of the lebranche mullet in the western south Atlantic has long been problematical. In most recent works either Mugil liza Valenciennes and M. platanus Gunther, 1880 or M. liza and M. cephalus Linnaeus, 1758 were recognized from the region and more rarely the occurrence of only one species has been proposed but without sufficient morphological, biochemical or molecular data to allow the designation of the taxonomically appropriate name. Analysis of meristic and morphometric data taken from samples collected from Venezuela to Argentina, clearly indicates that there is only one species of lebranche mullet in the Caribbean Sea region and the Atlantic coast of South America and that Mugil liza is the appropriate name. The comparison of the combined data from all the samples of M. liza with the data taken from one sample of M. cephalus that originated in the Mediterranean, the possible locality from which type specimens were collected (Eschmeyer and Fricke, 2009), revealed significant differences indicating that they are different species. It is also suggested that individuals from the western north Atlantic identified as M. cephalus might represent a population of M. liza in this region.

Molecular identification of mullet species of the Atlantic South Caribbean and South America and the phylogeographic analysis of mugil liza

Fundacao de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Karyotype characterization of Mugil incilis Hancock, 1830 (Mugiliformes: Mugilidae), including a description of an unusual co-localization of major and minor ribosomal genes in the family

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative cytogenetic and allozyme analysis of Mugil rubrioculus and M. curema (Teleostei : Mugilidae) from Venezuela

A comparative cytogenetic and allozyme analysis of sympatric specimens of Mugil rubrioculus and M. curema from Venezuela is reported. Specimens of M. rubrioculus exhibit a 2n=48 karyotype with exclusively acrocentric (NF=48) chromosomes, one pair of NORs interstitially located on chromosome pair number 8 and constitutive heterochromatin distributed in pericentromeric position of all chromosomes. Specimens of M. curema show cytogenetic features significantly different in comparison to M. rubrioculus in terms of chromosome number and morphology (2n=24 biarmed chromosomes, NF=48) and NORs location (telomeric region of the largest metacentric pair). Starch gel electrophoresis analysis at 20 presumptive loci reveals a reduced genetic difterentiation between the two species. In fact, though a total of ten private alleles are identified; all loci share alleles between the two species and the obtained Nei's genetic distance (D= 0.060) is lower than the values obtained between other congeneric mullet species. Thus, the cytogenetic and allozyme data sets indicate quite different degrees of genetic divergence between M. rubrioculus and M. curema. This could either reflect an underestimate of molecular divergence owing to cryptic variation or different rates of molecular/chromosomal evolution. Whatever the explanation, this study confirms the power of karyological data in discriminating species of Mugilidae.

Schooling behavior of Mugil curema (Perciformes: Mugilidae) in an estuary in southeastern Brazil

Schools of mullets, Mugilidae, are abundant in estuaries and shallow marine waters. We report on the schooling behavior of juvenile white mullet, Mugil curema, in the estuary of the Canto da Paciência stream, in Ubatuba, southeastern Brazil. Schools of small fish (15 to 35 mm TL) were composed of a larger number of individuals (up to a hundred individuals), and were found feeding mainly in shallow nearshore waters, whereas schools of larger fish (40 to 100 mm TL) were observed only in deeper waters. Three patterns of swimming were observed for the schools: stationary feeding, slow movement while searching for food, and rapid displacement. The variations observed in school structure and behavior seem to be related to the balance between predation risk and increasing food intake. Copyright © 2007 Sociedade Brasileira de Ictiologia.

Taxonomic review of the species of Mugil (Teleostei: Perciformes: Mugilidae) from the Atlantic South Caribbean and South America, with integration of morphological, cytogenetic and molecular data

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)